种植苜蓿对土壤肥力的影响

Effects of Planting Medicago sativa Lon Soil Fertility

通过对4年生苜蓿地和传统耕地(棉花)表层土壤分层(0～10,10～20,20～30cm)取样分析,从定量的角度研究了不同种植方式对表层土壤理化性质的影响。结果表明:与传统耕地相比,4年生苜蓿地在从未施用任何肥料的情况下,土壤有机质、全氮、全磷、全钾、速效氮、速效磷、速效钾的含量均比每年都施肥的传统耕地高,且差异显著。与种植棉花相比,种植苜蓿可以降低土壤容重,增加土壤孔隙度,显著降低土壤中总盐含量以及氯离子含量,充分表明苜蓿具有改良土壤的特性。但是苜蓿地土壤pH值比棉花地的高,具体原因尚需进一步研究。本研究同时分析了种植苜蓿与传统作物(棉花)对耕层土壤理化性质的影响是否存在垂直分布上的差异,各指标表现不一。

By experiment, in this paper the differences of physiochemical and microbiological properties of soils between Medicago sativa land and traditional farmland (cotton field) are researched. The soil samples were sampled from a four-year Medicago sativa land where fertilizers are not applied and a traditional farmland where cotton or wheat is grown and fertilizers are applied in Fifth Team of Hutubi Cattle Farm, Xinjiang. Some soil samples were sampled at soil depths of 0～10 cm,10～20 cm and 20～30 cm respectively in May 2004,which are used to measure the physiochemical properties of soils,and some others were sampled at soil depths of 0～10 cm and 10～20 cm respectively in June,which are used to measure the quantities of microorganisms in soils. The soil conditions in the Medicago sativa land and the traditional farmland are similar. The results show that contents of organic matter,total N,P and K as well as available N,P sand K in soil in four-year Medicago sativa land are all higher than that in the traditional farmland where fertilizers are applied every year. Planting Medicago sativa can decrease soil bulk density,total salt and cl-,and can also increase total soil porosity. These reveal that planting Medicago sativa can effectively improve soils. The main purposes of this study are to reveal the effect of planting Medicago sativa on soil fertility and provide the scientific basis for extensively planting Medicago sativa in soil improvement in Xinjiang.