How can the challenge of preventing and controlling agricultural and rural water pollution be solved?
Recently, a concentrated outbreak of blue-green algae in Dianchi Lake in Yunnan has become a hot topic of social concern during the peak summer tourism season. In recent years, concentrated outbreaks of blue-green algae in rivers and lakes have been common, highlighting the severe situation of the water environment in many rural areas of our country. Not long ago, the State Council issued the "Water Pollution Prevention and Control Action Plan", proposing to accelerate comprehensive rural environmental improvement, prevent and control livestock and poultry breeding pollution, control agricultural non-point source pollution, and adjust the structure and layout of the planting industry, precisely in order to fundamentally solve this problem. So how can the prevention and control of agricultural and rural water pollution break through the problem?
Comprehensive improvement raises water quality
“When I was a child, the river water was so clear. When guests came to the house, we boiled water, and I would go down to the river to catch fish on the spot, and I could catch one every time. Later, the river water became black and smelly, not even grass grew in the river, and the fish and shrimp were gone too.” Speaking of Tongxin River in front of his home, 65-year-old Zhao Genbao of Xinle Village, Kunshan, Suzhou City, Jiangsu Province, by the shore of Taihu Lake, was very distressed.
For decades, with economic development, the rural water environment in Suzhou has deteriorated day by day. Rural sewage was untreated and all directly discharged into river channels, and the river water turned black and smelly. The water body of Taihu Lake was polluted, the ecology deteriorated, and it accelerated toward swampification.
Under the severe situation of water ecology deterioration, Suzhou launched a comprehensive urban and rural water environment improvement project. According to Xia Jian, deputy director of the Suzhou Municipal Water Affairs Bureau, since 2007, Suzhou has established 337 long-term river channel management agencies, with more than 8,500 river channel cleaners alone, invested 137 million yuan, increased sewage pipe networks from 3,540 km to 10,024 km, and fully reached the Grade A standard for effluent. In addition, Suzhou established a mechanism of “regular rotational dredging” for rural river channels, clearly specifying the dredging cycle. At present, the water quality compliance rate of water function zones has increased from 15.4% in 2007 to 65%. Rural domestic sewage treatment started from zero, benefiting 289,000 farmer households in 1,728 natural villages. Tongxin River, which Zhao Genbao deeply worried about, after sewage interception, pollution control, dredging, and ecological restoration, now once again ripples with gentle blue waves.
Zero growth in chemical fertilizers and pesticides
“By 2020, the trend of intensifying agricultural non-point source pollution must be effectively curbed, and the application amount of chemical fertilizers and pesticides on major crops nationwide must achieve zero growth.” said Zhang Taolin, Vice Minister of Agriculture.
The agricultural and rural water pollution problem is prominent, and an important reason is excessive application of chemical fertilizers and pesticides, resulting in severe agricultural non-point source pollution. “Unreasonable fertilization and pesticide use are very common in our country. It is estimated that the average seasonal utilization rate of chemical fertilizers nationwide is only 35%, and the annual loss of fertilizer input caused by unreasonable fertilization reaches 130 billion yuan.” said Gao Xiangzhao, director of the Water-Saving Agriculture Technology Division of the National Agricultural Technology Center of the Ministry of Agriculture.
The solution is the “two reductions”, namely reducing the use of chemical fertilizers and pesticides. The "Water Pollution Prevention and Control Action Plan" clearly proposed: promote the pilot experience of subsidies for the use of low-toxicity and low-residue pesticides, and carry out green prevention and control and unified prevention and control of crop diseases and pests. Zhang Taolin said that the Ministry of Agriculture has launched an action for zero growth in chemical fertilizers and pesticides.
To achieve zero growth in chemical fertilizers, an important method is soil testing and formula fertilization. According to statistics from the National Agricultural Technology Center of the Ministry of Agriculture, the national area of soil testing and formula fertilization has reached 1.3 billion mu. “From 2005 to 2010, our country's grain output increased by 80 million tons, vegetable supply increased by 100 million tons, and fruit increased by 60.6 million tons. Calculated according to the current fertilizer utilization rate, an additional 19.4 million tons of chemical fertilizers would need to be applied, but due to the promotion of soil testing and formula fertilization, the national chemical fertilizer application amount increased by only 7.9546 million tons. The contribution of soil testing and formula ‘weight loss’ is still very large.” said Gao Xiangzhao.
Zero growth in pesticides depends on specialized unified prevention and control and green prevention and control of diseases and pests. It is understood that this year the Ministry of Agriculture continued to carry out pilot integration of specialized unified prevention and control and green prevention and control. This work focuses on crops such as rice, wheat, and corn, and established 218 demonstration bases nationwide. Among them, for rice, wheat, and corn, each base has a demonstration area of more than 10,000 mu, radiating and driving 100,000 mu; for potatoes, peanuts, and cotton, each base has a demonstration area of more than 5,000 mu, radiating and driving 50,000 mu; for apples, citrus, vegetables, and tea, each base has a demonstration area of more than 2,000 mu, radiating and driving 20,000 mu.
Zhang Taolin said that by deeply advancing the integration of specialized unified prevention and control and green prevention and control, effective organizational forms and full-process technical models suitable for different regions and different crops can be formed, and demonstration can drive large-scale promotion and application. Judging from the practical results of previous years, the use of chemical pesticides in pilot areas decreased by more than 20%, agricultural product quality met national food safety standards, and the ecological environment and biodiversity improved somewhat.