利用方式对贝加尔针茅草原土壤微生物群落结构与土壤酶活性的影响

Effects of Utilization Methods on Soil Microbial Community Structure and Soil Enzyme Activity in Stipa baicalensis Steppe

土壤微生物和土壤酶活性是影响土壤生态系统物质循环和能量流动的主要驱动力。研究3种利用方式(围封、放牧和刈割)对贝加尔针茅草原土壤微生物群落结构与土壤酶活性的影响,为探索草原可持续利用提供基础数据。结果表明:围封、放牧和刈割利用下土壤微生物PLFA总量分别为30.24nmol/g、16.22nmol/g和14.52nmol/g,且均呈显著差异。0~30cm土层,土壤蔗糖酶活性表现为围封>放牧>刈割;土壤脲酶和碱性磷酸酶活性均表现为刈割>围封>放牧,土壤过氧化氢酶活性在不同利用方式间没有显著差异。土壤微生物PLFA总量与土壤脲酶、蔗糖酶、碱性磷酸酶活性以及pH值、有机碳、全氮、微生物量碳均呈极显著或显著的相关关系。刈割会增加土壤脲酶和碱性磷酸酶活性,但土壤微生物PLFA总量最低;围封相对于放牧有利于增加土壤酶活性和土壤微生物群落结构。综合比较,围封更有利于遏制贝加尔针茅草原的退化。

Soil microbiota and soil enzyme activities are the main factors affecting material circulation and energy flow in soil ecosystem.The effects of three utilization methods(enclosure,grazing and mowing)on soil microbial community structure and soil enzyme activity in Stipa baicalensis steppe were explored to provide basic data for sustainable utilization of grassland.The results showed that there were significant differences in the content of phospholipid fatty acid(PLFA)under enclosure,grazing and mowing treatments(30.24nmol/g,16.22nmol/g and 14.52nmol/g,respectively).In 0~30 cm soil layer,the activity of soil sucrase was the highest in enclosure treatment,followed by grazing and mowing treatments;the activities of soil urease and alkaline phosphatase were the highest in mowing treatment,followed by enclosure and grazing treatments.There was no significant difference in the activity of soil catalase among different treatments.The content of soil microbial PLFA was significantly correlated with soil enzyme activities(urease,sucrase,alkaline phosphatase activities),pH value,organic carbon,total nitrogen,and microbial biomass carbon.According to analyses of soil microbial community structure and soil enzyme activity,mowing can increase soil urease and alkaline phosphatase activities,resulting in the lowest soil microbial PLFA content.Compared with grazing,enclosure was beneficial to increase soil enzyme activity and soil microorganism.In conclusion,enclosure was more conducive to prevent Stipa baicalensis grassland from degradation.