供氮水平和有机无机配施对麦田土壤氨挥发的影响

[目的]从提高肥料利用率出发,研究不同施氮量与不同配施方式下冬小麦田土壤氨挥发特征。[方法]采用田间通气法,于2006～2007年进行大田试验。设置4个施氮水平,每个施氮水平下再设4个有机无机肥料组合,研究不同施氮量与不同配施方式下基肥、追肥施用对华北地区冬小麦田土壤氨挥发的影响。[结果]土壤氨挥发速率、氨挥发累积量随施氮量的增大而增大;在施氮量相同的情况下,与单施有机肥或单施无机肥相比,有机无机肥料配施能够降低土壤的氨挥发损失量。基肥、追肥施肥后土壤的累计氨挥发量在5.354～8.916 kg/hm2,氨挥发损失率在1.824%～6.119%,追肥土壤的氨挥发损失量占累计氨挥发损失总量的97%以上。[结论]麦田土壤的氨挥发损失主要来自于追肥。

Effects of Nitrogen Fertilizer Rate and Combined Application of Organic Manure and Chemical Fertilizer on Soil Ammonia Volatilization in Winter-Wheat Field

[Objective]In order to find the optimal management practices for increasing nitrogen use efficiency,the characteristics of nitrogen fertilizer rate and combined application of organic manure and chemical fertilizer on soil ammonia volatilization in winter-wheat were studied.[Method]In situ experiments combined with venting method,a experiment was carried out to study the effects of nitrogen fertilizer rate and combined application of organic manure and chemical fertilizer on soil ammonia volatilization on winter-wheat in 2006-2007.Four application rates of pure nitrogen were set.Under every nitrogen application rate,four different combined rates were set.[Result] The rate of ammonia volatilization and the amount of accumulative ammonia volatilization was increased with the increase of nitrogen application rate.On the same nitrogen application rate,combined application of organic and chemical fertilizer could decrease the amount of accumulative ammonia volatilization.After fertilization,the amount of accumulative ammonia volatilization was between 5.354 and 8.916 kg/hm2,and the rate of ammonia volatilization was between 1.824% and 6.119%.The amount of accumulative ammonia volatilization after top-dressing made up to 97% of total ammonia loss by volatilization.[Conclusion]The ammonia loss by volatilization in winter-wheat field was mainly caused by top-dressing.