Effectiveness of wood waste material for improving infiltration and reducing interrill soil loss in clay-rich volcanic soil

Abstract

The addition of wood waste material to soil may improve infiltration and reduce soil erosion, but there is a need for research to determine the most effective mixing ratios in a range of soil types. We incorporated wood waste material in volumetric mixing ratios of 0.00, 0.05, 0.10, 0.15, 0.20, and 0.30 cm³ cm⁻³ (ft³ ft⁻³) into an allophanic Andisol taken from Tohaku in Tottori Prefecture, Japan, and measured the effects on the soil aggregate stability, soil hydraulic properties, and soil erosion under different simulated rainfall intensities. The amended soils were subjected to three separate rainfall intensities: 15, 30, and 60 mm h⁻¹ (0.59, 1.18, and 2.36 in hr⁻¹) for 2, 1, and 0.5 hours, respectively, in order to obtain the same amount of cumulative rain depth. The infiltration capacity increased significantly with increasing rainfall intensity and increased mixing ratio, up to 0.20 cm³ cm⁻³, and then leveled off. The incorporation of wood debris effectively improved the soil saturated hydraulic conductivity and infiltration capacity. The improvement of soil aggregate stability and decrease in dispersivity with amendment mixing ratio limited the development of seal at the soil surface. The interrill soil losses, which decreased significantly with rainfall intensity, decreased nonlinearly as a function of the wood debris mixing ratio. The soil loss ranged from 0.09 to 0.48 Mg ha⁻¹ h⁻¹ (0.04 to 0.21 tn ac⁻¹ hr⁻¹), 0.21 to 1.10 Mg ha⁻¹ h⁻¹ (0.09 to 0.50 tn ac⁻¹ hr⁻¹), and 0.68 to 3.27 Mg ha⁻¹ h⁻¹ (0.30 to 1.46 tn ac⁻¹ hr⁻¹) for soils subjected to 15, 30, and 60 mm h⁻¹ (0.59, 1.18, and 2.36 in hr⁻¹) rainfall intensities, respectively. In the case of soil loss splashed by the three rainfall intensities, the corresponding splashed soil ranged from 0.40 to 0.64 Mg ha⁻¹ h⁻¹ (0.18 to 0.28 tn ac⁻¹ hr⁻¹), 0.83 to 1.3 Mg ha⁻¹ h⁻¹ (0.37 to 0.58 tn ac⁻¹ hr⁻¹), and 1.47 to 2.67 Mg ha⁻¹ h⁻¹ (0.65 to 1.19 tn ac⁻¹ hr⁻¹), respectively, in which no significant effect of wood debris was found. In this study, the effect of wood debris on interrill soil loss was not significant.