太湖地区稻麦轮作系统不同氮肥管理模式对麦季氮素利用与流失的影响研究

通过对施氮管理模式的调整,研究太湖流域稻麦轮作系统不同模式下麦季氮素利用率以及土壤中氮素迁移对水体中氮的影响。试验设置6个处理：农户施肥处理、化肥减量处理、稻季按需施肥处理（麦季同化肥减量处理）、新型肥料处理、有机无机配施处理以及无氮处理。结果表明：有机无机配施处理在麦季持续减少25%施氮量的情况下不会影响产量及作物地上部分氮素总积累量,且氮素表观利用率显著高于其他处理,麦季径流与渗漏损失量主要受施氮量的影响,NO3-N是损失的主要形态;减氮处理可较农户处理降低7.7～12.0kg·hm-2的氮素流失;麦季有机无机配施减量处理,能够保证作物产量与氮素吸收并且有效降低氮素的流失,具备可持续性发展的前景。

Nitrogen Use Efficiency and Loss from Runoff and Leaching in Wheat Season with Rice-wheat Rotation System Under Different Nitrogen Management Methods in Taihu Lake Region,China

A field study was carried out focusing on utilization efficiency and loss of nitrogen from runoff and leaching in wheat season in Tailake region.The experiment was conducted with different nitrogen management methods including different nitrogen levels and different kind of fertilizers.Six treatments were designed：Farmer＇s N treatment（FN）,Reduced chemical N treatment（RCN）,Site-specific nitrogen management（SSNM）（for paddy season only,same as RCN in wheat season）,Organic chemical N treatment（OCN）,Control released urea treatment（CRU） and without nitrogen treatment（N0）.Results showed that under OCN treatment,the yield and above-ground nitrogen accumulation wouldn＇t be lessened when nitrogen input was continuously reduced by 25% in wheat season,and nitrogen utilization efficiency was significantly higher than other N treatments.Runoff was easier to occur in wheat season than rice season.N loss from runoff and leaching mainly depend on the N rate,and nitrate was the main form of N loss in runoff and leachate.Reducing N input about 25% could lower N loss about 25%～40%（7.0～11.0 kg hm-2） compared with farmer＇s N treatment.Organic combined with chemical N treatment in wheat season could ensure a stable yield and reduce the N loss to environment,and has the potential of sustainable development.