Abstract:

A lot of studies has demonstrated that preventing nitrogen and phosphorus from agricultural production into water and atmospheric environments has become one of the largest challenges facing modern agriculture. In order to understand status and problems existing in pollution control from agricultural sources in China, a comparative study between China and Germany on the control systems for agricultural source pollution was carried out. The relevant laws, regulations and technical standards issued by China and Germany were reviewed and summarized, and implementation effects of these regulations in recent years were compared. Study showed that similar to China, because of the short of per capita arable land resources in Germany, the family farm has been the main management form for agriculture in Germany. Farmers in Germany had always to face several problems, such as relatively small management scale, scattered fields, high risks and low profits, due to meteorological and marketing uncertainties. Financial subsidy by government has been essential to farmer’s surviving and agricultural development in Germany. Thus, attentions should always be paid not only on environmental objectives, but also on farmer’s interests, agricultural surviving and food security. In such conditions, main approach for agricultural source pollution control was to establish and running the control system and mechanisms with institutional guarantee, instead of simply adopting administrative punitive measures to farmers, such as closing, stopping, merging and turning over. For improving farmer’s knowledge and techniques of fertilization with the purpose to cut down fertilizer application amount, the most effective way was to design a complete quantitative criterions for best farmer’s fertilization practices with differentiated regions and classes’ specifications. These simple quantitative criterions were easy to be understood by farmers and applicable to soil and climate conditions in different regions. Subsequently, these quantitative criterions were easy to be disseminated and have contributed greatly in improving crop yield by decreased fertilizer application. For prevention of nitrogen and phosphorus releasing from agriculture into water and atmosphere, main measures in Germany were establishing and implementing a series of technical specifications with legal restriction and punishments, in which nitrogen input, nitrogen and phosphorus surplus of crop land, fertilizing seasons, fertilizing approach as well as crop rotations were clearly regulated. At the same time, new and more effective monitoring and management methods have been studied continuously in the purpose to enhance economic leverage’s role, to encourage and to help farmers for accepting more accurate and environmentally friendly technique alternatives. Through implementing agricultural source pollution control strategies, the fertilizer input of Germany has been reduced by 50% since the 1980s. The average fertilizer application amount in terms of farmland area (arable land area and long-term crop area) has been reduced from 404 kg·hm ^-2 to 192 kg·hm ^-2, which was 53% of the current value of China. In the same period, the average grain yield in Germany increased by 56%, from 4 779 kg·hm ^-2 to 7 464 kg·hm ^-2, which was about 37% higher than the current value of China. For improving farmer’s knowledge and techniques of fertilization with the purpose to cut down fertilizer application amount, the most effective approach was to design and complete a set of quantitative criterions for best farmer’s fertilization practices with differentiated regions and classes’ specifications. These simple quantitative criterions were easy to be understand by the farmers and applicable to soil and climate conditions in different regions. Subsequently, these quantitative criterions were easy to be disseminated and played important role in improving farmers' fertilization techniques and increasing crop yield continuously by decreased fertilizer amount. Up to now, there has been a lack of quantitative criterions for best fertilization practices designed for farmers in China, which were suitable for farmers' cognition and direct use. Also, there has been no technical specifications related to the national and local government's reward and punishment policies issued. Whether in nationwide or in a watershed case, it was still difficult to operate agricultural source pollution control with institutional guarantee. The area of vegetable, fruit, flowers and other cash crops accounted for 23.6% of the total cropping area in China, which was very common for farmers to apply fertilizer blindly or excessively. In such crop field, the nitrogen and phosphorus nutrient surplus far exceeds the environmental safety limit (50 kg N·hm ^-2, 10 kg P₂O₅·hm ^-2) given by German fertilizer regulations. Up to now, there has been a lack of quantitative criterions for the best fertilization practices designed for farmers in China, which were suitable for farmers' cognition and direct use. Also, there has been no technical specifications issued, which was related to the state or local government's reward and punishment policies for environment protection. Whether in nationwide or in a watershed case, it was still difficult to operate agricultural source pollution control with institutional guarantee. Analysis showed that the core for agricultural source pollution control was to issue and implement relevant laws, regulations, technical standards and monitoring methods by innovative research works. In recent years, however, the concerning research work has been weakened up due to homogenization and fragmentation of the research institutions, who are originally specialized for applied research works for soil and fertilization. Also, the quantitative evaluation system for scientific contribution and the excessive dependence on papers with high SCI-index has negative influences on the researches for practical use. This needs to be improved urgently.

Key words: agricultural source pollution, fertilization technique, agricultural environment standard, technique criterions for farmers, pollution control system, China, Germany