2 TIDAK SEMUA LAHAN DAPAT MENDUKUNG PRODUKSI KUBIS LAHAN KUBISTIDAK SEMUA LAHAN DAPAT MENDUKUNG PRODUKSI KUBIS
3 LAHAN = SUMBERDAYA EKONOMI Land is the economic resource encompassing natural resources found within a nation economy. This resource includes timber, land, fisheries, farms and other similar natural resources. Land is usually a limited resource for many economies. Although some natural resources, such as timber, food and animals, are renewable, the physical land is usually a fixed resource. Nations must carefully use their land resource by creating a mix of natural and industrial uses.Using land for industrial purposes allows nations to improve the production processes for turning natural resources into consumer goods.Gross Margin: The simplest economic measure is the gross margin, which is the cash flow out less the cash flow in, on a per unit area (normalized or standardized) or aggregate (per-field or per-farm) basis, in one accounting period (usually a year).The gross margin can be expressed in terms of the return to labor or the return to land.Return to labor: the farm family’s labor is not included as an expense, and the gross margin must be sufficient to allow the farm family an adequate income. This makes most sense if the gross margin is non-normalized, i.e., the actual amount received for the whole farm.Return to land: the farm family’s labor is included in the expenses, as if the labor had been contracted. If the ‘wage’ is at a reasonable level, the gross margin only has to be positive for the land use to be feasible. This makes most sense if the gross margin is normalized, i.e., the amount received per unit land area.Diunduh dari Sumber: /11/2012 .
4 LAHAN ….. Automated Land Evaluation System ‘ALES’. Land, In economics, the resource that encompasses the natural resources used in production. In classical economics, the three factors of production are land, labour, and capital.Land was considered to be the “original and inexhaustible gift of nature.” In modern economics, it is broadly defined to include all that nature provides, including minerals, forest products, and water and land resources. While many of these are renewable resources, no one considers them “inexhaustible.”The payment to land is called rent.Like land, its definition has been broadened over time to include payment to any productive resource with a relatively fixed supply.Automated Land Evaluation System ‘ALES’.How ALES links land characteristics with economic valuesStarting from the physical inventory of the characteristics of a land area, how do we arrive at an economic value of a land use if implemented on that land area?By means of severity levels of Land Qualities, which can either limit yield (and thus reduce income) or increase costs.Land Qualities, and their diagnostic Land Characteristics, can be divided into two type for this analysis:Location-independent (in-situ) andLocation dependent.E.g. (1) soil and climate qualities and characteristics, (2) distance,Adjacency.Diunduh dari Sumber: /11/2012 .
5 LAND QUALITY INDICATOR (LQI) Lahan pertanian produktif –mixed cropping Some generic indicators of land units that must be monitored, especially for:Condition of land resources, both positive and negative;Areas arising from different land uses;Rates of adaptation and adoption of recommended/suggested practices;Farm management practices;Yields and other outputs resulting from project interventions or other development;Rural development issues such as land tenure, population density;Water resources;Fisheries and aquaculture;Forest management;Land-soil nutrients.Lahan pertanian produktif –mixed croppingDiunduh dari Sumber: /11/2012 .
6 The holistic concept of Land (FAO ,1976; FAO, 1995) : "Land is a delineable area of the earth's terrestrial surface, encompassing all attributes of the biosphere immediately above or below this surface, including those of the near-surface climate, the soil and terrain forms, the surface hydrology (including shallow lakes, rivers, marshes and swamps), the near-surface sedimentary layers and associated groundwater reserve, the plant and animal populations, the human settlement pattern and physical results of past and present human activity (terracing, water storage or drainage structures, roads, buildings, etc.).“The functions of Land:Production functionBiotic environmental functionClimate-regulative functionHydrologic functionStorage functionWaste and pollution control functionLiving space functionArchive or heritage functionConnective space function.Diunduh dari Sumber: /11/2012 .
7 Land attributes, characteristics, properties and qualities (or limitations/ conditions): ATTRIBUTE, or variable, is a neutral, over-arching term for a single or compound aspect of the land;CHARACTERISTIC is an attribute which is easily noticed and which serves as a distinguishing element for different types of land; it may or may not have a practical meaning (e.g., soil colour or texture, or height of forest cover are characteristics without giving direct information on land quality);PROPERTY is an attribute that already gives a degree of information on the value of the land type;LAND QUALITY (or limitation) is a complex attribute of land which acts in a manner distinct from the actions of other land qualities in its influence on the suitability of land for a specified kind of use.Diunduh dari Sumber: /11/2012 .
8 KERANGKA-KERJA EVALUASI LAHAN DARI FAO 1976 LAND QUALITIES RELATED TO PRODUCTIVITY FROM CROPS OR OTHER PLANT GROWTHCrop yields (a resultant of many qualities listed below).Moisture availability.Nutrient availability.Oxygen availability in the root zone.Adequacy of foothold for roots.Conditions for germination.Workability of the land (ease of cultivation).Salinity or sodicity.Soil toxicity.Resistance to soil erosion.Pests and diseases related to the land.Flooding hazard (including frequency, periods of inundation).Temperature regime.Radiation energy and photoperiod.Climatic hazards affecting plant growth (including wind, hail, frost).Air humidity as affecting plant growth.Drying periods for ripening of crops.Diunduh dari Sumber: /11/2012 .
9 FRAMEWORK FOR LAND EVALUATION OF 1976 LAND QUALITIES RELATED TO DOMESTIC ANIMAL PRODUCTIVITYProductivity of grazing land.Climatic hardships affecting animals.Endemic pests and diseases.Nutritive value of grazing land.Toxicity of grazing land.Resistance to degradation of vegetation.Resistance to soil erosion under grazing conditions.Availability of drinking water.Lahan pertanian pada saat “bera” mernjadi sumber rumput pakan ternakDiunduh dari Sumber: /11/2012 .
10 FRAMEWORK FOR LAND EVALUATION OF 1976 LAND QUALITIES RELATED TO FOREST PRODUCTIVITYThe qualities listed may refer to natural forests, forestry plantations, or both.Mean annual increments of timber speciesTypes and quantities of indigenous timber species.Site factors affecting establishment of young trees.Pests and diseases.Fire hazard.Kawasan hutan tanaman jatiDiunduh dari Sumber: /11/2012 .
11 FRAMEWORK FOR LAND EVALUATION OF 1976 LAND QUALITIES RELATED TO MANAGEMENT AND INPUTSThe qualities listed may refer to arable use, animal production or forestry.Terrain factors affecting mechanization (trafficability).Terrain factors affecting construction and maintenance of access-roads (accessibility).Size of potential management units (e.g. forest blocks, farms, fields).Location in relation to markets and to supplies of inputs.FAO A framework for land evaluation. Soils Bulletin 32, FAO, Rome. 72 p. Also, Publication 22, (R. Brinkman and A. Young (eds.), ILRI, Wageningen, The Netherlands.FAO Planning for sustainable use of land resources: towards a new approach, W.G. Sombroek and D. Sims. Land and Water Bulletin 2, FAO, Rome.Diunduh dari Sumber: /11/2012 .
12 Land qualities related to vertical components of a natural land unit ATMOSPHERIC QUALITIESAtmospheric moisture supply: rainfall, length of growing season, evaporation, dew formation.Atmospheric energy for photosynthesis: temperature, daylength, sunshine conditions.Atmospheric conditions for crop ripening, harvesting and land preparation: occurrence of dry spells.LAND COVER QUALITIESValue of the standing vegetation as "crop", such as timber.Value of the standing vegetation as germ plasm: biodiversity value.Value of the standing vegetation as protection against degradation of soils and catchment.Value of the standing vegetation as regulator of local and regional climatic conditions.Regeneration capacity of the vegetation after complete removal.Value of the standing vegetation as shelter for crops and cattle against adverse atmospheric influences.Hindrance of vegetation at introduction of crops and pastures: the land "development" costs.Incidence of above-ground pests and vectors of diseases: health risks of humans and animals.Diunduh dari Sumber: /11/2012 .
13 Land qualities related to vertical components of a natural land unit LAND SURFACE AND TERRAIN QUALITIESSurface receptivity as seedbed: the tilth condition.Surface treatability: the bearing capacity for cattle, machinery, etc.Surface limitations for the use of implements (stoniness, stickiness, etc.): the arability.Spatial regularity of soil and terrain pattern, determining size and shape of fields with a capacity for uniform management.Surface liability to deformation: the occurrence or hazard of wind and water erosion.Accessibility of the land: the degree of remoteness from means of transport.The presence of open freshwater bodies for use by humans, animals or fisheries.Surface water storage capacity of the terrain: the presence or potential of ponds, on-farm reservoirs, bunds, etc.Surface propensity to yield run-off water, for local water harvesting or downstream water supply.Accumulation position of the land: degree of fertility renewal or crop damaging by overflow or overblow.Diunduh dari Sumber: /11/2012 .
14 Land qualities related to vertical components of a natural land unit SOIL QUALITIESPhysical soil fertility: the net moisture storage capacity in the rootable zone.Physical soil toxicity: the presence or hazard of waterlogging in the rootable zone (i.e. the absence of oxygen).Chemical soil fertility: the availability of plant nutrients.Chemical soil toxicity: salinity or salinization hazard; excess of exchangeable sodium.Biological soil fertility: the N-fixation capacity of the soil biomass; and its capacity for soil organic matter turnover.Biological soil toxicity: the presence or hazard of soil-borne pests and diseases.Substratum (and soil profile) as source of construction materials.Substratum (and soil profile) as source of minerals.Diunduh dari Sumber: /11/2012 .
15 Land qualities related to vertical components of a natural land unit SUBSTRATUM OR UNDERGROUND QUALITIESGroundwater level and quality in relation to (irrigated) land use.Substratum potential for water storage (local use) and conductance (downstream use).Presence of unconfined freshwater aquifers.Substratum (and soil profile) suitability for foundation works (buildings, roads, canals, etc.)Deskripsi profil tanahDiunduh dari Sumber: /11/2012 .
16 LUT LAND EVALUATION…. EVALUASI LAHAN Land evaluation is the process of assessment of land performance when used for specific purposes, involving the execution and interpretation of surveys and studies of land forms, soils, vegetation, climate and other aspects of land in order to identify and make a comparison of promising kinds of land use in terms applicable to the objectives of the evaluation.LUTA land utilization type (FAO, 1976) is a kind of land use described or defined in a higher degree of detail than that of a major kind of land use (such as rainfed agriculture or forestry), as an abstraction of actual land-use systems (which may be single, compound or multiple).Diunduh dari Sumber: /11/2012 .
17 Ketahanan suatu Lahan : KETAHANAN LAHANSome concepts of resilience of land and its productivity, comparing the situation in someindustrialized countries (A) with that of most developing countries (B). (Sombroek, 1993)Ketahanan suatu Lahan :The capacity of the land to recover quickly to former levels of productivity - or to resume the trend to increased productivity - after an adverse influence such as drought, floods, or human abandonment or mismanagement.Diunduh dari Sumber: /11/2012 .
18 MAJOR ISSUES OF LAND MANAGEMENT…. Decline in quality of soils as rooting environments;Erosion and loss of topsoil by wind and water;Loss of vegetation cover, including woody perennials;Acidification, soil fertility decline and plant nutrient depletion;Salinity and salinization, particularly in irrigated systems.Pengelolaan lahan sawah : Palawija musim kemarauDiunduh dari Sumber: /11/2012 .
19 INDICATOR : Land condition change (Change in land qualities). The type OF INDICATORS:Physical soil condition;Diversity or density of vegetation cover;Thickness of topsoil (by erosion or, conversely, by good management);Salinity or sodicity (alkaline conditions);Terracing;Establishment of contour vegetation strips.Unit in which the indicator is measured: areal extent and magnitude of change of the indicator types , with improvement and deterioration reported separately.Mulsa sisa-panen tanaman sebelumnya untuk mengendalikan evaporasiDiunduh dari Sumber: /11/2012 .
20 LAND QUALITY INDICATOR (LQI) I. Above the soil surface, as related with yields:Cover close to the ground: its density, distribution, duration, timing.Stress in plants: growth rates; timing and frequency of wilting; visible nutrient deficiencies or imbalances.II. On the soil surface, as affecting particularly soil moisture and runoff+erosion:Porosity of at least topsoil layers, in millimetric bands: proportions of incidentrainfall becoming infiltrated;III. Below the soil surface:Organic matter content and biological activity, as affecting multiple features:Soil architecture:. structural stability;. gas exchange. water movement and retention/release;Cation exchange capacity:. nutrient capture and retention;. pH buffering;. nutrient availability;. source of small amounts of recycled nutrients.Diunduh dari Sumber: /11/2012 .
21 LIMA MACAM LQI UNTUK PERTANIAN DAN KEHUTANAN NUTRIENT BALANCE: describes nutrient stocks and flows as related to different land management systems used by farmers in specific AEZs and specific countries.YIELD TRENDS AND YIELD GAPS: describes current yields, yield trends and actual:potential farm-level yields for the major food crops in different countries.LAND USE INTENSITY: describes the impacts of agricultural intensification on land quality. Intensification may involve increased cropping, more value-added production, and increased amounts and frequency of inputs; emphasis is on the management practices adopted by farmers in the transition to intensification.LAND USE DIVERSITY (agrodiversity): describes the degree of diversification of production systems over the landscape, including livestock and agroforestry systems; it reflects the degree of flexibility (and resilience) of regional farming systems, and their capacity to absorb shocks and respond to opportunities.LAND COVER: describes the extent, duration and timing of vegetative cover on the land during major erosive periods of the year. It is a surrogate for erosion and, along with land use intensity and diversity, it will increase understanding on the issues of desertification.Diunduh dari Sumber: /11/2012 .
22 PRODUKTIVITAS TANAH SAWAH IRIGASI TEKNIS SOIL Fertility is the inherent capacity of a soil to supply nutrients in adequate amounts and suitable proportions, whereas soil productivity is a wider term referring to the ability of a soil to yield crops (Brady, 1974).The chief factors in soil productivity are soil organic matter (including microbial biomass), soil texture, structure, depth, nutrient content, water-storage capacity, reaction and absence of toxic elements.The soil productivity depends on physical, hydric, chemical and biologic characteristics and their interaction.Brady, N.C The Nature and properties of soils. 8th Edition. Macmillan, New York.SAWAH IRIGASI TEKNISDiunduh dari Sumber: 3/11/2012 .
23 PRODUKTIVITAS LAHANLand productivity measures the wealth generated on a piece of land.High land productivity translates into :Lower resource wastage,Improved production processes,Shorter turn-around time and,Greater cost-savings.Mulsa plastik – ciri usahatani intensifDiunduh dari Sumber: /11/2012 .
