不同补播牧草配置对宁夏退化荒漠草原土壤活性有机碳的影响OA

To investigate the effects of artificial restoration on soil organic carbon(SOC)content and carbon sequestration capability in degraded grasslands,a field experiment was conducted in a degraded des-ert steppe in Yanchi County,Ningxia.Three reseeding regimes were established:grass mixture(P1),legume mixture(P2),and grass-legume mixture(P3),with a non-reseeded site serving as the control(CK).Soil physicochemical properties,organic carbon(SOC)and its active components,including easily oxidizable organic carbon(EOC),dissolved organic carbon(DOC),and microbial biomass carbon(MBC),were analyzed years after reseeding.The results showed that soil pH and water content significantly increased following reseeding(P<0.05).Soil total nitrogen content increased significantly under P1 and P2,and the electrical conductivity in the 20-40 cm layer under P1 and P3 were significantly higher than that in the CK(P<0.05).SOC content was significantly higher than the CK in the 0-20 cm layer under P3 and in the 20-40 cm layer under P2(P<0.05).Reseeding generally increased EOC content while decreasing DOC content,with significant changes observed under P1(P<0.05).Soil MBC content decreased signifi-cantly under P2(P<0.05).The DOC/SOC ratio declined after reseeding,whereas the EOC/SOC ratio under P1 was significantly higher than that under CK,P2,and P3(P<0.05).In the 0-20 cm layer,the MBC/SOC ratio under P1 was significantly higher than in the CK(P<0.05).Correlation analysis revealed significant negative correlations between EOC and DOC in both soil layers(P<0.05),and between SOC and EOC in the 0-20 cm layer(P<0.05).In conclusion,among the treatments,P3 demonstrated superior performance in promoting SOC sequestration and maintaining carbon pool stability,indicating that grass and legume mixture reseeding is a suitable strategy for restoring degraded desert steppe ecosystems.