中文摘要：

【目的】在中国集约化蔬菜种植区，传统的高水肥投入导致土壤氮素大量累积，致使氮素淋洗到土壤深层或进入地下水，造成地下水硝酸盐污染。种植填闲作物可控制和减少土壤深层硝态氮的累积，因此，本研究探讨不同填闲作物种类对消减土壤剖面累积硝态氮及下季作物生长的影响，筛选出适宜的填闲作物种类。【方法】以华北平原传统棚室黄瓜菜田为对象，在蔬菜休闲期通过种植深根型填闲作物，利用其根系发达、生长迅速、吸氮量大的特点，促使土层中硝态氮大量消耗，以消减土壤剖面根层NO3--N累积和降低土壤剖面NO3--N淋失。以此为目标，设置甜玉米、苋菜、甜高粱及休闲田间小区试验，采集测定土壤、植株及根系样品，分析不同填闲作物的消减效果。【结果】在这3种填闲作物中，甜玉米的生物量和吸氮量最大，整体根长密度大于其它填闲种类。从对土壤剖面NO3--N的消减能力来说，甜玉米的消减能力最高。2008、2009及2010年，甜玉米对0—200 cm土层土壤NO3--N的消减量分别为153.8、605.7和56.3 kg·hm-2。3年休闲期后，第一季前茬休闲处理的黄瓜产量、生物量及吸氮量均最高，在产量、吸氮量上与其他处理差异显著；第二季、第三季，前茬休闲的产量、生物量和吸氮量与其他处理差异不显著；填闲作物的种植并没有对黄瓜产量造成影响，并且黄瓜收获后土壤NO3--N含量明显降低。氮素表观平衡中0—200 cm土层，甜玉米-黄瓜的氮素亏缺量较大，说明甜玉米能显著降低土壤NO3--N的残留。种植填闲作物能够达到经济效益和生态效益的双赢，甜玉米、苋菜与甜高粱可分别为农民带来39467、497和16522元/hm2的净收入。【结论】棚室菜田夏季种植填闲作物不仅可以消减土壤剖面根层NO3--N累积，而且对下茬黄瓜产量未造成显著影响，黄瓜收获后土壤NO

英文摘要：

Objective]In intensive vegetable growing areas in China, the traditional high water and fertilizer inputs led to high soil nitrogen accumulation and nitrogen leaching into the deep layers of soil or groundwater, thus resulting in contamination of groundwater. Growing catch crops could control and reduce migration deep nitrate-nitrogen accumulation in soil to groundwater, therefore, this study was conducted to investigate the effects of different catch crops species on reducing nitrate accumulation in soil profile and crop growth in the next season, select the appropriate catch crop species.[Method]The field experiment was conducted in the traditional cropping systems of greenhouse in North China Plain. In the fallow period of vegetables, deep roots-catch crops including sweet corn, amaranth, and sweet sorghum were planted in order to employ their root systems, fast growing and large amount of nitrogen uptake to promote soil nitrate nitrogen consumption, reduce nitrate accumulation in the root layer of soil profile and nitrate leaching of soil profile. Fallow field plots were also designed. Soil, plant and root samples were collected and measured, and the reduction effects of different catch crop species were analyzed.[Result]The results indicated that among the three species, sweet corn was the best in biomass production, N uptake, and root length density. From the effect of soil profile NO3--N reduction, sweet corn was the best among them, the reduction of NO3--N was 153.76, 605.70, and 56.3 kg·hm-2 in 2008, 2009, and 2010. In the first quarter, the previous crop of cucumber was the highest in yield, N uptake and biomass production, and there was a significant difference with others in yield and N uptake. In the second and third quarters, there were no too clear difference in yield, N uptake and biomass production. Catch crops had little effect on vegetable production, but also reduced the accumulation of soil NO3--N. The N deficient ullage of sweet corn-cucumber was larger in 0-200 cm soil layer of the N appar