水保所知识产出(1956---)知识库

Cover crops have been increasingly grown for improving soil health and crop production and minimizing en-
vironmental impact compared to no cover crop. Systematic documentation of cover cropping effects on soil
microbial abundance and community structure, however, is scarce. A meta-analysis including data from 81
available studies was conducted to elucidate the effect of “cover crop” versus “no cover crop” on soil microbial
community abundance and structure. Microbial biomass C and N (MBC and MBN) and total phospholipid-de-
rived fatty acids (PLFA) were taken as proxies for soil microbial abundance, and total fungi, total bacteria, gram-
positive and -negative bacteria, actinomycete, and arbuscular mycorrhizal fungi (AMF) for microbial community
structure. Compared to no cover crop, cover crop overall enhanced PLFA, MBC, and MBN by 24, 40, and 51%,
respectively. Soil total bacteria and total fungi, and the groups in them increased by 7–31% with cove crop
compared to no cover crop. Fungi were affected more by cover crop than bacteria as indicated by the greater
fungi/bacteria ratio. In depth categorical meta-analyses revealed that the legume and nonlegume cover crop
mixture reduced MBC, PLFA, and actinomycete compared to legume or nonlegume cover crop alone. Legume
cover crop enhanced actinomycete in comparison to nonlegume or the cover crop mixture. Incorporation of
cover crop residue into the soil increased PLFA, total bacteria, AMF root colonization, and spore density, but
decreased gram-positive and -negative bacteria and AMF compared to residue placed at the surface or removed
from the soil. Microbial parameters due to cover crop compared to no cover crop were related to soil properties
and annual precipitation. Medium-textured soils showed greater response of cover crop on PLFA, total bacteria
and fungi, and actinomycete than fine- or coarse-textured soils. We conclude that cover crops enhance soil
microbial community biomass and affected community structure compared to no cover crop and the responses of
microbial parameters to cover crop varied with soil and climatic conditions. Cover crops can enhance biological
soil health by enhancing microbial community abundance compared to no cover crop.