Effects of biochar nanoparticles as a soil amendment on the structure and hydraulic characteristics of a sandy loam soil
Xiaopeng Chen, Manli Duan, Beibei Zhou, Lei Cui
Abstract
Abstract Biochar as a soil amendment can influence the physical and solute transport properties of soils and, thus, provide a means to improve soil fertility. However, the use of different sized biochar particles down to the nano‐scale has revealed inconsistent results, with the mechanisms poorly understood owing to a lack of experimental data. This study investigated the effects and mechanisms of nano‐sized biochar particles (NBC) applied to a sandy loam soil with regard to impacts on the hydraulic characteristics and soil structure. Column experiments were carried out with NBC application rates of 0.0%, 0.3%, 0.5%, 0.7% and 1.0% (by weight). It was found that the NBC changed the distribution of the soil pore structure and affected the degrees of anisotropy, fractal dimension, soil porosity and stability of soil aggregates. NBC applications also increased the water repellency of the soil and reduced the surface energy of soil particles. Regarding soil hydraulic properties, NBC applications increased the saturated hydraulic conductivity of the soil and decreased soil water retention. Increasing the amount of NBC applied to the mixing‐layer decreased cumulative infiltration values (reduced by 3.75%–13.75%). The above results reveal how NBC affects the soil pore structure and soil hydraulic characteristics, which provides a theoretical basis for the systematic evaluation of soil improvement and environmental effects of nano‐sized biochar.