南方湿润平原区露天菜地氮磷流失特征及其防控

Characteristics and Control of Nitrogen and Phosphorus Loss in Open Vegetable Fields in Moist Southern Plains

为探究南方湿润平原区的露天菜地氮磷流失特征及其防控效果,设置了常规施肥(CK)、优化施肥(KF)以及优化施肥结合地膜覆盖(BMP)3个处理,在2015-2022年间开展了定位观测。结果表明:各处理径流中的氮均以硝态氮为主,占比85.22%~86.10%,其总氮含量随种植年限增加均呈现先升高再降低趋势,KF和BMP处理分别显著降低径流总氮含量14.29%和21.43%;可溶性磷是径流中磷的主要形态,占比76.87%~79.16%,径流总磷含量呈现逐年升高趋势,KF和BMP处理可使其显著降低26.78%和29.10%。即便优化施肥并覆盖地膜后,径流氮、磷含量仍超出地表水V类标准限值,其风险尚需重视。

To explore the characteristics of nitrogen and phosphorus loss in open vegetable fields in moist southern plains and the effectiveness of their control,three treatments were set up:conventional fertilization(CK),optimized fertilization(KF),and optimized fertilization combined with plastic film mulching(BMP).Positioned observations were conducted from 2015 to 2022.The results show that nitrogen in runoff is mainly nitrate nitrogen,accounting for 85.22%–86.10%.The total nitrogen content increases first and then decreases with the increase in planting years for all treatments.KF and BMP treatments significantly reduce total nitrogen content in runoff by 14.29%and 21.43%,respectively.Soluble phosphorus is the main form of phosphorus in runoff,accounting for 76.87%–79.16%.The total phosphorus content in runoff shows an increasing trend year by year,and KF and BMP treatments can significantly reduce it by 26.78%and 29.10%.Even with optimized fertilization and plastic film mulching,nitrogen and phosphorus content in runoff still exceeds the Class V standard limit for surface water,indicating that the risks still need to be addressed.