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

Effect of Intercropping and Nitrogen Regulation on Nitrate Accumulation in Soil Profiles and the Apparent Loss of Nitrogen of Vegetable

作物根系分布深度不同,其吸收养分的土壤区域也有所不同。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。研究表明,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。

Vegetables with different root depth have different nutrient uptake characters.In this research,a field experiment with different cropping system,intercropping and monocropping,and different nitrogen fertilization was conducted to study the effect on temporal and spatial dynamic of soil nitrate,and the apparent loss of nitrogen.This study chose eggplant and green onion as experimental crops which as the deep and the shallow root vegetable respectively.The results showed that the soil nitrate accumulation and migration of the intercropping treatments were less than the monoculture under the fertilizer optimizing conditions.It showed that intercropping can prevent nitrate leaching effectively and reduce the amount of nitrate.Under the conditions of intercropping cultivation,fertilizer optimizing treatments reduced the soil nitrate content,especially in the deep soil layer.The nitrate content of the optimizing treatment was lower than the conventional fertilization significantly during the whole growing period.The nitrate accumulation of the fertilizer optimizing area was also lower than the normal one in the whole soil profile.The apparent loss of nitrogen could be reduced by using intercropping or fertilizer optimizing management.