Presentation on theme: "Chapter 20 Agro - environmental management and practice."— Presentation transcript:
Chapter 20 Agro - environmental management and practice
Main content 20.1 Agricultural ecological environmental problems and its harm 20.2 Agro - environmental management and practice 20.3 Ecological agriculture 20.4 Modern intensive sustainable agriculture 20.5 Case study
20.1 Agricultural ecological environmental problems and its harm 20.1.1 Environmental problems of agricultural production Figure 20-1 Schematic diagram of common agricultural environmental problems and its harm
（ 1 ） Pesticide pollution Migration, proliferation, residues, aggregation behavior will pollute the atmosphere, water and soil and is harmful to the organisms The organisms accumulate gradually in vivo by the food chain,which make the top of the food chain organisms (including humans) with higher pesticide content in vivo It makes ecosystems lose their balance, cause the system’s structure variation and function decline, and loss biodiversity.
Figure 20-2 The cycle of pesticide in the environment （ Li and Fleck, 1972 ）
① Organochlorine pesticides Chlorinated aromatic derivatives,including BHC, Dieldrin,and DDT etc. Stable structure,difficult to be oxidized, difficult to be dissociated,high toxic, easy to be dissociated in organic solvents, particularly in adipose tissue, and is high efficient, high toxic,and high pesticide residue It accumulates in the organisms’ fat and liver by the food chain in a large number, harms the nerve center,casues liver enzyme changing, has pathological changes by violating the kidney, and the toxicity is difficult to degrade. It has been forbidden to use since 1983, but the accumulation of pesticides in the past, will continue to play a role in quite a long time
② O rganophosphorus pesticide Most containing phosphorus organic compounds are phosphate or amides, such as DDVP, 1605, malathion and kitazine etc. Highly toxic, easy to break down,the time of residue in the environment is short,not easy to accumulate in plants and animals,so it is often considered safe pesticides But it’s high toxicity to humans and animals,it can inhibit the acetylcholine esterase, lipase and serine proteases aliphatic in the body to disrupt normal nerve function, causing disorders of biochemical processes in vivo with the symptoms as vomiting, diarrhea, fecal incontinence and blood pressure rising, eventually leading to death. Therefore, its environment toxicity still can not be ignored.
③ Carbamate pesticides With phenyl-N-alkyl ester’s structure, the same as organic phosphorus pesticides,they all have a role in anti-cholinesterase, the same in poisoning symptoms, but there are differences in the mechanism It is easy to decompose in the natural environment, and can be metabolized rapidly in vivo. Usually the metabolites have more toxicity than their own, and are low-residue pesticides. Some species have acute toxicity, such as furadan, its oral LD50 is 8-14mg/Kg,and it is a high toxic pesticide This kind of pesticides may have the potential to cause carcinoma and teratogenesis.
（ 2 ） Fertilizer pollution It play a considerable role in agricultural production, but if applying improperly it may be seriously cause the impact and harm to the soil, air, water, agricultural products, and the whole ecosystem. Ecosystem pollution is a multi-media environment pollution and contaminants in various environment media have physical, chemical and biological processes.So the pollutants in multi- media environment demonstrate relevance, transferability and cycle. （ figure 20-3)
Figure 20-3 Migration transformation rule of chemical fertilizer nutrient element in the environment
② Phosphate fertilizer pollution Phosphate fertilizer is not to be volatiled and weted.It has less effect to the atmospheric and ground water. However,it usually contains a variety of heavy metal and has potential impact to the soil and crops. In our phosphate rock, the amount of its fluoride containing is basically proportional to the phosphate containing, resulting increasing the fluoride content in the soil Phosphate fertilizer also contains trace amounts of natural radioactive elements. Especially in surrounding of the phosphate rock, there is a potential danger of radioactive pollution,and it is also polluting the environment in production process, transportation, and the trial process.
③ Potassium fertilizer and microelement fertilizer pollution With the development of agricultural production, potash fertilizer and trace fertilizer are used widely. But if it is used improperly,it may still harm to the environment It may easy to destroy soil structure resulting in soil compaction,if improper use of potassium sulfate;It may accumulate the chloride ion in the soil, destroy soil structure, and reduce the quality and yield of some crops,if potassium chloride is used improperly. Excessive trace elements could easily pollute the soil poisoning the crops, affecting the yield and quality
（ 3 ） Poultry excrement pollution Large -scale livestock breeding base takes great pollution to the environment According to the statistics,the amount of livestock manure is more than 2.5 billion ton in China in year 2000,and is much more than the total national industrial solid waster Take a sample of the Hangzhou Bay,which has the most pollution in Yangtze River region. Its pollution is mainly caused by agricultural pollution,especially pesticides, fertilizers and poultry excrement pollution. Research shows that poultry excrement is the main renson which causing the pollution indicators of Hangzhou Bay exceeding the standard seriously.(see table20-1) At the same time, the pollution proportion is trending to increase(see table 20-2).
