Presentation on theme: "BAHAN KAJIAN: STELA-SMNO.FPUB.APRIL2013. CONCEPTS, DEFINITIONS AND PRINCIPLES "Lahan adalah area tertentu di permukaan bumi, yang melingkupi semua atribut."— Presentation transcript:
BAHAN KAJIAN: STELA-SMNO.FPUB.APRIL2013
CONCEPTS, DEFINITIONS AND PRINCIPLES "Lahan adalah area tertentu di permukaan bumi, yang melingkupi semua atribut biosfir di atas dan di bawah permukaan, termasuk iklim di dekat permukaan, tanah dan bentuk lahan, hidrologi permukaan (termasuk danau dangkal, sungai, rawa-rawa), the near-surface sedimentary layers and associated groundwater reserve, populasi tumbuhan dan binatang, pola permukiman dan sifat fisik akibat aktivitas manusia (terras, bangunan air dan drainage, jalan raya dan bangunan gedung, dll.).“ Sumber: FAO Land and Water Bulletin No
Fungsi-fungsi lahan: 1. Fungsi Produksi 2. Fungsi Lingkungan Biotik 3. Fungsi regulasi iklim 4.· hydrologic function 5.· storage function 6.· waste and pollution control function 7.· living space function 8.· archive or heritage function 9.· connective space function Sumber: FAO Land and Water Bulletin No
FUNGSI PRODUKSI Lahan merupakan basis bagi berbagai sistem penunjang kehidupan, melalui produksi biomasa yang menyediakan makanan, pakan- ternak, serat, bahan-bakar, bahan bangunan dan material biotik lainnya bagi manusia, secara langsung atau melalui budidaya ternak, termasuk akuakultur dan perikanan tangkap. Sumber: FAO Land and Water Bulletin No
FUNGSI LINGKUNGAN BIOTIK Lahan merupakan basis bagi buiodiversitas terrestris dengan menyediakan habitat biologis dan plasma nutfah bagi tanaman, binatang, dan mikroba yang hidup di atas dan di bawah permukaan. Sumber: FAO Land and Water Bulletin No
FUNGSI LAHAN: REGULASI IKLIM land and its use are a source and sink of greenhouse gases and form a co-determinant of the global energy balance - reflection, absorption and transformation of radiative energy of the sun, and of the global hydrological cycle Sumber: FAO Land and Water Bulletin No Fungsi Lahan: Koneksi Ruang land provides space for the transport of people, inputs and produce, and for the movement of plants and animals between discrete areas of natural ecosystems
FUNGSI LAHAN FUNGSI HIDROLOGI Land regulates the storage and flow of surface and groundwater resources, and influences their quality Sumber: FAO Land and Water Bulletin No FUNGSI PENGENDALI PENCEMARAN DAN LIMBAH land has a receptive, filtering, buffering and transforming function of hazardous compounds FUNGSI GUDANG land is a storehouse of raw materials and minerals for human use
FUNGSI RUANG KEHIDUPAN land provides the physical basis for human settlements, industrial plants and social activities such as sports and recreation. FUNGSI ARSIP ATAU WARISAN Land is a medium to store and protect the evidence of the cultural history of humankind, and source of information on past climatic conditions and past land uses. Sumber: FAO Land and Water Bulletin No
Lahan mempunyai Atribut, Karakteristik, Sifat & Ciri, dan Kualuitas (atau Kondisi/Pembatas): 1.an attribute, or variable, is a neutral, over-arching term for a single or compound aspect of the land; 2.a 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); 3.a property is an attribute that already gives a degree of information on the value of the land type; 4.a 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. Sumber: FAO Land and Water Bulletin No
Land qualities are not absolute values, but have to be assessed in relation to the functions of the land and the specific land use that one has in mind. Some examples: 1.Land recently cleared from forest has a positive quality in respect of arable cropping (clearing, as "development costs", adding to the value of potential agricultural land), but has a negative quality in respect of sustainable use of the natural vegetative cover; 2.Land with a high degree of short-distance variation in soil and terrain conditions has a positive quality for biodiversity, is a large drawback to large-scale mechanized arable farming, but has a smaller limitation - or even an advantage - for smallholders' mixed farming; 3.The presence of scattered clumps of trees or shrubs in an open savannah area with harsh climatic conditions is a positive quality for extensive grazing (shelter against cold, heat or wind) but may be less important, or negative, for arable farming; 4.The presence of small land parcels, of woody or stony hedgerows and terraces, or of archaeological remains, is a positive quality in relation to the archival function of the land, but can conflict with its production function; 5.The propensity of the soil surface to seal and crust is a negative quality for arable farming (poor seedbed condition; reduced moisture intake of the soil), but is an asset of the land as regards water harvesting possibilities for crop growing in lower parts of the landscape wherever rainfall is submarginal. Sumber: FAO Land and Water Bulletin No
KUALITAS LAHAN & PRODUKTIVITAS TANAMAN 1.Crop yields (a resultant of many qualities listed below). 2.KETERSEDIAAN LENGAS TANAH. 3.KETERSEDIAAN HARA. 4.KETERSEDIAAN OKSIGEN DI ZONE AKAR. 5.Adequacy of foothold for roots. 6.KONDISI PERKECAMBAHAN. 7.Workability of the land (ease of cultivation). 8.SALINITAS ATAU SODISITAS. 9.TOKSISITAS TANAH. 10.RESISTENSI TERHADAP EROSI TANAH. 11.Pests and diseases related to the land. 12.Flooding hazard (including frequency, periods of inundation). 13.REGIM SUHU. 14.RADIASI ENERGI DAN FOTOPERIODE. 15.Climatic hazards affecting plant growth (including wind, hail, frost). 16.Air humidity as affecting plant growth. 17.PERIODE KERING UNTUK PEMASAKAN/PEMATANGAN TANAMAN. Sumber: FAO Land and Water Bulletin No
Crop yields (a resultant of many qualities listed below). Sumber: Crop production provides the food for human beings, fodder for animals and fiber for cloths. Land is the natural resource which is unchanged & the burden of the population is tremendously increasing, thereby decrease the area per capita. Therefore it is necessary to increase the production per unit area on available land. This necessitates the close study of all the factors of crop production viz. 1.The soil in which crops are grown 2.The water which is the life of plant 3.The Plant which gives food to man & fodder to his animals 4.The skillful management by the farmer himself 5.The climate which is out of control of man & but decided the growth, development & production. 6.The genetic characters of crop plant which is the genetic makeup & can be exploited for crop production.
KETERSEDIAAN LENGAS TANAH Sumber: Available water capacity is the amount of water that a soil can store that is available for use by plants. It is the water held between field capacity and the wilting point adjusted downward for rock fragments and for salts in solution. Field capacity is the water retained in a freely drained soil about 2 days after thorough wetting. The wilting point is the water content at which sunflower seedlings wilt irreversibly. Available water is expressed as a volume fraction (0.20), as a percentage (20%), or as an amount (in inches). An example of a volume fraction is water in inches per inch of soil. If a soil has an available water fraction of 0.20, a 10 inch zone then contains 2 inches of available water.
