Grass Clippings Mulching Improves Infiltrability of Low-Permeability Dryland Soils

In arid and semiarid regions, the high compactness and poor water permeability of the soils severely limit agricultural production. This study aims to shed light on techniques to enhance the permeability of these soils—specifically, by improving soil properties through mulching with organic grass clippings. We evaluated the effects of mulching with clippings of two organic grasses: alfalfa ( Medicago sativa L.) and ryegrass ( Lolium perenne L.) on soil porosity, water - holding capacity, and infiltrability of low-permeability soil. Following mulching with the 5-cm-long organic grass clippings, we found that the water-holding capacity and soil porosity improved compared with untreated soils. The saturated water content of soil mulched with Medicago sativa and Lolium perenne increased by 8% and 12%, respectively. The total porosity of the soils mulched with Medicago sativa and Lolium perenne increased by 2% and 1%, respectively, and the non-capillary porosity increased by 16% and 33%, respectively. In addition, compared with untreated soils, the soils treated with grass mulching saw increases in initial and steady-state infiltration rates. By demonstrating the clear benefits of grass mulching for improving soil physical parameters, such as soil porosity and permeability, this study provides a tested theoretical basis for incorporating grass mulching of low-permeability soils to enhance the sustainability of croplands.