Influence of Coal Gangue Mulching With Various Thicknesses and Particle Sizes on Soil Water Characteristics

Abstract

Water availability seriously affects vegetation restoration in arid mining areas, and mulching is an effective way to improve soil water conditions. Coal gangue occupies large swathes of land resources, resulting in ecological fragility and various environmental problems. Despite coal gangue having mineral elements similar to those in soil, its potential function as a mulch for soil water conservation has been unclear. Herein, mulching on the surfaces of soil columns was conducted using four particle size ranges and four thicknesses under laboratory conditions to investigate water infiltration and evaporation under different conditions. Apart from the treatments with particle size of 0–0.5 cm, the remaining mulch treatments with 16 cm thickness involved greater infiltration and lower evaporation. Therefore, we recommend a 16 cm-thick mulch treatment as the preferred mulching style. Treatments with a particle size of 0–0.5 cm and those with 4-cm thickness are not suggested due to their lower infiltration and higher evaporation characteristics. Overall, to enhance the soil water storage capacity in mining areas, the results suggest that mulching coal gangue with particle size exceeding 0.5 cm and a thickness exceeding 8 cm is suitable.