不同施肥模式下苕溪流域水稻田和蔬菜地氮磷流失规律

Characteristics of nitrogen and phosphorus loss by runoff from paddy and vegetable fields under different fertilization modes in Tiaoxi catchment

采用田间径流池小区试验方法,在自然降水条件下,于2016—2017年连续2 a在余杭区对不同施肥模式下地表径流及氮磷流失特征进行田间实地监测。结果表明:年际间因降水原因导致氮素流失差异。不同施肥处理下,2016年和2017年水稻田的全氮流失量分别为12. 76～16. 97、15. 40～17. 60 kg·hm^(-2),蔬菜地的全氮流失量分别为23. 06～25. 72、18. 11～27. 93 kg·hm^(-2)。水稻田和蔬菜地的氮素流失均以硝态氮为主。不同施肥处理下,2016年和2017年水稻田全磷流失量分别为2. 36～2. 62、3. 57～4. 05 kg·hm^(-2)。不同施肥处理对水稻田和蔬菜地径流水中总磷浓度无显著影响。水稻田磷素流失以可溶态磷为主,蔬菜地磷素流失以颗粒态磷为主。相比水稻田,蔬菜地的氮素流失量更高,而磷素流失量更低。减氮施肥和有机肥替代可在保证产量的基础上降低7%～35%的总氮径流损失。

A continuous two-year field experiment with building runoff ponds on the typical paddy and vegetable lands in Tiaoxi basin was conducted to study the characteristics of nitrogen and phosphorus loss with surface runoff.The nitrogen loss was different between years due to the precipitation.The total nitrogen losses in 2016 and 2017 were 12.76-16.97,15.40-17.60 kg ·hm^-2,respectively,in paddy field,and were 23.06-25.72,18.11-27.93 kg·hm^-2,respectively,in vegetable field.The total nitrogen loss was mainly in NO3^--N state in both paddy field and vegetable field.The total phosphorus losses in 2016 and 2017 were 2.36-2.62,3.57-4.05 kg ·hm^-2,respectively,in paddy field.Compared with the conventional fertilization,nitrogen reduction or organic fertilizer did not significantly influence the phosphorus loss.The total phosphorus loss was mainly in soluble phosphorus state in paddy field,whereas it was the particle phosphorus state in vegetable field.The total nitrogen losses were higher in vegetable fields than that in paddy fields,but the total phosphorus losses were the opposite.The fertilizer reduction or organic fertilizer treatments decreased the N loss loading by 7%-35% as compared to the conventional treatment,yet maintained the yield.