24 KUALITAS & SIFAT-CIRI, KARAKTERISTIK TANAH Soil quality is generally defined in terms of the capacity of a soil to perform specific functions in relation to human needs or purposes, including maintaining environmental quality and sustaining plant and animal production (Lal, 1998a).Soil quality, in turn, derives from a variety of particular physical, chemical, and biological properties that support these functions, including topsoil depth, texture, bulk density, and water-holding capacity; organic matter, pH level, and extractable nitrogen, phosphorus, and potassium; and microbial biomass (Mausbach and Seybold, 1998).Some of these properties (e.g., pH, N, P, and K) are characterized by optimum levels; departures from these optima (in either direction) are associated with reduced soil quality. Other properties (e.g., topsoil depth and microbial biomass) contribute positively to soil quality at all levels, while some (e.g., bulk density) are inversely related to soil quality.In addition to soil properties, other characteristics also play a critical role in determining land quality, including aspects of terrain (such as slope) and climate (such as temperature and precipitation, and thus the length of growing period).Lal, R a. “Soil Erosion Impact on Agronomic Productivity and Environment Quality.” Critical Reviews in Plant Sciences 17(4):Mausbach, M. J., and C. A. Seybold “Assessment of Soil Quality.” In Soil Quality and Agricultural Sustainability, edited by Rattan Lal. Chelsea, MI: Ann Arbor Press.Diunduh dari Sumber: 3/11/2012 .
25 STORIE INDEXThe Storie index is a method of soil rating based on soil characteristics that govern the land's potential utilization and productivity capacity. It is independent of other physical or economic factors that might determine the desirability of growing certain plants in a given location.The evaluation is easy to be realized, being this an advantage of this method.A variety of categories are comprised in few categories.Four or five parameters are evaluated:A: Soil depth and texture;B: Soil permeability;C: Soil chemical characteristics;D: Drainage, Surface runoff;E: Climate (only if it is not homogeneous, if so than it should not be included in the formula);The index is calculated from the multiplication of these parameters, that is:Sindex = A x B x C x D x EThe disadvantage of this method is that if we have a value of zero in any category, than the result will be zero and won't be suitable for using.Diunduh dari Sumber: 3/11/2012 .
26 STORIE INDEX RATING SYSTEM The Storie Index Rating system ranks soil characteristics according to their suitability for agriculture from Grade 1 soils (80 to 100 rating), which have few or no limitations for agricultural production to Grade 6 soils (less than 10), which are not suitable for agriculture.Under this system, soils deemed less than prime can function as prime soils when limitations such as poor drainage, slopes, or soil nutrient deficiencies are partially or entirely removed.The six grades, ranges in index rating, and definition of the grades, as defined by the NRCS, are provided below in Table Storie Index Rating System.Tanah yang mempunyai rating tinggi cocok untuk multiple croppingDiunduh dari Sumber: 5/11/2012 .
27 Storie Index Rating System … Diunduh dari Sumber: /11/2012 .
28 Rating soils for agricultural, forest and grazing use. STORIE, R. E.Journal Transactions 4th Int. Cong. Soil Sci Vol. 1 pp …. The Storie Index, a general soil-rating system of particular use in evaluating soils from an agricultural standpoint for tax assessment, land appraisal and general land-use planning purposes, is obtained by the multiplication of the per cent ratings given to FACTORS:A, the soil-profile depth and permeability;B, texture;C, slope andX, factors modifiable by management, namely drainage, salinity or alkalinity, nutrient level, acidity, erosion and micro-relief.The crop-productivity rating of a soil type is based on its yield as compared with that of the soil types giving the highest yield under stated management practices and climatic conditions, and is expressed in ratios from 10 to 1 (that is 100% to 10% of highest yields).A given soil type may have one rating when undrained, another when drained and a third when d "a ned and fertilized and so on.Timber soil ratings are similarly handled but where production is unknown, they are worked out by multiplying the ratings for factors A, depth and texture; B, permeability; C, chemical properties such as salinity; D, drainage and runoff and E, climate, including rainfall, temperature, aspect.Diunduh dari Sumber: /11/2012 .
29 STORIE INDEX RATING SYSTEM… GradreIndex RatingDefinition1 – Excellent80 through 100Soils are well suited to intensive use for growing irrigated crops that are climatically suited to the region.2 – Good60 through 79Soils are good agricultural soils, although they may not be so desirable as Grade 1 because of moderately coarse, coarse, or gravelly surface soil texture; somewhat less permeable subsoil; lower plant available water holding capacity, fair fertility; less well drained conditions, or slight to moderate flood hazards, all acting separately or in combination.3 – Fair40 through 59Soils are only fairly well suited to general agricultural use and are limited in their use because of moderate slopes; moderate soil depths; less permeable subsoil; fine, moderately fine, or gravelly surface soil textures; poor drainage; moderate flood hazards; or fair to poor fertility levels, all acting alone or in combination.4 - PoorSoils are poorly suited. They are severely limited in their agricultural potential because of shallow soil depths; less permeable subsoil; steeper slope; or more clayey or gravelly surface soil textures than Grade 3 soils, as well as poor drainage; greater flood hazards; hummocky micro-relief; salinity; or fair to poor fertility levels, all acting alone or in combination.5- Very PoorSoils are very poorly suited for agriculture, are seldom cultivated and aremore commonly used for range, pasture, or woodland.6 – Non-agriculturalless than 10Soils are not suited for agriculture at all due to very severe to extreme physicallimitations, or because of urbanization.Source: USDA-NRCS 2010
30 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XFaktor A : Rating karakter fisik profil tanahITanah-tanah aluvial muda yang profilnya belum berkembang100 %xFase dangkal (pada material bahan induk yang konsolidated) kedalaman 2 feet50-60Fase dangkal (pada material bahan induk yang konsolidated) kedalaman 3 feet70gSubsoil sangat berkerikil80-95sSubsoil liat terstrataIITanah-tanah aluvial muda yang profilnya baru-sedikit berkembang%xFase dangkal (pada material bahan induk yang konsolidated) kedalaman 2 feet50-60Fase dangkal (pada material bahan induk yang konsolidated) kedalaman 3 feet70gSubsoil sangat berkerikil80-95sSubsoil liat terstrataSumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
31 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XFaktor A : Rating karakter fisik profil tanahIIITanah-tanah aluvial yang PERKEMBANGAN profilnya moderat (subsoilnya agak padat)80-95 %xFase dangkal (pada material bahan induk yang konsolidated) kedalaman 2 feet40-60Fase dangkal (pada material bahan induk yang konsolidated) kedalaman 3 feet60-70gSubsoil sangat berkerikil60-90IVTanah-tanah yang profilnya sudah berkembang (Subsoiolnya liat rapat /padat)40-80 %VTanah-tanah yang profilnya mempunyai subsoil cadas (hardpan) pd kedalaman kurang dari 1 foot5-20 %Pada kedalaman 1-2 feet20-30Pada kedalaman 2-3 feet30-40Pada kedalaman 3-4 feet40-50Pada kedalaman 4-6 feet50-80Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
32 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XFaktor A : Rating karakter fisik profil tanahVITanah-tanah yang subsoilhya liat rapat terletak pada bahan induk yang konsolidated (moderat konsolidated)40-80 %VIITanah-tanah pada dataran upland yang batuan induknya berupa batuan beku yang keras pada kedalaman kurang dari 1 foot10-30 %Pada kedalaman 1-2 feet30-50Pada kedalaman 2-3 feet50-70Pada kedalaman 3-4 feet70-80Pada kedalaman 4-6 feetPada kedalaman lebih dari 6 feet80-100100Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
33 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XVIIITanah-tanah pada dataran upland yang bahan induknya berupa batuan sedimen yang konsolidated pada kedalaman kurang dari 1 foot10-30 %Pada kedalaman 1-2 feet30-50Pada kedalaman 2-3 feet50-70Pada kedalaman 3-4 feet70-80Pada kedalaman 4-6 feetPada kedalaman lebih dari 6 feet80-100100IXTanah-tanah pada dataran upland yang bahan induknya berupa material lunak yang konsolidated pada kedalaman kurang dari 1 foot20-40 %Pada kedalaman 1-2 feet40-60Pada kedalaman 2-3 feet60-80Pada kedalaman 3-4 feet80-90Pada kedalaman 4-6 feetPada kedalaman lebih dari 6 feet90-100100Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
34 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XFAKTOR B. RATING BERDASARKAN TEKSTUR TANAH LAPISAN ATASTekstur halus atau beratLiat berdebu, sangat berkapur70-90Liat berdebu, tidak berkapur60-70Liat, sangat berkapur70-80Liat tidak berkapur50-70Tekstur Medium:Lempung berpasir halus100%Lempung100Lempung debuLempung berpasir95Lempung liat berdebu, berkapurLemp. Liat berdebu, non kapur90Lemp. Liat berkapurLemp. Liat tidak berkapur85-90Tekstur Kasar atau ringan:Lempung berpasir kasar90Pasir berlempung80Pasir snagat halusPasir halus65Pasir60Pasir kasar30-60Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
35 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XFAKTOR B. RATING BERDASARKAN TEKSTUR TANAH LAPISAN ATASBerkerikilLempung berpasir halus berkerikil70-80Lempung berkerikil60-80Lempung debu berkerikilLempung perbasir berkerikil50-70Lemp. Liat berkerikilLiat berkerikil40-70Pasir berkerikil20-30BerbatuLempung berpasir halus berbatu70-80Lempung berbatu60-80Lempung debu berbatuLempung perbasir berbatu50-70Lemp. Liat berbatu50-80Liat berbatu40-70Pasir berbatu10-40Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
36 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XFAKTOR C. RATING BERDASARKAN KEMIRINGANAHampir datar (kemiringan 0-2%)100%AAAgak berombak (kemiringan 0-2%)95-100BAgak miring (kemiringan 3-8%)BBBerombak (kemiringan 3-8%)85-100CMiring (kemiringan 9-15%)80-95CCBergelombang (kemiringan 9-15%)DSangat miring (kemiringan 16-30%)70-80DDBerbukit (kemiringan 16-30%)ECuram (kemiringan %)30-50FSangat curam (kemiringan lebih dari 45%)5-80Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
37 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XFAKTOR X. RATING BERDASARKAN FAKTOR LAINNYA, SELAIN FAKTOR A, B, DAN C.DrainageBaik100%Cukup baik80-90Tergenang moderat40-80Tergenang parah10-40Subyek banjirvariabelAlkaliBebas alkali100%Sedikit terpengaruh alkali60-95Pengaruh moderat30-60Pengaruh agak parah15-30Pengaruh parah5-15Unsur Hara (kesuburan)Tinggi (subur)100%Cukup95-100Miskin80-95Sangat miskin60-80KemasamanSesuai dnegan pH80-95%Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
38 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XFAKTOR X. RATING BERDASARKAN FAKTOR LAINNYA, SELAIN FAKTOR A, B, DAN C.Erosi tanah: Tidak ada – Ringan100%Deposisi berbahaya75-95Erosi permukaan moderat80-95Alur dangkal jarang70-90Erosi permukaan moderat dg alur dangkal60-80Alur dalam10-70Erosi permukana moderat dg alur dalam10-60Erosi permukaan parah50-80Erosi permukaan parah dg alur dangkal40-50Erosi permukaan parah dg alur dalam10-40Erosi sangat parahErosi angin moderatErosi angin parah30-80Relief mikro:Smooth100%Channel60-95HogwallowLow hummock80-95High hummock20-60Dunes10-40Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
39 .Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X SOIL RATING CHART.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor XSOIL GRADINGGRADE 1 (Excelent)Tanah-tanah yang mempunyai rate % dan cocok untuk berbagai jenis tanaman, tanaman pangan, perkebunan dan hutanGRADE 2 (Good)Tanah-tanah yang mempunyai rate 60-79% dan cocok untuk banyak jenis tanaman. Hasil tanaman umumnya baik hingga sangat baikGRADE 3 (Fair)Tanah-tanah yang mempunyai rate 40-59% dan kualitasnya cukup baik, cocok bagi cukup banyak jenis tanaman, Hasil jenis tanaman tertentu cukup baikGRADE 4 (Poor)Tanah-tanah yang mempunyai rate 20-39% dan mempunyai peluang terbatas bagi pertanian, misalnya beberapa tanah cocok untuk sawahGRADE 5 (Very Poor)Tanah-tanah yang mempunyai rate 10-19% dan penggunaan pertanian snagat terbatas, kendala serius seperti solum dangkal, berbatu, atau alkalisGRADE 6 (Non-agriculture)Tanah-tanah yang mempunyai rate kurang dari 10% dan faktor pembatasnya snagat serius, seperti sangat curam, pasang-surut, lembah banjir.Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc California. 1978
40 KUALITAS & KARAKTERISTIK LAHAN "Karakterisik lahan" merupakan atribut lahan yang dapat diukur atau diestimasi. Misalnya: kemiringan, curah hujan, tekstur tanah, kapasitas air tersedia, biomasa vegetasi, dll."Kualitas lahan" adalah kompleks atribut lahan yang mempunyai peranan spesifik dalam menentukan tingkat kesesuaian lahan untuk suatu penggunaan tertentu. Misalnya: ketersediaan air, resistensi erosi, bahaya banjir, dan aksesibilitas."Kriteria diagnostik" adalah suatu peubah yang mempunyai pengaruh tertentu terhadap hasil (atau input yang diperlukan ) pada penggunaan tertentu, dan peubah ini juga berfungsi sebagai dasar untuk menilai kesesuaian suatu bidang lahan bagi penggunaan tertentu.“Kriteria diagnostik” ini dapat berupa kualitas lahan, karakteristik lahan, atau beberapa karakteristik lahan.Diunduh dari sumber: 5/11/2012
41 KUALITAS LAHANHubungan antara kualitas dan karakteristik lahan yang dipakai pada metode evaluasi lahan (Djaenudin et al. 2003)..Kualitas LahanKarakteristik LahanTemperatur (tc)Temperatur rata -rata (oC)Ketersediaan air (wa)Curah hujan (mm), Kelembaban (%), Lamanya bulan kering (bln)Ketersediaan oksigen (oa)DrainaseKeadaan media perakaran (rc)Tekstur, Bahan kasar (%), Kedalaman tanah (cm)GambutKetebalan (cm), Ketebalan (cm) jika ada sisipan bahan mineral/pengkayaan, KematanganRetensi hara (nr)KTK liat (cmol/kg), Kejenuhan basa (%), pH , C-organik (%)Toksisitas (xc)Salinitas (dS/m)Sodisitas (xn)Alkalinitas/ESP (%)Bahaya sulfidik (xs)Bahaya sulfidik (xs) Kedalaman sulfidik (cm)Bahaya erosi (eh)Lereng (%), Bahaya erosiBahaya banjir (fh)GenanganPenyiapan lahan (lp)Batuan di permukaan (%), Singkapan batuan (%)Diunduh dari sumber: 5/11/2012
42 LAND USE Land use is the human use of land. Land comprises the physical environment, including climate, relief, soils, hydrology and vegetation, to the extent that these influence potential for land use. It includes the results of past and present human activity, e.g. reclamation from the sea, vegetation clearance, and also adverse results, e.g. soil salinization. Purely economic and social characteristics, however, are not included in the concept of land; these form part of the economic and social context.(sumber:Land use is the human use of land.Land use involves the management and modification of natural environment or wilderness into built environment such as fields, pastures, and settlements.“LAND USE” has also been defined as "the arrangements, activities and inputs people undertake in a certain land cover type to produce, change or maintain it" (FAO, 1997; FAO/UNEP, 1999)..Diunduh dari sumber: en.wikipedia.org/wiki/Land_use …… 5/11/2012
43 LAND UTILIZATIONA land utilization type consists of a set of technical specifications in a given physical, economic and social setting. This may be the current environment or a future Betting modified by major land improvement e, e.g. an irrigation and drainage scheme. Attributes of land utilization types include data or assumptions on:Produce, including goods (e.g. crops, livestock timber), cervices (e.g. recreational facilities) or other benefits (e.g. wildlife conservation)Market orientation, including whether towards subsistence or commercial productionCapital intensityLabour intensityPower sources (e.g. man's labour, draught animals machinery using fuels)Technical knowledge and attitudes of land usersTechnology employed (e.g. implements and machinery, fertilizers, livestock breeds, farm transport, methods of timber felling)Infrastructure requirements (e.g. sawmills, tat factories, agricultural advisory services)Size and configuration of land holdings, including whether consolidated or fragmentedLand tenure, the legal or customary manner in which rights to land are held, by individuals or groupsIncome levels, expressed per capita, per unit of production (e.g. farm) or per unit area.Diunduh dari sumber: …… 5/11/2012
44 Neoclassical Production Theory The neoclassical production function for a single output and two variable inputs can be written:y = f(x1,x2)where y is the quantity of output and xi is the quantity of the ith variable input.The properties of this production function are specified by assumptions:Xi ≥ 0 and finite (non-negative, real inputs);f(X1,X2) is finite, nonnegative, real valued, and single valued for all possible combinations of X1 and X2;f(X1,X2) is everywhere continuous and everywhere twice continuously differentiable;f(X1,X2) is subject to the "law" of diminishing returns.Diunduh dari sumber: …… 5/11/2012
45 INPUT / FAKTOR PRODUKSI Of the three factors of production in classical economics, land, labor, and capital, land may be the most difficult to define. Does it refer to just the land itself?Or is land a generic term referring to all natural resources? Air, sunshine, and water, necessary to make land productive, are all part of the surrounding ecosystems. While ownership of land itself can easily be demarcated, ownership of mobile, associated resources is trickier.Diunduh dari Sumber: 2/10/2012 .