Table 20-1 The proportion of main sources of pollution indicators of Hangzhou Bay in year 1994 （ unit ： % ） pollution source livestock manure agriculture fertilizers industrial pollution domestic pollutant other pollution inorganic nitrogen 3540510 total phosphoru s 21601459 BOD180172243 Notes ： quoted from Yang Chaofei ， 2001
Table 20-2 The proportion of main sources of pollution indicators of Hangzhou Bay in year 2013 （ unit ： % ） pollution source livestock manure agriculture fertilizers industrial pollution domestic pollutant other pollution inorganic nitrogen 4932478 total phosphorus 291072430 BOD290172430 Notes ： quoted from Yang Chaofei ， 2001
The reason of why the faeces cause the pollution is that it has high concentrations of pollutants,and also contains large amounts of protein nitrogen, albuminoid nitrogen,ammonia nitrogen and many phosphorus and a large number of pathogens (see table 20-3) When the faeces was directly discharged into the environment without treatment,it may : Pollute the soil and groundwater Pollute the surface water, even the drinking water and endangering human health Stench pollution of the livestock’s faeces
Table 20-3 Physical and chemical properties of livestock wastes Itemcattle manure bovine urine pig manure pig urinechicken manure human excrement s Moisture （ % ） 86.294.270.595.577.5 pH7.08.37.28.06.367.0~9.0 suspended matter （ ppm ） 1190005000223000450013280022000~26 000 BOD （ ppm ） 240003900620005000654008000- 15000 COD （ ppm ） 19600599735030929745000 total nitrogen （ ppm ） 9430834446647780146005000~ 6000 ammonia nitrogen （ ppm ） 2086320426108211503000~ 4000 Notes ： quoted from Chen Weixin ， 1993
（ 4 ） Biological pollution ① Biology invasion The harm caused by biology invasion to the agricultural ecological environment and natural resources damage is irreversible,and it accelerates biodiversity loss and species extinction Once the success alien species invasion, it will be very difficult to eradicate, and it will be expensive to control the damage. The direct economy loss caused by biological invasion is 122.6 billion U.S. dollars annually in America. The economy loss caused by several main invasive species is 54.7 billion Yuan per year,in China
② Transgenic organism As unnatural evolution products, it has been widely disputed for its potential impact in human health and ecological environment safety since the success of recombinant DNA technology. Some experts believe that transgene crops or its wild relatives species can be changed to "super" weeds; may cause gene escape, resulting in "super virus"; danger to biological diversity; may adversely affect to human health
20.1.2 Agro-ecosystems damage （ 1 ） The reduction of biodiversity On one hand,agricultural production activities such as farming, the use of pesticide and fertilizer and plant and animal genetic improvement in agriculture improves the productivity,on the other hand it also impacts the biological diversity in agricultural ecosystems. Figure 20-5 shows the components and functions of biological diversity in agricultural ecosystems
Figure 20-5 Component and function of biodiversity in agro-ecosystems Notes ： quoted from Chenxin,etc ， 2002
（ 2 ） Soil degradation It is a phenomena and process,which the soil environment quality and carrying ability decline rapidly caused by human’s improper development and utilization in natural environment. In the early stage of reclamation soil, it only destroys the balance of the natural vegetation and fertility of the soil and the vegetation can also be restored by abandonment of cultivated land and the fertility can be restored by use organic manure. But overuse of soil may cause the soil erosion, desertification, salinization, swampiness and soil fertility decline and other soil degradation phenomenon. Figure 20-6 is the classification of soil degradation
Figure 20-6 Classification pattern of soil degradation （ quoted from Li Tianjie ， 1995 ）
20.2 Agro - environmental management and practice 20.2.1 Agricultural environmental management system (1) Agricultural environmental management agency Our national first-level environment division is Environment Protection Energy department of agriculture ministry.Meanwhile Agriculture Ministry sets up Environment Protection Committee to organize and coordinate environmental protection work in various sectors of agriculture.The corresponding environment management institution has also been set up in the agricultural sector of each province, autonomous region and municipality.