KETERSEDIAAN LENGAS TANAH Sumber: Tekstur Tanah Fraksi air tersedia Sands, and loamy sands and Less than 0.10 sandy loams in which the sand is not dominated by very fine sand Loamy sands and sandy loams in which very fine sand is the dominant sand fraction, and loams, clay loam, sandy clay loam, and sandy clay Silty clay, and clay Silt, silt loam, and silty clay loam
KETERSEDIAAN HARA. This soil quality is decisive for successful low level input farming and to some extent also for intermediate input levels. Diagnostics related to nutrient availability are manifold. Important soil characteristics of the topsoil (0-30 cm) are: Texture/Structure, Organic Carbon (OC), pH and Total Exchangeable Bases (TEB). For the subsoil ( cm), the most important characteristics considered are: Texture/Structure, pH and TEB. The soil characteristics relevant to soil nutrient availability are to some extent correlated. For this reason, the most limiting soil characteristic is combined in the evaluation with the average of the remaining less limiting soil characteristics to represent soil quality. Soil QualitiesSoil Characteristics Nutrient availabilitySoil texture, soil organic carbon, soil pH, total exchangeable bases Sumber:
pH – KEMASAMAN TANAH Crops vary in their response to pH; calcifuge plants dislike lime while calciphilous plants are lime-loving. There are very few crops that grow well in calcareous soils that do not grow equally well at a pH above 6 under lime- free conditions. Several crops, such as tea, require acid conditions. Many crops are affected by micro-nutrient deficiencies or toxicities at certain pH levels. The availability of various macro and micronutrients over the pH scale is illustrated ; however, this availability varies from crop to crop. Sumber:
Relative availability of common elements in mineral soils with pH (after Truog 1948) Sumber:
KAPASITAS RETENSI HARA Nutrient retention capacity is of particular importance for the effectiveness of fertilizer applications and is therefore of special relevance for intermediate and high input level cropping conditions. Nutrient retention capacity refers to the capacity of the soil to retain added nutrients against losses caused by leaching. Plant nutrients are held in the soil on the exchange sites provided by the clay fraction, organic matter and the clay-humus complex. Losses vary with the intensity of leaching which is determined by the rate of drainage of soil moisture through the soil profile. Soil texture affects nutrient retention capacity in two ways, through its effects on available exchange sites on the clay minerals and by soil permeability. The soil characteristics used for topsoil are respectively: Organic Carbon (OC), Soil Texture (Text), Base Saturation (BS), Cation Exchange Capacity of soil (CECsoil), pH, and Cation Exchange Capacity of clay fraction (CECclay). Soil pH serves as indicator for aluminum toxicity and for micro-nutrient deficiencies. Kualitas Tanah: Nutrient retention capacity Karakteristik Tanah: Soil Organic carbon, Soil texture, base saturation, cation exchange capacity of soil and of clay fraction Sumber:
Ketersediaan Oksigen di Zone Perakaran Oxygen availability in soils is largely defined by drainage characteristics of soils. The determination of soil drainage classes is based on procedures developed at FAO (FAO 1995). These procedures take into account soil type, soil texture, soil phases and terrain slope. Apart from drainage characteristics, the soil quality of oxygen availability may be influenced by soil and terrain characteristics that are defined through the occurrence of specific soil phases. Kualitas Tanah: Oxygen availability to roots Karakteristik Tanah: Soil drainage and soil phases affecting soil drainage. Sumber:
TEMPAT PANCANGNYA AKAR TANAMAN Sumber:http://soils.usda.gov/sqi/publications/files/avwater.pdf The rooting depth affects the total available water capacity in the soil. A soil that has a root barrier at 20 inches and an available water fraction of 0.20 has 4 inches of available water capacity. Another soil, that has a lower available water fraction of 0.10, would, if the roots extended to a depth of 60 inches, have 6 inches of available water capacity. For shallow rooting crops, like onions, the available water below 1-2 feet has little significance. For deeper rooting crops, like corn, the available water at the greater depth is very important.
KONDISI UNTUK PERKECAMBAHAN KONDISI PERAKARAN Rooting conditions include effective soil depth (cm) and effective soil volume (vol. %) related to presence of gravel and stoniness. Rooting conditions may be affected by the presence of a soil phase either limiting the effective rooting depth or decreasing the effective volume accessible for root penetration. Rooting conditions address various relations between soil conditions of the rooting zone and crop growth. The following factors are considered in the evaluation: 1.Adequacy of foothold, i.e., sufficient soil depth for the crop for anchoring; 2.available soil volume and penetrability of the soil for roots to extract nutrients; 3.space for root and tuber crops for expansion and economic yield in the soil; and 4.absence of shrinking and swelling properties (vertic) affecting root and tuber crops. Soil depth/volume limitations affect root penetration and may constrain yield formation (roots and tubers). Relevant soil properties considered are: soil depth, soil texture/structure, vertic properties, gelic properties, petric properties and presence of coarse fragments. This soil quality is estimated by multiplying of the soil depth limitation with the most limiting soil or soil phase property. Sumber:
KONDISI PERAKARAN. Soil phases that relevant for rooting conditions vary somewhat with source of soil map and soil classification used. In the HWSD these are: 1.FAO 74 soil phases: stony, lithic, petric, petrocalcic, petrogypsic, petroferric, fragipan and duripan. 2.FAO 90 soil phases: rudic, lithic, pertroferric, placic, skeletic, fragipan and duripan. 3.ESB soil phases and other soil depth/volume related characteristics: stony, lithic, petrocalcic, petroferric, fragipan and duripan, and presence of gravel or concretions, obstacles to roots (6 classes), and impermeable layers (4 classes). Rooting conditionsSoil textures, bulk density, coarse fragments, vertic soil properties and soil phases affecting root penetration and soil depth and soil volume Sumber:
Workability of the land (ease of cultivation). Sumber: Workability or ease of tillage depends on interrelated soil characteristics such as texture, structure, organic matter content, soil consistence/bulk density, the occurrence of gravel or stones in the profile or at the soil surface, and the presence of continuous hard rock at shallow depth as well as rock outcrops. Some soils are easy to work independent of moisture conditions, other soils are only manageable at an adequate moisture status, in particular for manual cultivation or light machinery. Irregular soil depth, gravel and stones in the profile and rock outcrops, might prevent the use of heavy farm machinery. Kualitas Lahan: Land Workability (constraining field management) Karakteristik Lahan: Soil texture, effective soil depth/volume, and soil phases constraining soil management (soil depth, rock outcrop, stoniness, gravel/concretions and hardpans)
Salinity or sodicity. KELEBIHAN GARAM Accumulation of salts may cause salinity. Excess of free salts referred to as soil salinity is measured as Electric Conductivity (EC in dS/m) or as saturation of the exchange complex with sodium ions, which is referred to as sodicity or sodium alkalinity and is measured as Exchangeable Sodium Percentage (ESP). Salinity affects crops through inhibiting the uptake of water. Moderate salinity affects growth and reduces yields; high salinity levels may kill the crop. Sodicity causes sodium toxicity and affects soil structure leading to massive or coarse columnar structure with low permeability. Apart from soil salinity and sodicity, conditions indicated by saline (salic) and sodic soil phases may affect crop growth and yields. In case of simultaneous occurrence of saline (salic) and sodic soils the limitations are combined. The most limiting of the combined soil salinity and/or sodicity conditions and occurrence of saline (salic) and/or sodic soil phase is selected. Excess salts.Soil salinity, soil sodicity and soil phases influencing salt conditions Sumber:
Salinity The adverse effects of soil salinity on plant growth vary with the crop being grown. The presence of salinity in the soil solution resulting from either indigenous salt in the soil, or from salt added by irrigation water can affect growth (i) by reducing water available to the crop (the osmotic effect) and (ii) by increasing the concentration of certain ions that have a toxic effect on plant metabolism (the specific ion effect). Many plants, for example, barley, wheat and maize, are sensitive to the osmotic effect during germination and the early seedling stages, but have greater tolerances at later stages (USDA 1954). Salt damage is aggravated by hot, dry conditions and may be less severe in cool humid conditions. Salt tolerance data for any given crop cannot be considered as fixed values, but should be used as guidelines. Sumber:
Salt tolerances of various crops to salinity as measured in the saturation extract ECe. Field crops. Sumber: Maas and Hoffmann 1977; James et al 1982.
