放牧对草地群落与土壤特征的影响  

Effects of Grazing on Community and Soil Characteristics in the Semi-arid Grassland

作　　者：刘玉[1] 常小峰[1] 田福平[2] 刘振恒 党志强[1] 武高林[1] 

机构地区：[1]中国科学院水利部水土保持研究所西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨陵712100 [2]中国农业科学院兰州畜牧与兽药研究所农业部兰州黄土高原生态环境重点野外科学观测试验站,兰州730050 [3]甘肃省玛曲县草原工作站,甘肃玛曲747300

出　　处：《西北植物学报》2016年第12期2524-2532,共9页Acta Botanica Boreali-Occidentalia Sinica

基　　金：中国科学院"西部之光"项目(XAB2015A04);中国科学院青年创新促进会项目(2011288);陕西省科技计划(2014KJXX-15)

摘　　要：针对放牧干扰对草地生态系统的影响,采用回归分析和典型对应分析(CCA)方法,研究放牧对草地植物群落物种多样性与生产力、土壤碳氮含量与生物量关系的影响。结果表明:(1)与休牧草地相比,放牧草地的地上生物量降低31.63%,凋落物生物量降低134.29%;放牧草地的禾草类生物量提高19.77%,而杂草类生物量和豆科类生物量分别降低31.09%和23.42%。(2)当物种多样性指数小于1.3时,休牧草地的生产力明显高于放牧草地;当物种多样性指数大于1.3时,放牧草地的生产力高于休牧草地。(3)CCA分析显示,家畜主要通过影响群落地上生物量、凋落物质量和土壤容重进而影响土壤的碳氮含量。(4)当群落地上生物量小于100g·m-2时,休牧草地的土壤有机碳和全氮含量高于放牧草地,当群落地上生物量大于100g·m-2时,放牧草地则略高于休牧草地。(5)当群落地下生物量小于1 200g·m-2时,放牧草地土壤有机碳、全氮含量高于休牧草地;当地下生物量大于1 200g·m-2时,放牧草地则略低于休牧草地。To explore how grazing affects grassland ecosystem,we studied the relationship of grassland community and soil characteristics in both grazing and rest-grazing grasslands.The object of this study was to determine the changes of the relationships between species diversity and productivity,soil characteristics（soil organic carbon,nitrogen contents）and biomass in the grazing grassland.The results showed that：（1）the above biomass and litter biomass were decreased significantly by livestock ingestion.From the perspective of functional groups,the biomass of grasses in grazing grassland was 19.77% more than in rest-grazing grassland.However,the biomass of forbs and legumes in grazing grassland were 31.09%and 23.42%less than in rest-grazing grassland.The ingested strategies of livestock were changed in the communities with different species diversity.Community productivity was decreased significantly by ingesting enormous grasses,which is the dominant species in community,in the communities with lower species diversity.（2）When diversity was less than 1.3,the productivity of rest-grazing grassland is higher than that of grazing grassland,but when diversity was more than 1.3,community productivity showed a contrary trend.（3）Results from Canonical Correlation Analysis（CCA）showed that livestock influenced soil carbon and nitrogen contents through changing above-ground biomass,litter biomass and soil bulk density.（4）Above-biomass was significantly influenced by livestock in the lower above-ground biomass community（100g·m-2）,so the soil organic carbon and total nitrogen contents responding to the same aboveground biomass were higher in rest-grazing grassland than that in grazing grassland.However,there was a contrary trend in the high above-biomass grassland（100g·m-2）.（5）When below-ground biomass was less than 1 200g·m-2,soil organic carbon and total nitrogen contents were higher in grazing grassland than that in rest-grazing grassland,but when below-ground biomass was more than 1 200g�

关 键 词：物种多样性 土壤特征 放牧生态系统 草地生产力 多样性与生产力 

分 类 号：Q948.112[生物学—植物学]