Fungi show broader environmental thresholds in wet than dry agricultural soils with distinct biogeographic patterns

Abstract

It is critical to establish response thresholds for fungal communities to global environmental change and assess the relationship between fungal diversity and nutrient cycling in soils. However, these have not yet been evaluated in agro-ecosystems. Here we report the findings of a survey across eastern China on the soil fungi and physicochemical properties in adjacent maize and rice fields. The results revealed a wider range of environmental thresholds for soil fungi in rice than maize fields. We found that the dominant fungal taxa only accounted for 0.6% of all taxa, but constituted >50% of total fungi. Based on their habitat preferences, distinct distribution maps between maize and rice fields were constructed, which indicated niche differentiation of soil fungi between dry and waterlogged soils. Rice fields showed higher fungal richness in low latitude regions, consistent with latitudinal richness patterns found in natural terrestrial ecosystems; however, no such trend was observed in maize fields. Fungal richness was positively correlated with nutrient cycling in rice soils and fungal beta diversity with nutrient cycling in maize soils. These findings provide response thresholds for fungal community change across environmental gradients, advancing our understanding of soil fungal diversity patterns in agricultural ecosystems. Differences between wetland and dryland should be taken into consideration when formulating sustainable management plans and baselines for assessments of future global change and resilience of agricultural fields.