Effects of Different Land Use Types on Soil Organic Carbon and Microbial Respiration in Huang-Huai-Hai Plain
Soils are the largest carbon pools in terrestrial ecosystems.Soil organic carbon can be decomposed by microorganisms and release CO2 to atmosphere.Minor changes in soil carbon pool will significantly affect atmospheric CO2 concentration and global carbon cycling.Under the current background of frequent human activities and land use/cover changes (LUCC),it is necessary to study the effects of different land use types on soil physico-chemical properties and microbial functions (such as soil organic carbon and microbial respiration) to illuminate the key factors of influence soil carbon sequestration function and provide scientific evidence for future land use management.This study chose Kaifeng as pilot city and measured soil moisture,soil pH,NH4+,NO3-,total carbon,total nitrogen,organic carbon,dissolved organic carbon,microbial biomass carbon,microbial biomass nitrogen,microbial respiration and its temperature sensitivity in different land use types,including old-field,grassland,orchard,farmland,and forest in Huang-Huai-Hai Plain.The results showed that:(1) All soil moisture,total carbon,total nitrogen,organic carbon (1.48％),microbial biomass carbon and nitrogen in forest were significantly higher than that in other land use types.However,microbial respiration (101.06 mg·kg-1·d-1) and its temperature sensitivity (1.18) were minimum.(2) Soil total carbon,total nitrogen,organic carbon,microbial biomass carbon and nitrogen in farmland were lower than that in forest,but higher than that in other land use types.Microbial respiration rate (128.55 mg·kg-1·d-1) was high in farmland.(3) Soil carbon,nitrogen,and microbial carbon and nitrogen contents in old-field,grassland,and orchard were less than forest and farmland.And (4) structural equation model showed that land use type directly explained 68％ of soil organic carbon and indirectly influenced soil organic carbon and microbial respiration through soil moisture.Soil organic carbon and microbial respiration were explained 93％ and 54％,respectively,by soil moisture and NO3-.The results indicate that forest ecosystem will facilitate soil organic carbon sequestration,and their minor temperature sensitivity of microbial respiration will be of great importance in countermeasure of global climatic change in future.Farmland cover larger area.Carbon sink function should be developed by no-tillage and straw return in agricultural management in the meantime of crop production are protected.
soil physico-chemical propertiesorganic carbon mineralizationcarbon sequestrationland managementstructural equation model
国家科技期刊平台
NSTL
万方数据
维普
