围封年限对草原土壤养分及球囊霉素相关土壤蛋白含量的影响

目的]通过分析不同围封年限的草原土壤养分与球囊霉素相关土壤蛋白(GRSP)的动态变化及相互关系,研究围封育草措施恢复退化草原的合理年限。方法]以锡林郭勒不同围封年限(围封0 a、围封13 a、围封33 a)的羊草草原为研究对象,测定不同土层土壤有机碳、全氮、全磷及GRSP含量。结果]随着围封年限的增加,土壤有机碳含量呈显著增加趋势;围封13 a土壤全氮含量在0~20 cm土层中显著增加,但随围封年限增加有降低趋势,全磷含量不受围封影响;表层土壤(0~5 cm)中GRSP含量受围封年限影响显著;GRSP、有机碳、全氮含量相互之间呈极显著相关。结论]围封年限虽能增加有机碳含量、GRSP的产生量,但年限过长易造成土壤中氮的匮乏,不应无限期围封。

Impact of Enclosure Duration on Soil Nutrients and Glomalin Related Soil Protein in Grassland

Objective] To study reasonable time of enclosed measures for recovering degraded grassland by analyzing association between soil nutrients and glomalin related soil protein ( GRSP) in grassland with different enclosure duration. Method] Chinese wildrye grassland of dif-ferent enclosure duration (0, 13 and 33 a) in Xilingol was selected as object in this study.We determined some soil parameters in different soil layer, including soil organic carbon ( SOC) , total nitrogen ( N) , total phosphorus ( P) and GRSP content. Result] Enclosure duration was positively correlated with SOC.Soil N of 0-20 cm could significantly increase in enclosure of 13 years, and there was a decreased trend with increasing enclosure duration.Soil P was not affected by different enclosure duration.GRSP content of surface soil (0-5 cm) could sig-nificantly increase in the process of enclosure.Meanwhile, highly significant correlations among SOC, N and GRSP were observed in this stud-y.Conclusion] Although enclosure duration could increase SOC and GRSP, longer duration was liable to reduce soil N.Consequently, en-closure duration cannot be sustained indefinitely.