大面积冬小麦夏玉米农田土壤的氨挥发

Ammonia Volatilization from Large Field Planted with Winter Wheat and Summer Maize

报道了利用微气象学法 (梯度扩散法 )测定大面积农田土壤氨挥发的试验结果。在华北平原种植冬小麦夏玉米的生产实际中 ,施肥后土壤氨挥发的损失量 (N)在 18 9～ 6 3 5kg·hm- 2 之间 ,占施N量的 9 9%～ 37 0 %。氨挥发过程主要发生在日间 ,日内挥发高峰多出现在 12 :0 0～ 16 :0 0 ,并与季节有关 ,土壤施尿素或碳铵后氨挥发日间变化方式基本一致。当表层 1cm土壤的NH4 (N)下降到 2 0～ 30mg·kg- 1时 ,施肥引起的氨挥发基本结束。

The results of ammonia volatilization measured with micrometeorological(gradient diffusion) method in the field cropping with winter wheat and summer maize was reported.Under the production condition at the North Plain of China,the loss of ammonia (N)after fertilizer application ranged from 18.9 to 63.5 kg·hm -2 ,9.9% to 37.0% of the applied N.Ammonia volatilization occurred mainly during the daytime and the peak volatilization appeared between 12:00-16:00 pm each day.The ammonia volatilization pattern after application of urea was generally the same as that of the ammonium bicarbonate.Under the experimental conditions,ammonia volatilization caused by N fertilizer application stopped when the ammonium concentration (N) in the top 1-cm layer soil decreased to 20-30 mg·kg -1 soil.