通过对毛乌素沙地沙柳、柠条、杨柴三种灌木林地凋落物的数量、分解速度、土壤养分积累、土壤物理性质等的测定,探讨了人工固沙灌木林改良土壤的过程。研究结果表明:树种不同,凋落物生物量存在着较大的差异,其中沙柳最多,其次为杨柴,柠条最少;凋落物的分解受树种和环境因素两方面的影响,各处理失重率表现为埋置处理>地表淋溶>地表无淋溶,相同处理下柠条失重率显著高于杨柴,杨柴显著高于沙柳;沙柳、杨柴、柠条灌木林地均显著增加了土壤有机质、全氮、全磷含量,且增加主要表现在0～25 cm土层;灌木林较流动沙丘显著降低了土壤容重,增加了土壤孔隙度。毛乌素沙地人工固沙灌木林地通过凋落物的产生及分解,使土壤有机质、全氮、全磷养分含量不断提高、土壤容重降低、孔隙度增大、促进了土壤的改良。

The litter biomass,decomposition rate,soil nutrients and soil physical properties were measured to investigate the improvement process of soil physical properties of artificial shrubs in Maowusu sandy Land.The results showed that there was a big difference in litter biomass among three shrubs,Salix psammophila C was biggest,Hedysarum leave Maxim was second,Caragana korshinskii Kom was least.The litter decomposition rate was affected by both species and environmental factors,the rate of weight loss was under-ground > leach above ground> inleach above ground,the rate of weight loss of Caragana korshinskii Kom was significantly higher than Hedysarum leave Maxim,and Hedysarum leave Maxim was significantly higher than Salix psammophila C under the same treatment.All the three shrubs significantly increased soil organic matter,total nitrogen,total phosphorus content,and increased the role mainly in the 0~25 cm soil.Shrubbery significantly reduced soil bulk density than mobile sand,and increased soil porosity.Artificial sand-fixing shrub forest increased soil organic matter,total nitrogen,total phosphorus nutrient content,reduced soil bulk density,increased soil porosity,improved soil physical and chemical properties through litter decomposition in Maowusu sandy land.