水氮耦合对水稻田间氨挥发规律的影响

在防雨棚池栽试验中应用通气法研究了水氮耦合对稻田土壤氨挥发速率的动态变化及损失量。结果表明,稻田施用氮肥后有明显NH3挥发损失,整个生育期累计氨挥发量为31.67～69.70kg·hm^-2,占施氮量的17.95%～28.64%;不同生育时期氨挥发量的大小依次为返青期〉拔节孕穗期〉分蘖期〉抽穗开花期〉乳熟期,挥发高峰出现在施氮肥后的1～3d内;随着施氮水平增加,田间氨挥发量显著增加。与此同时,稻田水分状况对NH3挥发损失具有重要影响,与常规灌溉模式相比,控制灌溉条件下氨挥发总量和氨挥发损失率均较小,且不同施氮水平间差异显著。就氨挥发损失率而言,在试验条件下水氮耦合效应显著,以控制灌溉模式下施氮量为180kg·hm^-2时的氨挥发损失率最低,为17.59%。

Effects of Irrigation and Nitrogen Fertilization on Ammonia Volatilization in Paddy Field

Controlling the ammonia（NH 3）volatilization from nitrogen（N）fertilization could be a good strategy to reduce N loss in crop growing season.The interaction of irrigation and N fertilization NH 3 volatilization were conducted in an experiment of pool culture within rainproof shelter in paddy field.Data were collected during the growing season of 2009 and 2010 from treatments under controlled and conventional irrigation receiving N application of 90 kg·hm^-2,180 kg·hm^-2,and 270 kg·hm^-2.The NH 3 volatilization was determined by the venting method.Results showed that the total amounts of NH 3 volatilization in the whole growth period ranged from 31.67 kg·hm^-2 to 69.70 kg·hm^-2 among the treatments,accounting for 17.95%～28.64% of N applied.The peak of ammonia volatilization appeared in 1～3 days after each N application,regardless of treatments.The NH 3 volatilization during the whole growing season was in order：returning green stagejointing-booting stagetillering stageheading-flowering stagemilky stage.Irrigation and N fertilization significantly influenced on NH 3 volatilization.Total amounts and loss rate of NH 3 were lower in controlled irrigation compared with conventional irrigation.With the increment of N application rates,NH 3 volatilization significantly increased.The loss rate of NH 3 volatilization（17.59%）was lowest under controlled irrigation with N application of 180 kg·hm^-2.We concluded that combining controlled irrigation and reducing N fertilization can reduce NH 3 volatilization in the Paddy field.