EFEK FISIKA SODISITAS The presence of excessive amounts of exchangeable sodium in soil promotes the dispersion and swelling of clay minerals. The soil becomes impermeable to both air and water. The infiltration and hydraulic conductivity decrease to the extent that little or no water movement occurs. The soil is plastic when wet and becomes hard (brick-like) when dry. Tillage becomes difficult and soil crusting occurs. Recent research (Frenkel et al. 1978) has indicated that dispersion blocks soil pores, whereas swelling reduces pore sizes. Sumber:
EFEK FISIKA SODISITAS The effect is most pronounced on soils containing clays which swell and shrink. Soils containing non-expanding clays such as kaolinite and sesquioxides are relatively insensitive to the physical effects of exchangeable sodium. However, heavy cracking clays may be so impermeable when wet that the decreased permeability associated with a high sodium content may not matter. Sodicity is determined as the exchangeable sodium percentage (ESP). In rating sodicity one should take into account the changes in ESP which will take place after the land is irrigated. Sumber:
CRITICAL LIMITS FOR SODICITY TOLERANCE 1. 1/ Ratings may be raised one level if permeability is more than 2 cm/hr (e.g. as in loamy and sandy soils). 2.2/ Soil depth ranges in cm. 3.3/ SAR may be used if ESP figures seem unreliable. Sumber: Factor Ratings 1/ ESP % SAR 3/SAR (0 - 30) 2/( )(0 - 30)( ) s1<10<20<8<18 s s n>35>50>38>68
Sodium toxicity Plants vary considerably in their ability to tolerate sodium ions. Most tree crops and other woody-type perennials are particularly sensitive to low concentrations of sodium. Most annual crops are less sensitive, but may be affected by higher concentrations. Sodium toxicity is often modified and reduced if calcium is also present, therefore a reasonable evaluation of the potential toxicity is possible using the SAR for the soil water extract and the SAR of the irrigation water. Symptoms of sodium toxicity may appear only after a period of time during which toxic concentrations accumulate in the plant: the symptoms appear as a burn or drying of tissues first appearing at the outer edges of leaves. Table |40 can be used to evaluate the sodium hazard for representative crops. Sumber:
TOLERANCE OF VARIOUS CROPS TO EXCHANGEABLE SODIUM (ESP) UNDER NONSALINE CONDITIONS Sumber: Tolerance to ESP and range at which affected CropGrowth response under field conditions Extremely sensitive (ESP = 2-10) Deciduous fruits Nuts Citrus (Citrus spp.) Avocado (Persea americana Mill.) Sodium toxicity symptoms even at low ESP values Sensitive (ESP = 10-20) Beans (Phaseolus vulgaris. L)Stunted growth at these ESP values even though the physical condition of the soil may be good Moderately tolerant (ESP = 20-40) Clover (Trifolium spp.) Oats (Avena sativa L.) Tall fescue (Festuca arundinacea Schreb.) Rice (Oryza sativa L.) Dallis grass (Paspalum dilatum Poir.) Stunted growth due to both nutritional factors and adverse soil conditions Tolerant (ESP = 40-60) Wheat (Triticum aestivum L.) Cotton (Gossypium hirsutum L.) Alfalfa (Medicago sativa L.) Barley (Hordeum vulgare L.) Tomatoes (Lycopersicon esculentum Mill.) Beets (Beta vulgaris L.) Stunted growth usually due to adverse physical conditions of soil Most tolerant (ESP = more than 60) Crested and Fairway wheatgrass (Agropyron spp.) Tall wheatgrass (Agropyron elongatum (Host) Beau.) Rhodes grass (Chloris gayana Kunth) Stunted growth usually due to adverse physical conditions of soil
Soil toxicity. Sumber: Toxicities Low pH leads to acidity related toxicities, e.g., aluminum, iron, manganese toxicities, and to various deficiencies, e.g., of phosphorus and molybdenum. Calcareous soils exhibit generally micronutrient deficiencies, for instance of iron, manganese, and zinc and in some cases toxicity of molybdenum. Gypsum strongly limits available soil moisture. Tolerance of crops to calcium carbonate and gypsum varies widely (FAO, 1990; Sys, 1993). Low pH and high calcium carbonate and gypsum are mutually exclusive. Acidity related toxicities such as aluminum toxicities and micro-nutrient deficiencies are accounted for respectively in nutrient availability, and in nutrient retention capacity. This soil quality is therefore only including calcium carbonate and gypsum related toxicities. The most limiting of the combination of excess calcium carbonate and gypsum in the soil, and occurrence of petrocalcic and petrogypsic soil phases is selected for the quantification. Soil ToxicityCalcium carbonate and gypsum
KETAHANAN EROSI Sumber: Climate, soil and topographic characteristics determine runoff and erosion potential from agricultural lands. The main factors causing soil erosion can be divided into three groups 1.Energy factors: rainfall erosivity, runoff volume, wind strength, relief, slope angle, slope length. 2.Protection factors: population density, plant cover, amenity value (pressure for use) and land management. 3.Resistance factors: soil erodibility, infiltration capacity and soil management.
Soil ERODIBILITY. Sumber: The soil erodibility factor (K-factor) is a quantitative description of the inherent erodibility of a particular soil; it is a measure of the susceptibility of soil particles to detachment and transport by rainfall and runoff. For a particular soil, the soil erodibility factor is the rate of erosion per unit erosion index from a standard plot. The factor reflects the fact that different soils erode at different rates when the other factors that affect erosion (e.g., infiltration rate, permeability, total water capacity, dispersion, rain splash, and abrasion) are the same. Texture is the principal factor affecting K fact, but structure, organic matter, and permeability also contribute. The soil erodibility factor ranges in value from 0.02 to 0.69 (Goldman et al. 1986; Mitchell and Bubenzer 1980).
Sumber: Stewart et al. (1975) also developed a table indicating the general magnitude of the K-factor as a function of organic matter content (Pom) and soil textural class. P om (%) Textural Class<0.524 Sand Fine sand Very finesand Loamy sand Loamy finesand Loamy veryfine sand Sandy loam Fine sandyloam Very fine sandy loam Loam Silt loam Silt Sandy clayloam Clay loam Silty clayloam Sandy clay Silty clay Clay
Sumber: The soil texture, and other soil characteristics, affect its susceptibility to erosion. The soil K factors were determined experimentally in test plots that were 72.6 ft long and had a uniform slope of 9%. The nomograph used to determine the K factor for a soil, based on its texture (% silt plus very fine sand, % sand, % organic matter, soil structure, and permeability. The NRCS county soil maps list the K factors for all soils in each county. However, significant disturbance and modifications of the soil obviously occurs at construction sites and care needs to be taken to ensure that the K factor is based on the actual surface soil conditions. As an example, the organic matter (decreases as the top soils are removed), permeability (decreases with compaction with heavy equipment), and soil structure (subsurface soils more massive than surface soils) could all likely change, causing the K factor to increase for a soil undergoing modification at a construction site. Soil ERODIBILITY Factor (K).
