AUTHOR=Dou Ying , Wen Mengmeng , Yang Caidi , Zhao Fazhu , Ren Chengjie , Zhang Nannan , Liang Yinyan , Wang Jun 

TITLE=Effects of straw and plastic film mulching on microbial functional genes  involved in soil nitrogen cycling

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1205088

DOI=10.3389/fmicb.2023.1205088

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>Microorganisms regulate soil nitrogen (N) cycling in cropping systems. However, how soil microbial functional genes involved in soil N cycling respond to mulching practices is not well known.</p></sec><sec><title>Methods</title><p>We collected soil samples from a spring maize field mulched with crop straw (SM) and plastic film (FM) for 10-year and with no mulching (CK) in the Loess Plateau. Microbial functional genes involved in soil N cycling were quantified using metagenomic sequencing. We collected soil samples from a spring maize field mulched with crop straw (SM) and plastic film (FM) for 10-year and with no mulching (CK) in the Loess Plateau. Microbial functional genes involved in soil N cycling were quantified using metagenomic sequencing.</p></sec><sec><title>Results</title><p>Compared to that in CK, the total abundance of genes involved in soil N cycling increased in SM but had no significant changes in FM. Specifically, SM increased the abundances of functional genes that involved in dissimilatory nitrate reduction to ammonium (<italic>nirB</italic>, <italic>napA</italic>, and <italic>nrfA</italic>), while FM decreased the abundances of functional genes that involved in ammonification (<italic>ureC</italic> and <italic>ureA</italic>) in comparison with CK. Other genes involved in assimilatory nitrate reduction, denitrification, and ammonia assimilation, however, were not significantly changed with mulching practices. The <italic>nirB</italic> and <italic>napA</italic> were derived from <italic>Proteobacteria</italic> (mainly <italic>Sorangium</italic>), and the <italic>ureC</italic> was derived from <italic>Actinobacteria</italic> (mainly <italic>Streptomyces</italic>). Mental test showed that the abundance of functional genes that involved in dissimilatory nitrate reduction was positively correlated with the contents of soil microbial biomass N, potential N mineralization, particulate organic N, and C fractions, while ammonification related gene abundance was positively correlated with soil pH, microbial biomass C and N, and mineral N contents.</p></sec><sec><title>Discussion</title><p>Overall, this study showed that SM could improve soil N availability and promote the soil N cycling by increasing the abundance of functional genes that involved in DNRA, while FM reduced the abundance of functional genes that involved in ammonification and inhibited soil N cycling.</p></sec>