46 PROSES PRODUKSI TANAMAN Many processes affect crop performance : the conservative efficiency of the use of radiation, water and nutrient on crop growth, those contributing to the soil water balance and those affecting soil fertility.Crop growth has been modelled successfully as a function of environmental factors using the concept of these conservative efficiencies.Crop production will be described for these levels in terms of potential and water- or nutrient limited production .The most suitable cereal crop (depending on the agro-ecological conditions wheat, rice, maize, millet or sorghum) is taken as a proxy for a wide range of crops that could be grown, with yields expressed in 'grain equivalents'.In practice actual production levels may differ from these calculated levels due to deviant agricultural management. Actual yield is a function of biophysical as well as the socio-economic conditionsLevels of production and required data for its assessment. (Modified from Rabbinge, 1993).Rabbinge, R., The ecological background in food production . In: Crop protection and sustainable agriculture. John Wiley and Sons, Chichester (Ciba Foundation Symposium 177), ppDiunduh dari Sumber: 5/11/2012 .
47 INPUT-OUTPUT PROCESS RELATIONSHIPS Stylized Production Functions or Input-Output Relationships for a Single Variable InputFigure illustrates some differently shaped production functions for the case of a single-variable input production process.Each graph shows the physical input-output relationship or total physical product curve as the level of the single variable input is increased with all other input factors held constant.In graphs A and B, the law of diminishing returns (sometimes called the law of variable proportions) prevails - beyond some point, as the level of the variable input increases with no change in the level of other input factors, increases in output occur at a diminishing rate (the marginal product is decreasing) and eventually, beyond the point of maximum output, output declines in absolute terms (the marginal product becomes negative).Diunduh dari Sumber: 5/11/2012 .
48 Keterkaitan Faktor Produksi Kaitan Faktor Manajemen Dengan Faktor Produksi LainAda empat faktor produksi pertanian yaitu:Alam (lahan, iklim, radiasi matahari, air, udara, dll), Tenaga kerja, Modal, dan Pengelolaan (manajemen).Faktor produksi alam dan tenaga kerja sering disebut sebagai faktor produksi primer,faktor produksi modal dan pengolaan disebut faktor produksi sekunder.Diunduh dari Sumber: ocw.usu.ac.id/...PERTANIAN/sep_203_handout_faktor-faktor_prod /11/2012 .
49 EKSTERNALITASDalam proses produksi pertanian, masukan-masukan yang berupa material, tekno¬logi, menejemen dan unsur-unsur agro ekologi akan diproses untuk menghasilkan keluaran-keluaran yang berupa hasil-hasil tanaman dan ternak.Hasil-hasil sampingan dan limbah dari proses produksi tersebut dapat berupa hasil sedimen, hasil air, dan bahan-bahan kimia yang dapat menjadi pencemar lingkungan. Limbah ini biasanya diangkut ke luar dari sistem produksi dan menimbulkan biaya eksternal dan efek eksternalitas.Biasanya sistem produksi pertanian di daerah hulu sungai mempunyai efek eksternal yang cukup luas dan akan diderita oleh masyarakat di daerah bawah.Dalam suatu daerah aliran sungai yang mempunyai bangunan pengairan seperti bendungan, waduk dan jaringan irigasi, efek eksternalitas tersebut menjadi semakin serius, karena dapat mengancam kelestarian bangunan-bangunan tersebut.Diunduh dari Sumber: /11/2012 .
50 EKSTERNALITAS“Eksternalitas” timbul kalau kegiatan produksi (dan konsumsi) memiliki pengaruh yang tidak diharapkan (tidak langsung) terhadap produsen dan /atau konsumen lain.“Eksternalitas positif” terjadi kalau kegiatan yang dilakukan oleh seseorang memberikan manfaat pada pihak lain tanpa melalui mekanisme pasar.“Eksternalitas negatif” terjadi kalau kegiatan oleh individu menghasilkan dampak yang merugikan pihak lain.Pencemaran air sungai atau air sumur dapat ditimbulkan oleh proses produksi pertanian yang berasal dari penggunaan pestisida dan pupuk.Adanya eksternalitas menyebabkan terjadinya perbedaan antara manfaat (biaya ) sosial dengan manfaat (biaya) privat. Perbedaan manfaat (biaya ) ini berkaitan dnegan alokasi sumberdaya yang tidak efisien. Pihak yang menyebabkan eksternalitas tidak memiliki dorongan untuk menanggung dampak dari kegiatannya yang diderita oleh pihak lain.Diunduh dari Sumber: 5/11/2012 .
51 EKSTERNALITAS EROSI TANAH. “Erosi tanah” merupakan proses terangkutnya material tanah atau sedimen oleh aliran air yang terjadi di permukaan tanah.Kerusakan yang dialami oleh tanah di tempat yang ada erosi a.l.:Kehilangan unsur hara dan bahan organik.Menurunnya kapasitas infiltrasi (kemampuan tanah untuk meresapkan air) dan kemampuan tanah menyimpan air.Meningkatnya kepadatan dan ketahanan penetrasi tanah.Berkurangnya kemantapan struktur tanah yang pada akhirnya menyebabkan memburuknya pertumbuhan tanaman dan menurunnya produktifitas.Eksternalitas lingkungan akibat erosi tanah a.l.:Sedimentasi dan pendangkalan wadukTertimbunnya (sedimentasi) jaringan irigasi.Memburuknya kualitas air sungai , air sumur, air permukaan lainnya,Kerugian ekosistem perairan.Diunduh dari Sumber: 5/11/2012 .
52 The problem is that the way owners use their land may affect others. EKSTERNALITASThe problem is that the way owners use their land may affect others.If they dump garbage on their neighbors' land, clearly they are infringing upon others' rights. But how about if they burn garbage and the resulting smoke blows onto nearby properties?What if they pollute a stream and it ends up affecting everyone's water source, or flush sewage away and it ends up in an ecologically stressed bay?Although the field of economics traditionally likes to deal with items that can be easily demarcated, quantified, and tagged with ownership, this becomes difficult when dealing with our shared ecosystems.Economics has dealt with this largely by labeling such items externalities, costs for which the responsible party does not pay.It then becomes up to the community, and usually the government, to decide how to deal with externalities.Diunduh dari Sumber: 16/11/2012 .
53 EXTERNALITYUntil now we have assumed that market price includes or 'internalizes' all relevant costs and benefits. This means the consumer captures all benefits and the producer pays all the costs. An externality refers to costs and benefits that are not captured by market price for whatever reasons, i.e., they are external to market price.In effect, the market demand curve reflects only marginal private benefits (MPB) of consumers but not the external benefits accruing to society. When such external benefits are added, vertically, we derive the marginal social benefit curve (MSB) inclusive of both private and public benefits.Similarly, the market supply curve reflects only marginal private costs (MPC) but not costs external to the firm’s accounting, e.g., pollution that society must pay. When social costs are added, vertically, to the supply curve we derive the marginal social cost (MSC) curve inclusive of both private and public costs.Diunduh dari Sumber: /11/2012 .
55 EXTERNAL COST MC = MPC MSC = MC + MEC MSC = marginal social cost; MC = marginal costMSC = MC + MECMEC = marginal external costMPC = marginal private costMC = MPCDiunduh dari Sumber: /11/2012 .
56 EKSTERNAL COST - INEFISIENSI Adanya biaya eksternal mengakibatkan in-efisiensi dalam proses produksi
57 NEGATIVE EXTERNALITIES Inefficiency from Negative Externality A negative externality is a cost associated with an action that is not borne by the person who chooses to take that action.Inefficiency from Negative ExternalityWhen there is a negative externality, the market equilibrates where the total social marginal cost exceeds the marginal benefit of the last unit of a good and society is not as well off as it could be if less were produced.Diunduh dari Sumber: 5/11/2012 .
58 Over-production with a negative externality PsPpQsQpThe failure to internalize the negative externality results in diminished social well-being.The over-production occurs when the external costs of waste disposal in the community are ignored (not internalized).In this figure, the private profit- maximizing quantity of landfill deposits produced (Qp ) are greater than the socially optimal production that occurs when the external costs are included (Q s ).The amount of overproduction is equal to the distance from Qp to Qs . In order to account for the external costs imposed on the community from producing additional (aggregates) deposits into the landfill, it is important to increase the costs of these deposits from Pp to Ps .Diunduh dari Sumber: 5/11/2012 .
59 Pigouvian tax applied to a negative externality What happens when one form of government intervention (a Pigouvian tax on the disposal of aggregates) is implemented.With a Pigouvian tax, the tax is set equal to the marginal external costs at the socially optimal point of production.In this case, the tax on deposits elevates the price of disposal, leading to a reduction in the amount of deposits.A reduction of deposits into the local landfill would most likely result from corresponding reductions in the amount of aggregates waste created in the production process or from finding alternative means of disposal of the waste.Diunduh dari Sumber: /11/2012 .
60 . Adverse environmental impacts as negative externalities Some adverse environmental impacts may be internalised into a farmer's decision-making process, e.g. soil erosion, as this may impact on the revenue-generating potential of the farm in the future. However, the problem with many environmental impacts is that the costs are not borne by the producer because there is no mechanism to price the damage being done and require the producer to pay.These environmental costs are externalised, and there is thus divergence between the marginal private cost of production (to which the producer responds) and the marginal social cost of production (which determines the socially optimal level of production).Over-production of farm output which causes environmental damage is shown in the following diagram.The farmer would produce at Q1 where his marginal private cost equals marginal revenue, although the socially efficient level of output is Qo which takes into account the additional social costs of agricultural production.Diunduh dari Sumber: /11/2012 .
61 Divergence between private and social costs of upland production. The paper defines the concept of land degradation and costs and effects of soil erosion. Through the concept of optimal levels of soil erosion, a conceptual model of the social costs of soil degradation is elaborated.The discussion focuses on the measurement aspects of the economic scarcity of soil in the agriculture sector. Reliable estimates of the true impacts of soil degradation can only be made if data on marginal damage costs and marginal conservation costs are available.The different scarcity indicators are evaluated and competitive land rental prices are considered as appropriate in indicating soil scarcity in agriculture.Diunduh dari Sumber: /11/2012 .
62 Optimal level of soil quality and soil costs. Diunduh dari Sumber: /11/2012 .
63 EKONOMI LAHANThere has been a paper recently published by Andrew Leigh, Economics Professor at ANU, which empirically estimates the impact of stamp duties on the housing market. His main finding is that if stamp duties are raised, house prices will fall by more than in the increase in the tax. Did you get that? If you increase stamp duty, the total price of housing (price plus stamp duty) will fall. Sellers suffer, buyers benefit. It’s a classic land tax - there is no deadweight loss, as shown in the figure.Diunduh dari Sumber: 31/10/2012 .
64 PASAR LAHANHow can such a thing occur? For any other product, assuming a competitive market, if you add costs to production, prices will have to go up (even if quantity sold goes down), or margins will go down (temporarily at least). Land, however, has some characteristics that make it quite different to other goods1. There is a fixed supply (vertical supply curve), and2. It is costless to produce (the producer surplus starts at a price of zero)Some would argue that land available to be developed is not in fixed supply, and that town planning regulations can change that supply. I agree. But these are regulations, they are not market players, and that does not make supply of land price elastic (although I would suggest the supply curve for serviced residential lots above the intersection with demand is quite elastic as land parcels are brought to market). I think both sides would agree that from a theoretical standpoint, the supply curve is vertical below the intersection with the demand curve.Diunduh dari Sumber: /10/2012 .
65 Diunduh dari Sumber: .................... 31/10/2012 . PASAR LAHANIt is the second point that is far more important to understanding the land market. Land itself is costless to produce. That means that the level of demand determines the price of land at any point in time. Not supply, demand. So when you increase a tax on land the total land and tax price stays constant, but the underlying value of the land declines (as shown by the reduced producer surplus in the figure above).I have been quite baffled by the success of Christopher Joye’s argument that the supply of housing is a major factor determining prices. He maintains two contradictory positions. The first is that we have a land price boom, not a house price boom. The second is that we should elastify the supply of housing to avoid further unnecessary price increases. Hang on chap. We don’t have a problem supplying housing. Our problem is that we all decided to pay ridiculously high prices for land.There are two more characteristics to the land market that make analysis difficult. There is competitive behaviour in the market for buying land, both development sites and serviced land parcels, but not a competitive market for the sale of land. Diunduh dari Sumber: /10/2012 .
66 RATIONALITASLand resources support life, underpin the economies of nations and the livelihoods of people across the worldIn many places these resources are being degraded by a series of pressures, and climate change will only make things worseUnsustainable land uses and practices take place for many different reasons, and may produce irreversible losses in fragile ecosystemsThe value of land resources to national development and poverty reduction is often not understood properlyInvestments in land, sectors or technologies driven by short-term gains may generate huge negative externalities, leading to serious depreciation of natural capitalSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
67 APAKAH SUMBERDAYA ALAM ? "Value" has multiple meanings, and we must get a clear understanding about what we mean.Monetary or "market" value is determined by exchange of money. If I have a tree and you want a tree, how much money will I accept and give you my tree in exchange?The market value, therefore, depends on a tension between one person wanting to retain what they have, and another person wanting to have what the first person has.The resolution of the tension is achieved when ownership changes simultaneously with a flow of money from the buyer to the seller, and a flow of ownership from the first owner to the second owner.Market value refers only to what we can obtain from other humans. What can people have? What can people exchange for money?Are natural resources always exchangeable for money? Can humans "make" a tree? Who or what makes it "ownable," or makes it "property"?Diunduh dari Sumber: /10/2012 .
