刈割强度对大针茅草原植物群落特征和土壤理化性质的影响

探究不同刈割强度对大针茅典型草原植物群落特征以及土壤理化性质的影响，可为大针茅草原制定合理科学的刈割制度提供理论依据。本研究以大针茅典型草原为对象，于2020年在内蒙古锡林浩特市毛登牧场刈割实验平台进行野外植被调查和取样。该实验平台于2014年建立，以不刈割为对照（CK），设置轻度（LM）、中度（MM）及重度刈割（HM）3个处理。本研究通过计算物种重要值和多样性指数，测定植物群落地上、地下生物量以及土壤理化性质，探究群落特征与土壤理化性质的关系。结果表明：1）与不刈割相比，不同刈割强度均增加了新物种，且中度刈割的物种数最多；与不刈割相比，不同刈割强度均显著增加了群落的丰富度和Shannon-Wiener指数，且轻度刈割显著增加了优势度和均匀度指数，表明轻度刈割最有利于群落多样性的维持；不同刈割强度对大针茅草原的生产力均无显著影响；2）土壤全碳、全氮和pH均在中度刈割时最高，且显著高于不刈割，表明中度刈割对土壤养分有积极影响；3）硝态氮是影响草地生产力的主要土壤因子，土壤含水量是影响草地群落多样性的主要土壤因子。本研究可为大针茅典型草原群落结构、物种多样性以及生产力等方面的研究提供重要参...

Effects of mowing intensity on community characteristics and soil physicochemical properties of Stipa grandis steppe， Inner Mongolia， China

This study investigated the effects of different mowing intensities on plant community characteristics and soil physicochemical properties of Stipa grandis steppe in order to provide a theoretical and scientific basis for establishing an appropriate mowing system in S. grandis steppe. We conducted a field vegetation survey and sampling in an experimental mowing area at Maodeng Ranch， Xilinhot， Inner Mongolia， China in 2020. The experimental mowing area was established in 2014 with no mowing as control （CK） and three treatments of light （LM）， moderate （MM） and heavy mowing （HM）. In this study， we investigated the relationship between community characteristics and soil physicochemical properties by calculating species importance values and diversity indices， and measuring above- and below-ground biomass of plant communities and soil physicochemical properties. It was found that： 1） Compared with no mowing， new species were increased under the various mowing intensities， and the number of species was highest under MM. Compared with no mowing， the mowing treatments significantly increased community richness and the Shannon-Wiener index， and light mowing also significantly increased the Simpson and Pielou indexes， indicating that light mowing was most beneficial to maintaining community diversity. Variation in mowing intensity had no significant effect on productivity of S. grandis steppe. 2） Soil total carbon， total nitrogen and pH were the highest under MM， and under this treatment were significantly higher than under no mowing， indicating that moderate mowing had positive effects on soil nutrient status. 3） Nitrate nitrogen was the main soil factor affecting grassland productivity， and soil water content was the main soil factor affecting grassland community diversity. This study provides important reference information for the study of community structure， species diversity and productivity of S. grandis steppe.