Soil organic matter and water retention

Abstract

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. 1 INTRODUCTION Global warming has already reached 1 • C above the preindustrial levels (Lindsey & Dahlman, 2020; Sánchez-Lugo, Berrisford, Morice, & Nicolas, 2018), which in turn has aggravated the severity of drought caused by soil moisture deficit (Berg & Sheffield, 2018). Additionally, the positive net ecosystem exchange (NEE), caused by soilwater deficit, can make soil a net source of CO 2 (Green et al., 2019), especially following some repeated summer droughts (Sowerby, Emmett, Tietema, & Beier, 2008). Further, anthropogenic perturbations may even destabilize the

The role of soil in regulation of climate

“…Soils are also important in regional water cycles [69], which may in turn impact evapotranspiration rates and sensible heat fluxes [70] and thereby affect to an extent local climate, though the impact of soils is difficult to quantify at larger scales. When soils are managed well to maximize SOC storage, they hold water better and are also more fertile [2,71]. This, in turn, may reduce the need for irrigation, and could reduce fertilizer needs.…”

Soil Water Retention and Soil Compaction Assessment in a Regional-Scale Strategy to Improve Climate Change Adaptation of Agriculture in Navarre, Spain

“…In this sense, both components of AWHC, namely soil moisture retention at field capacity and permanent wilting point, are often related to SOC content [95]. In general, soil moisture at field capacity shows a clearer response to SOC, while the response of the soils moisture at wilting point usually is more variable and may depend, in part, on texture [96][97][98].…”

Effects of Application of Recycled Chicken Manure and Spent Mushroom Substrate on Organic Matter, Acidity, and Hydraulic Properties of Sandy Soils

“…Changes in the soil structure and pore size distribution in response to organic additions affect soil water retention (WRC) and hydraulic conductivity [ 36 , 37 ]. The soil hydraulic properties governing water storage and movement within the soil profile are essential for effective and adequate management of drainage and agricultural irrigation [ 38 , 39 , 40 , 41 ].…”