沙漠化过程对植物凋落物分解的影响

应用分解袋法测定分析了沙漠化过程对凋落物分解及碳氮释放的影响。结果表明,潜在、轻度、中度、重度和严重沙漠化沙地土壤中的凋落物经过110d的分解后,干物质残留率分别为38.5%,40.8%,45.2%,55.6%和58.8%,C残留率分别为37.1%,36.6%,41.4%,53.6%和51.1%,N残留率分别为43.8%,47.6%,54.2%,59.4%和58.9%。说明随着沙漠化程度的增加,凋落物的干物质失重率降低,分解速率减小,C、N释放速率减缓。分解过程中,凋落物在各生境土壤中C的释放速率明显快于N;C含量变化趋势为先下降后略有上升,但总体低于初始C含量;N含量总体表现为上升的趋势。

Effects of Desertification on Litter Decomposition in Horqin Sandy Land

In this paper,the effects of desertification on litter decomposition,carbon and nitrogen release were studied using mesh bags in Horqin sandy land.The results showed that the dry weight remaining rate of litter at the 110 d was 38.5%,40.8%,45.2%,55.6% and 58.8%,respectively,in potential,light,moderate,severe,and most-severe desertification sand land,while percentage of C remained in litter was 37.1%,36.6%,41.4%,53.6% and 51.1%,and N remained was 43.8%,47.6%,54.2%,59.4% and 58.9%,respectively.This indicated that the rate of weight loss and rate of C and N release were slowed down with desertification. During the decomposition process in different sand habitats,release rate of C in litter was faster than that of N;C concentration in litter was decreased in early days of decomposition,and then increased slightly,but C concentration,after decomposition of 110 days,was lower than that at the beginning;N concentration in litter was increased consistently with time.