68 APAKAH SUMBERDAYA ALAM ? Humans make artifacts (production) and can give their time and labor (services).Humans do not make natural resources, which are unrelated to either human time or human production. Humans may only modify natural resources.Natural resources are made by Nature and the energy to make them comes from geochemical, geophysical and solar energy.Humans cannot make petroleum, which once was living plants that have been processed for millions of years before humans existed, slowly becoming petroleum.Petroleum is a natural resource that we consider to be "nonrenewable" because it takes too long to make by the time scale that we can experience. But we can change where petroleum is located, and we can process it into components parts.Diunduh dari Sumber: /10/2012 .
69 APAKAH SUMBERDAYA ALAM ? So, when we say that petroleum is valuable, we refer only to what we do with it. Humans may own the use of petroleum and control the ways that other people can use it.Ownership is a concept of humans, who invented laws to formalize the concept. Groups of humans then agreed to abide by the rules spelled out in the laws.Laws are also artifacts and laws make money "legal tender." If we "own the right to modify a right to modify a natural resource" then we may exchange our right of modification with other people who give us money.Money is another human artifact and its value is defined by laws, and ultimately, by many people's opinion about its value. Money cannot be used to make natural resources, but money and laws are used to influence what other humans do with natural resources.Diunduh dari Sumber: /10/2012 .The effects of soil productivity on food quality, health and environmental quality.Sumber:
70 APAKAH SUMBERDAYA ALAM ? So, the monetary value of natural resources is what people believe the value to be. Our ignorance can cause the resources to be greatly undervalued, which is a major problem. We may not consider the "replacement cost" of a limited natural resource when we establish a monetary value. Humans are inherently ignorant; we simplify complex things and processes because we do not understand the "whole"! Natural resources and the ecosystem processes producing them are the most complex systems we can imagine -- if, in fact, we actually can imagine them accurately. Why are natural resources valuable to us? What do we assume about natural resources and their "value" when we equate their existence and use with money?Ecosystem services keep our habitat comfortable and livable without the outlay of money. Nature's processes work for free, powered totally by solar energy. Some examples are:Pest controlFlood controlWater filtrationSoil fertilizationFood productionOxygen productionClimate stabilizationRecreation opportunitiesDiunduh dari Sumber: /10/2012 .
71 APAKAH SUMBERDAYA ALAM ? These services to some extent also can be achieved by technological means, but at significant monetary investment. Furthermore, continuing costs are necessary to maintain the services.The ecosystem, however, will maintain these services without cost, unless we interfere with these processes. In certain instances there is a "loss of opportunity value," such as avoiding building highways or buildings in such a way that they destroy or damage the ecosystem processes.The loss of opportunity value is offset by the ecosystem services value they supply.We may choose one form value over another form of value, such as short term use value for long term service value.Such a choice resembles a decision to save or invest money in order to allow the investment to grow (increase in monetary value) or to preserve future options and benefits that may not be fully recognized. Such long range value requires imagination of future needs and recognition of the benefits of preserving options for those that may be valuable in ways we cannot imagine today.Such projected values require understanding of management of systems, and possibilities regarding the "replacement value" of a resource. Making good decisions implies an awareness of many factors and consequences not easily understood today, or a belief that present people have an obligation to future generations of people to have options, opportunities, similar to those we have today.Diunduh dari Sumber: /10/2012 .
72 APAKAH SUMBERDAYA ALAM ? Sedimentation in the aquifer cannot be removed, and chemicals flush very slowly through the aquifer. Those people who "develop" the areas that damage the aquifer do not pay the costs of cleaning the water and keeping it clean. Nor do they pay the cost of sedimentation filling in the aquifer.This cost is "externalized" by the perpetrators of the damage since it is paid with tax funds (the public pays) or by the individuals who acquire their water from the aquifer directly. The permanent loss of the capacity of the aquifer by sedimentation filling it instead of water is paid by all who eventually lose its "free" services or "use potential" of unknown possibilities in the future.Externalizing costs while retaining the right to have an income from the development seems unfair, but it has been declared legal. The developers thereby are subsidized by others who receive no benefits from the ecologically damaging development.This is a "market failure" for monetized value whereby the human(s) who benefit do not pay the cost of their benefits.Diunduh dari Sumber: /10/2012 .
73 NRDA : Natural Resources Damage ASSESSMENT The NRDA valuation techniques considers five general classes of valuation techniques:Market-based techniques, which rely on historical information on market prices and transactions to determine resource values;Nonmarket techniques that rely on indirect estimates of resource values;Nonmarket techniques that are based on direct estimates of resource values;Cross-cutting valuation techniques, which combine elements of one or more of these methods; andEcological valuation techniques used in the emerging field of ecological economics.Diunduh dari Sumber: 31/10/2012 .Calculating productivity loss due to land degradationNew method to assess the loss of productivity due to soil degradation.There is compelling evidence that soils are degrading because of problems such as erosion and soil depletion. However, nobody knows how serious the problem really is.Estimates of the rate of global soil degradation, the economic losses, and the impact on food security are extremely variable.This variability is due to various reasons such as lack of an objective definition of soil degradation and uncertainties in underlying information.Consequently, soil degradation appears to be underemphasized on policy agendas and the investments required to safeguard future food security are unknown.Diunduh dari Sumber: /11/2012 .
74 TEKNIK-TEKNIK VALUASI SUMBERDAYA ALAM Valuation Techniques, Benefit Types, and Selected Case StudiesDiunduh dari Sumber: 31/10/2012 .
75 TEKNIK-TEKNIK BERBASIS PASAR The pioneers of natural and environmental resource valuation relied onthe “law of demand” as a way to measure the market values for naturalresources and environmental amenities.While the same is true today, thedegree of sophistication in the measurement of these values has increasedconsiderably.Three market-based techniques that have recorded a significant history of natural and environmental resource valuations are described here:The market price approach,The appraisal method, andThe resource replacement costing.Diunduh dari Sumber: 31/10/2012 .
76 PENDEKATAN HARGA PASAR Demand, Supply, and Market Valuation Demand for natural resources is measured on the assumption that many factors that might influence demand, such as personal income, the prices of related goods and services, and individual tastes and preferences, remain unchanged during the study period.Under these assumptions, the estimated demand curve is a systematic measure of how people value the resource.To illustrate, the figure shows that 20,000 acres of land were sold at a market price of $1500 per acre. In the course of these land transactions, $30.0 million exchanged hands in the land market, i.e., 20,000 x $1500. Had land become increasingly scarce, this scarcity would ultimately be reflected in higher land prices.Diunduh dari Sumber: 31/10/2012 .
77 CONCUMER SURPLUS… Economic surplus Diunduh dari Sumber: 3/10/2012 .Now, consider the total area beneath the demand curve up to 20,000 acres, as defined by A+B. This area measures the value of the resource in terms of the maximum willingness to pay for the 20,000 acres of land.The total willingness to pay for 20,000 acres is calculated by adding up what was actually spent in buying the land, A = $30 million, plus the additional triangular area B, which defines consumer surplus.Consumer surplus is the difference between people’s maximum willingness to pay for 20,000 acres of land (A+B) and what they actually paid (A).In essence, the area gives a dollar measure of satisfaction that people received from the land, less what they actually pay for it.Diunduh dari Sumber: 31/10/2012 .
78 PRODUCER SURPLUS …Producer surplus and economic rent are two other measures of thebenefits (or damages) associated with natural resources and resourceservices.Producer surplus measures monetary gains from the production of natural resources, which is the difference between revenues (C+D) and the economic costs of producing these resources (D). Similarly, economic rent measures monetary gains from using natural resources as factors of production, which is the difference between the actual payments made in using resources and the lowest payment that their owners would have been willing to accept in supplying these resources or resource services.Thus, producer surplus refers to the sellers’ gains from trade in the product market, while economic rent measures the sellers’ gains from trade in the input market.Accordingly, the use of producer surplus or economic rent in resource valuation problems depends on whether the natural resource is considered as a final product or as an input in the production of a final product.Diunduh dari Sumber: 31/10/2012 .
79 PRODUCER SURPLUS …Referring again to Figure 1, producer surplus is shown by the area C, which is bordered by the resource supply curve and the market price of the resource, P = $1500. This measure reflects changes in the availability of the natural resource. For example, if the natural resource were damaged, its supply curve would shift leftward and producer surplus would diminish.A similar description could be given to natural resource damages that result in a reduction in economic rent. Here, the damages would be incurred by the owners of the resources. As in the case of measuring the consumer surplus, both producer surplus and economic rent require historical information on the market prices and quantities of natural resources. In addition, the measures of producer surplus and economic rent require information relating to the economic costs of producing and/or supplying the resource to the market.Diunduh dari Sumber: 31/10/2012 .
80 APPRAISAL METHOD…Appraisal methods are particularly well suited to cases involving natural resources that have been damaged. In the case of land, for example, the appraiser identifies the fair market value for comparable properties in both the uninjured and injured conditions.The fair market value of the resource (land) is roughly defined as the amount a knowledgeable buyer would pay a knowledgeable seller for the resources. This value should reflect, as closely as possible, the price at which the resource would actually sell in the market place at the time of the injury.The application of appraisal methods would seem to hold particular promise in DOE natural and environmental resource planning and guidance. However, the point to keep in mind is that the method is, in fact, quite dependent on the appraiser’s judgment.It may be very difficult to identify comparable sales, particularly for properties that are “comparably” injured. In addition, the types of natural resources to which this method can be applied are limited since many natural and environmental resources are not traded in markets.Nevertheless, appraisal methods are applicable to soil and water treatment at federal facilities. Therefore, it is instructive to consider a notable protocol in applying appraisal methods.Diunduh dari Sumber: 31/10/2012 .
81 Scott, M.J., et al “The Valuation of Ecological Resources and Functions.” Environmental Management (forthcoming). …Scott et al. (1997) estimated the “fair market value” associated with shrub-steppe conversions based on sample data from Benton-Franklin Counties of eastern Washington State. The data were obtained from the Benton County Assessor’s Office and represent sales transactions in Benton County involving 7700 acres during the calendar year.The sample was selected to ensure the identification of recent patterns in the regional development of shrub-steppe land. Consequently, the sample contained 17 transactions of property for residential and/or commercial development (urban use) and 31 transactions involving property destined for agricultural development (agricultural use).The authors categorized the sales of predisposed agricultural land according to whether it was irrigated, or whether it would be used as dry pasture land or dry farm land.The sampling of real estate transactions found that shrub steppe for urban development had the highest average value, $9208 per acre. Dry pasture land had the lowest average value, $67 per acre. Meanwhile, irrigated farm land sold for $1484 per acre.Diunduh dari Sumber: 31/10/2012 .
82 RESOURCE REPLACEMENT COST METHOD… The costs of replacing natural and environmental resources are sometimes a useful way of approximating resource values under specific conditions. The resource replacement cost method determines damages for natural resources based on the cost to restore, rehabilitate, or replace the resource or resource services without injury to the level of the resource stock or service flow. In instances where the underlying resource is not unique and substitutes are readily available, the application of the replacement cost method is relatively straightforward.The investigator proceeds by gathering a sample of values for the substitutes from primary or secondary source information. Based on this sample of cost information, the analyst then prepares an estimate of the most likely range of expected replacement costs for the underlying resource or service.Diunduh dari Sumber: 31/10/2012 .
83 Contamination Episodes,” Shechter, M “Economic Aspects in the Investigation of GroundwaterContamination Episodes,”in Ground Water, Volume 23, Number 2, U.S. Environmental Protection Agency. Guidance Manual for Minimizing Pollution from Waste Disposal Sites, EPA 600/ , Washington, D.C. Environmental Science and Technology Groundwater Strategies, Vol. 14, pp …Shechter (1985) applied the replacement cost method at the Price Landfill in New Jersey to obtain cost estimates of alternatives to deal with groundwater contamination.Estimates were based on information obtained from the U.S. Environmental Protection Agency (1978) and Environmental Science and Technology (1980). Excluding excavation and reburials, the estimated costs ranged from $5 million to $8 million (in 1980 dollars) and included containment and management of the plume, along with the performance of water treatment until the aquifer had been purged of noxious substances.If excavation and reburial were undertaken as part of the restoration process, the researchers suggest that the period of plume management and groundwater flow control could be shortened, but that total cost would rise by about $15 million to $18 million.Other site restoration activities included in their estimation focused on securing alternative sources of water to meet Atlantic City’s water demand for the foreseeable future. These included cost estimates for the development of a well field to replace four threatened wells, varying between $6.5 million and $9.3 million. The researchers omitted other administrative costs from consideration in applying the method, such as the costs of undertaking various federal, state, and local studies on the landfill problem, and the attendant litigation costs that might be involved. It was believed that these administrative costs had the potential to raise the total cost by another $1.5 million.Diunduh dari Sumber: 31/10/2012 .
84 Nonmarket Valuation: Indirect Techniques… Using market-based techniques to measure the monetary value of natural resources is feasible provided there is sufficient market data. In many cases, however, market information relating to prices and quantities is not available to estimate the value of the resource or resource service. In these cases, researchers must employ what are referred to as nonmarket valuation methods.These methods include indirect techniques that rely on observable behavior in order to deduce how much something is worth to individuals. Value estimates obtained using indirect nonmarket valuation techniques are conceptually identical to the otherwise unobservable market value.The indirect nonmarket valuation techniques considered in this section include the travel cost method, the random utility method, the hedonic pricing method, and the factor income method.Diunduh dari Sumber: 31/10/2012 .
85 TRAVEL COST METHOD..The travel cost method is popular for describing the demand for the natural resource service(s) and environmental attributes of specific recreational sites. Designated wilderness areas, ecological parks, fishing and hunting sites, and scenic sites are examples. People visit such sites from diverse distances or points of origin.This observed “travel behavior” is then used to evaluate the willingness to pay to visit the site; essentially, the different travel costs from these diverse points of origin serve as proxies for willingness to pay to visit the site.Intuitively, one would expect that the environmental attributes of sites influence the use of these sites.As such, changes in visitation rates may reflect changes in the quality of natural resources particular to the site, thereby providing an estimate of the value of changes in natural resource and environmental quality.Diunduh dari Sumber: 31/10/2012 .
86 TRAVEL COST METHOD..The greatest disadvantage of travel cost and other indirect techniques is that they cannot be used unless there is some easily observable behavior that can be used to reveal values. In addition, travel cost models can be technically and statistically complicated.Data must be employed to statistically estimate increasingly sophisticated econometric models that take into account sample selection problems and nonlinear consumer surplus estimates.In addition, the resulting estimates sometimes have been found to be rather sensitive to arbitrary choices of the functional form of the estimating equation, the treatment of the value of an individual’s time, the existence of multiple stops during the travel period, and the recognition of substitute sites.Finally, the travel cost approach requires that the analyst be in a position to correlate environmental changes with the behavior of visitors.Diunduh dari Sumber: 31/10/2012 .
87 . Hedonic Price Method - Amenity Value. Hedonic pricing is a useful tool in the assessment of amenity value. Early analysis related residential property values to neighborhood amenities.These models provided an inferential measure of people’s willingness to pay for the amenity under study.The method is used mostly to estimate the willingness to pay for variations in property values due to the presence or absence of specific environmental attributes, such as air quality, noise, and panoramic vistas. By comparing the market value of two properties having different degrees of a specific attribute, analysts extract the implicit value of the attribute to property buyers and sellers.A variation on the approach is to compare the price of a single piece of property over successive sales. By correcting for other factors that might have influenced the value of the property, the analyst can isolate the implicit price of an amenity or bundle of amenities that have changed over time.The relationship between house price and the presence of trees, in order to gain an awareness of the value of trees in the urban environment.Diunduh dari Sumber: 31/10/2012 .
