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采用二因素四水平随机区组试验设计,利用模拟径流小区观测的方法,研究氮肥形态和覆盖对坡耕地玉米产量及土壤氮素流失通量及途径的影响。结果表明:土壤径流以地表径流为主,氮素主要流失途径是地下径流,占总径流量的71.3%,氮素流失的主要形态是硝态氮,占无机氮的92.0%,占水溶性总氮的57.1%。地膜覆盖降低径流深和土壤侵蚀量,增加水溶性氮流失量,提高玉米产量,但是酰胺态氮肥和缓控释肥地膜覆盖可降低氮素流失量,且酰胺态氮肥对玉米增产效果显著;裸地条件下硝态氮肥和缓控释肥可降低地下径流深和氮素流失量,且缓控释肥对玉米增产效果显著。综合考虑水土流失治理和粮食增产增收,四川紫色坡耕地适宜肥料类型为缓控释肥,其次是硝态氮肥,酰胺态氮肥通过地膜覆盖也能较好地控制氮素流失和增加玉米产量。
A two-factor and four-level randomized block trial design was used to study the effects of nitrogen fertilizer forms and mulching on corn yield and soil nitrogen flux and pathway in sloping fields by simulating runoff observation. The results show that the main runoff of soil is surface runoff, and the main runoff of nitrogen is underground runoff, accounting for 71.3% of the total runoff. The main form of nitrogen loss is nitrate nitrogen, accounting for 92.0% of inorganic nitrogen, 57.1% of nitrogen. Film mulching reduced runoff depth and soil erosion, increased water-soluble nitrogen loss, and increased corn yield. However, mulching with amide-type nitrogen fertilizer and controlled-release film-mulching reduced the amount of nitrogen loss and the effect of amylose nitrogen fertilizer on corn yield was significant. Under the conditions of nitrate nitrogen and controlled release fertilizer can reduce the depth of underground runoff and nitrogen loss, and controlled release fertilizer on corn yield significantly. Taking soil erosion control and grain yield increasing into account, the suitable fertilizer type of purple slope farmland in Sichuan is controlled release fertilizer followed by nitrate nitrogen fertilizer. Amide nitrogen fertilizer can also control nitrogen loss and increase corn yield through plastic film mulching.