Effects of Biochar with Two Paticle Sizes on Soil Water Characteristic Curves of Soils with Different Textures

The effects of biochar on soil water characteristic curve were studied through adding fine biochar and coarse biochar with the rates of 0%,3%,5%to loamy sand,loam,silty clay loam.Results showed that:fine biochar and coarse biochar both increased water retention of loamy sand and reduced water retention of silty clay loam.Coarse biochar increased water retention of loam,but there was no effect of fine biochar on water retention of loam.The effects of fine biochar and coarse biochar on three types of soils were similar with biochar rate of 3%.With biochar rate of 6%,fine biochar increased the water retention of loamy sand observably while coarse biochar increased the water retention of loam significantly.Therefore,effects of biochar on soil water retention depended on soil texture,biochar particle size and biochar rate.