88 .. HEDONIC PRICE FUNCTION However, the reader should be made aware of caveats pertaining to the values obtained from hedonic price functions. In particular, the resource values that are obtained directly from the estimated hedonic price function are subject to fairly restrictive assumptions.It may be necessary to employ additional information from multiple commodity markets relating to the resource under consideration. Overall, the resulting hedonic price will depend on the availability of market information pertaining to the resource, and the revelation of buyer and seller preferences through market behavior.Market data on property sales and characteristics are available through real estate services and municipal sources and can be readily linked with other secondary data sources.Despite these positives, a guarded interpretation of the estimated welfare changes is recommended. Estimation and interpretation of these measures can be complex and the data requirements demanding, and there is a need to control for many important socio-demographic characteristics.Diunduh dari Sumber: 31/10/2012 .
89 Hedonic Price Method - Value of Life.. Hedonic pricing methods have also been applied in the estimation ofeconomic damages associated with occupational health and safety risks and are becoming more widely accepted in the determination of personal injury awards in liability cases.Application in this branch of the hedonic valuation literature often refers to the “value of life” or the “hedonic value of life.” Clearly, there is no such thing as a unique value of life. Consequently, meaningful estimates of the hedonic value of life vary according to the specific context under consideration.For one, it must be made clear whose value is under consideration: Is it a worker who understands and accepts a health/safety risk, or is it a passer-by who is unaware of the risk but nevertheless is predisposed to some adverse health impacts?Moreover, does the hedonic value under consideration concern the prevention of adverse health consequences from a potential accident, or does it concern an after-the-fact compensation to be given to survivors of an accident?To better understand the significance of these questions, it is instructive to clarify the concepts that are involved by distinguishing between two basic hedonic damage values:the insurance value and the deterrence value.Diunduh dari Sumber: 31/10/2012 .
90 . Adapted from W. Kip Viscusi. 1990. “The Value of Life: Has Voodoo Economics Come to the Courts?” Journal of Forensic Economics 3(3):Consider a situation in which an ER worker faces a relatively small risk of losing his life, one that is equal to the average hazard posed by a typical job - an annual risk of death of 1 in 10,000 accidents. Assume that a hedonic wage study of risk preferences across ER workers is undertaken thereby revealing that such workers are willing to accept an annual wage premium (or income compensation) of $500 in order to face this risk of death. Together, the presence of the health risk and the hedonic value estimate of the required wage offset establish the “risk-dollar tradeoff” for the typical worker. In other words, they establish a price for bearing human health risk. In this example, $500 compensation for each risk of 1/10,000 of death implies a total compensation level per statistical death of $5 million.Assume next that risk mitigation measures are taken that effectively reduce the chances of an accident by one-half, consistent with an ALARA-calibrated risk involving the potential death of 1 in 20,000 accidents (or what is equivalent to 0.5 in 10,000). Assuming that workers risk preferences remain unchanged as reflected by the $500 wage offset, the compensation level per statistical death would also be reduced by one-half: from $5 million to $2.5 million.As a measure of deterrence value, this $2.5 million reflects the workers’ valuation of riskmitigating measures. In this way, hedonic value estimates concerning human health and safety would appear to have particular relevance in measuring the benefits of achieving ALARA-type standards.Diunduh dari Sumber: 31/10/2012 .
91 FACTOR INCOME METHOD…The factor income method is used as a means of valuation in applications where natural resources are used as inputs in the production of other goods and services.Accordingly, the resulting economic costs of production are an important source of information in applying the factor income approach. While the method of factor income is not as welldefined or widely referenced as the hedonic price or travel cost methodologies, it is recognized by the U.S. Department of Interior’s natural resource damage assessment regulations.There are several types of resources for which the factor income approach is potentially well-suited, including surface water and groundwater resources, forests, and commercial fisheries. Surface and groundwater resources may be inputs to irrigated agriculture, to manufacturing, or to privately owned municipal water systems.The products in these cases (agricultural crops, sawlogs, manufactured goods, and municipal water) may all have market prices. Similarly, commercial fishery resources (fish populations or stocks) are inputs to the production of a catch of saleable fish. A variation on this theme may be useful for valuing damages to water resources.Diunduh dari Sumber: 31/10/2012 .
92 …FACTOR INCOME APPROACH There are, however, potential problems in applying the factor income approach.First, a particular treatment option might not be the least-cost or optimal response on the part of the water-using entity.For example, it might be cheaper to change the production process, buy municipal water or otherwise obtain a different source of water, or make other changes to the equipment or materials used. In this case, changes in water treatment costs may overstate damages.Second, it is possible that other things may change, particularly price and output levels.These potential problems can complicate the analysis and require the researcher to obtain additional technical information concerning the supply and demand of the underlying resource or resource service.Diunduh dari Sumber: 31/10/2012 .
93 Nonmarket Valuation: Contingent Valuation… Contingent market analysis has estimated a wide variety of use and nonuse values.The most obvious way to measure nonmarket values is to ask people how much they would be willing to pay for the resource or avoid any damages that might be sustained by the resource. Alternatively, one could ask how much people would be willing to accept as compensation for damages to the resource.Measures obtained using this technique rely on people’s hypothetical willingness to pay rather than actual market-information on their behavior: hence, the term contingent valuation (CV).The contingent valuation method is a survey-based approach to the valuation of nonmarket goods and services. It uses questionnaires to elicit information about the preference-related value of the natural resource in question.The value is said to be contingent upon the existence of a hypothetical market as described in the survey put to respondents. In principle, contingent valuation could be used to estimate the economic value of almost anything.By default, it is the only method that holds the promise of measuring nonuse values since all other methods depend on observing actual behavior associated with the natural resource.Diunduh dari Sumber: 31/10/2012 .
94 Contingent valuation surveys … Contingent valuation surveys may be conducted as face-to-face interviews, telephone interviews, or mail surveys based on a randomly selected sample or stratified sample of individuals. Face-to-face interviews are the most expensive survey administration format, but they are generally considered the best, especially if visual material needs to be presented.The central goal of the survey is to generate data on respondents’ willingness to pay for (or willingness to accept) some program or plan that will impact their well-being.Each respondent is given information about a particular problem. Each is then presented with a hypothetical occurrence (e.g., specie endangerment) or a policy action that ensures against the disaster (e.g., species protection). Each respondent is asked how much he/she would be willing to pay either to avoid the negative occurrence or bring about the positive occurrence.The means of payment (i.e., the payment vehicle) can take on any number of different forms, including a direct tax, an income tax, or an access fee. The actual format may take the form of a direct question (“how much?”), a bidding procedure (a ranking of alternatives), or referenda votes. Using a referendum to elicit values is preferred because it is the one that people are most familiar with.Resulting data are then analyzed statistically and extrapolated to the population that the sample represents. These responses are gathered along with socio-demographic information and test statistics required to determine the consistency of responses and the sensitivity to scope.Diunduh dari Sumber: 31/10/2012 .
95 Wiley and Sons, Inc. New York, pp. 365-388.… Kopp, R. J., and V. K. Smith “Eagle Mine and Idarado.” In NaturalResource Damage: Law and Economics, K. M. Ward and J. W. Duffield (ed.), JohnWiley and Sons, Inc. New York, pp …The Eagle Mine case study (Kopp and Smith 1992) exemplifies how contingent valuation methods can be applied in resource damage assessments. Contingent valuation questions were presented in both an Eagle County and a statewide survey, to elicit respondents’ willingness to pay for the Eagle River cleanup. The Eagle County survey asked respondents about their willingness to make annual payments over 10 years to clean up 200 waste sites involving current legal action.Respondents were given brief descriptions of each site. The survey requested each respondent to perform two allocations: 1) specify from a schedule of percentages the percent of their total bid for all sites that they would like to assign to the seven sites, and 2) identify a most important site among these seven and the percentage of their bid they would like to have allocated to this one particular site. In addition, respondents were asked to allocate the percentages of their total bid (for cleanup of all 200 sites) that they associated with use and nonuse values.The table below details the results of the analysis. In the Eagle County survey, questions were designed so that the willingness to pay estimates included both use and nonuse values, but allowed for the disaggregation of water and nonwater-based values. In the survey of Colorado residents, no differentiation between water-based and nonwater-based values was possible, but an allocation between use and nonuse values was made. The table displays the mean estimates of annual willingness to pay derived from each survey. In the case of Eagle County residents, the analysts multiplied the annual mean willingness-to-pay estimates by growth of 6063 households, carried forward for 10 years, assuming a population growth of 2 percent, and then discounted back to 1985 at 10 percent. The analysts employed a similar aggregation procedure for the statewide estimates.Diunduh dari Sumber: 31/10/2012 .
96 … CONTINGENT VALUATION SURVEY QUESTIONNAIRE The quality of a contingent valuation survey questionnaire is sensitive to the amount of information that is known beforehand about the way people think about the underlying natural resource. Certainly, prior information on the ecological attributes or environmental qualities of a particular resource are critical factors in conducting a successful contingent valuation survey.The key point is that, while all the information necessary for assessing an individual’s value of the resource is collected in the survey, the analyst must also be able to identify a truly representative sample of well-informed respondents in order to allow extrapolation to the general subject population. Thus, information on who uses the resource and who knows about it is critical.An individuals total value curve for increments and decrements in the level of provision of an environmental good (after Bradford, 1972).Diunduh dari Sumber: 31/10/2012 .
97 CROSS-CUTTING METHODS … At the present time, there is considerable professional interest in natural resource valuations that are based on cross-cutting methods. These valuation techniques combine elements from market-based methods with pre-existing estimates of natural resource values based on either direct or indirect nonmarket valuation techniques.The interest in applying crosscutting techniques is motivated by the relative simplicity of using a preexisting study based on an accepted method, as well as the cost considerations in undertaking a fresh natural resource valuation study.Two cross-cutting resource valuation techniques that have gained increased professional attention due to their simplicity and economy of application are discussed here: benefit transfer and unit day value.Conceptual model of winegrowing impacts on ecosystem services.Diunduh dari Sumber: /11/2012 .
98 Benefit Transfer …Benefit transfer is the use of the estimated values or demand relationship in existing studies to evaluate a site or event for which no site-specific study is available. Given the expense and time associated with the estimation of values of nonmarket natural resources and services, benefit transfer may be a reasonable method by which to determine such values under well-defined conditions.The analyst should consider all available estimates at the onset of the study. Each estimate should be evaluated by comparing the methodology and results of the original studies that may have been undertaken in selecting one that best matches the policy study under consideration.The following criteria have proved to be potentially useful in making this determination:Purpose of original value estimatesUser group(s) consideredNature of substitutes in the initial study areaGeographic areaDemographic and socio-economic characteristicsBaseline conditionsSpecific or unique problem that may be influenced by the magnitude of the estimatesGeneral attitudes, perceptions, or levels of knowledgeOmitted variables described above.Diunduh dari Sumber: 31/10/2012 .
99 Ulibarri, C. A. and S. Ghosh. 1995. “Benefit-Transfer Valuation of Ecological Resources.” Pacific Northwest National Laboratory, Richland,Washington; and Rowe et al “An Experiment on the Economic Value ofVisibility.” Journal of Environmental Economics and Management, …Ulibarri and Ghosh (1995) provide a willingness-to-pay estimate to reduce high particulate matter (PM ) levels using the benefit-transfer method. Their application focuses on willingness-to-pay estimates for improved visibility in Benton-Franklin Counties in eastern Washington state. The authors’ estimates are based on key parameter values derived by Rowe et al. (1980) using a CV survey instrument.In using the Rowe et al. parameter estimates, the authors note that their commodity specification (quality of visibility) is similar to the one evaluated by Rowe et al. However, to capture the aesthetic realities of the study site, the authors obtained daily observations of PM levels over the period from the Benton-Franklin County Clean Air Authority.In addition, the authors adjusted the various independent variables identified in Rowe et al. using county-level census data on the urban/rural population, age distribution, ethnicity and gender, and the levels of household income.Upon making these adjustments, the authors found a measure of the collective willingness to pay across 54,000 household in the Benton-Franklin area of approximately $364,395 per exceedance day, i.e., a day on which PM levels equal or exceed 150 micrograms per meter, the safe minimum standards under the Environmental Protection Agency’s National Ambient Air Quality Standards.Diunduh dari Sumber: 31/10/2012 .
100 Unit Day Value Method …The unit day value method is similar to the benefit transfer method, except that an average value is derived based on multiple value estimates from existing studies. Consequently, the unit day value of the underlying resource reflects a resource having average preference-related attributes, amenities, or qualities.Any of the valuation approaches described above can potentially serve as underlying studies from which unit day values are drawn. The application of the unit day value method may also involve groups of experts attempting to interpret from the existing set of estimates (regardless of method used in the original study) a best estimate for each of a set of generic types of environmental resources or activities.The unit day value approach then combines and converts these estimates into a standardized unit of measure that reflects the average value of one unit of the resource on a per-day basis.Diunduh dari Sumber: 31/10/2012 .
101 ECOLOGICAL VALUATION … The conventional natural resource valuation techniques described above have made little progress in providing a framework to assess the monetary value derived from ecological functions.One reason is that ecological functions are often overlooked in terms of providing preferencerelated value to humans. Thus, the state of the art in natural resource valuation is in search of a framework for addressing natural resource values derived from ecological functions.The emerging field of ecological economics.It then considers gross primary energy valuation and non-glamorous resource valuation, which are two approaches to measure ecological values in the emerging field of ecological economics.Valuing Ecosystem Goods and ServicesThe importance (or ‘value’) of ecosystems is roughly divided into three types: ecological, socio-cultural and economic value. It is reasoned here that the concept of ecosystem goods and services is inherently anthropocentric: it is the presence of human beings as valuing agents that enables the translation of basic ecological structures and processes into value-laden entities.Diunduh dari Sumber: /11/2012 .
102 ECOLOGICAL ECONOMICS… Although controversial, some resource valuation professionals believe that changes in the service flows from ecological systems to human society can be valued in monetary terms, given existing knowledge, scientific data, and estimation techniques.They believe that this would bring such services into management discussions in terms symmetric with marketed goods and services. As a general matter, this could improve the efficiency with which society uses resources.One reason for this view is the belief that such pricing would encourage preservation by making explicit the opportunity cost of development and other economic activities.These people support the continued refinement and extensions of economic valuation techniques based on people’s preferences over ecological resources.Diunduh dari Sumber: 31/10/2012 .
103 VALUASI ENERGI PRIMER (PRODUKSI PRIMER) BRUTO Gross Primary Energy ValuationThis procedure has been applied to the valuation of different wetland types (Constanza et al. 1989). It is argued that estimates of gross primary production have merit since the entire food chain depends upon this primary production.The methodology is not without its problems, however. For instance, it is not well understood whether those species supported by a particular food chain have equal social values. In general, the embodied energy approach measures only ecologically based values.Unlike an economic valuation approach, values for such functions and services as storm protection, aesthetics, and water treatment are completely ignored.PRODUKSI PRIMERPlants produce plant matter from soil nutrients, water and carbon dioxide, using the energy of light. It is called primary production. The diagram shows the carbon flows (is equal to energy flows).Diunduh dari Sumber: 3/10/2012 .Diunduh dari Sumber: 31/10/2012 .