Sumber: USDA nomograph used to calculate soil erodibility (K) factor. Soil ERODIBILITY Factor (K).
Pests and diseases related to the land. Sumber: The categories of problem may be listed as due to (i) wild animals, (ii) arthropods including insects and mites, (iii) parasitic nematodes, (iv) fungal pathogens, (v) bacterial pathogens, and (vi) virus diseases. In reconnaissance studies these should be considered in selecting alternative LUTs. Pests, diseases and weeds may be 'class-determining' because of the variability from one land unit to another in exposure to wild animals, in microclimate or soils, or in other land characteristics. Insect problems, particularly in cotton, have led to the failure of large irrigation schemes.
Flooding hazard Sumber: In shallow water rice areas and in areas producing other crops, spasmodic floods not only affect the crop, but also damage the soil and the infrastructure, e.g. rice-field bunds, pathways, temporary and permanent houses, roads and bridges etc. Flood damage is most likely to occur on river flood plains, alluvial and coastal plains, regions with large seasonal variations in rainfall and liable to intensive rain over hours or days. The detailed pattern of incidence is thus related to landforms. In setting critical limits for flood hazard, two criteria may be used: period of inundation, and flood frequency. The period of inundation is the average number of days during the cropping season or year when the land is covered by water. This may be obtained from records or estimated. The flood frequency is the probability of occurrence of damaging floods during the year.
Flooding hazard (including frequency, periods of inundation). Sumber: A damaging flood is one that destroys or causes severe damage to the crop, land or infrastructure. Where required, a damaging flood may be defined quantitatively in terms of period of inundation and/or speed of flow or volume of discharge of moving water. The following scale can be applied quantitatively where data are available, but will usually form the basis for subjective estimation. Frequency of damaging floods: Very rare or neverLess than 1 year in 20 or never known to occur RareLess than 1 year in 5 InfrequentBetween 1 year in 5 and one per year Very frequentMore than 5 times per year
Storm, hail and wind hazard Sumber: The exposure of land to storm and wind and the susceptibility or tolerance to these for different crops often needs assessment in land evaluation. A judgement needs to be made of the economic impact which is probable for respective land units and crops. Two aspects are the general prevalence of the hazard (e.g. wind) and the occurrence of special events such as high intensity rainfall, cyclones and hurricanes. The latter are considerations in the selection of LUTs, but the extent of the damage and the ability of the crop to survive and sustain production after the event may be aggravated at specific sites, which could be differentiated into factor ratings. Amongst crops there is a clear distinction between short-term crops and perennial crops. The survival of short-term crops in the event of an infrequent storm hazard is of less consequence than for tree crops and orchards which might be completely destroyed. Bananas have the capability of regrowth from underground shoots if the above ground parts of the plant are destroyed; most tree crops do not have this capability. Hail can severely damage or destroy crops in many parts of the world and may have a bearing on the crops chosen. Hail damage is often very localized. The possibility of insurance against hail damage may also affect the choice of crops.
Frost hazard Sumber: Where it occurs, frost can be an important land class- determining factor. Frost pockets occur in valley floors owing to katabatic air movements. Frost can destroy the flowers of temperate fruit crops and consequently affect yields. Rare frosts are particularly important in the case of orchards (e.g. citrus) where trees of all ages may be destroyed. Damaging frosts can be defined in terms of temperatures, duration, and periods of the year during which damage may occur using data from climatic records. Local experience is often helpful in indicating the effect of landforms (i.e. the greater incidence in valley floors and the increase in incidence with altitude).
SOIL Temperature regime. Sumber: In soil taxonomy, soil temperature regimes are based on mean annual soil temperatures. Soil temperatures are taken at a depth of 50 cm from the soil surface, using the Celsius (centigrade) scale. These regimes greatly affect the use and management of soils, particularly for the selection of adapted plants. The ten soil temperature regimes are cryic, frigid, hyperthermic, isofrigid, isohyperthermic, isomesic, isothermic, mesic, pergelic, and thermic. The cryic soil temperature regime has mean annual soil temperatures of greater than 0 °C, but less than 8 °C, with a difference between mean summer and mean winter soil temperatures greater than 5 °C at 50 cm, and cold summer temperatures.
REZIM SUHU TANAH Sumber: The frigid soil temperature regime has mean annual soil temperatures of greater than 0 °C, but less than 8 °C, with a difference between mean summer and mean winter soil temperatures greater than 5 °C at 50 cm below the surface, and warm summer temperatures. The hyperthermic soil temperature regime has mean annual soil temperatures of 22 °C or more and a difference between mean summer and mean winter soil temperatures of less than 5 °C at 50 cm below the surface.
Sumber: The isofrigid soil temperature regime has mean annual soil temperatures of greater than 0 °C, but less than 8 °C, with a difference between mean summer and mean winter soil temperatures of less than 5 °C at 50 cm. below the surface, and warm summer temperatures. The isohyperthermic soil temperature regime has mean annual soil temperatures of 22 °C or more and a difference between mean summer and mean winter soil temperatures of less than 5 °C at 50 cm below the surface. REZIM SUHU TANAH
Sumber: The isomesic soil temperature regime has a mean annual soil temperatures of 8 °C or more, but a difference between mean summer and mean winter soil temperatures of less than 5 °C at 50 cm below the surface. The isothermic soil temperature regime that has mean annual soil temperatures of 15 °C or more but, 5 °C difference between mean summer and mean winter soil temperatures at 50 cm. below the surface. The mesic soil temperature regime has mean annual soil temperatures of 8 °C or more, but less than 15 °C, and the difference between mean summer and mean winter soil temperatures is greater than 5 °C at 50 cm below the surface. REZIM SUHU TANAH
Sumber: The pergelic soil temperature regime has mean annual soil temperatures of less than 0 °C at 50 cm below the surface. In this terperature regime, permafrost is present. Thermic The thermic soil temperature regime has mean annual soil temperatures of 15° C or more, but less than 22 °C; and a difference between mean summer and mean winter soil temperatures of greater than 5 °C at 50 cm below the surface. REZIM SUHU TANAH
Radiation energy and photoperiod. Sumber: Three relevant aspects of radiation are (i) daylength, (ii) its influence on photosynthesis and dry matter accumulation in crops, and (iii) its effects on evapotranspiration. Radiation levels may also be important in the drying and ripening of crops, but this is evaluated under heading B.17. Daylength may be a relevant class-determining factor in evaluations carried out at low intensity across different latitudes as already discussed under 'Growing Period' (Tables 32 and 33). Daylength affects photoperiod-sensitive cultivars of crops such as rice, influencing floral initiation and the onset or length of vegetative and reproductive phases of growth and development. The interaction of daylength with water availability or temperature can sometimes prove 'class-determining' at project level (e.g. in influencing the flowering of sugarcane, flowering and fruiting of mangoes, and in the bulbing and ripening of onions, etc.). The influence of radiation on photosynthesis and dry matter accumulation in crops has been reviewed by Monteith (1972).
