浙江省农田养分平衡的时空变化及环境风险分析

为评价浙江省农业生产对环境的影响，采用2000~2014年统计年鉴的农业生产数据，建立农田养分平衡模型，对氮（N）、磷（P）养分输入强度和利用效率的变化趋势进行分析，并以地级市为单位分析养分盈余率的空间差异。结果表明：2000~2014年期间，N输入强度基本保持稳定，利用效率提高了1.4%；P输入强度增加了20.5%，但利用效率下降幅度达17.5%。N、P养分的平均利用效率分别为0.36和0.28，利用效率均偏低。化肥是养分的首要来源。对各市养分盈余率进行空间和时间序列趋势分析发现，金华和温州是N、P养分盈余最为严重的城市，湖州是唯一N、P盈余率均显著增加的城市。P污染风险的大小和影响范围均大于N污染风险。为此，建议浙江省降低化肥施用量，特别减少P素施用量，提高养分利用效率，着重加强金华、温州、湖州等重点区域的污染控制，以此降低农业面源污染风险。 关键词： 养分平衡；养分利用效率；农业面源污染；空间分析；时间序列趋势分析

Analysis of Temporal and Spatial Variations of Nutrient Balance and Its Environmental Risk in Zhejiang Province

The nutrient balance can be served as an effective indicator of the environment performance of agricultural production.To estimate environmental impacts of agriculture production in Zhejiang Province,temporal trend of nutrient input,use efficiency and surplus intensity,together with the regional difference in nutrient surplus among cities,were analyzed based on agricultural data derived from statistic yearbook from 2000 to 2014.Chemical fertilizer was the primary source of nutrient input.The nitrogen (N) input intensity basically remained stable,while the phosphorus (P) input intensity increased by20.5％.Simultaneously,the N use efficiency increased by 1.4％,while the P use efficiency decreased by 17.5％.The average use efficiencies of N and P were low and had a value of 0.36 and 0.28,respectively.Results of GIS and temporal trend analyses showed that pollution risk of P input was higher than that of N in terms of risk magnitude andinfluence sphere.Jinhua and Wenzhou suffered the most from nutrient surplus,and Huzhou was the only city exhibiting significant positive trends of both N and P surplus ratios.This work suggests that reduction in chemical fertilizer application and enhancement of nutrient use efficiency,should help reducing the risk of non-point source pollution.Reduction of P input and nutrient management in key areas such as Jinhua,Wenzhou and Huzhou should be given higher priority.This work provides more targeted evidence of agricultural non-point source pollution control in Zhejiang Province.