104 VALUASI SUMBERDAYA EKOLOGI The need for a framework addressing the value of ecological functions is particularly acute in assessing policy choices that affect the integrity of ecological systems.Using the example of wind-blown dust, Ulibarri and Ghosh (1995) suggest that these policy decisions require a weighting of ecological values based on two related subsets of information: what is valued by humans as an eco-good (i.e., cleaner air) and what has intrinsic value to the natural eco-system (i.e., vegetative cover).Using the term ecological resources, the authors focused attention on resource services that are functionally important to ecosystems but frequently overlooked in terms of providing value to humans.Such resources have received very little attention relative to their more glamorous cousins, such as endangered salmon runs or old-growth timber stands.Diunduh dari Sumber: 31/10/2012 .
105 VALUASI SUMBERDAYA EKOLOGI The preliminary work undertaken by Scott et al. (1997) considered social values associated with undeveloped shrub-steppe sites; these are arid environs which are traditionally overlooked in land-use decisions.Relative to the perceived values, the authors attempted applications of the benefit transfer method, the travel cost method, and the method of hedonic damage-pricing. In order to estimate the intrinsic values of natural ecosystems, they applied a replacement cost methodology based on the idea of replacing the functions performed by the natural ecosystem through a human engineered analog.Using these cross-cutting resource valuation techniques, the authors maintained that the economic value of shrub-steppe sites reflects both their ecological services and recreational uses.Given the uncertainty that exists as to the social benefits from preserving undeveloped shrub-steppe, they suggest the need for further analysis in order to establish credibility in ecological site valuations.Diunduh dari Sumber: 31/10/2012 .
106 issues in the valuation of natural resources and the environment: UNRESOLVED ISSUES…The following discussion focuses on a series of distinct and challengingissues in the valuation of natural resources and the environment:The choice of a discount rate in assessing the present and future values of benefits and costs;The individual’s time-preference in deriving benefits over the near term as opposed to later on;The role of equity and fairness in resource valuations involving present and future generations;The conceptual understanding of risk and uncertainty in the valuation of natural resources and the environment; and e) qualification of the measurement errors in the application of the natural resource valuation techniques discussed in this handbook.Without identifying the potential importance of these factors in the valuation process, the analysis of natural resource values will remain incomplete.Diunduh dari Sumber: 31/10/2012 .
107 Discounting and Time Preference Discount rates enable one to determine the present value of the benefits and costs associated with the future use and enjoyment of natural resources. If the analyst of future benefits and costs sets a high discount rate, say 10 percent, the present value of benefits in the distant future becomes insignificant when compared with the present value of benefits in the near-term future.For example, using continuous discounting at the rate of 10 percent, the present value of $1000 of benefits obtained 2 years in the future is $818.73, and in 10 years becomes $367.88, less than half as much. By choosing a lower discount rate, say 2 percent, the analyst reduces this temporal bias: $1000 of benefits 10 years hence becomes $Given the implications of this basic arithmetic on natural resource valuations, it is no wonder there is so much controversy among economists, scientists, and policy makers over the applications of appropriate discount rates.Diunduh dari Sumber: 31/10/2012 .
108 EQUITY AND FAIRNESSThe valuation of natural and environmental resources under ethicalcriteria diverges sharply from that of the conventional utilitarianapproach. Land or water values provide some perspective on this.Assume, for example, that a tract of land is privately owned. Its market price reflects the private benefits that it can provide. If we assume there exists a well-specified system of property rights over the parcel of land, individual self-interest would lead to a negotiated settlement over the rights to buy or lease the land according to the marginal values of the land in its various alternative uses. It would be in the owner’s self-interest to ensure that the land would be allocated to those uses which command highest value before considering other uses which have lower marginalvalues.This typifies economically efficient resource allocations, whereby relatively lower-valued uses are effectively excluded from consideration. It makes no difference if the land were under public stewardship, because a similar means of allocation could be achieved by administering an auction for land-use rights, thereby ensuring that the land was used where it commanded highest value.Diunduh dari Sumber: 31/10/2012 .
109 RISIKO & KETIDAK-PASTIAN… Natural resource and environmental valuation is difficult, even when there is relative certainty over prevailing economic and environmental conditions. In the “real world,” analysts must confront risky outcomes in proposing environmental decisions or taking regulatory actions under conditions of uncertainty about the benefits and costs of these actions.Consequently, the notions of risk and uncertainty are related: risk relates to recurring events whose relative frequencies are known from past experience, while uncertainty relates to unique events whose probabilities can only be subjectively estimated.Uncertainty over the outcomes of environmental actions and policies can influence the valuation of natural and environmental resources. For instance, can we say with certainty that the decontamination of DOE land will increase property values? If not, the analyst may need to introduce probability beliefs into the valuation process.The presence of risk and uncertainty affects both willingness to pay or willingness to accept compensation, with the extent of each depending on the degree of economic and environmental uncertainty confronting individuals and on their attitudes towards risk and uncertainty.Together, risk and uncertainty affect the valuation of natural and environmental resources and are commonly examined by the analyst based on extensions of the uncertainty affect the valuation of natural and environmental resources.Diunduh dari Sumber: 31/10/2012 .
110 MARGIN OF ERROR: AN ORDER OF MAGNITUDE? The foregoing discussion points out that monetary valuations involvingnatural resources, human health, and the environment are fraught withmany difficulties.These difficulties are not in the economic theory, butrather the application of relatively new valuation techniques.Manypractitioners would agree that considerable progress has been made in the application of the techniques described in this handbook — an empirical claim that can only be validated through further applications and comparative analyses. However, in view of the uniqueness of circumstances surrounding each application and study site, it may be inappropriate to compare the estimated values from one study to another.For this reason, researchers have attempted to differentiate between the systematic biases in estimated values — ones which can be explained by site or sample characteristics — and their “purely random” counterparts.To illustrate, we consider the “margin of error” in value of life estimations investigated by Miller (1990).Diunduh dari Sumber: 31/10/2012 .
111 NILAI EKONOMI TOTALSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
112 LAYANAN (JASA-JASA) EKOSISTEM Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
113 JASA-JASA PEMBEKALAN (provisioning services) Ecosystem servicesDirect market pricingFactor IncomeAvoided CostReplacement costMitigation & restoration CostTravel CostContingent ValuationBenefit transferTEVTotalProvisioning services18.104.22.168.141.7Regulating services22.214.171.124.413.624.4Supporting services4.611.4Cultural services126.96.36.1994.1Sum of all services38.28.426.3188.8.131.52.738.58.931.24.3100.0Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China OctoberMethodologies for Economic Valuation of Drylands (J. Schild, Global Mechanism, 2010)
114 KISARAN NILAI YG SANGAT BESAR Ecosystem servicesNo. of data entriesAverage monetary valueMonetary value rangeMinimumMaximumProvisioning1373 71112931 653Regulating857 9916638 776Supporting421 3561607 890Cultural531 5050.3210 209All services31714 56335588 527TEV294 1556333 195Total (TEV + all services)34618 718418Price per hectare per year (USD 2007)Based on 346 data entriesSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China OctoberMethodologies for Economic Valuation of Drylands (J. Schild, Global Mechanism, 2010)
115 NILAI EKONOMI TOTALSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
116 ADAKAH HARGA KESETIMBANGAN UNTUK ASET-ASET ALAMI? Kurva SuplaiKESETIMBANGANKurva PermintaanKuantitas KeseimbanganKuantitasSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
117 Land ecosystem services Ecosystem services should be compensatedMore transparency on opportunities and trade-offsBetter estimation of valuesCharge/benefit transfer mechanismsIncentives to cooperateEnabling conditionsAdvocacyPolitical willSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
118 Sustainable land management : SLM What drives decisions to use/manage natural resources responsibly and sustainably?Why are the economic benefits of SLM not recognised? Benefits of SLM are often difficult to specify Several of these benefits have a public goods character and/or are not traded in a market Often a mismatch between the stakeholders that pay the (opportunity) costs of maintaining an environmental benefit (e.g. by not converting a forest to cropland) and the beneficiaries of that benefit (e.g. downstream water users benefiting from the regulation of water flows).identification of incentives for SLM mobilization of financial mechanismsSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
119 MEMAHAMI HAL YANG TIDAK DIHARAPKAN Some of the costs of land degradation and benefits of SLM can be unexpected but of great significanceFor example, agricultural lands are the source of 30% of GHG emissions, whilst conversely soils have the potential to be a major ‘sink’ for carbon sequestrationEven remote impoverished drylands and fragile ecosystems may be endowed with substantial natural wealth (e.g. Salar de Uyuni in Bolivia: the 10,000 sq km high-altitude salt flat stores more than half of the world’s supply of lithium, but is also a tourist attraction and a natural habitat for many species)difficult choices and tradeoffsSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
120 EVL: supporting decision making Reveal the economic costs and benefits of land use conversion, or of different types of land managementShow the interests of different groups of stakeholders in land and ecosystem management, thereby providing a basis for conflict resolution and integrated, participatory planning of resource managementCalculation of economic efficient land management optionsProvide the basis for setting up Payment for Ecosystem Services type of schemes, for allocating funds from the beneficiaries of ecosystem services to the providers of these servicesSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
121 . Land Quality Indicators for Sustainable Land Management: Yield Gap P.S. Bindraban, D.M. Jansen, J. Vlaming, J.J.R. GrootActual yield is a function of biophysical as well as the socio-economic conditions.Levels of production and required data for its assessment. (Modified from Rabbinge, 1993)Sumber: /11/2012 .
122 The Economics of Ecosystems and Biodiversity (TEEB) Quantification of global economic benefits of biodiversityCosts of biodiversity loss, ecosystem degradation and declines in ecosystem servicesSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
123 INISIATIF LAINNYA YANG RELEVAN Natural Capital Project (WWF, Stanford)Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST)Development of natural capital databaseLand Degradation Assessment in Drylands (LADA)Development of global indicators for land degradationUse of Sustainable Livelihoods FrameworkGlobal baseline for future monitoringHein & de GrootPartial valuation concept focussing on a small number of ecosystem services providing the bulk of benefitsGlobal Methodology for Mapping Human Impacts on the Biosphere (GLOBIO)Analysis of changes in land use and its impact on ecosystem servicesDynamic Integrated Model of Climate and the Economy (DICE)Estimated value on the negative effects of global warming in a number of crucial areas such as agricultureSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
124 INISIATIF LAINNYA YANG RELEVAN OECD Driver-Pressure-State-Impact-Response (DPSIR) FrameworkDevelopment of DPSIR Framework for land degradationOther relevant models:Landscape Ecological Decision & Evaluation Support System (LEDESS)Conversion of Land Use and its Effects (CLUE)Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
125 KAJIAN-KAJIAN SEBELUMNYA Studies on the costs of land degradation (GM, Berry et al., 2003)7 country case studies showed 3 – 7 % loss of agricultural GDP due to land degradationInvestment required in remedial action an order of magnitude smaller than the estimated costs to the national economyStudies on ‘costs of inaction’ (WB, Rydén, 2005)25% increase in number of hungry people in Africa south of the Sahara due to land degradation and agricultural yield changes between 2000 – 2010Economic returns in success stories (GM, Reij & Steeds, 2003)30 % in irrigation, Mali20 % in soil and water conservation, NigerMore than 20% in forestry, Ethiopia12 % in forestry, TanzaniaOver 40% small-scale irrigation in northern Nigeria & Komadougou valley, NigerSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
126 TERPADU DAN DINAMIKMultidimensional - modular approach integrating different methodologiesMultilevel approachTop-down aggregated economic analysisNational-level sectoral economic impact assessmentSub-national local case studiesAssessment of aspects of the relation between land resources and economic developmentSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
127 KOMPREHENSIF & TER-SEKALA Applicable to:Different spatial scales (local, national, regional, global)Specific study objectivesTotal Economic Value:Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
128 IMPLEMENTASI BERTAHAP 1) Scoping:Identification of scope, location, spatial scale and strategic focus based on stakeholder consultationPreparation of background information on socio-economic and environmental context2) Assessment of land cover type:Assessment of quantity, spatial distribution & ecological characteristics of land coverMethod (national level): GIS analysis with categorization by agro-ecological zones (governments, FAO)Method (local level): participatory GIS, supplemented with CLUE or LEDESS modelSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
129 IMPLEMENTASI BERTAHAP 3) Analysis of ecosystem services:Analysis of stocks and flows for each land cover category based on 4-fold categories of ecosystem services (MA)Expert judgement and stakeholder consultation on suitable methodologyMethod: Choice from common valuation techniques, including list of indicators for ecosystem services and their calculationSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
130 IMPLEMENTASI BERTAHAP 4.) Economic significance of study area:Analysis of role of ecosystem services in community livelihoods (local) and overall economic development (national)Method (local): Secondary statistics & field researchMethod (macro-economic): National accounting frameworks5.) Assessment of land degradation:Identification of patterns, pressures, spatial distribution, causes, driving forcesAnalysis of future risks & vulnerabilitiesAssessment of ‘costs of inaction’Method: GIS analysis including defined set of degradation drivers6.) Sustainable Land Management:Analysis of options for reducing/removing degradation pressures, including their economic viability and suitable locationsMethod: GIS analysis, perhaps supplemented by models as LEDESS or CLUESumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
131 EKONOMI SUMBERDAYA LAHAN Nilai lahanRationale – why shall we care about the value of landMethodologies – which models are currently availableApproach – is there a cost-effective integrated approachCountry case studies – where is being appliedSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
132 KAJIAN-KAJIAN NEGARA : Cambodia Ministry of Agriculture, Forestry and Fisheries (MAFF)Economic Valuation Study (EVS) of land resources in Cardamom MountainsCapacity building at national level to undertake future valuationsIntegration of study results into national development planning processesIdentification of specific financial opportunities for scaling up SLM investmentsEconomic valuation approach:Assessment of the inherent value of Cambodia’s land resourcesAssessment of the costs of land degradationAnalysis of future risks and vulnerabilitiesAssessment of the costs of inactionIdentification and assessment of SLM optionsPolicy dialogue with key stakeholdersSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
133 KAJIAN-KAJIAN DI NEGARA : Tanzania The Relationships among Sustainable Development, Sustainable Land Management, Sustainable Agriculture, and Sustainable Soil Management. (Redrawn from Dumanski 1997)Vice President OfficeEconomic Valuation Study (EVS) of land resourcesCapacity building at national level to undertake future valuationsIntegration of study results into national development planning processesIdentification of specific financial opportunities for scaling up SLM investmentsEconomic valuation approachSumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China OctoberSumber: . 2/11/2012
134 KAJIAN-KAJIAN DI NEGARA : Zambia Ministry of Tourism, Environment and Natural Resources (MTENR)Zambia Development Agency (ZDA) – Environmental Council of Zambia (ECZ)Macro-economic valuation of land in most affected regionsCapacity building at national level to undertake future valuationsIntegration of economic valuation programme into 6th National Development PlanIdentification of mechanisms and incentives for scaling up SLM investmentsApproach (same as above)Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini. Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China October
136 Fixed supply of land (to all uses) The supply of land to all uses is fixedOwners receive economic rent
137 Land supply to a given use The supply of land to a given use is upward slopingLand is shifted to its most valuable use (subject to restrictions in zoning laws, etc.)The economic suitability of a land area for a land use ( Barlowe, 1986, land use capacity) is the predicted net economic benefit to a specified party (e.g., landowner, land user, society) to be expected if the land area is dedicated to the use.The economic value of a land use system implemented on a given land area is not synonymous with the market value of the land area (land evaluation) although the predicted return to a land unit of various land uses obviously influences its price.(In fact, the price should be at least the greatest Net Present Value of the possible land uses).
