An arthropod-based assessment of biological soil quality in winter wheat fields across Hungary

Intensive agriculture can induce soil degradation through various mechanisms, resulting in a decline in soil health and functionality. Soil arthropods, as an essential component of soil biodiversity, play a pivotal role in numerous ecosystem services for sustainable and productive crop cultivation. This research presents the inaugural nationwide evaluation of agricultural soils in Hungary, using microarthropods as soil quality indicators. Through the examination of 133 soil samples from 78 farms, we explored the direct and indirect effects of soil, plant, climatic variables and farming practices on the biological soil quality of winter wheat fields. Collembola and Acari were the two most common and abundant soil microarthropods. All arthropod-based soil quality and community metrics (QBS-ar, Collembola/Acari, richness, density) exhibited a negative correlation with bulk density, indicating the adverse effects of soil compaction. Notably, soil moisture was found to be a crucial factor that positively influenced the integrated faunal indices, QBS-ar and Collembola/Acari abundance ratio. Collembola proved to be the most responsive taxon, being highly sensitive to variations in both soil moisture and bulk density. In addition, bulk density had a negative effect on the abundance of Pauropoda, Diplura and Formicidae. The frequency of rainy days during the growing season had both direct and indirect positive effects on soil microarthropods, particularly in terms of density. Soil management, specifically ploughing and the number of tillage operations, emerged as primary drivers, indirectly affecting biological soil quality by altering soil structure and moisture conditions. Low-input farming under Hungarian agri-environmental schemes had comparable arthropod-based soil quality indices to conventional wheat fields. In conclusion, our study confirmed that soil microarthropods are suitable for nationwide assessments of agricultural soils and we found that the measures of the Hungarian Agri-Environmental Programme 2004–2009 were insufficient to improve soil biological quality. It is therefore imperative to implement more efficient farming practices that take better account of soil biodiversity and health.