【摘要】 在河西盐渍化土地区选择了天然草地、小麦地、1年生苜蓿地、2年生苜蓿地和3年生苜蓿地,就不同利用方式对盐渍化土有机质和盐分的影响进行了研究。结果表明,种植农作物后,土壤的有机质含量明显下降;种植苜蓿后,前2年土壤有机质含量减少,3年后显著增加。土壤盐分在开垦种植后显著下降,苜蓿地的降盐效果更好。可溶性阳离子中,Mg2+含量的下降趋势最大,其变化曲线与全盐相同;Na+向土壤下层迁移,Ca2+含量随土壤深度的增加而降低,K+含量下降。更多还原

【Abstract】 Five types of land use patterns(native pasture,farmland,1,2,and 3 year-old Medicago sativa cultivations),were studied to investigate changes in soil organic matter concentration and soil salt.Soil organic matter decreased dramatically after cultivating crops and 1 or 2 year-old M.sativa,but increased after 3 year-old M.sativa.Soil salt decreased markably when native pasture was reclaimed,especially in M.sativa land.Concentrations of soluble cations were reduced through to greater soil depths.A significant decline of Mg2+ was observed and was significantly correlated with soil salt.Na+ tended to move to greater soil depths.The concentration of Ca2+ decreased with depth of the soil layer and K+ decreased in the soil.更多还原