Effect of Different Set-Aside Management Systems on Soil Biological Fertility and Biodiversity of Bacterial and Microarthropod Communities

Soil health and agricultural sustainability are primarily threatened by organic matter depletion and a decline in biodiversity. To mitigate these processes, managing set-aside systems remains a simple practice to preserve biodiversity and functions essential to soil fertility. The objective of this study was to evaluate the effectiveness of medium-term set-aside management in preventing soil degradation using changes in microbial and microarthropod communities, both of which are involved in organic matter degradation. Three different set-aside managements, with mowing (May or July) and without mowing, were compared to conventional rotation in three sites located in North, Central, and South Italy. The microbial community was analyzed through both biochemical methods, such as the assessment of soil respiration and microbial biomass, and molecular techniques, such as Denaturing Gradient Gel Electrophoresis. Soil fertility was assessed by the Biological Fertility Index, while soil biodiversity was assessed with microbial and microarthropod indicators. All set-aside management showed a statistically significant separation from conventional crop rotation for both microbial and microarthropod communities. Indicators highlighted a lower efficiency of set-aside management in organic matter use compared to conventional crop rotation, while microbial and microarthropod biodiversity increased in all set-aside managements. The QBS-ar index showed good soil quality standards in each set-aside management, benefiting the euedaphic microarthropods, whereas soil microbial respiration highlighted a higher microbial activity in the same experimental context.