138 Renewable and Non-renewable resources Nonrenewable resources (also known as exhaustible resources) have a finite supply that is depleted as the resource is consumedRenewable resources – can be replenished by producersEconomic suitability of land depends on three types of factors:The in-situ resource quality, i.e. the response of the land to the use without regard to its location (Ricardo). Example: predicted crop yield.The accessibility, and by extension, all costs and benefits associated with the specific location as opposed to the resource quality (von Thünen). Classic example: transportation costs for inputs and products.Other spatial attributes of the site, not including accessibility, for example, size, shape, adjacency, and contiguity. Example: more efficient field work if the parcel is the correct shape and size.
139 Price of a nonrenewable resource over time Price changes over time for nonrenewable resource:Owner may sell a unit today or sell it later at a higher priceOwner supplies more today if the expected rate of price increase is less than the interest rate:leads to lower price today and higher price laterOwner supplies less today if the expected rate of price increase exceeds the interest rate:leads to higher price today and lower price laterIn equilibrium – rate of price change = interest rate
141 This is often referred to as “willingness to pay.” NILAI EKONOMI LAHANEconomic value is one of many possible ways to define and measure value. Although other types of value are often important, economic values are useful to consider when making economic choices – choices that involve tradeoffs in allocating resources.\Measures of economic value are based on what people want – their preferences. Economists generally assume that individuals, not the government, are the best judges of what they want. Thus, the theory of economic valuation is based on individual preferences and choices. People express their preferences through the choices and tradeoffs that they make, given certain constraints, such as those on income or available time. The economic value of a particular item, or good, for example a loaf of bread, is measured by the maximum amount of other things that a person is willing to give up to have that loaf of bread. If we simplify our example “economy” so that the person only has two goods to choose from, bread and pasta, the value of a loaf of bread would be measured by the most pasta that the person is willing to give up to have one more loaf of bread. Thus, economic value is measured by the most someone is willing to give up in other goods and services in order to obtain a good, service, or state of the world. In a market economy, dollars (or some other currency) are a universally accepted measure of economic value, because the number of dollars that a person is willing to pay for something tells how much of all other goods and services they are willing to give up to get that item.This is often referred to as “willingness to pay.” Diunduh dari Sumber: 31/10/2012 .
142 NILAI EKONOMI LAHANIn general, when the price of a good increases, people will purchase less of that good. This is referred to as the law of demand—people demand less of something when it is more expensive (assuming prices of other goods and peoples’ incomes have not changed). By relating the quantity demanded and the price of a good, we can estimate the demand function for that good. From this, we can draw the demand curve, the graphical representation of the demand function.It is often incorrectly assumed that a good’s market price measures its economic value. However, the market price only tells us the minimum amount that people who buy the good are willing to pay for it. When people purchase a marketed good, they compare the amount they would be willing to pay for that good with its market price. They will only purchase the good if their willingness to pay is equal to or greater than the price. Many people are actually willing to pay more than the market price for a good, and thus their values exceed the market price.In order to make resource allocation decisions based on economic values, what we really want to measure is the net economic benefit from a good or service. For individuals, this is measured by the amount that people are willing to pay, beyond what they actually pay. Thus, two goods that sell for the same price may have different net benefits. For example, I may have a choice between wheat and multi-grain bread, which both sell for $2.00 per loaf. Because I prefer multi-grain, I am willing to pay up to $3.00 for a loaf. However, I would only pay $2.50 at the most for the wheat bread. Therefore, the net economic benefit I receive for the multi-grain bread is $1.00, and for the wheat bread is only $.50. The economic benefit to individuals is often measured by consumer surplus. This is graphically represented by the area under the demand curve for a good, above its price. Diunduh dari Sumber: 31/10/2012 .
143 SURPLUS KONSUMEN LAHAN The economic benefit to individuals, or consumer surplus, received from a good will change if its price or quality changes. For example, if the price of a good increases, but people’s willingness to pay remains the same, the benefit received (maximum willingness to pay minus price) will be less than before. If the quality of a good increases, but price remains the same, people’s willingness to pay may increase and thus the benefit received will also increase.KURVA PERMINTAANHargaSURPLUS KONSUMENHarga PasarKuantitasDiunduh dari Sumber: /10/2012 .
144 NILAI EKONOMI – HARGA LAHAN Economic values are also affected by the changes in price or quality of substitute goods or complementary goods . If the price of a substitute good changes, the economic value for the good in question will change in the same direction. For example, wheat bread is a close substitute for multi-grain bread. So, if the price of multi-grain bread goes up, while the price of wheat bread remains the same, some people will switch, or substitute, from multi-grain to wheat bread. Therefore, more wheat bread is demanded and its demand function shifts upward, making the area under it, the consumer surplus, greater.Similarly, if the price of a complementary good, one that is purchased in conjunction with the good in question, changes, the economic benefit from the good will change in the opposite direction. For example, if the price of butter increases, people may buy less of both bread and butter. If less bread is demanded, then the demand function shifts downward, and the area under it, the consumer surplus, decreases.Producers of goods also receive economic benefits, based on the profits they make when selling the good. Economic benefits to producers are measured by producer surplus, the area above the supply curve and below the market price. The supply function tells how many units of a good producers are willing to produce and sell at a given price. The supply curve is the graphical representation of the supply function. Because producers would like to sell more at higher prices, the supply curve slopes upward. If producers receive a higher price than the minimum price they would sell their output for, they receive a benefit from the sale—the producer surplus. Thus, benefits to producers are similar to benefits to consumers, because they measure the gains to the producer from receiving a price higher than the price they would have been willing to sell the good for.Diunduh dari Sumber: /10/2012 .
145 MANFAAT EKONOMI DARI LAHAN When measuring economic benefits of a policy or initiative that affects an ecosystem, economists measure the total net economic benefit. This is the sum of consumer surplus plus producer surplus, less any costs associated with the policy or initiative.Kurva Suplai danSurplus ProdusenHargaSurplus ProdusenHarga PasarKuantitasDiunduh dari Sumber: /10/2012 .
146 EKONOMI MLAHANLand Economics In a market economy, most of the urban land can be freely sold or purchased. Thus land economics are concerned about how the price of urban land is established and how this price will influence the nature, pattern and distribution of land uses. The above figure provides some basic relationships between the quantity of land and its price and assumes that there is a free land market. This market mechanism follows the standard relationship between supply and demand, where an equilibrium price is reached. A quantity of land Q1 would be available at a price of P1. However, what is particular to cities is that the supply is fixed since there is a limited amount of available land. When land is reasonably available (Q1), the price (P1) will be moderate.Moving towards the downtown the demand rises, land becomes scarcer (Q2) and its price goes up (P2).Moving towards the periphery, more land is available, demand drops (Q3), and so does the price (P3).Not every type of activities is willing to pay a price P1. Some may even need a price lower than P3. High land values impose a more intensive usage of space so a higher number of activities can benefit from a central location. The logic behind the construction of skyscrapers is therefore obvious and takes place at optimal locations of competition for land. Different type of activities, each having their own land use, are willing to pay different rents.Diunduh dari Sumber: 31/10/2012 .
147 SOIL EVALUATION THE ROLE OF SOIL SCIENCE IN LAND EVALUATION… A review has been made on the concepts and the methodology of land evaluation.The results of several evaluation methods have been compared, applying them to a selection of diverse soils. Although the studies on land evaluation have been conducted on a broad diversity of characteristics—not only physical but also social, economic and political—in practice, it is frequent to limit such studies to the physical medium, given the heterogeneity of these projects.Land evaluation requires a team of multidisciplinary evaluators.The difficulty of forming these teams makes it common for such studies on land evaluation to be reduced to the analysis of the physical medium of the soil, creating a certain confusion. Therefore, we propose using the term “soil evaluation” for the assessment of the soil properties as a phase prior to land evaluation, considering soil properties in their broader sense, both the intrinsic ones (those of the soil itself: depth, texture, etc.) as well as the extrinsic ones (the soil surface: topography, climate, hydrology, vegetation, use, etc.).Soil evaluation would be similar to what today is understood as land evaluation, but excluding all the social, economic and political characteristics which would be covered under the concept of “land evaluation.”Diunduh dari Sumber: 31/10/2012 .
148 Environmental indicators of the degree of suitability of soils for agricultural use.… Very favourableFavourableUnfavourableVery unfavourableIntrinsic propertiesEffective depth, cm>120120-7070-30<30Texturebalancedmoderate heavyheavylightCourse fragments, %<1010-3030-60>60Structuref, md, 3, 2c, 1sg, 0ms, 0Compact, cemen, gr, cmAbsentmd, >60md, >20 or st, >60st, < 30Available water, mm>100100-6060-20<20Internal drainageWithout hydroHydro > 80 cmHydro > 40 cmHydro a 0 cmPermeability, cm/hour>22-0.5<0.1Organic matter, %>55-22-1<1CEC, cmol(+)kg-1>4040-2020-10Saturation degree, %>7575-5050-25<25pHoror<4.5 or >9.0Carbonates, %<77-1515-25>25Salinity, dSm-1<22-66-12>12Extrinsic propertiesSlope, %<44-1010-25Surface stoniness,%2-20>50Surface rockiness, %Flooding, months1-3>3Erosion, Tm/ha/year10-2020-60Ploughingno problemslimitedseverevery severePrecipitation, mm>1000<300Frost, Tª<0º, months3-6>6Diunduh dari Sumber: 31/10/2012 .
149 Comparisons between the classes defined by the soil-evaluation systems. LCC, Land Capability Classification; Si, Storie Index; RPI, Riquier Productivity Index; FK, FAO Framework.LCCSIRPIFKIntensive soil cultivationI1P1S1Moderate soil cultivationII2P2S2Limited soil cultivationIII3P3Occasional soil cultivationIV4S3GrazingV, VI5P4NForestryVII6P5Natural reservesVIIIDiunduh dari Sumber: 31/10/2012 .
150 Diunduh dari Sumber: .................... 31/10/2012 . … Storie Index (1933).This represents the first parametric approach that was developed. It is an index that uses the multiplicative scheme. In addition, it uses intrinsic properties of the soils (genetic profile, parent material, profile depth, texture, drainage, nutrients, acidity an alkalinity), characteristics of the soil surface (slope and microrelief) and aspects of soil conservation (degree of erosion). The evaluation properties are grouped into four factors that are quantified in the corresponding tables. The factors are weighed a priori, the more important being related on a scale from 5 to 100 and the less important factors from 80 to 100.With this index, general agricultural soil uses can be evaluated (hence it is a soil-capability evaluation method). To formulate the index, the four factors are multiplied together and the index is expressed as a percentage. Six classes are defined at the degree level, with decreasing values from 1 to 6.The degrees 1 to 3 are for agricultural use, degree 4 for very limited agricultural use, 5 for pasture and 6 without use. Subdegrees are established according to limiting factors: “s” for depth, “p” for permeability, “x” for texture, “t “ slope, “d” for drainage and “a” for salts.It is important to emphasize that this system does not consider climatic characteristics. Thus the evaluation is of the soil itself, valid for comparing the soils of a certain region with the same type of climate.This evaluation index was developed for California, and thus application to other regions of the world has involved numerous modifications (in Canada by Bowser, 1940; in India by Shome and Raychaudhuri, 1960; in tropical countries by Sys and Frankart, 1972; in arid regions by Sys and Verheye, 1974).Diunduh dari Sumber: /10/2012 .
151 Land Capability Classification. … This method was established by the Soil Conservation Service de USA according to the system proposed by Klingebiel and Montgomery (1961) and has been widely used throughout the world with numerous adaptations. It is a categorical system that uses qualitative criteria.The inclusion of a soil within a class is made in the inverse manner—that is, without directly analysing its capacity, but rather its degree of limitation with respect to a parameter according to a concrete use. Some factors that restrict soil use can be used to define the productive capacity (intrinsic: soil depth, texture, structure, permeability, rockiness, salinity, soil management; extrinsic: temperature and rainfall) and yield loss (slope of the terrain and degree of erosion). Five systems of permanent agricultural exploitation are considered: permanent soil cultivation, occasional soil cultivation, pasture, woods and natural reserves. This system seeks maximum production with minimum losses in potential.Depending on the type of limitation, various subclasses of capacity are established: e, for erosion risks; w, for wetness and drainage; s, for rooting and tillage limitations resulting from shallowness, drought risk, stoniness, or salinity; c, for climatic limitations. The capability units represent similar proposals of use and management. Diunduh dari Sumber: 31/10/2012 .
152 Productivity index of Riquier et al. (FAO, 1970). The basic concept of this method is that agricultural-soil productivity, under optimal management conditions, depends on the intrinsic characteristics. This is a multiplicative parametric method to evaluate soil productivity, from a scheme similar to the Storie index. The concept of productivity is defined as the capacity to produce a certain quantity of harvest per hectare per year, expressed as a percentage of optimal productivity, which would provide a suitable soil in its first year of cultivation. The introduction of improvement practices leads to a potential productivity or potentiality. The quotient between the productivity and the potentiality is called the improvement coefficient. The evaluation is made for three general types of use: agricultural crops, cultivation of shallow-rooted plants (pastures), and deep-rooted plants (fruit trees and forestation). The determining factors of soil depth are: wetness, drainage, effective depth, texture/structure, base saturation of the adsorbent complex, soluble-salt concentration, organic matter, cation-exchange capacity/nature of the clay and mineral reserves. The parameters of the soil surface (e.g., slope, erosion, flood tendency, or climate) are not considered The different parameters are evaluated in tables and, as also occurs in the Storie index, the evaluation factors present different weights.Productivity is expressed as the product of all these factors expressed in percentages. Five productivity classes are defined: class P1 = excellent; class P2 = good, valid for all types of agricultural crops; class P3 = medium, for marginal agricultural use, suitable for non-fruiting trees; class P4 = poor, for pasture or forestation or recreation; class P5 = very poor or null, soils not adequate for any type of exploitation.Diunduh dari Sumber: /10/2012 .
153 Soil Fertility Capability Classification (FCC). … This was proposed by Buol et al., (1975) and modified by Sanchez et al. (1982) to evaluate soil fertility. In this system, three levels or categories were established.The first, the type, was determined by the texture of the arable layer, or of the first 20 cm, if this is thinner. Its denomination and range are: S, sandy (sandy and sandy loam); L, loams <35% clay (excluding sandy and sandy loam); C, clayey > 35% clay; O, organic > 30% organic matter to 50 cm or more.The type of substrate is the second level and is used when there is a significant textural change in the first 50 cm of the soil. It is expressed with the same letters, adding “R” when a rock or a hard layer is found within this depth.The third level is comprised of the modifiers, which are the chemical and physical parameters that negatively influence soil fertility. These are numerous and are represented by lower-case letters.In the denomination of the soil class, the principle limitations for use are directly represented. For example, for an Orthic Solonchak, the FCC class that represents it is LCds, which signifies that it is a soil susceptible to severe erosion (L), limited drainage (C), dry soil moisture regime (d) and with salinity (s).Diunduh dari Sumber: /10/2012 .
