Soil macrofauna are important bioindicators of soil quality in agroecosystems under different management

Regenerative and resource conserving agriculture has gained recognition as a sustainable substitute to intensive agricultural models to reduce soil degradation and loss of ecosystem services. However, the major stumbling block to the successful implementation of these practices by farmers is the difficulty in measuring their sustainability and effectiveness. Understanding the status of soil quality in agroecosystems has been proposed as a fundamental step towards agricultural productivity and sustainability. In this research, different indicators were used to evaluate soil quality and function within differently managed land uses with special emphasis on soil macrofauna as biological indicators. Soil physical, chemical and biological samples were collected using soil monoliths within four land uses located in the Thabo Mofutsanyane district, Free State province, South Africa (Bethlehem and Reitz areas): (1) conservation management, (2) livestock integration within the cropping systems, (3) conventional management, and (4) natural grasslands used as reference sites. These data allowed for the identification of soil macrofauna bioindicator species which represented important features of soil quality (biodiversity, chemical fertility, and physical quality). The integrated land use demonstrated the uppermost values of soil quality according to the biological, chemical, and physical indicators. Most of the indicator variables which indicated poor soil quality were greatly associated with the conventional land use. The biodiversity indicator was found to be closely linked with the overall indicator, suggesting that soil macrofauna might be the major drivers of soil quality but importantly can be used to assess overall soil quality. Twenty-five species were identified as bioindicators of soil quality. The soil macrofauna bioindicators could greatly simplify the assessments of land use management effects by farmers within the study area, thereby encouraging them to actively participate in decision-making concerning land use management. The overall results demonstrated that regenerative practices could restore degraded soils and ecosystem services.