减氮条件下不同施肥模式对稻田氮素淋溶流失的影响

稻田氮素淋溶流失是农田面源污染的主要流失途径之一.为探究洱海流域稻田合理的施肥模式，减少稻田氮素淋溶流失，通过田间小区试验，在减氮条件下设置单施化肥、单施有机肥、有机无机配施和单施缓控释肥处理，研究不同施肥模式对稻田氮素淋溶流失和水稻产量的影响.结果表明，与常规施肥处理（CF）相比，单施化肥处理（T1）和有机无机配施处理（T3）水稻籽粒和秸秆产量无显著差异；单施有机肥处理（T2）水稻籽粒产量降低13.0%，秸秆产量降低17.1%；单施缓控释肥处理（T4）水稻籽粒和秸秆产量分别增加15.7%和21.0%.与常规施肥处理（CF）相比，单施化肥处理（T1）、单施有机肥处理（T2）和有机无机配施处理（T3）土壤30 cm处总氮淋溶流失量分别降低了26.9%、18.0%和33.9%，铵态氮淋溶流失量分别降低了24.4%、36.9%和36.6%，硝态氮淋溶流失量分别降低了40.2%、4.8%和46.4%；土壤60 cm处总氮淋溶流失量分别降低了34.2%、26.3%和42.1%，铵态氮淋溶流失量分别降低了31.4%、35.7%和46.6%，硝态氮淋溶流失量分别降低了8.0%、10.1%和23.9%，单施缓控释肥处理（T4）在30和60 cm深度总氮流失量增加41.6%和14.0%.综合考虑不同施肥模式的农学效益和环境效益等因素，单施化肥处理T1和有机无机配施处理T3是可供选择的环境友好型施肥模式.

Effects of Different Fertilization Patterns on Nitrogen Leaching Loss from Paddy Fields Under Reduced Nitrogen

Nitrogen leaching loss in paddy fields is one of the main ways of farmland non-point source pollution. To explore the suitable fertilization of rice fields in the Erhai Lake Basin and reduce the nitrogen loss from paddy fields, a field experiment was conducted by setting single applications of chemical or organic fertilizer, combined organic and inorganic application, and single application of controlled release fertilizer under reduced nitrogen conditions. The results showed that, compared with the conventional fertilization treatment(CF), there was no significant difference in rice grain and straw yield between the single chemical fertilizer treatment(T1) and the organic-inorganic combined treatment(T3); the single organic fertilizer treatment(T2) decreased the rice grain yield by 13.0%, and decreased straw yield by 17.1%; single application of controlled-release fertilizer(T4) increased rice grain and straw yield by 15.7% and 21.0%, respectively. Further, compared with CF, the single application of chemical fertilizer(T1), organic fertilizer(T2), and organic-inorganic combined application(T3) reduced the total nitrogen leaching loss at 30 cm depths by 26.9%, 18.0%, and 33.9%, respectively. The loss of ammonia nitrogen leaching with T1, T2, and T3 decreased by 24.4%, 36.9%, and 36.6%, respectively, and the loss of nitrate nitrogen leaching decreased by 40.2%, 4.8% and 46.4%. The total nitrogen leaching at 60 cm soil depths was reduced by 34.2%, 26.3%, and 42.1%, the loss of ammonia nitrogen leaching was reduced by 31.4%, 35.7%, and 46.6%, and the loss of nitrate nitrogen leaching was reduced by 8.0%, 10.1%, and 23.9% for T1, T2, and T3, respectively. The total nitrogen loss at 30 and 60 cm depths increased by 41.6% and 14.0% in the single application of controlled release fertilizer(T4) treatment. Considering factors such as agronomic and environmental benefits of different fertilization modes, T1 and T3 are suitable environmentally friendly alternative fertilization modes.