Identification of Soil Quality Factors and Indicators in Mediterranean Agro-ecosystems

Soil quality offers a holistic approach to understanding the relationships between soil’s biological, chemical, and physical properties, which is crucial for the sustainable land use and the management of non-renewable soil resources. This study evaluates the impact of land use on 23 physicals, chemicals, and biologicals soil quality indicators (SQIs) across five land uses of the Mediterranean agro-ecosystems: forest, olive groves, wheat fields, and a corn / wheat crop rotation system. Over two consecutive years, seasonal soil samplings were conducted across three conventionally farmed fields for each land use. Through multivariate analysis, five key soil quality factors—organic matter, microbial biomass, nutrients, the C/N ratio, and compaction—were identified as reflective alterations in soil quality due to land use change. Discriminant analysis revealed the soil properties of total nitrogen (Ntot) and the C/N ratio, which highlights the quantity and quality of soil organic matter, as particularly sensitive indicators of soil quality changes in Mediterranean agroecosystems incorporating most of the information derived from the entire set of initials SQIs. These proposed indicators offer a simplified yet effective means of assessing soil resource sustainability in the Mediterranean agroecosystems, providing practical tools for monitoring and managing soil quality.