蔬菜间作及氮肥调控对土壤硝酸盐及氮素表观损失的影响

摘要

[目标]研究蔬菜间作及氮肥调控对土壤硝酸盐及氮素表观损失的影响，为菜地合理施肥及减少环境污染提供理论依据。[方法]采用大田试验方法，选择深根系的茄子和浅根系的大葱进行间作种植，并辅以氮素调控措施，研究其对土壤硝态氮时空变异规律及氮素表观损失的影响；[结果]在减量施肥条件下，土壤硝酸盐运移和累积的规律均为间作区含量低于单作区，表明与单作相比，茄子与大葱间作能有效阻截硝酸盐的向下淋洗，并有效减少土壤中硝酸盐累积量。间作种植模式下，减量施肥能够减少土壤中硝酸盐含量，特别是深层土壤，在作物生长期间，硝酸盐含量均比常规施肥区明显降低；土壤剖面硝酸盐累积量也表现为减量施肥区明显低于常规施肥区。采用蔬菜间作和减量施肥，均能不同程度地减少氮素的表观损失。[结论]该研究结果为蔬菜高产种植及田间合理施肥奠定了基础，在减少环境污染上有重要意义。%[Objective] The aim was to investigate effect of intercropping and nitrogen regulation on nitrate and apparent loss of nitrogen, providing theoretical references for reasonable fertilization and pollution reduction. [Method] In the research, deeprooted eggplants and shallow-rooted scallions were intercropped with nitrogen regulat- ed to study on effect of the cropping system on temporal and spatial changes of ni- trate nitrogen and apparent loss of nitrogen. [Result] When the fertilizers were re- duced, contents of nitrate were less in intercropped field than that in mono-cropped one, indicating that eluviation of nitrate would be blocked and nitrate accumulation would be lowered effectively by intercropped eggplants and scallions. With intercrop- ping adopted, the reduced fertilizers would lower nitrate content in soil, deep soil in particular, and nitrate was significantly lower than that fertilized with conventional quantity during vegetable growth period. In addition, nitrate accumulation in soil profiles was also significantly shorter in field applied with reduced fertilizers than that with conventional one. It was shown that intercropping and fertilizer reduction would both cut apparent loss of nitrate down in varying degrees. [Conclusion] The research lays basis for high production of vegetables, reasonable fertilization and pollution reduction.