降雨对施用两种尿素坡地氮素空间分布的影响

采用自动模拟降雨系统,设置恒定降雨强度,在室内对施用普通尿素和树脂包膜控释尿素的土槽进行模拟降雨试验。通过模拟降雨试验,比较研究了降雨对施用两种尿素的坡地氮素空间分布及氮素流失特征影响。研究结果表明:树脂包膜控释尿素在棕壤、褐土及红壤坡地上施用,均能显著减小降雨对坡地氮素空间分布的影响;与普通尿素相比,模拟降雨后,树脂包膜控释尿素处理的3种类型土壤坡地氮素残余量变异系数为普通尿素的14.08%~31.89%;且树脂包膜控释尿素显著缩小了降雨对3种类型土壤坡地表层与下层氮素空间分布影响间的差异;树脂包膜控释尿素在3种类型土壤坡地上施用均能减少降雨造成的氮素流失,与普通尿素施用相比,氮素流失分别减少了7.32%~17.35%(P0.05)、17.95%~24.24%(P0.05)、72.45%~78.84%(P0.01);同时,树脂包膜控释尿素还能减小降雨造成的坡地表层与下层氮素流失量间的差异,下层坡面氮素损失量仅比表层增加1.63%~5.02%。因此,降雨条件下,在坡地上施用树脂包膜尿素有利于控制氮素的分布失衡及流失。

Effect of Rainfall on Slope Nitrogen Spatial Distribution of Two Kinds of Urea

Adopt automatic rainfall simulation system and set up the simulated rainfall intensity constantly to carry out the experiment indoor on soil bin, which using common urea and controlled releases urea coated by polymer. Through simulated rainfall experiment, the nitrogen spatial distribution and nitrogen loss characteristics of common urea and controlled releases urea coated by polymer were analyzed. The results showed that: controlled release urea coated by polymer brown, cinnamon and red soil slope could all reduce influence of nitrogen spatial distribution by rainfall. After simulated rainfall, the nitrogen residue variance coefficient of controlled releases urea coated by polymer were common urea’s 14.08%–31.89%, At the same time, the controlled release urea could reduce the difference of the rainfall impact on nitrogen spatial distribution between surface soil and subsoil of the slopes of all three soil types. Controlled releases urea coated by polymer applied on three soil types slope could reduce nitrogen loss, compared with common urea, nitrogen loss decreased by 7.32%–17.35% (P<0.05), 17.95%–24.24% (P<0.05), 72.45%–78.84% (P<0.01) respectively. In addition, the controlled releases urea could also reduce the difference of nitrogen loss between the surface soil and subsoil of the slopes of three soil types under rainfall, and the nitrogen loss from subsoil of the slope only increased by 1.63%–5.02% compared with surface soil of the slope. So under rainfall, controlled releases urea coated by polymer applied on soil slope could control nitrogen distribution unbalance and nitrogen loss.