154 KERANGKA EVALUASI LAHAN The FAO Framework for Land Evaluation (1976). The FAO Framework for Land Evaluation (FAO 1976 and subsequent guidelines: for rainfed agriculture, 1983; forestry, 1984; irrigated agriculture, 1985; extensive grazing, 1991) is considered to be a standard reference system in land evaluation throughout the world (Dent and Young, 1981; van Diepen el al., 1991), and has been applied both in developed as well as developing countries. This framework is an approach, not a method. It is designed primarily to provide tools for the formulation of each concrete evaluation. The system is based on the following concepts:The land is qualified, not only the soil.Land suitability must be defined for a specific soil use (crop and management).Land evaluation was to take into account both the physical conditions as well as economic ones;The concept of land evaluation is essentially economic, social and political.The evaluation requires a comparison between two or more alternative kinds of use.The evaluation must propose a use that is sustainable.A multidisciplinary approach is required (Purnell, 1979; van Diepen et al., 1991).These limiting factors are used to define the third category of the system, which is the subclass. In the symbol of each subclass, the number of limitations involved should be kept to the minimum one letter, or, rarely, two. The limitations proposed include: t, slope; e, erosion risk; p, depth; s, salinity; d, drainage; c, bioclimatic deficiency; r, rockiness; i, flood risk.Diunduh dari Sumber: /10/2012 .
155 Evaluation of 30 soils by four methods of soil-capability evaluation. … Soil typeParent materialLCCSIRPIFK1 Typic CryosapristmicaschistIVsp4psP5fp-->(P3)S3sp2 Typic XerofluventalluvialII2P2S23 Typic XerofluventI1P1S14 Typic XeropsammentdolomiteVIIr3g-->(6)P5gS3r-->(N)5 Lithic XerorthentVIIs6dgP5dgNs6 Lithic XerorthentVIgr5dgrP5dg-->(P4)S3d-->(N)7 Typic Chromoxeretmarl3p-->(2)P2pS3-->(S2)8 Calcixerollic XerochreptIVd4dP3dS3d9 Calcixerollic XerochreptsandstoneVIg4gd-->(5)P5g-->(P4)S2-->(N)10 Calcixerollic XerochreptconglomerateIII3dP2-->(P3)LCC, Land Capability Classification; SI, Storie Index; RPI, Riquier Productivity Index; FK, FAO Framework.Limiting characteristics: e, erosion; d, depth; g, gravels; f, frozen; m, moisture; p, permeability or drainage or flooding; r, rocks or pebbles or stones; s, slope; t, texture or structure. In bold, the results that do not coincide with the evaluations of the other methods; in parenthesis the results that would correspond with the other methods. In bold and cursive, results that strongly differ from those of the other methods.Diunduh dari Sumber: 31/10/2012 .
156 Evaluation of 30 soils by four methods of soil-capability evaluation. … 11 Lithic XerochreptslateIIId-->(4)5dr-->(4)P3dS3d12 Lithic XerochreptgraniteIId3d-->(2)P2dtS213 Typic HumaqueptmicaschistVp5pP5p-->(P4)S3pf-->(N)14 Typic CryumbreptIIIs-->(IV)4s5fg-->(P3)S3sf15 Typic HaplumbertVIIs5sg-->(6)P5gfNs16 Vertic HaplargidandesiteVm2-->(5)P5m-->(P4)Nm17 Petrogypsic Gypsiorthidsilts, gypsumIVdg5dg-->(4)P4dg-->(P3)18 Lhitic HaploxerollconglomerateVIIrd6dP5dgNd19 Calcic Haploxeroll4dg-->(6)P2-->(P5)20 Typic HaploxerollsandstoneLCC, Land Capability Classification; SI, Storie Index; RPI, Riquier Productivity Index; FK, FAO Framework.Limiting characteristics: e, erosion; d, depth; g, gravels; f, frozen; m, moisture; p, permeability or drainage or flooding; r, rocks or pebbles or stones; s, slope; t, texture or structure. In bold, the results that do not coincide with the evaluations of the other methods; in parenthesis the results that would correspond with the other methods. In bold and cursive, results that strongly differ from those of the other methods.Diunduh dari Sumber: 31/10/2012 .
157 Evaluation of 30 soils by four methods of soil-capability evaluation. … 21 Typic HaploxerollmicaschistsVIIs6sP5gfNs22 Udic HaplustollserpentineIIId3dtP3dS223 Mollic HaploxeralflimestoneIVd4dS3d24 Typic HaploxeralfslateIIIe3eP2-->(P3)S3e25 Xerochreptic HaploxeralfIIIs3seP1-->(P3)S3se26 Typic RhodoxeralfconglomerateI1P1S127 Calcic RhodoxeralfIIg1-->(2)P1-->(P2)S2m28 Mollic PalexeralfIIIr3tP2t-->(P3)29 Typic Palexerult3r30 Typic PalexerultclaysIIes-->(III)P3tLCC, Land Capability Classification; SI, Storie Index; RPI, Riquier Productivity Index; FK, FAO Framework.Limiting characteristics: e, erosion; d, depth; g, gravels; f, frozen; m, moisture; p, permeability or drainage or flooding; r, rocks or pebbles or stones; s, slope; t, texture or structure. In bold, the results that do not coincide with the evaluations of the other methods; in parenthesis the results that would correspond with the other methods. In bold and cursive, results that strongly differ from those of the other methods.Diunduh dari Sumber: 31/10/2012 .
159 LAND ECONOMIC RENT = Sewa-ekonomi Lahan Definition of 'Economic Rent'The amount of money an owner of a factor of production must receive in order for that owner to rent out that factor of production. Factors of production include labor, capital and land.Sewa-ekonomi “lahan” adalah bagian pembayaran atas “lahan” yang melebihi dari pendapatan yang diterima dari pilihan terbaik penggunaan lahan yang mungkin dilakukan; dalam hal ini “lahan” dipandang mempunyai beberapa macam kegunaan.DETERMINATION OF LAND RENTChanges in the demand for land...SIf demand decreases...rent decreases.R1Land Rent (dollars)R2D1D2Acres of LandDiunduh dari Sumber: /11/2012 .
160 Diunduh dari Sumber: .................... 5/11/2012 . . SEWA-EKONOMI LAHAN - David RicardoEconomic rent on land is the value of the difference in productivity between a given piece of land and the poorest [and/or most distant], most costly piece of land producing the same goods (e.g. bushels of wheat) under the same conditions (of labour, capital, technology, etc.).Productivity is defined here in terms of both:The natural fertility of the soil; and the productivity of the existing technology in utilizing currently available labour and capital;The relative distance from the same market:We are discussing this in terms of regional economics with one market.This part of theorem, on the ‘distance from the market’, did not originate with Ricardo, but rather with a German economist: Johann Heinrich von Thünen ( ), who noted , some years after the publication of Ricardo’s Principles, that the closer a piece of land was to the urban core the higher was its market rent (reflecting economic rent).You can readily appreciate the significance of this by noting that Toronto rents in the heart of the financial district on Bay or University are higher than those in, say, Orangeville or Bolton to the north of Toronto.3. Thus productivity differences reflect the cost differences in supplying grain to that one market from that piece of land.Diunduh dari Sumber: /11/2012 .
161 SEWA-EKONOMI LAHAN - VON THUNEN Von Thünen mengembangkan teori dasar konsep marginal produktivitas secara matematis, dan menyusun rumus sewa lahan:R = Y(p − c) − YFm,dimana R=sewa LAHAN; Y=hasil per unit tanah; c=pengeluaran produksi per unit komoditas; p=harga pasar per unit komoditas; F=harga pengangkutan; m=jarak ke pasar.Model Von Thünen untuk lahan pertanian diciptakan dengan asumsi:Kota terletak terpusat di dalam keadaan terisolirKeadaan terisolir dikelilingi oleh alam liar.Lahan benar-benar datar dan tidak memiliki sungai atau pegunungan.Kualitas tanah (kesuburan tanah) dan iklim yang konsisten.Petani di keadaan terisolir mengangkut barang mereka sendiri ke pasar melalui gerobak melewati tanah langsung ke pusat kota, tidak ada jalan.Petani bersikap rasional untuk memaksimalkan keuntungan.Diunduh dari Sumber: 5/11/2012 .
162 KESUBURAN TANAH - PRODUKTIVITAS… Ksuburan tanah merupakan “kualitas tanah” dalam hal kemampuannya untuk menyediakan unsur hara yang sesuai, dalam jumlah yang cukup , dalam keseimbangan yang tepat dan lingkungan yang sesuai untuk pertumbuhan dan produksi spesies tanaman.Kesuburan tanah merupakan manifestasi dari sifat dan kemampuan tanah.Produktivitas Tanah merupakan “kemampuan tanah” untuk memproduksi sesuatu spesies tanaman dengan sistem pengelolaan tertentu.Aspek pengelolaan yang dimaksud misalnya pengaturan jarak tanaman, pemupukan, pengairan, pemberantasan hama dan penyakit, dll.Diunduh dari Sumber: /11/2012 .
163 Ada dua segi penting produktivitas tanah, yaitu: Produktivitas tanah pada dasarnya adalah konsep ekonomi dan bukan sifat tanah, ada tiga hal yang terlibat:Masukan (sistem pengeloalaan khusus),Keluaran (hasil tanaman tertentu),Tipe tanah.Dengan menetukan biaya dan haraga, keuntungan bersih dapat dihitung dan digunakan sebagai dasar untuk menentukan nilai lahan, yang penting dalam penaksiran NILAI SEWA-EKONOMI LAHAN.Ada dua segi penting produktivitas tanah, yaitu:Tanah yang berbeda mempunyai kapasitas yang berbeda untuk menyerap masukan (INPUT) PRODUKSI untuk menghasilkan keuntungan tertinggi.Tanaman yang berbeda mempunyai kapasitas yang berbeda untuk meyerap masukan (input) produksi untuk menghasilkan keuntungan tertinggi pada tipe tanah tertentu.Diunduh dari Sumber: /11/2012 .
164 INDEKS PRODUKTIVITAS TANAH PI ∑ = S (Ai x Bi x Ci x Di x Ei x Wfi) Neill’s (1979) productivity index was modified by Pierce et al. (1983).The productivity index was based on the use of simple easily measurable soil properties to predict the effect of soil environment on root growth. This is expressed as follows:rPI ∑ = S (Ai x Bi x Ci x Di x Ei x Wfi)i=1where: PI = productivity index; Ai = Sufficiency for available water capacity for the ith soil layer; Bi = Sufficiency for aeration for the ith soil layer; Ci = Sufficiency for pH for the ith soil layer; Di = Sufficiency for bulk density for the ith soil layer; Ei = Sufficiency for electrical conductivity for the ith soil layer; Wfi = Root weighting factor; r = Number of horizons in the rooting zone.Other parameters like nutrients, management, climate and genetic factors are presumed to be constant.Diunduh dari Sumber: 5/11/2012 .
165 INDEKS PRODUKTIVITAS TANAH . Neill’s model (1979) did not take care of some soil parameters such as organic carbon, available phosphorus and exchangeable aluminium that exert key influence on the productivity of tropical soils. Consequently, a modifixation was carried out to include these three sufficiencies. The modified expressions are as follows:rP1Mi = ∑ (Ai x Ci x Di x Wfi).Where: P1Mi = Modified productivity index that involves the exclusion of sufficiencies for aeration and electrical conductivity.P1M2 = ∑ (Ai x Ci x Di x Ji x Ki x Li x Wfi).Where: P1M2 = Modified productivity index that involves the inclusion of sufficiencies for organic carbon, available phosphorus and exchangeable aluminium with simultaneous exclusion of sufficiencies for aeration and electrical conductivity; Ji = Sufficiency for organic carbon for the ith soil layer; Ki = Sufficiency for available phosphorus for the ith soil layer; Li = Sufficiency for exchangeable aluminium for the ith soil layer.The sufficiencies for available water capacity, bulk density, pH and root weighting factor for this modification were as established by Pierce et al. (1983), while other sufficiencies were established in this research.Diunduh dari Sumber: /11/2012 .
166 . KECUKUPAN KADAR C-ORGANIK The rating of organic carbon (Source: Enwezor et al.( 1981 )Organic carbon content (%) Sufficiency2.0 and aboveSource: Enwezor et al.( 1981 )A sufficiency of 1.0 was assigned fororganic carbon content of 2.0 percent in the study area.It is presumed that soil productivity approaches zero at organic carbon content of 0.5 or less (Enwexor et al., 1981).Enwezor, W.O. Udo, E.J. and Sobulo, R.A. (1981). Fertility Status and Productivity of acid sands. In: Acid of Southeastern Nigeria. Monograph No. 1 Soil Sci. Soc. of Nigeria 56-73pp.Diunduh dari Sumber: /11/2012 .
167 Sufficiency rating of available phosphorus . KECUKUPAN P-TERSEDIASufficiency rating of available phosphorusIn this study, a sufficiency of 1.0 was assigned for the highest available phosphorus content of 50 Cmol kg-1 and it is assumed that soil productivity declines at available phosphorus of 15 cmol kg-1 or less (Landon, 1991).Available phosphorusSufficiency50.1100.2150.3200.14250.5300.6350.7400.8450.9501.0Landon, J.R. (eds). (1991). Booker tropical Soil Manuel: A Handbook for Soil Survey and Agricultural land Evaluation in the Tropics and Sub-tropics. John Wiley and Sons Inc. Third Avenue, New York, U.S.A. 474pp.Diunduh dari Sumber: /11/2012 .
168 . KECUKUPAN Al.dd Sufficiency rating of exchangeable aluminium The highest sufficiency of 1.0 was assigned for exchangeable aluminium concentration of 2.8 cmol kg-1.Soil productivity approaches zero at exchangeable aluminium concentration of 14.0 cmol kg-1 and above(Pratt, 1966;Mclean and Gilbert, 1927).Sufficiency rating of exchangeable aluminiumExchangeable aluminiumconcentration (cmol kg-1)Sufficiency2.81.05.60.88.40.611.20.414.0 and above0.2Mclean, F.T. and Gilbert, B.E. (1927). The relative aluminium tolerance of crop plants. Soil Sci. 24:Pratt, F.P. (1966) Aluminium. Department of Soil and Plant nutrition, University of California Div. Agric, Sci. 12pp..Diunduh dari Sumber: /11/2012 .
169 …Bergstrom, J. C., B. L. Dillman, and J. R. Stoll “Public Environmental Amenity Benefits of Private Land: The Case of Prime Agricultural Land.” Southern Journal of Agricultural Economics 17(1):Bergstrom, J. C., J. R. Stoll, J. P. Titre, and V. L. Wright “Economic Value of Wetlands-Based Recreation.” Ecological Economics 2(2):Crocker, T. D “On the Value of the Condition of a Forest Stock.” Land Economics 61(3):Diamond, D. B., Jr., “The Relationship Between Amenities and Urban Land Prices.” Land Economics 56(1):21-32.Loomis, J., and Anderson, P “Idaho v. Southern Refrigerator.” In Natural Resource Damages: Law and Economics, Ward, K. M. andDuffield, W. J. (ed.), Wiley Law Publications, New York, ppPalmquist, R. B., and L. E. Danielson “A Hedonic Study of the Effects of Erosion Control and Drainage on Farmland Values.” American Journal of Agricultural Economics 71:55-62.Diunduh dari Sumber: 31/10/2012 .