摘要
为了揭示放牧扰动下荒漠草原土壤有机碳组分变化特征,通过野外调查与室内分析相结合的方法,以围封样地为对照(NG),选择轻度(LG)、中度(MG)、重度(HG)放牧退化草地,连续2年开展放牧强度对荒漠草原土壤有机碳组分的影响,为北方草地生态保护和优化管理提供有效的科学支持。结果表明:随着放牧强度的增加,荒漠草原丰富度指数(12.3~18.9)、均匀度指数(1.03~1.68)、多样性指数(0.35~0.79)呈先增加后降低趋势,大致表现为MG>LG>NG>HG,而优势度指数(2.56~4.23)呈相反的变化趋势。随着放牧强度增加,地上生物量(158.2~221.3 g·m^(-2))和地下生物量(126.9~152.3g·m^(-2))均呈递减趋势,土壤容重随放牧强度的增加而增加,而总孔隙度随放牧强度的增加而减小。土壤微生物量碳(MBC)、易氧化有机碳(EOC)、颗粒有机碳(POC)、轻组有机碳(LFOC)和水溶性有机碳(WSOC)明显受放牧强度的的影响,呈现出一致性规律,大致表现为MG>LG>HG>NG。ω(EOC)/ω(SOC)比例和微生物商[ω(MBC)/ω(SOC)]随放牧强度的增加呈先增加后降低趋势,其中MG显著高于NG、LG和HG(P<0.05),NG、LG和HG差异不显著(P>0.05)。相关分析表明,地下生物量与土壤活性有机碳组分呈显著正相关(P<0.05),其相关系数绝对值最大,是影响荒漠草原土壤活性有机碳组分变化的重要影响因素。
In order to explore the changes of soil organic carbon fractions under grazing in desert steppe of China,the soil organic carbon fractions under different grazing intensity(NG,no grazing;LG,light grazing;MG,moderate grazing;HG,heavy grazing)were studied in desert steppe,in two years by the field investigation and indoor analysis,providing some effective measures and optimal management for the grassland in northern,China.The results were as follows:Plant species richness,evenness,diversity index significantly reduced with the increasing of grazing intensity with MG>LG>NG>HG,while the dominance index showed the opposite change trend.The aboveground biomass and belowground biomass gradually reduced with the increasing of grazing intensity with NG>LG>MG>HG,suggesting that grazing intensity could reduce plant biomass in this region.Similarly,soil bulk density increased and soil total porosity decreased with the increasing of grazing intensity.Compared with NG,soil microbial biomass carbon(MBC),the easy oxidation of soil organic carbon(EOC),particulate organic carbon(POC),light group of organic carbon(LFOC),water soluble organic carbon(WSOC),soil microbial biomass carbon(MBC)had the same change trends,which showed MG>LG>HG>NG.Further,the ratio of EOC/SOC first increased and then deceased with the increasing of grazing intensity,and there was no significant difference in NG,LG and HG(P>0.05).In addition,correlation analysis showed that belowground biomass was strong related to soil organic carbon fractions,which could be regarded as the mainly driving factors for soil organic carbon fractions in desert steppe in Inner Mongolia.
作者
通乐嘎
赵斌
吴玲敏
TONG Lega;ZHAO Bin;WU Lingmin(Hetao College,Bayan Nur 015000,China)
出处
《生态环境学报》
CSCD
北大核心
2018年第9期1602-1609,共8页
Ecology and Environmental Sciences
关键词
放牧强度
荒漠草原
土壤有机碳组分
土壤理化性质
grazing
desert steppe
soil organic carbon fractions
soil physical-chemical properties
