华北地区几种冬闲覆盖作物碳氮蓄积及其对土壤理化性质的影响

充分利用华北地区冬季空闲耕地及光热资源,以冬闲耕地为对照,研究二月兰（Orychophragmus violaceus）、毛苕（Vicia uillosa Roth.）、黑麦草（Secale cereale L.）、草木樨（Melilotus officinalis）、紫花苜蓿（Medicago satiua L.）5种不同冬闲覆盖作物地上部、地下部以及总碳、氮的蓄积量及其对土壤理化性质的影响。结果表明：5种覆盖作物总干物质质量在4.6-8.82 t.hm-2之间,是冬闲田干物质质量的1.6-3.1倍。5种覆盖作物全碳蓄积量在1.80-3.14 t.hm-2之间,是冬闲田碳蓄积量的1.9-3.3倍。与对照相比,各覆盖处理均明显提高氮素蓄积,尤以苜蓿最佳,达到了202.8 kg.hm-2,差异显著。试验选择5种肥覆盖均可提高土壤有机质质量分数（0.90-2.86 g.kg）;黑麦草覆盖可明显降低土壤容重（0.08 g.cm3）;毛苕和苜蓿栽培均可显著降低土壤pH,但同时土壤盐分有所增加;二月兰和黑麦草栽培在提高土壤水分含量方面表现最好。

Carbon-nitrogen fixation and effects on the physical and chemical properties in winter cover crop in north China

In this paper, using idle farmland and light and heat resources in winter in North China, compared winter idle land, effect of five cover crops planted in China＇s north region as winter cover crops on carbon-nitrogen fixation and effects on the physical and chemical properties. Results showed that dry matter yield of five crops were 4.6-8.82 t·hm2, respectively, which was significantly higher than that of a fallow field. Carbon fixation of five crops were 1.80-3.14 t·hm2, Compared with fallow, planting winter cover crops increased Carbon fixation. Compared with fallow, planting winter cover crops increased nitrogen fixation, the better crop was alfalfa, its yield was 202.8 kg·hm2, respectively. The treatments of five cover crops got significantly higher organic matter contents. Ryegrass cover can significantly reduce soil bulk density; vetch and alfalfa cultivation could significantly reduce soil pH, but increased soil salt; Orychophragrnus Violaeeus and ryegrass have shown to improve the soil water content, indicating that winter cover crops may fix carbon and nitrogen greatly and improve soil quality.