ABSTRACT
Soil degradation threatens global food production and security, clean water and air, and animal and human health. Degradation occurs in different forms and at different rates and can be categorized into three types – chemical, physical and biological – each of which does not exist individually but is the product of multiple interactions and feedback loops. Chemical deterioration primarily involves loss of nutrients and/or soil organic matter (SOM), salinization, acidification, pollution and eutrophication. Physical deterioration includes loss of soil, nutrients and SOM from wind and water erosion, compaction, sealing, crusting, water logging and loss of rooting depth. Biological deterioration is likely the least understood but critical to overall soil function and crop productivity and involves the loss of biodiversity, keystone taxa or consortia, and an overall reduction in efficient biological processes. Soil microbes play a direct role in driving multiple soil chemical and physical processes important for overall ecosystem function, but also have direct and indirect effects on plant productivity and quality. As a result, we suggest that soil conservation (i.e. protection and minimization of soil loss) and regeneration (i.e. rejuvenation of degraded soils) should focus not only on erosion and soil loss but also on the status of the soil
biological community and its function. In other words, both are different forms of soil health management and although minimizing erosion is a worthy goal, optimum soil function and health remains paramount to plant productivity and sustainability.