PHOTOPERIODISME. Sumber: Photoperiodism is the physiological reaction of organisms to the length of day or night. It occurs in plants and animals. Photoperiodism can also be defined as the developmental responses of plants to the relative lengths of the light and dark periods. Here it should be emphasized that photoperiodic effects relate directly to the timing of both the light and dark periods.
Radiation energy and photoperiod. Sumber: Long-day plants flower when the day length exceeds their critical photoperiod. These plants typically flower in the northern hemisphere during late spring or early summer as days are getting longer. In the northern hemisphere, the longest day of the year is on or about 21 June (solstice). After that date, days grow shorter (i.e. nights grow longer) until 21 December (solstice). This situation is reversed in the southern hemisphere (i.e. longest day is 21 December and shortest day is 21 June). In some parts of the world, however, "winter" or "summer" might refer to rainy versus dry seasons, respectively, rather than the coolest or warmest time of year.
Radiation energy and photoperiod. Sumber: Short-day plants flower when the day lengths are less than their critical photoperiod. They cannot flower under long days or if a pulse of artificial light is shone on the plant for several minutes during the middle of the night; they require a consolidated period of darkness before floral development can begin. Natural nighttime light, such as moonlight or lightning, is not of sufficient brightness or duration to interrupt flowering. In general, short-day (i.e. long-night) plants flower as days grow shorter (and nights grow longer) after 21 June in the northern hemisphere, which is during summer or fall. The length of the dark period required to induce flowering differs among species and varieties of a species.
Calculating Photoperiods. Sumber: sunset 9:36convert to 24 hour clock 21:36 sunrise 6:14 - 6:14 photoperiod 15:2215 hours and 22 minutes Convert sunrise and sunset numbers to a 24-hour clock and subtract sunrise from sunset.
Photoperiod: Duration of Irradiation Sumber: Duration refers to the period of time in 24 hours that plants are exposed to light. In temperate regions where greenhouse crops are grown, day length changes seasonally. This change results occurs because the earth's axis is tilted 23½ degrees from a line perpendicular to the plane of the earth's orbit about the sun. At the equator, the day length is relative constant at 12 hours and 7 minutes during the year. As the distance from the equator increases (north latitude), day lengths are longer in the summer and shorter in the winter. The longest day of the year is the summer solstice ( ≃ June 21) and the shortest is the winter solstice ( ≃ December 21). Day and night lengths are equal on the autumnal equinox ( ≃ September 21) and vernal equinox ( ≃ March 21). When considering day length, weather services report sunrise to sunset, however many plants can perceive twilight. So day length for plants is sunrise to sunset plus twilight.
Illustration of the radiation balance. Sumber:
Solar radiation (R s ) Sumber: Solar radiation (R s ) is that part of the extraterrestrial radiation which is not absorbed and scattered when passing through the atmosphere, together with some of the scattered radiation that also reaches the earth's surface. A proportion of this radiation (about 50%) is photosynthetically active radiation (PAR) (Szeicz 1974). Values of solar radiation can be obtained from direct measurements or approximated by using: R s = ( n/N) R a, where n is the actual bright sunshine hours (e.g. measured with a Campbell Stokes solarimeter) and M is the maximum possible sunshine hours for a given month and latitude
Climatic hazards affecting plant growth (including wind, hail, frost). Sumber: Definition of a climatic hazard: 1.Extreme climatic/weather event(s) causing harm and damage to people, property, infrastructure and land uses. 2.It includes not only the direct (primary) impacts of the climate/weather event itself but also 3.the other indirect (secondary) hazards 'triggered' by that event e.g. land slides 'triggered' by torrential rain. The Impact is dependent upon: 1.The severity of the event and also the path/track and spatial extent of that weather event. 2.The density and distribution of the people and density and types of human activity in the areas affected. 3.The preparedness and capacity of the authorities and people to cope with the impact of the event.
HAIL = HUJAN ES-BATU Sumber: Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Unlike graupel, which is made of rime, and ice pellets, which are smaller and translucent, hailstones – on Earth – consist mostly of water ice and measure between 5 and 200 millimetres (0.20 and 7.9 in) in diameter. The METAR reporting code for hail 5 mm (0.20 in) or greater is GR, while smaller hailstones and graupel are coded GS. Hail is possible within most thunderstorms as it is produced by cumulonimbi, and within 2 nautical miles (3.7 km) of the parent storm. Hail formation requires environments of strong, upward motion of air with the parent thunderstorm (similar to tornadoes) and lowered heights of the freezing level. In the mid-latitudes, hail forms near the interiors of continents, while in the tropics, it tends to be confined to high elevations.
ANGIN Sumber: Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the bulk movement of air. Winds are commonly classified by their spatial scale, their speed, the types of forces that cause them, the regions in which they occur, and their effect.
Sumber: General wind classificationsTropical cyclone classifications (all winds are 10-minute averages) Beaufort scale  10-minute sustained winds (knots)knots General term   N Indian Ocean IMD IMD SW Indian Ocean MF MF Australian region South Pacific BoM, BMKG, FMS, MSNZ BoMBMKG FMSMSNZ NW Pacific JMA JMA NW Pacific JTWC JTWC NE Pacific & N Atlantic NHC & CPHC NHCCPHC 0<1Calm Low Pressure Area Tropical disturbance Tropical low Tropical Depression Tropical depression 11–3Light air 24–6Light breeze 37–10Gentle breeze 411–16Moderate breeze 517–21Fresh breeze Depression 622–27Strong breeze 7 28–29 Moderate galeDeep depression Tropical depression 30–33 834–40Fresh gale Cyclonic storm Moderate tropical storm Tropical cyclone (1) Tropical storm 941–47Strong gale 1048–55Whole gale Severe cyclonic storm Severe tropical storm Tropical cyclone (2) Severe tropical storm 1156–63Storm 1264–72 Hurricane Very severe cyclonic storm Tropical cyclone Severe tropical cyclone (3) Typhoon Hurricane (1) 1373–85Hurricane (2) 1486–89 Severe tropical cyclone (4) Major hurricane (3) 1590–99 Intense tropical cyclone 16100–106 Major hurricane (4) –114 Severe tropical cyclone (5) 115–119 Very intense tropical cyclone Super typhoon >120 Super cyclonic storm Major hurricane (5)
ENERGI ANGIN Wind energy is the kinetic energy of the air in motion. Total wind energy flowing through an imaginary area A during the time t is: E = A·v·t·ρ·½ v 2, where v is the wind velocity and ρ is the air density. The formula presented is structured in two parts: (A·v·t) is the volume of air passing through A, which is considered perpendicular to the wind velocity; (ρ·½ v 2 ) is the kinetic energy of the moving air per unit volume. Total wind power is: P = E/t = A·ρ·½ v 3 Wind power is thus proportional to the third power of the wind velocity. Sumber:
KELEMBABAN UDARA – PERTUMBUHAN TANAMAN Sumber: Relative humidity is the ratio of the partial pressure of water vapor in an air-water mixture to the saturated vapor pressure of water at a prescribed temperature. The relative humidity of air depends not only on temperature but also on the pressure of the system of interest.
