改性尿素施用对氨挥发量及无机氮变化的影响

Effect of modified urea on ammonia volatilization and soil inorganic nitrogen

采用室内土壤培养和玉米幼苗盆栽试验的方法,研究了改性尿素施用后的氨挥发量及其对土壤无机氮和pH值的影响。结果表明:(1)表施改性尿素比表施普通尿素的氨挥发量显著减少,从而降低氮素的损失;在一定范围内,土壤含水量越大,氨挥发量越低。(2)硝化抑制剂双氰胺(DCD)能够抑制土壤硝化作用,使NH+4-N能较长时间存在土壤中,从而减少NO-3-N的损失;在一定范围内,DCD施用浓度越大,抑制效果越好。(3)土壤pH值与铵态氮呈极显著指数正相关,与硝态氮呈极显著线性负相关,与无机氮呈多项式相关。因此,改性尿素能够显著减少氨挥发量,抑制土壤硝化作用,从而降低尿素的氮素损失。

The indoor soil cultivation and corn seedlings pot experiment were conducted to research ammonia volatilization and the effect of modified urea on soil inorganic nitrogen and pH. The results showed that： （1） ammonia volatilization of modified urea significantly reduced compared to that of common urea, thereby reducing the loss of nitrogen; within a certain range, the greater soil moisture, the lower ammnia volatilization. （2） Nitrification inhibitor dieyandiamide （DCD） could inhibit soil nitrification, which prolonged the duration of NH 4 -N in soil, thus reducing the loss of NO 3 -N ; and within a certain range, the higher concen- tration of DCD, the better effect of suppressing. （3） Soil pH had a very significant index positive correlation with NH ＋4-N, a very significant negative linear correlation with NO 3-N, and a very significant polynomial correlation with soil inorganic nitrogen. Therefore, the modified urea could significantly reduce NH3 volatilization and inhibit soil nitrification to lower nitrogen losses.