Establishment of a complete monitoring and evaluation system for non-point source pollution

In recent years, the impact of agricultural production on ecological environment and the pressure of ecological environment on agricultural production have been paid more and more attention. With the acceleration of labor price rise, the aggravation of international market impact and the fluctuation of domestic grain price, the profit space between "ceiling" and "floor" of agricultural production is getting smaller and smaller. How to keep healthy and rapid development of agriculture while reducing environmental pressure has attracted more and more experts and scholars 'attention.

Non-point source pollution, also known as non-point source pollution or diffusion pollution, mainly comes from agricultural chemicals use, livestock breeding, agricultural and rural wastes, etc. Its most prominent characteristics are strong uncertainty, large temporal and spatial differences, complex influencing factors and action processes.

"Agricultural chemicals (fertilizer, plastic film, pesticides) a large number of inputs, improper straw treatment and livestock manure are ** currently the main agricultural non-point source pollution sources. The behavior and decision-making of farmers is the main reason that directly leads to agricultural non-point source pollution. Professor Ma Huilan of the School of Economics and Trade of Agricultural University told reporters.

China is a big country of chemical fertilizer application. In recent years, China has used nearly 30% of nitrogen fertilizer in less than 10% of the world's cultivated land. "The survey in typical areas of ** Tarim River Basin found that farmers with lower education level, less family labor force and longer planting years tend to apply more chemical fertilizers." Ma Huilan told reporters,"Many farmers 'fertilizer application decisions mainly rely on personal habits and introduction of relatives and neighbors, there are obvious imitation and mutual learning behavior, there is a strong convergence. Therefore, it is very important to publicize and demonstrate the rational use of fertilizer and soil testing and formula fertilization."

In the survey, farmers in Tarim River Basin generally believe that the rapid increase in chemical fertilizer prices in recent years does not affect their increase in chemical fertilizer application, because compared with the application of organic fertilizer and green manure, the effect of increasing production brought by chemical fertilizer is often "immediate", while the effect of organic fertilizer and green manure for improving soil quality often takes several years or longer to be seen. Farmers 'expectation of pursuing short-term benefits makes it difficult for them to put their eyes on longer-term, scientific and reasonable fertilization.

** As the most important cotton producing area in China, the use of plastic film is very large, but the reality of thin plastic film and low recovery rate is not optimistic. "At present, ** rural plastic film is sold by weight, that is to say, the same weight and price of plastic film, the cost of using thin plastic film is lower, farmers will naturally choose thin plastic film, resulting in recovery difficulties, and then bring a large range and degree of pollution","although more than half of the farmers in the survey said that their cotton field plastic film recovery area reached 100%, but there are still more than 15% of farmers do not recycle plastic film at all." Ma Huilan told reporters,"Farmers 'participation in recycling plastic film is relatively high, but many treatment methods are unreasonable. Most farmers dispose of waste plastic film by incineration or landfill. The less educated farmers are, the more inclined they are to incinerate." It is gratifying that the survey found that the longer the planting time, the stronger the willingness of farmers to treat waste plastic film, and the higher the tendency of plastic film recycling.

In addition to water and fertilizer, pest control is also a crucial link in crop cultivation. There are great differences in pesticide types, spraying methods and frequency among grain crops, cash crops and fruit crops. ** Cotton has the largest pesticide input, averaging 50 yuan ~100 yuan per mu, while wheat and corn have relatively small pesticide input, averaging 10 yuan ~30 yuan. In addition to pesticide residues, pesticide packaging and improper handling of residual pesticides will also cause great pollution. "Improper and unsafe disposal of empty pesticide containers by investigated farmers is common, only a few farmers will take them out of the field or recycle them uniformly, and the way farmers store pesticides and dispose of residual pesticides is unreasonable." Ma Huilan said,"Although farmers have a strong sense of safety in the process of pesticide application, most farmers know the toxic side effects of pesticides, but not many farmers know that the state prohibits highly toxic pesticides."

Untreated or incinerated straw is also one of the reasons for agricultural non-point source pollution in Tarim River Basin. Investigation shows that lack of time, high cost and too much trouble are the reasons why farmers do not treat or incinerate straw.

Peasant households pursue the maximization of their own interests, which is understandable. However, it is currently impossible for farmers to control their own behavior and consciously reduce pollution. "This requires the government to guide and restrict through policies." Ma Huilan said,"First of all, the state should pay attention to agricultural non-point source pollution, carry out monitoring and forecasting of agricultural non-point source pollution, and establish a complete monitoring and evaluation system for agricultural non-point source pollution." Secondly, improve and perfect relevant policies, and restrict the behavior of agricultural non-point source pollution through subsidies, taxes, supporting laws and regulations and other policy means. At the same time, further strengthen publicity, guide farmers rational input, scientific use, establish environmental awareness. More importantly, we should increase and strengthen the research and development of degradable agricultural film, low toxicity and low residue pesticides, soil testing and formula fertilization, biological breeding and other technologies, as well as the promotion, demonstration and application of scientific and technological achievements, so as to fundamentally control and reduce non-point source pollution."