Air humidity as affecting plant growth. Sumber: The relative humidity of an air-water mixture is defined as the ratio of the partial pressure of water vapor (H 2 O) in the mixture to the saturated vapor pressure of water at a given temperature. Relative humidity is normally expressed as a percentage and is calculated by using the following equation: The humidity of an air-water vapor mixture is determined through the use of psychrometric charts if both the dry bulb temperature (T) and the wet bulb temperature (T w ) of the mixture are known. These quantities are readily estimated by using a sling psychrometer.
Psychrometric charts Sumber:
Psychrometric charts Sumber:
Measuring relative air humidity with dry and wet bulb temperatures Sumber:http://www.engineeringtoolbox.com/humidity-measurement-d_561.html. Relative Humidity - RH (%) Difference Between Dry Bulb and Wet Bulb Temperatures T db - T wb ( o C) Dry Bulb Temperature - T db ( o C)
GROWING PERIOD Sumber: The growing cycle is the period required for an annual crop to complete its annual cycle of establishment, growth and production of harvested part. Perennial crops have growing cycles of more than one year. The growing period for annual crops is the duration of the year when temperature, soil. water supply and other factors permit crop growth and development. Thus, a growing cycle is a property of the crop (i.e. a crop requirement) whereas a growing period is a condition of the land (i.e. a land quality or land characteristic). Growing periods can be constrained by wet or humid conditions that limit opportunities for ripening and drying the crop, or which lead to problems of quality (e.g. reduced sugar content of sugarcane, staining of cotton, blemishes on fruits, etc.).
DRYING PERIODS FOR RIPENING OF CROPS. Sumber: FAO 1980c, p. 355; Higgins and Kassam MAJOR CLIMATES Climate Major climates during growing period 24 hr mean (daily) temperature (C) regime during the growing period Suitable for consideration for crop group (Table 33) No.Descriptive name Tropics All months with monthly mean temperatures, corrected to sea level, above 18°C 1Warm tropicsMore than 20II and III 2Moderately cool tropics 15-20I and IV 3Cool tropics5/ I 4Cold tropicsLess than 5Not suitable
DRYING PERIODS FOR RIPENING OF CROPS. Sumber: FAO 1980c, p. 355; Higgins and Kassam MAJOR CLIMATES Subtropics One or more months with monthly mean temperatures, corrected to sea level, below 18°C but all months above 5°C 5Warm/moderately cool subtropics (summer rainfall) More than 20II and III 6Warm/moderately cool subtropics (summer rainfall) I and IV 7Warm subtropics (summer rainfall) More than 20II and III 8Moderately cool subtropics (summer rainfall) I and IV 9Cool subtropics (summer rainfall)5/ I 10Cold subtropics (summer rainfall)Less than 5Not suitable 11Cool subtropics (winter rainfall)5/ I 12Cold subtropics (winter rainfall)Less than 5Not suitable
CROP ADAPTABILITY GROUPS, BASED ON PHOTOSYNTHETIC PATHWAY AND RESPONSE TO RADIATION AND TEMPERATURE TE = Temperate cultivars; TR = Tropical (lowland) cultivars; TH = Tropical (highland) cultivars. Source: Based on information extracted from FAO 1978a and FAO 1980c. Crop adaptability group IIIIIIIVV Photo- synthetic pathway C3 C4 CAM Optimum temperature for photosynthesis (°C) Sugarbeet Phaseolus Wheat Barley Oats Potato Bean (TE) Chickpea Soybean (TR) Phaseolus; Rice Cassava Sweet Potato Yams; Bean (TR) Groundnut Cotton; Tobacco Banana; Coconut Rubber; Oil palm Sorghum (TR) Maize (TR) Pearl millet Panicum Millet (TR) Finger millet Setaria Sugarcane Panicum Millet (TE, TH) Sorghum (TE, TH) Maize (TE, TH) Setaria Sisal Pineapple
GROWING PERIOD Sumber:http://www.fao.org/docrep/X5648E/x5648e0e.htm Type of growing period (under rainfed conditions which might be modified by irrigation) – Normal. a - Beginning of rains and growing period b 1 and b 2 - Start and end of humid period respectively c - End of rains and rainy season d - End of growing period P - Precipitation PET - Potential evapotranspiration (after FAO 1978a)
GROWING PERIOD Sumber:http://www.fao.org/docrep/X5648E/x5648e0e.htm Type of growing period (under rainfed conditions which might be modified by irrigation) - Intermediate
GROWING PERIOD Sumber:http://www.fao.org/docrep/X5648E/x5648e0e.htm Type of growing period (under rainfed conditions which might be modified by irrigation) - All year round humid
GROWING PERIOD Sumber:http://www.fao.org/docrep/X5648E/x5648e0e.htm type of growing period (under rainfed conditions which might be modified by irrigation) - All year round dry
LAND QUALITIES RELATED TO DOMESTIC ANIMAL PRODUCTIVITY PRODUKTIVITAS LAHAN GEMBALAAN : 1.Climatic hardships affecting animals. 2.Endemic pests and diseases. 3.Nutritive value of grazing land. 4.Toxicity of grazing land. 5.Resistance to degradation of vegetation. 6.Resistance to soil erosion under grazing conditions. 7.Ketersediaan Air Minum. Sumber: FAO Land and Water Bulletin No
LAND QUALITIES RELATED TO FOREST PRODUCTIVITY The qualities listed may refer to natural forests, forestry plantations, or both. Mean annual increments of timber species : 1.Types and quantities of indigenous timber species. 2.Site factors affecting establishment of young trees. 3.Hama dan Penyakit. 4.Bahaya Kebakaran. Sumber: FAO Land and Water Bulletin No
LAND QUALITIES RELATED TO MANAGEMENT AND INPUTS 1.The qualities listed may refer to arable use, animal production or forestry. 2.Terrain factors affecting mechanization (trafficability). 3.Terrain factors affecting construction and maintenance of access-roads (accessibility). 4.Size of potential management units (e.g. forest blocks, farms, fields). 5.Location in relation to markets and to supplies of inputs. Sumber: FAO Land and Water Bulletin No
Land qualities related to vertical components of a natural land unit ATMOSPHERIC QUALITIES 1.Atmospheric moisture supply: rainfall, length of growing season, evaporation, dew formation. 2.Atmospheric energy for photosynthesis: temperature, daylength, sunshine conditions. 3.Atmospheric conditions for crop ripening, harvesting and land preparation: occurrence of dry spells. Sumber: FAO Land and Water Bulletin No
Land qualities related to vertical components of a natural land unit LAND COVER QUALITIES 1.Value of the standing vegetation as "crop", such as timber. 2.Value of the standing vegetation as germ plasm: biodiversity value. 3.Value of the standing vegetation as protection against degradation of soils and catchment. 4.Value of the standing vegetation as regulator of local and regional climatic conditions. 5.Regeneration capacity of the vegetation after complete removal. 6.Value of the standing vegetation as shelter for crops and cattle against adverse atmospheric influences. 7.Hindrance of vegetation at introduction of crops and pastures: the land "development" costs. 8.Incidence of above-ground pests and vectors of diseases: health risks of humans and animals. Sumber: FAO Land and Water Bulletin No
Land qualities related to vertical components of a natural land unit LAND SURFACE AND TERRAIN QUALITIES 1.Surface receptivity as seedbed: the tilth condition. 2.Surface treatability: the bearing capacity for cattle, machinery, etc. 3.Surface limitations for the use of implements (stoniness, stickiness, etc.): the arability. 4.Spatial regularity of soil and terrain pattern, determining size and shape of fields with a capacity for uniform 5.management. 6.Surface liability to deformation: the occurrence or hazard of wind and water erosion. 7.Accessibility of the land: the degree of remoteness from means of transport. 8.The presence of open freshwater bodies for use by humans, animals or fisheries. 9.Surface water storage capacity of the terrain: the presence or potential of ponds, on-farm reservoirs, bunds, etc. 10.Surface propensity to yield run-off water, for local water harvesting or downstream water supply. 11.Accumulation position of the land: degree of fertility renewal or crop damaging by overflow or overblow. Sumber: FAO Land and Water Bulletin No
