北运河上游昌平区化肥面源污染年际间差异分析

以2014年、2017年260份调查问卷和582个土壤样品及年度农用化肥总量为依据，梳理了昌平区年际间施肥量、土壤养分、氮磷环境风险和污染源变化，以期为北运河上游化肥面源污染防控提供理论依据.结果表明，相比于2014年，2017年粮食、果类蔬菜、叶类蔬菜和草莓的化肥平均用量分别减少了26.3%、25.5%、20.4%和15.0%，蔬菜和草莓的有机肥平均用量分别减少了42.6%和6.67%.粮田和菜地氮盈余均为无风险，2017年氮素地下淋溶和地表径流损失相比于2014年分别减少了27.8%和56.0%.粮田不存在磷环境风险，菜地磷环境风险等级从2014年的高风险降至2017年的中风险.与2014年相比，2017年污染物流失量降低了47.8%.区域地表水环境均以总氮污染为主，其次是总磷和氨氮.本研究提出在夏玉米上推广环境友好型肥料和免耕措施；对果类蔬菜采取养分总量控制与分期调控的施肥策略；引导叶菜生产采用滴灌或微喷；开展草莓与多种作物间套作，加大土壤盈余氮、磷的吸收；探索建立推动土肥社会化服务的应用.

Analysis of inter-annual variation in chemical fertilizer non-point source pollution in upper stream of Beiyunhe River, Changping District

Based on 260 questionnaires, 582 soil samples in 2014 and 2017, and annual farm-oriented chemical fertilizer consumption data, inter-annual changes in fertilizer application, soil nutrient, environmental risk of nitrogen and phosphorus, pollution source in Changping district were analyzed to provide a theoretical basis for prevention and control of chemical fertilizer non-point source pollution in the upper stream of Bei yunhe river. Results showed that, compared to 2014, the average amount of chemical fertilizer applied on grains, fruit vegetables, leaf vegetables and strawberry decreased by 26.3%, 25.5%, 20.4% and 15.0%, respectively, and the average amount of organic fertilizer applied on vegetables and strawberry reduced by 42.6% and 6.67% in 2017.N surplus in both grain and vegetable fields were risk-free, with N subsurface leaching and surface runoff loss reduced by 27.8% and 56.0% in 2017 compared to 2014,separately. There is no P environmental risk in grain fields, while vegetable fields P environmental risk was declined from high risk in 2014 to medium in 2017. Pollutant loss was reduced by 47.8% in 2017 compared to 2014. Regional surface water environment were dominated by TN, followed by TP and ammonia nitrogen. It was proposed to promote environmental friendly fertilizer and no-till measures on summer corn; to adopt a fertilization strategy of total nutrient control and phased control of fruit vegetable; to guide the production of leaf vegetables by drip or micro-spray irrigation; to carry out intercropping between strawberry and other crops to increase the absorption of surplus N and P; to explore the establishment of social services to promote right application of fertilizer and soil protection.