Mulching practices decreased soil microbial carbon degradation potential under spring maize in the Loess Plateau of China

Surface mulching with crop straw or plastic film has a great potential in soil carbon (C) sequestration. A 10-yr field experiment on spring maize was conducted in the Loess Plateau of China to compare the impacts of crop straw (SM) and plastic film (FM) mulching on soil microbial C-degradation genes using a metagenomic approach. Compared to those with no mulching (CK), soil C fractions significantly increased under SM while decreased under FM. However, the relative abundance of total microbial C-degradation genes did not change under SM, but was significantly lower by 3.9 % under FM. Specifically, the relative abundance of genes involved in stable C degradation did not vary with mulching, while those in labile C degradation decreased by 14.0 % (p