Land qualities related to vertical components of a natural land unit SOIL QUALITIES 1.Physical soil fertility: the net moisture storage capacity in the rootable zone. 2.Physical soil toxicity: the presence or hazard of waterlogging in the rootable zone (i.e. the absence of oxygen). 3.Chemical soil fertility: the availability of plant nutrients. 4.Chemical soil toxicity: salinity or salinization hazard; excess of exchangeable sodium. 5.Biological soil fertility: the N-fixation capacity of the soil biomass; and its capacity for soil organic matter turnover. 6.Biological soil toxicity: the presence or hazard of soil-borne pests and diseases. 7.Substratum (and soil profile) as source of construction materials. 8.Substratum (and soil profile) as source of minerals. 9.Biological soil toxicity: the presence or hazard of soil-borne pests and diseases. Sumber: FAO Land and Water Bulletin No
Land qualities related to vertical components of a natural land unit SUBSTRATUM OR UNDERGROUND QUALITIES 1.Groundwater level and quality in relation to (irrigated) land use. 2.Substratum potential for water storage (local use) and conductance (downstream use). 3.Presence of unconfined freshwater aquifers. 4.Substratum (and soil profile) suitability for foundation works (buildings, roads, canals, etc.) Sumber: FAO Land and Water Bulletin No
The GLASOD criteria for degrees of land degradation tried to specify resilience as follows: 1.Light degradation: The terrain has somewhat reduced agricultural suitability, but is suitable for use in local farming systems. Restoration to full productivity is possible by modifications of the management system. Original biotic functions are still largely intact. 2.Moderate degradation: The terrain has greatly reduced agricultural productivity but is still suitable for use in local farming systems. Major improvements are required to restore productivity. Original biotic functions are partially destroyed. 3.Strong degradation: The terrain is non-reclaimable at farm level. Major engineering works are required for terrain restoration. Original biotic functions are largely destroyed. 4.Extreme degradation: The terrain is unreclaimable and beyond restoration. Original biotic functions are fully destroyed. Sumber: FAO Land and Water Bulletin No
FIGURE 1. Some concepts of resilience of land and its productivity, comparing the situation in some industrialized countries (A) with that of most developing countries (B). Source: Sombroek, 1993 Sumber: FAO Land and Water Bulletin No
LQI LAND QUALITY INDICATOR Sumber: FAO Land and Water Bulletin No
PSR – PRESSURE STATE RESPONSE Sumber: FAO Land and Water Bulletin No
Three groups of LQIs have been developed to reflect the PSR structure: Group 1. Pressure on the land resource Indicators in this group include those activities that relate to the degree of intensification and diversification of agricultural land uses, and result in increased pressure on land quality. This may include : 1.the number of crops in a cropping system per year or per hectare, 2.type and intensity of tillage, 3.degree of removal of biomass, 4.integration with livestock systems, 5.number of food and fibre products produced annually, etc. Sumber: FAO Land and Water Bulletin No
Three groups of LQIs have been developed to reflect the PSR structure: Group 1. Pressure on the land resource These indicators must be seen within the context of major socio-demographic factors such as population pressures, land tenure, etc., but the latter do not qualify for inclusion as LQIs. This is because these major forces do not influence land quality directly, but rather through the land practices that are adopted by farmers as a consequence. It is these management systems and their impacts that we wish to capture as LQIs, although changes in the major driving forces may provide some "early warning" signals. Sumber: FAO Land and Water Bulletin No
Group 2. State of land quality State indicators reflect the conditions of the land as well as its resilience to withstand change as a consequence of sector pressures. This may include indicators which express : 1.Changes in biological productivity (actual and potential), 2.Extent and impacts of soil degradation, including erosion, salinization, etc., 3.Annual and long-term balance of nutrients (exported and imported by the cropping systems), 4.Degree and type of contamination or pollution (by direct application, atmospheric transport, etc.), 5.Changes in organic matter content, water holding capacity, etc. The changes in state may be negative with poor management, or positive with good management. Sumber: FAO Land and Water Bulletin No
Group 3. Societal response(s) The response mechanisms are normally achieved through direct actions by the farmers themselves in evolving or adopting improved land management systems, or through complementary activities whereby adoption of conservation technologies is stimulated by general economic, agricultural and conservation policies and programmes. In rare instances, environmental regulations may be necessary to effect proper control of land resource degradation. Response indicators may include number and types of farmer organizations for soil conservation, extent of change in farm technologies, risk management strategies, incentive programmes for adoption of conservation technologies, etc. Response indicators should be distinguished into those categories promoted by governments, those undertaken by individual farmers and those supported by agri-business. Sumber: FAO Land and Water Bulletin No
Erosion Productivity Impact Calculator (EPIC): EPIC was developed by the United States Department of Agriculture (USDA) and Agricultural Research Service (ARS) originally as a tool to analyse the impacts of soil management and erosion on crop yields, but more recently it has been expanded to include assessments of water quality, pesticides, etc. EPIC consists of ten major subroutines, namely, weather, hydrology, wind and water erosion, nitrogen and phosphorus transformations, soil temperature, crop growth, tillage, plant environment control (irrigation, lime, etc.), pesticide routines and economic crop budgets. Interim and final output is available from each subroutine, either in daily, monthly or annual increments. Although the model inputs are flexible through the use of many data defaults (for missing data), the model requires reliable data on soil properties, crop inputs and tillage management (weather is generated through a weather generator). Sumber: FAO Land and Water Bulletin No
Erosion Productivity Impact Calculator (EPIC): EPIC generates several potentially useful outputs for LQIs, namely: 1.yield, for several economically important crops; 2.erosion, wind and water, rate (t/ha) and impacts on yield; 3.change in nitrogen and phosphorus (crude estimate). Sumber: FAO Land and Water Bulletin No
Erosion Productivity Impact Calculator (EPIC): Rates of change are calculated by running EPIC using various land management scenarios over many years (usually 30 years). Increasingly, EPIC is being adapted to many temperate as well as tropical regions as a tool to evaluate land management practices, particularly tillage and residue management. It also has been integrated with large economic optimizing models to provide analytical systems for evaluation of environmental impact prior to implementation of agricultural policies and programmes. Sumber: FAO Land and Water Bulletin No
CENTURY The CENTURY model simulates the effects of erosion on long-term storage of soil organic carbon under field conditions. Briefly, soil organic matter is divided into pools with active (1.5y), slow (25y) and passive (1 000y) turnover rates. A plant production subroutine simulates the allocation of carbon into shoots and roots, dividing plant residue into a metabolic (0.1-1y) and a structural (1-5y) pool based on the lignin:nitrogen ratio. The model then transfers the carbon to the soil, and simulates carbon stability through interactions with clay and organic molecules. Estimates of soil carbon change are obtained by running CENTURY under initial (usually current) conditions, then again for future scenarios under new management technologies. Sumber: FAO Land and Water Bulletin No
