Mitigating NO emissions from agricultural soils with fungivorous mites.

Nitrous oxide (NO) is an important greenhouse gas and an ozone-depleting substance. Due to the long persistence of NO in the atmosphere, the mitigation of anthropogenic NO emissions, which are mainly derived from microbial NO-producing processes, including nitrification and denitrification by bacteria, archaea, and fungi, in agricultural soils, is urgently necessary. Members of mesofauna affect microbial processes by consuming microbial biomass in soil. However, how microbial consumption affects NO emissions is largely unknown. Here, we report the significant role of fungivorous mites, the major mesofaunal group in agricultural soils, in regulating NO production by fungi, and the results can be applied to the mitigation of NO emissions. We found that the application of coconut husks, which is the low-value part of coconut and is commonly employed as a soil conditioner in agriculture, to soil can supply a favorable habitat for fungivorous mites due to its porous structure and thereby increase the mite abundance in agricultural fields. Because mites rapidly consume fungal NO producers in soil, the increase in mite abundance substantially decreases the NO emissions from soil. Our findings might provide new insight into the mechanisms of soil NO emissions and broaden the options for the mitigation of NO emissions.