PAM对黄土坡地水分养分迁移特性影响的室内模拟试验

Laboratory simulation experiment of impact of polyacrylamide on transportation of soil water and nutrients from the loess sloping land

为了研究聚丙烯酰胺(PAM)在黄土区集中暴雨条件对坡地水土及养分流失的影响,采用室内降雨模拟试验方法,探讨了在暴雨(2mm/min)条件下施加PAM对黄土坡地土壤养分流失及硝态氮淋溶特征的影响。试验结果表明,与对照处理相比较,施加PAM对径流硝态氮流失的影响不明显,但显著改变了径流磷和钾浓度随时间变化过程,分别降低了径流磷和钾的流失量为82%和84%;施加PAM减少了坡地土壤流失量93%,也降低了泥沙中硝态氮、速效磷和速效钾的流失量分别为78%,95%和95%;施加PAM影响了坡地土壤水分再分布过程,减少了土壤水分深层的渗漏,从而降低了土壤硝态氮淋失的潜在风险。

In order to study the impact of applied polyacrylamide （PAM） on the transportation of soil, water and nutrients from the loess sloping land during the heavy storms in the loess section, the stimulated rainfall experiment in laboratory was designed to investigate the influence of PAM on characteristics of runoff nutrients concentrations, nutrients losses and redistribution of soil water and NO^-3-N in soil profile during the heavy rainstorm （rainfall intensity is 2 mm/min）. The results show that, as compared with control experiments, PAM treatment has little effect on the NO^-3-N loss process, however, affects significantly the variability with time of PO4^3--P and K^＋ concentrations in runoff, and reduces the losses of PO4^3--P and K^＋ in runoff by 82% and 84% respectively. PAM, a new type of effective soil structure-improved additive, decreases soil loss by 93%, as well as reduces the losses of NO^- 3-N, PO4^3--P and K^＋ with sediment by 78%, 95% and 95% respectively. Applied PAM has changed soil water redistribution processes in soil profile, and degrades the potential hazard of the soil NO^- 3-N leaching loss.