氮肥形态对坡耕地雨季土壤养分流失的影响

为了明确氮肥形态对土壤养分流失通量及途径的影响,采用随机区组试验设计,利用模拟径流小区观测的方法,研究在地膜覆盖与不覆盖情况下氮肥形态对坡耕地雨季土壤养分流失通量及途径的影响。研究结果表明：壤中流氮、磷和钾的流失量分别占总径流流失量的71.30%、6.36%和8.85%,说明磷和钾流失的主要途径是地表径流,而氮流失的主要途径是壤中流,地膜覆盖降低酰胺态氮肥和缓控释肥处理氮素流失量,其中酰胺态氮肥处理地膜覆盖较不覆盖壤中流氮流失浓度和径流氮素流失量分别降低40.40%和29.32%。在无覆盖条件下,各处理径流氮素流失顺序表现为：酰胺态氮肥〉铵态氮肥〉缓控释肥〉硝态氮肥,施用硝态氮肥氮素流失量最低,较施用酰胺态氮肥氮素流失少40.86%。在地膜覆盖条件下,各处理径流中氮素流失顺序表现为：铵态氮肥〉酰胺态氮肥〉硝态氮肥〉缓控释肥,施用缓控释肥氮素流失量最低,较施用铵态氮肥氮素流失少59.60%。结果表明在四川紫色丘陵区为了有效控制水土养分流失,在肥料形态的选择上,以无覆盖条件下施用硝态氮肥较好,以地膜覆盖条件下施用缓控释肥较好。

Effect of Nitrogenous Fertilizer Modality on Soil Nutrient Loss of Sloping Land in Rainy Season

In order to discuss the effects of nitrogen forms on soil nutrient loss fluxes and approach,we used randomized block experiment design,under simulated runoff observation method to study the effect of nitrogen forms and mulching on soil nutrient loss fluxes and approach in slope land. The results showed that the interflow loss of nitrogen,phosphorus and potassium was 71.30%,6.36% and 8.85% respectively of the total runoff. It indicated that the main way of phosphorus and potassium loss in the runoff was surface runoff,but the main way of nitrogen loss in the runoff was interflow. The nitrogen loss of amide nitrogen fertilizer and controlled release fertilizer was reduced by plastic mulching,the interflow nitrogen concentration and nitrogen loss quantity of amide nitrogen fertilizer by plastic mulching was reduced 40.40% and 29.32% compared with no mulching. On no mulching,the total nitrogen loss of runoff was given as follows： amide nitrogen fertilizerammonium nitrogen fertilizercontrolled release fertilizernitrate fertilizer,the nitrogen loss was minimum by nitrate nitrogen fertilizer on no mulching,it was 40.86% fewer than that of using amide nitrogen fertilizer. On plastic mulching,the total nitrogen of runoff was given as follows： ammonium nitrogen fertilizeramide nitrogen fertilizernitrate fertilizercontrolled release fertilizer,the nitrogen loss was minimum by slow controlled release fertilizer on plastic film mulching conditions,it was 59.60% fewer than that of using ammonium fertilizer. In order to effectively control water and soil nutrient loss of purple hilly area in Sichuan Province,we recommend using nitrate nitrogen in bare soil conditions and using controlled release fertilizer in the plastic mulching conditions.