Land-use intensity and soil properties shape the composition of fungal communities in Mediterranean peaty soils drained for agricultural purposes

Anthropogenic effects on soil fungi have been poorly investigated in peaty soils, where they have a crucial role in the maintenance of soil fertility and in the regulation of nutrient cycles. In this study, we assessed the effects of land-use intensification on the composition of fungal communities in Mediterranean peaty soils drained for agricultural purposes. To this end, a continuous maize cropping system was compared with an extensive grassland and an agricultural soil left abandoned for 15 years. Molecular diversity and community composition of total soil fungi and arbuscular mycorrhizal fungi (AMF) were assessed, as well as soil chemical properties potentially responsible for fungal shifts. The relative roles of intensification and soil chemical properties were also quantified by applying variation partitioning analysis. Multivariate analyses show that: (i) land-use intensification shapes the composition of the community of total soil fungi and AMF in soil and roots; (ii) base saturation (Bas Sat) and exchangeable calcium (ExchCa) in soil are the significant soil chemical drivers of the composition of the total soil fungal community; (iii) Bas Sat is the only significant chemical parameter shaping the soil AMF community; and (iv) no soil chemical properties affect root AMF. Based on variation partitioning, which highlights a large overlap between land-use intensification and Bas Sat, we can assert that land-use intensification is well-correlated with Bas Sat in shaping the total soil fungal community composition, as well as the AMF. By contrast, intensification acts as a major driver with respect to ExchCa in shaping the composition of the total soil fungal communities.