Symbiotic soil fungi suppress N2O emissions but facilitate nitrogen remobilization to grains in sandy but not clay soils under organic amendments

Abstract

Arbuscular mycorrhizal fungi (AMF) can form symbiotic relationships with roots of plants and potentially affect nitrogen (N) cycling in cropping systems. However, it is unclear how AMF influence N2O emissions and crop N assimilation, two key N cycling steps which are closely related to climate change and food production, under different soil management regimes. A microcosm experiment was conducted to test the effects of AMF on N2O emission and plant N assimilation, with wheat as a model crop, under organic (straw) amendment in soils with different textures. We found that AMF suppressed N2O emissions, promoted mycorrhizal N uptake and remobilization to grains and increase grain biomass under organic amendment in the sandy soil. However, AMF did not affect N2O emission, although increased plant N uptake, but inhibited mycorrhizal N remobilization to grains under organic amendment in the clay soil. These findings highlight that AMF have different effects on N2O emission and N translocation between sandy and clay soils. Appropriate soil management for mycorrhizal symbiosis in the cropping system can combat climate change and ensure food production.