中文摘要：

【目的】利用不同植物轮作，通过生物修复耗竭深层土壤剖面的累积硝态氮，从而控制集约化粮田过量施氮造成的硝酸盐淋洗。【方法】通过田间试验，比较小麦一玉米轮作、休闲一玉米、小麦一休闲、紫花苜蓿连作、紫花苜蓿＋苇状羊茅间作、黑麦一苋菜轮作、黑麦一高丹草轮作、黑麦一甜高梁轮作对土壤剖面硝态氮累积和淋洗的降低效果。【结果】紫花苜蓿、高丹草、黑麦1-2m土体根系占0-2m土体总根系的比例最高；黑麦一苋菜、黑麦一高丹草和黑麦一甜高梁处理具有较高的年吸氮量（330-390kgN·hm^-2）；与小麦一玉米传统轮作相比，夏季休闲增加了土壤硝态氮淋洗。经过1年的田间试验，5个修复植物处理0-1m、1-2m的硝态氮累积量分别降低124．3和81．2kgN·hm^-2，其中苋菜、甜高梁、高丹草对深层土壤中硝态氮的消减作用较大；甜高梁、高丹草、苋菜种植下1m处土壤溶液中硝态氮浓度一直处于最低水平，平均仅8．6mg·L^-1。【结论】在本试验条件下，黑麦一高丹草轮作是一年内提取深层土壤累积硝态氮效果最好的种植模式。

英文摘要：

[ Objective ] This study aimed to use plants in cropping systems for bioremediation, depleting nitrate nitrogen in deep soil profile to control nitrate leaching caused by excessive nitrogen fertilizer application. [Method] Different treatments were designed in a plot experiment, including conventional wheat-maize rotation system, fallow-summer maize system, winter wheat-fallow system, rye-amaranth rotation system, rye-sorghum hybrid sudan grass rotation system, rye-sweet sorghum rotation system, alfalfa continuous cropping and alfalfa＋fescue inlercropping. The effects of each cropping system on the decrease of accumulation and leaching of soil nitrate nitrogen was analyzed. [Result] The results show that alfalfa, sorghum hybrid sudan grass and rye had the highest percentage of roots in 1-2 m soil profile. Annual plant N uptake under rye-amaranth, rye-sorghum hybrid sudan grass and rye-sweet sorghum treatments were the highest, about 300-390 kgN.hm-2. Fallow in summer season increased nitrate leaching from 0-1 m soil profile. After the first year＇s remediation, all the five treatments significantly reduced nitrate accumulation in 0-1 m and 0-2 m soil profile, decresed 124.3 kgN.hm^-2 and 81.2 kgN.hm^-2 respectively. Sorghum hybrid sudan grass, sweet sorghum and amaranth were more effective in decreasing nitrate nitrogen accumulation in deep soil layers. Nitrate concentration in soil solution under rye-sweet sorghum, rye-sorghum hybrid sudan grass and rye-amaranth systems was in the lowest level, averaged only 8.6 mg·L^-1 [Conclusion] According to the first year＇s results, rye-sorghum was the best cropping system to decrease the accumulated nitrate in deep soil layers and further control nitrate pollution.