How can non-point source pollution be prevented and controlled? Green agriculture has the answer
According to reports, agriculture has now overtaken industry to become China's largest non-point source pollution sector. Agriculture, which should be green and healthy, why has it instead become an “accomplice” to pollution? How can we tackle agricultural non-point source pollution and restore the land to a naturally fresh and clean appearance?
[Current situation]
No. 1 in the world in fertilizer and pesticide use; agriculture has overtaken industry to become the largest non-point source pollution sector
At present, agriculture has overtaken industry to become China's largest non-point source pollution sector. “Agricultural non-point source pollution is large in volume, diverse in type and wide in distribution, and the overall situation is not optimistic,” said Zhang Taolin, Vice Minister of Agriculture.
Northwest arid regions: the problems of agricultural film pollution and white pollution are prominent
Central and eastern regions: the problem of non-point source pollution from pesticides and fertilizers is prominent
Southern regions: the problem of pollution from livestock and poultry manure in agriculture is prominent
The biggest characteristics of agricultural non-point source pollution are its hidden nature, long-term nature and dispersed nature; it is generated consciously or unconsciously in every link and every process of agricultural production, and is relatively troublesome to deal with. Experts say that China's fertilizer and pesticide use is considerable, with both production and use ranking first in the world. However, the utilization rate of fertilizers and pesticides is 15%-20% lower than that of developed countries, so reducing usage and raising the utilization rate is imperative.
Heavy metal pollution becomes an “invisible killer” of agricultural product quality
According to the “Communique on the National Survey of Soil Pollution” published by the Ministry of Environmental Protection and the Ministry of Land and Resources, the overall national soil environmental situation is not optimistic, soil pollution in some areas is relatively serious, and the exceedance rate at cultivated land soil sampling points is 19.4%, with the main pollutants being cadmium, nickel, copper, arsenic, mercury, lead, DDT and polycyclic aromatic hydrocarbons.
Experts point out that “invisible” heavy metal pollution is playing the role of an “invisible killer” in the quality and safety of agricultural products, and may not only affect farmland and the surrounding rural environment, but also make ordinary consumers doubtful about the quality and safety of agricultural products. “In addition to soil heavy metal pollution caused by the discharge of industrial waste, the massive input of agricultural chemicals can lead to land pollution caused by the enrichment of nutrients, heavy metals and toxic organic matter in the soil, directly threatening the quality and safety of agricultural products,” said Zhang Fusuo, a professor at China Agricultural University.
[Prevention and control]
“One reduction, two controls, three basics”
China's agricultural resources and environment are under the dual pressure of exogenous pollution and endogenous pollution, and the sustainable development of agriculture has encountered a bottleneck. In order to curb the expanding trend of agricultural non-point source pollution, the Ministry of Agriculture issued the “Implementation Opinions on Fighting the Tough Battle of Agricultural Non-point Source Pollution Prevention and Control.” Regarding the prevention and control of agricultural non-point source pollution, the Opinions put forward the goal of “one control, two reductions, three basics”: “one control” means strictly controlling the total amount of agricultural water use and vigorously developing water-saving agriculture; “two reductions” means reducing the use of chemical fertilizers and pesticides and implementing an action for zero growth in chemical fertilizers and pesticides; “three basics” refers to the basically resource-oriented utilization of livestock and poultry manure, crop straw and agricultural film.
Foreign experience can be drawn on
According to a 1990 survey and assessment report in the United States, non-point source pollution in the United States accounted for about 2/3 of total pollution, of which agricultural non-point source pollution accounted for 68%-83% of the total non-point source pollution, causing 50%-70% of surface water bodies to be polluted or affected. After years of effective treatment and control, agricultural non-point source pollution in the United States has been greatly reduced. According to 2006 statistics, the area of agricultural non-point source pollution in the United States was reduced by 65% compared with 1990. So what measures has the United States taken?
First, policy measures. The United States has a systematic legal framework for agricultural pollution control; it enacted its first non-point source pollution control law in 1936, which has since been amended many times. In addition, the U.S. Environmental Protection Agency implemented a non-point source pollution management plan, the Department of Agriculture implemented the Rural Clean Water Program, the National Irrigation Water Quality Program, the Agricultural Soil and Water Conservation Program, and others, while other national functional departments formulated such things as the Clean Water Act, the maximum daily load plan, and the pesticide implementation plan, and actively encouraged farmers to take the initiative in controlling agricultural pollution, which played a great role in reducing non-point source pollution. For those who voluntarily adopt prevention and control measures for non-point source pollution, the government will share part of the costs; for those who voluntarily adopt other measures, the government gives policies such as tax reductions and exemptions.
Second, technical measures. Alternative technologies that are simple to operate and cheap in price are the key to agricultural non-point source pollution control. In controlling agricultural non-point source pollution, the United States gives farmers no subsidies or only very few, mainly encouraging farmers to voluntarily adopt environmentally friendly alternative technologies. Management measures for non-point source pollution targets include 2 types: engineering type and non-engineering type. Engineering-type measures include constructed wetlands, vegetative filter strips and grassland, riparian buffer strips, stormwater retention ponds and sedimentation ponds, etc.; non-engineering-type measures include no-till and reduced-till methods, integrated management of harmful substances, and reuse of biological waste, etc. The Department of Agriculture sets aside special funds to support farmers in developing ecological agriculture to reduce non-point source pollution, the Soil Conservation Service provides technical guidance to help local governments control soil erosion, and the Department of the Interior and the Environmental Protection Agency provide intelligence and information for water resource planning and non-point source control at different scales and levels.
Third, other measures. The United States has introduced operating models such as biological agriculture, organic agriculture, regenerative agriculture and green agriculture, and effectively controls the input of highly toxic pesticides in agricultural production through legal, technical and other means.