围封对当雄县高寒草原土壤微生物和酶活性的影响  

Effects of fencing on microbial communities and soil enzyme activities in Damxung alpine grassland

作　　者：斯贵才[1] 袁艳丽[2] 王建[2,3] 王光鹏[2] 雷天柱[1] 张更新[2] 

机构地区：[1]甘肃省油气资源研究重点实验室,中国科学院油气资源研究重点实验室,中国科学院地质与地球物理研究所兰州油气资源研究中心,甘肃兰州730000 [2]中国科学院青藏高原研究所,高寒生态学与生物多样性实验室,北京100101 [3]中国科学院大学,北京100049

出　　处：《草业科学》2015年第1期1-10,共10页Pratacultural Science

基　　金：中国科学院重要方向性项目(KZCX2-EW-112);国家自然科学基金项目(41072107)

摘　　要：过度放牧会严重破坏土壤生态系统,造成土壤退化,土壤一旦退化,即使很长年限也难以恢复。本研究通过围栏禁牧(1、4、6年)对青藏高原当雄县高寒草原退化草地进行修复,分析围封时间对高寒草原土壤理化性质、土壤微生物和酶活性的影响,以期阐明围封对高寒退化草地修复的影响。结果表明,与放牧土壤相比,围封1、4和6年的草地土壤水溶性有机碳和水溶性有机氮含量显著提高(P<0.05),围封6年的土壤含水量显著增加,p H值显著降低;围封显著改变了土壤蔗糖酶和L-天冬酰胺酶活性,土壤蔗糖酶和L-天冬酰胺酶活性均随着围封年限的延长有增加的趋势;围封6年土壤细菌、放线菌和革兰氏阳性细菌含量相比放牧显著升高。因此,围封不仅会引起土壤物理化学性质的变化,而且土壤酶活性与土壤微生物群落结构都会发生相应改变。Pearson相关性分析表明,水溶性有机碳、水溶性有机氮、土壤水均与土壤酶活性和微生物类群生物量显著或极显著(P<0.01)相关,因此这些指标可以指示退化草地修复状况。围栏禁牧有利于提高土壤易降解有机质含量,从而促进微生物生长,加速营养物质循环,促进高寒草原生态系统的恢复。The deterioration of soil ecosystem and soil degradation related to overgrazing were serious and cannot be restored in short period.In order to determine the impacts of fencing on the soil enzyme activities and soil microbial communities in Damxung steppe,the activities of β-glucosidase,invertase,phenol oxidase,peroxidase,L-asparaginase,protease,urease and alkaline phosphatase were investigated,as well as the biomass of bacteria,fungi,actinomycete,gram-positive bacteria and gram-negative bacteria.Water soluble organic carbon(WSOC) and water soluble organic nitrogen(WSON) in soils with all fencing treatments were significantly higher(P < 0.05) than that in grazing soils.There were significant variations of soil moisture and p H between grazing and fencing 6 years.Invertase and L-asparaginase activities significantly increased with the fencing year extended.The biomass of bacteria,actinomycete and gram-positive bacteria in soil with 6 years fencing were significantly higher(P < 0.05) than that in soil.All of these results suggested that fencing changed not only soil physicochemical properties,but also soil enzyme activities and microbial communities.The further pearson correlation analysis showed that WSOC,WSON and moisture had significantly positive correlation with soil enzyme activities and soil microbial communities which suggested that all of tested factors could be good indicators for grassland degradation and restoration.All of these results showed that fencing helped improving soil organic matter to promote growth of microorganism and recovery of alpine grassland ecosystem.

关 键 词：土壤微生物 土壤酶活性 青藏高原 过度放牧 

分 类 号：S812.2[农业科学—草业科学]