Three‐Year Monitoring of the Arthropod‐Based Soil Biological Quality Index (QBS‐ar) in Arable Fields of the Sentina Reserve: Spatial and Temporal Patterns and Environmental and Management Correlates

Although the arthropod-based Biological Soil Quality Index (QBS-ar) is widely used to assess soil biological quality in agroecosystems, interpreting its variation under field conditions remains challenging. We characterised spatial and temporal patterns in QBS-ar and complementary arthropod-based indicators across four arable fields belonging to two farms within the Sentina Reserve (Central Italy): Fattoria Ferri (FE1 and FE2) and Selva Giurata (RL1 and RL2). Each field was sampled on six occasions, in June and October of each year from 2021 to 2023. Six exploratory multiple linear regression models examined associations between sub-sample level QBS-ar (partial QBS-ar) and six predictor groups: agricultural practices, soil chemistry, textural parameters, soil environmental factors, weather conditions and landscape composition. Across the 24 field-by-occasion assessments, total QBS-ar ranged from 102 to 209. Values were generally higher in the Selva Giurata fields, with RL2 and FE2 showing the highest and lowest mean values, respectively. The complementary biotic metrics followed a similar field-level pattern. At least one term in each predictor-group model met the significance threshold. These terms included exchangeable potassium, tillage for seedbed preparation, harvesting, very fine sand, temperature, relative humidity, soil moisture and the proportions of land classified as agricultural areas and of forest and semi-natural areas. Together, these results show the value of considering both management and environmental context when interpreting QBS-ar variation in field monitoring. The field-specific patterns identified here provide testable hypotheses for broader studies with independent farm-level replication.