CENTURY Output useful for LQIs include: 1.total soil carbon, used to estimate carbon sequestration; 2.rapid turn-over fraction, a surrogate for microbial biomass In terms of land quality, rapid turn-over of carbon is a better LQI than total carbon. Sumber: FAO Land and Water Bulletin No
NUTMON: This is a recently developed model for estimating regional losses or gains of nutrients as a consequence of nutrient inputs (mineral fertilizers, organic manures, wet and dry deposition, nitrogen fixation, sedimentation), compared to nutrient losses (harvested product, crop residue removal, leaching, erosion, denitrification) (Smaling, 1993). Data for nutrient inputs and nutrients removed by harvest are gathered for various land use systems, and estimates for the other variables are calculated using various available models. NUTBAL then calculates whether the systems are gaining or losing for each macronutrient. Results can be extrapolated to wider areas using GIS techniques. NUTBAL is still experimental, but it has been used for studies in Kenya with good success. Sumber: FAO Land and Water Bulletin No
SUSTAINABILITY REFERENCE SYSTEMS (SRS) The sustainability barometer of Prescott-Allen (1996) Prescott-Allen (1996) has proposed a "sustainability barometer" based on a graphical representation of the location of an exploited ecosystem on an orthogonal system in which the two axes represent indexes of human well-being and of ecosystem well-being, considered as the two fundamental dimensions of sustainability. The aim of the barometer is to (a) give a picture of the whole system; (b) treat ecosystem and human well-being as equally important; (c) facilitate a rigorous and transparent progress towards sustainability. Used as orthogonal axes, the human and ecological dimensions, with a scale normalized between 0 and 1, provide an orthogonal system of reference in which the position of an exploitation system (e.g., a fishery) can be located if the corresponding values on the two axes can be estimated. Sumber: FAO Land and Water Bulletin No
Static representation of sustainability. The Sustainability Reference System (SRS) slightly modified from the "Sustainability Barometer" of Prescott-Allen (1996) Sumber: FAO Land and Water Bulletin No
SUSTAINABILITY REFERENCE SYSTEMS (SRS) The scales of the barometer include also "value judgements" corresponding to the various intervals on the axes, e.g. the interval is considered "Bad" while the interval is considered "Good". Prescott-Allen stresses the importance of the "scaling" of the barometer and the amount of case-specific judgement involved in it. The paper does not explain how the numerical value of the coordinates is arrived at but examples are given in this paper in the specific case of fisheries. Prescott-Allen called it a "sustainability barometer“ used to "measure" exploitation pressure, by analogy with the instrument used to measure atmospheric pressure. Because this device does not provide a "measure" of sustainability but helps representing it, locating an exploited ecosystem in a system of reference, in the rest of this paper I shall refer to it and to other similar devices as "Sustainability Reference Systems“ (SRSs). Sumber: FAO Land and Water Bulletin No
The indicator of change. The four quadrants represent the areas of unsustainability (U), sustainability (S), as well as social and ecological instability (SU, EU). Sumber: FAO Land and Water Bulletin No
SUSTAINABILITY REFERENCE SYSTEMS (SRS) Figure illustrates this additional concept. Assuming that a fishery could be located on a SRS, the direction in which (and the rate at which) the situation is changing would be as important as the position on the SRS. Direction and rate of change would indeed provide useful foresight. Sumber: FAO Land and Water Bulletin No
Dynamic representation of sustainability: combination of the SRS and the IC. The strings of white squares illustrate different “trajectories” of the fishery in the SRS. Sumber: FAO Land and Water Bulletin No
A sustainability kite diagram Star diagrams are often used to represent multivariate properties of a system, e.g., to summarize the performance of a computer with scores referring to its performance in terms of processor velocity, RAM capacity, hard disk capacity, file transfer speed, energy efficiency, interface user-friendliness, etc. A theoretical example of such a diagram and illustrates the fact that it can be used to compare the profile (the "signature") of different systems including the "ideal" one with optimal values for all parameters. Sumber: FAO Land and Water Bulletin No
Theoretical example of a star diagram Sumber: FAO Land and Water Bulletin No
Theoretical example of a 4-axis isometric SRS. The situation of a particular fishery is represented on it by a “kite”. Sumber: FAO Land and Water Bulletin No
SRS - SUITABILITY REFERENCE SYSTEM A theoretical example of such a diagram for fisheries, using only 4 axes (kite diagram) for the sake of simplicity. The parameters represented are arranged in two domains corresponding respectively to ecosystem and human well- being (in order to remain in the terminology used by Prescott-Allen (1996). Each axis can be scaled from 0 to 1 and the grey scale refers to the assessment categories used in the preceding SRS (black= Bad, light grey= Good). A fishery can be re-presented on this referential system by a polygon and two fisheries can be compared by comparing their polygons. In addition, the position of the polygon in relation to each axis indicates in which sphere action might be required to improve the situation. Sumber: FAO Land and Water Bulletin No
SEKALA SUMBU SRS Prescott-Allen gives a detailed account of many of the problems encountered and options available when scaling the axes of the SRS. Scaling requires the determination of the scale boundaries (0-1 or ) and the relevant subdivisions of that scale according to the value judgements (e.g., deciding whether "Bad" goes from 0 to 0.2 or from 0 to 0.5). The latter could sometimes be arbitrary or conventional, but should in most instances refer to the target and limit reference points. In the example given by Prescott-Allen for the sustainability barometer the two axes are scaled from 0 to 1 and the value judgements (i.e., Good to Bad) are evenly distributed on both axes. Sumber: FAO Land and Water Bulletin No
SEKALA SUMBU SRS In most instances, the true values of the sustainability indicators (e.g., the size of the spawning biomass) will not be between 0 and 1 but, say, between the value of Bv, the biomass of the virgin stock, and zero. In this case, rescaling will be needed, e.g., by using ratio indicators (e.g., B/Bv). In the section on "Indicators of level", above, an attempt has been made to scale, from 0 to 1, the degree of people’s participation in a management system and arbitrary value judgements were given. To use the SRS, the same effort would be required for all potentially useful indicators, using as quantitative methods as possible for the estimates, and a set of criteria for the value judgements. Sumber: FAO Land and Water Bulletin No
Theoretical example of a 4-axes anisometric SRS. Sumber: FAO Land and Water Bulletin No
Stochastic and dynamic representation of a sustainability kite. Sumber: FAO Land and Water Bulletin No
LAND QUALITY Three broad types of key indicators OF LAND QUALITY may be the most important: a. Above the soil surface, as related with yields: 1.Cover close to the ground: its density, distribution, duration, timing. 2.Stress in plants: growth rates; timing and frequency of wilting; visible nutrient deficiencies or imbalances. b. On the soil surface, as affecting particularly soil moisture and runoff + erosion: Porosity of at least topsoil layers, in millimetric bands: proportions of incident rainfall becoming infiltrated; Sumber: Sumber: FAO Land and Water Bulletin No
LAND QUALITY c. 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. Sumber: Sumber: FAO Land and Water Bulletin No