Mitigating N2O emissions from agricultural soils with fungivorous mites

Abstract

Nitrous oxide (N 2 O) is an important greenhouse gas and an ozone-depleting substance. Due to the long persistence of N 2 O in the atmosphere, the mitigation of anthropogenic N 2 O emissions, which are mainly derived from microbial N 2 O-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 N 2 O emissions is largely unknown. Here, we report the significant role of fungivorous mites, the major mesofaunal group in agricultural soils, in regulating N 2 O production by fungi, and the results can be applied to the mitigation of N 2 O 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 N 2 O producers in soil, the increase in mite abundance substantially decreases the N 2 O emissions from soil. Our findings might provide new insight into the mechanisms of soil N 2 O emissions and broaden the options for the mitigation of N 2 O emissions.

An agroecological structure model of compost—soil—plant interactions for sustainable organic farming

“…S 15c ). Fungi having cytochrome P450nor that generates N 2 O gas are considered as a major biological factor in the generation of greenhouse gases [ 42 – 44 ]. Potato dextrose power, which can generally be used as a medium for fungi, was added to the soil for the test.…”

Mites as a natural weapon against soil-borne fungal diseases

“…The soil is an Andisol, which is the most widespread upland agricultural soil type in Japan 56 . Its average physical-chemical properties are as follows: total carbon, 39 g C/kg dry soil; total nitrogen, 2.6 g N/kg dry soil; bulk density, 0.81 g cm3; solid-phase rate, 34.5%; and pH, 6.5 57 . The soil was passed through a 2-mm or 6-mm mesh sieve for the microcosm experiment or the spinach pot experiment (Soils used for other pot/crate experiments were not sieved).…”

“…Mite-free soils were prepared by storing the soil at 4 °C in sealed plastic bags for more than 1 month (Fig. S1e) 57 .…”

“…The fungal community composition in the gut of soil mites was determined and compared with that in soils by extracting the total DNA from mite bodies and soils, respectively, followed by amplicon sequencing targeting the fungal ITS2 region. Mite DNA and soil DNA samples were obtained from the soil microcosms in a previously reported study (Shen et al, 2021 57 , the "Second Soil Microcosm Experiment"). Each microcosm (in triplicate) containing 150 g (in dry weight) of soil was applied 2 g of organic fertilizer and 80 mite individuals and incubated at 25 °C.…”

An evaluation of homeostatic plasticity for ecosystems using an analytical data science approach

“…In addition, the generation of nitrous oxide, a greenhouse gas, has a direct impact on global warming: it is essential to control denitrification. These controls are expected to involve symbiotic relationships between multiple organisms, including nitrogen-fixing bacteria, anammox bacteria, fungi [17] , [18] , ticks [19] , and insects [20] . Furthermore, management in recycling [21] , [22] and livestock management technology [23] will also be affected.…”