What are the main problems with chemical fertilizer application in China?

First, the amount of chemical fertilizer applied is still too large. In 2012, China's total agricultural chemical fertilizer application reached 58.39 million tons (pure nutrient basis, same below), accounting for about 1/3 of the world's total chemical fertilizer application, equal to the sum of the United States and India, and China has become the world's largest chemical fertilizer consuming country. China's average chemical fertilizer application per mu of crops is 21.2 kg, far higher than the world average of 8 kg, 3 times that of the United States, and 2.5 times that of India and the European Union. Excessive fertilization not only increases agricultural production costs, but also consumes a large amount of resources and energy, causing soil and groundwater pollution.

Second, the fertilization structure is still not quite reasonable. For a long time, farmers have developed the habit of emphasizing nitrogen fertilizer while neglecting phosphate and potassium fertilizers, emphasizing macroelement fertilizers while neglecting medium and trace element fertilizers, and emphasizing chemical fertilizers while neglecting organic fertilizers. At present, China's utilization rate of organic fertilizer resources is about 25%, among which the rate of livestock and poultry manure nutrients returned to the field is about 50%, and the rate of straw nutrients directly returned to the field is only 35%. Organic nutrients account for 40% of total nutrient input, 10 percentage points lower than the reasonable application ratio.

Third, fertilization methods are still relatively backward. The corn production areas of Northeast China and the Huang-Huai-Hai region mostly adopt the "one-shot" fertilization method, causing fertilizer waste and fertilizer shortage in the later stage. In addition, with rising labor costs and unsupported fertilization equipment, shallow application, surface application, and broadcast application of chemical fertilizers are relatively common. Expert analysis shows that more than 80% of topdressing for wheat, rice, and soybean uses surface broadcasting, while vegetable topdressing mostly uses the method of flushing with large amounts of water, resulting in relatively serious fertilizer loss.