围封对流动沙丘表层土壤有机碳、全氮和活性有机碳的影响

Effects of Exclosure on Topsoil Organic Carbon,Total Nitrogen and Labile Organic Carbon of Mobile Dune in Horqin Sandy Land

以流动沙丘为对照,研究不同围封年限(14年和26年)下科尔沁退化沙质草地表层(0-15cm)土壤有机碳、全氮及活性有机碳的变化。结果表明:流动沙丘围封显著提高了土壤有机碳(SOC)、全氮(TN)、轻组有机碳(LFOC)和微生物量碳(MBC)含量,14年和26年围封样地SOC、TN、LFOC和MBC含量均随围封年限的增加而增加,且0-5cm层增幅高于5-15cm层。14年和26年围封样地土壤碳氮比显著高于流动沙丘,但2个围封样地之间差异不显著。流动沙丘围封也显著增加了表层SOC、TN、LFOC和MBC储量,0-15cm土层SOC、TN、LFOC和MBC储量均表现为26年围封地>14年围封地>流动沙丘。相关分析表明,LFOC、MBC均与SOC存在极显著正相关关系,说明LFOC和MBC均可作为衡量土壤有机碳变化的敏感指标。

This paper studied the changes in surface（0-15 cm） soil organic carbon（SOC）,total nitrogen（TN）,light-fraction organic carbon（LFOC） and microbial biomass carbon（MBC） after 14 and 26 years of exclosure,which established in areas with mobile dunes in Horqin sandy land.The results indicated that SOC,TN,LFOC and MBC contents in 0-15 cm soil layer increased significantly with increasing exclosure period,but they tended to decrease with increasing soil depth.The soil C/N ratio in 14 and 26 years exclosure sites were significantly higher than that in mobile dune,whereas there was no significant difference between the two exclosure sites.Exclosure increased the storages of SOC,TN,LFOC and MBC in the order of 26 years exclosure 〉14 years exclosure〉 mobile dune.Correlation analysis showed that LFOC and MBC contents were significantly related to SOC content（p〈0.01）,which suggested that both LFOC and MBC could be used as the sensitive indicators to evaluate SOC change.