灌丛防治荒漠化后土壤有机碳及其密度组分的变化

Changes of Soil Organic Carbon and Its Density after Shrub Control Desertification

面对土地的沙化和草地退化问题,可以在土地表面种植灌木丛。灌木丛的出现一方面会有效抑制沙漠化,同时,也会影响土壤中有机碳的含量以及组分。本研究主要是研究沙漠化后种植柠条锦鸡儿(20年)的退化牧场以及沙地的土壤有机碳、轻组分有机碳、重组分有机碳含量变化。结果表明,种植灌木可导致沙地土壤有机碳含量增加,而使退化草地土壤有机碳含量下降。沙地土壤有机碳含量的增加主要是基于轻组分有机碳的累积。退化草地土壤有机碳的流失是由于重组分有机碳浓度的降低造成的,这可能与深层土壤中草本细根生物量和土壤含水量的减少有关。因此,控制荒漠化的灌木种植并不总能提高西北地区土壤有机碳的数量和稳定性。

In the face of desertification and grassland degradation,bushes can be planted on the surface of the land.On the one hand,the appearance of bushes will effectively inhibit desertification,at the same time,it will also affect the content and composition of organic carbon in soil.We assessed the changes in stocks of SOC,light fraction of SOC(LF-SOC)and heavy fraction of SOC(LF-SOC)after planting Caragana korshinskii(CK,20 years)in sand land and degraded pasture.The results indicate that planting shrubs can result in an increase of SOC in sand land,whereas that can lead to a decrease of SOC in degraded pasture.The increase of SOC in sand land mainly bases on the accumulation of dry weight of LF-SOC.The loss of SOC in degraded pasture is caused by the decrease of carbon concentrations of LF-SOC,which can be related to the reduction of HFRB and SWC in deep soil layer.Therefore,shrub-planting for desertification control did not always improve the quantity and stability of SOC in northwest China.