不同施氮量下双季稻连作体系土壤氨挥发损失研究

Effects of different nitrogen application rates on ammonia volatilization from paddy fields under double-harvest rice system

采用密闭室间歇通气法研究双季稻连作体系不同施氮量下土壤氨挥发损失。结果表明:早稻氨挥发损失主要发生在施肥后的15d内,第3～5d出现峰值,损失总量为N 22.60～162.0 kg/hm2,损失率为29.29%～52.32%;晚稻氨挥发主要发生在施肥后的11d内,第3 d出现峰值,损失总量为N 22.35～141.4 kg/hm2,损失率为35.75%～46.82%;早、晚稻各生育期及连作周期的氨挥发量均与施氮量呈显著线性关系。

An enclosed intermittent vent method was used to measure the ammonia （NH3 ） volatilization from a paddy soil of double-harvest rice system under different application amounts of urea. The results show that the NH3 -N volatilization （NV） loss occurs mainly within 15 days, and the peak occurs during 3-5 days after the fertilization in the early rice season, and in the late rice season the NV loss occurs mainly within 11 days, and the peak appears in the third days after the fertilization. The total NV losses vary from N 22.60 - 162.0 kg/hm^2 and N 22. 35 - 141.4 kg/hm^2 in the early and late rice seasons, respectively, and the percents of the losses to the applied N amounts range from 29.29%-52.32% and 35.75%-46. 82%, respectively. The total NV losses and their percentages in all of the early rice, late rice or the double-harvest seasons are linearly increased with the increase of the urea application rates.