20.2.2 Agricultural environmental management approach Figure 20-8 The classification of agricultural environmental management measures
20.2.3 Agricultural environmental management policy (1) Environment management in the constructing process in small towns ① industrialization makes agriculture lose the resources in process of urbanization land occupation the loss of high-quality workforce the of resources
Table 20-4 The environment problem in small town construction ② The environment problem in small town construction Main problemCause Production problem Occupy land in large numberAbuse arable land, unreasonable land planning,large waste of land resources Serious pollution of township form High energy consumption, high pollution, increasing emissions, as the main pollution source of small town Ecological damageMany unreasonable conduct in construction, resulting in the rapid decay of natural resources even to depletion Live problemSerious water pollutionLack appropriate sewage disposal system, poor infrastructure Solid waste pollutionNo facility for garbage to pile up
③ Environment measures to small towns construction Adhere to balance the construction and ecological protection, enlarge environment planning for the small town Adhere to innovate in Intermediated Financing pluralistic system, enlarge investment in small-town environment protection Adhere to the sustainable development strategy, enlarge the ecological environment construction of small town
（ 2 ） Reform of agricultural production mode Agricultural industrialization is the new reform of agricultural production mode figure 20-9 The agricultural production mode change meaning to the environment
20.3 Ecological agriculture 20.3.1 Basic principles of Chinese eco-agriculture construction 20.3.2 Technology type of ecological agriculture Figure 20-10 Mulberry-Dyke-Fish-Pond—Schematic diagram of water and land exchange production systems （ quoted from the State Environmental Protection Administration ， Chinese Eco-Agriculture ， 1991 ）
20.3.3 Typical technology and environmental protection （ 1 ） Main techniques and environment effects of material cycles in ecological agriculture system Figure20-11 Main practical technology and environmental benefits
（ 2 ） In-system matter cycle process Figure 20-12 Cycle model of Guquan ecological farm （ quoted from the State Environmental Protection Administration ， 1991 ）
（ 3 ） Ecological agricultural system and environment of circular use of materials Biogas is central link of system energy conversion, material recycling and comprehensive utilization of organic fertilizers, is the tie combining the primary producers, primary consumers and decomposers As the figure 20-13a,the energy substance is not fully used and just used a part of it in the agricultural cycle without biogas. The cycle becomes perfect and improves the utilization of energy substance after using the biogas (see figure 20-13b).It reduces the harm to the resource environment and is conducive to agricultural environment protection
a.The traditional agricultural circulation （ incomplete circulation ） b. Virtuous circle of ecological agriculture system Figure 20-13 Comparison figure of two agricultural circulation
（ 4 ） Ecological agricultural system energy analysis of circular use of materials The energy input of natural ecosystem is maily the solar energy.But the energy inputs of artificial ecosystem are with many additional energy beside the solar energy which is named as artificial energy Agro-ecosystem is an artificial ecosystem,it can determine whether high yield and stability, and can find the problem in certain places and certain aspects to adopt effective measures by the analysis of energy input-output.
Figure 20-14 Input/output of material circular ecological agriculture system energy
20.4 Modern intensive sustainable agriculture 20.4.1 The concept and aim of modern intensive sustainable agriculture Definition: an acceptable mode of agricultural production operation which adopts the base methods to maintain the natural resource, ensures the people of present and future generations to meet the demand for agricultural products by technology and mechanisms transform, maintains the land, water, plant and animal genetic resources,and will not cause environment degradation.Its technology is appropriate,and also feasible in economy point. Aim ： Resource intensivism Production modernization Management industrialization
20.5 Case study The construction of Dazu eco-agriculture demonstration zones Dazu County locates in southeast of Sichuan Basin,and west of Chongqing City Survey and zoning work of agricultural resources have been taking in Dazu County from 1980 -1982,and there were serious problems in agriculture ecological environment: the forest cover reduces to 320,000 mu in 1987 from the 1190,000 mu in early 1950’s,and the soil erosion is serious, the loss area achieving 40.2% of the whole county covers area. In view of this serious situation, " the overall planning of eco-agriculture for south-north Mountain of Dazu County,."was completed in May 1984
Figure 20-15 Geographical diagram of Dazu(map of Chongqing)
Figure 20-16 The content of ecological agriculture construction in Dazu
(1) Ecological benefits analysis ① The ecological benefits analysis of rice-fish culture model Use of resources have been improved Improve the soil fertility and save the amount of fertilizer Beneficial to inhibit weed and pests, reducing the use of pesticide
Figure 20-17 Material cycle and energy conversion brief chart of fishing in paddy field
② Analysis on biogas ecological project Dazu county is an agricultural county, and the straw output of rice, wheat, corn, beans, sorghum and other crops is much.The annual output of straw is 355,300 tons. It can produce 71 million m3 biogas if fully used the straw as raw material
Figure 20-5 Analysis on typical model Samples of model Financial analysis Environment Economy analysis The main problem of effecting the promotion Policy focus Rice-fish culture excellent Whether the financial benefits can be achieved smoothly,it mainly depends on whether the output and price of fish is stable Maintain the financial benefits of the farmers Biogas engineering Just so soexcellentOne-time investment is too large and it needs operating cost. Farmers’s direct financial benefit is not high external benefits from the society to the farmers Grain for Green Project PoorexcellentIt requires considerable material and labor, and financial gain is difficult to implement in a short term Encourage and guide the farmers to adjust mode of operation