Soil moisture and land use are major determinants of soil microbial community composition and biomass at a regional scale in northeastern China

[摘要] Global environmental factors impact soil microbial communities and furtheraffect organic matter decomposition, nutrient cycling and vegetationdynamic. However, little is known about the relative contributions ofclimate factors, soil properties, vegetation types, land managementpractices and spatial structure (which serves as a proxy for underlying effects oftemperature and precipitation for spatial variation) on soil microbialcommunity composition and biomass at large spatial scales. Here, wecompared soil microbial communities using phospholipid fatty acid methodacross 7 land use types from 23 locations at a regional scale innortheastern China (850 × 50 km). The results showed that soilmoisture and land use changes were most closely related to microbialcommunity composition and biomass at the regional scale, while soil total Ccontent and climate effects were weaker but still significant. Factors suchas spatial structure, soil texture, nutrient availability and vegetationtypes were not important. Higher contributions of gram-positive bacteriawere found in wetter soils, whereas higher contributions of gram-negativebacteria and fungi were observed in drier soils. The contributions ofgram-negative bacteria and fungi were lower in heavily disturbed soils thanhistorically disturbed and undisturbed soils. The lowest microbial biomassappeared in the wettest and driest soils. In conclusion, dominant climateand soil properties were not the most important drivers governing microbialcommunity composition and biomass because of inclusion of irrigated andmanaged practices, and thus soil moisture and land use appear to be primarydeterminants of microbial community composition and biomass at the regionalscale in northeastern China.

[学科分类] 地球化学与岩石