河北省不同利用方式农田土壤氮磷环境风险分析

弄清不同利用方式农田土壤氮磷养分平衡状况,进而明确其环境风险特征,为进一步指导土壤养分管理及环境政策制定具有重要意义。研究以河北省的粮田、果园和菜地为研究对象,通过分析三种利用方式氮磷的输入、化肥和有机肥的分配比例及氮磷养分的盈余状况,并结合化肥使用环境风险指数,评价三种不同利用方式化肥氮磷的环境风险类型。结果表明,氮总输入量为菜地明显高于果园和粮田,磷总输入量为菜地和果园明显高于粮田,且粮田和菜地氮磷输入主要以化肥为主。三种不同利用方式农田氮磷均呈盈余状态,其中氮盈余率为果园(532.6%)明显高于菜地(61.5%)和粮田(31.6%),磷盈余率为菜地(700.4%)和果园(615.7%)明显高于粮田(66.6%)。化肥氮磷的环境风险指数均为菜地(0.83)明显高于粮田(0.59-0.62),三种不同利用方式下化肥氮磷的环境风险类型均达低度风险及以上,特别是菜地达严重风险。为了农业的可持续发展,河北省粮田应控制氮磷肥的投入,果园和菜地应加大减少氮磷肥化肥投入,以减少对环境的潜在危害。同时为了更好地培肥地力,在控制施肥总量的前提下应加大粮田和菜地有机肥的投入比例。

ENVIRONMENT RISK ANALYSIS OF SOIL NITROGEN AND PHOSPHORUS IN FARMLANDS OF HEBEI PROVINCE WITH DIFFERENT LAND USE

Understanding nutrient balance of soil nitrogen and phosphorus and its environmental risks in farmlands with different land use is critical to guide the nutrient management and formulate environmental policy. Taking the grainfield, orchard and vegetable field of Hebei province as an example, this paper analyzed the input of nitrogen and phosphorus, proportion of chemical fertilizer and organic fertilizer, nutrient surplus and fertilization environmental risk indexes, and further evaluated the environmental risk of chemical fertilizer N and P in the three land use farmland. The results showed that nitrogen input was significantly higher in the vegetable field than that in the orchard and grainfield, and phosphorus input was significantly higher in the vegetable field and orchard than that in the grainfield. A large part of nutrient source was from chemical fertilizer in the grainfield and vegetable field.Nitrogen surplus was significantly higher in the orchard (532.6%) than that in vegetable field (61.5%) and grainfield (31.6%). Phosphorus surplus was significantly higher in the vegetable field (700.4%) and orchard (615.7%) than that in the grainfield (66.6%). Fertilization environmental risk index was significantly higher in vegetable field(0.83) than that in grainfield (0.59-0.62). Types of environmental risk of nitrogen and phosphorus in the three farmlands were all exceeded light risk. Especially, fertilization environmental risk in vegetable field was more serious.It suggested that the input of chemical fertilizer nitrogen and phosphorus should be reduced, especially in the orchard and vegetable fields, to reduce the potential environment harm and maintain the sustainable development of agriculture. Meanwhile, the proportion of organic fertilizer input in the grainfield and vegetable field should be enhanced to improve soil fertility under the controlling of total amount of fertilizer.