How to establish a complete non-point source pollution monitoring and evaluation system

In recent years, the impact of agricultural production on the ecological environment, as well as the pressure of the ecological environment on agricultural production, has attracted increasing attention and emphasis. With the accelerating rise in labor prices, intensifying shocks from the international market, and fluctuations in domestic grain prices, the profit margin of agricultural production, squeezed between the "ceiling" and the "floor," has become increasingly narrow. How to maintain sound and rapid agricultural development while reducing environmental pressure has drawn the attention of more and more experts and scholars.

Non-point source pollution, also known as diffuse pollution or scattered pollution, mainly comes from the use of agricultural chemicals, livestock and poultry farming, and agricultural and rural waste. Its most prominent characteristics are strong uncertainty, large spatial and temporal differences, and complex influencing factors and action processes.

"The massive input of agricultural chemicals (chemical fertilizers, plastic film, pesticides), improper straw disposal, and livestock and poultry manure are **currently the main sources of agricultural non-point source pollution. And farmers' behavioral decisions are the most direct cause of agricultural non-point source pollution."** Professor Ma Huilan of the College of Economics and Trade at **Agricultural University told reporters.

China is a major consumer of chemical fertilizers. In recent years, China has used nearly 30% of the world's nitrogen fertilizer on less than 10% of the world's cultivated land. "In a survey of typical areas in the **Tarim River Basin, it was found that farmers with lower education levels, fewer family laborers, and longer planting years tend to apply more chemical fertilizer." Ma Huilan told reporters, "Many farmers make fertilizer application decisions mainly based on personal habits and introductions from relatives and neighbors, with obvious imitative and mutual learning behavior and strong conformity. Therefore, publicity and demonstration for rational fertilizer use and soil testing-based formula fertilization are very important."

In the survey, farmers in the Tarim River Basin generally believed that fertilizer prices had risen rapidly in recent years, but this did not affect their increased use of chemical fertilizers, because compared with applying organic fertilizer and green manure, the yield-increasing effect of chemical fertilizers is often "immediate." The effects of organic fertilizer and green manure in improving soil quality often take several years or longer to be seen. Farmers' expectation of pursuing short-term interests makes it difficult for them to take a longer view and apply fertilizer scientifically and rationally.

**As China's most important main cotton-producing area, the amount of plastic film used is very large. However, the reality that thin plastic film is dominant and the recovery rate is relatively low is not optimistic. "At present, **rural plastic film is sold by weight. That is to say, for plastic film of the same weight and the same price, the cost of using thin plastic film is lower, so farmers naturally choose thin plastic film, which leads to difficulties in recovery and thus causes pollution over a large scope and to a great extent." "Although more than half of the farmers in the survey said that the plastic film recovery area in their cotton fields reached 100%, more than 15% of farmers still do not recover plastic film at all." Ma Huilan told reporters, "Farmers' participation in recovering plastic film is relatively high, but many disposal methods are unreasonable. The vast majority of farmers dispose of used plastic film by burning or burying it, and farmers with lower education levels are more inclined to burn it." What is gratifying is that the survey found that farmers with longer planting time also have a stronger willingness to dispose of used plastic film and a higher tendency to recover plastic film.

In crop cultivation, in addition to water and fertilizer, pest and disease control is also a crucial link. The types of pesticides used, spraying methods, and frequencies differ greatly among grain crops, cash crops, and forest and fruit crops. **Cotton has the largest pesticide input, averaging 50 yuan to 100 yuan per mu, while wheat and corn have relatively lower pesticide inputs, mostly averaging 10 yuan to 30 yuan. In addition to pesticide residues themselves, improper disposal of pesticide packaging and leftover pesticides can also cause great pollution. "Improper and unsafe handling of empty pesticide containers by surveyed farmers is relatively common. Only a very small number of farmers take them out of the fields or recover them centrally, and farmers' methods of storing pesticides and handling leftover pesticides are also unreasonable." Ma Huilan said, "Although farmers have a strong awareness of self-protection during pesticide application, and most farmers know that pesticides are toxic and have side effects, few farmers know that the state has regulations banning highly toxic pesticides."

Discarding straw in piles without treatment or burning it is also an aspect of agricultural non-point source pollution in the Tarim River Basin. The survey found that lack of time, high disposal costs, and it being too troublesome are the reasons why farmers do not treat or burn straw.

It is understandable that farmers pursue the maximization of their own interests. 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 analyzed, "First, the state should attach importance to agricultural non-point source pollution, carry out monitoring and forecasting of agricultural non-point source pollution, and establish a complete agricultural non-point source pollution monitoring and evaluation system. Second, improve and perfect relevant policies, and restrict behavior that causes agricultural non-point source pollution through policy means such as subsidies, taxes, and supporting laws and regulations. At the same time, further strengthen publicity, guide farmers to make rational inputs and use them scientifically, and establish environmental awareness. More importantly, research and development of technologies such as degradable agricultural film, low-toxicity and low-residue pesticides, soil testing-based formula fertilization, and biological breeding should be increased and strengthened, as should the promotion, demonstration, and application of scientific and technological achievements, so as to fundamentally control and reduce non-point source pollution."