Soil organic matter and water retention

The current and projected anthropogenic global warming and the attendant increase in the severity and extent of soil degradation may exacerbate the intensity and duration of drought occurrence in agroecosystems. Restoration of the soil organic matter (SOM) content of degraded/depleted soils can increase soil water retention (SWR) more at field capacity (FC) than that at the permanent wilting point (PWP), and thus increase the plant available water capacity (PAWC). The magnitude of increase in PAWC may depend on soil texture and the initial SOM content. Thus, restoration of the SOM content of degraded/depleted soils can make them as well as agroecosystems climate-resilient. Management practices which enhance soil health by restoring SOM content include conservation agriculture, cover cropping, residue mulching, and complex farming systems involving integration of crops with trees and livestock. Such technologies must be fine-tuned under site-specific conditions. Additional research is needed to establish the cause-effect relationship between increase in SOM content and PAWC and the ameliorative effect on drought-resilience for diverse crops and cropping systems.