Improved water and ions dynamics in a clayey soil amended with different types of agro-industrial waste biochar

Biochar is a beneficial amendment for fine-textured soils. In addition, the interaction of biochar particles with soil components influences the dynamics of water and ions, which is particularly important to remediate salt-affected soils. We investigated the effect of sugarcane bagasse (SB), orange bagasse (OB), and corncobs (CB) biochar on water movement and ion leaching in clayey soil. Non-amended soil (CT) column and soil amended with gypsum (CTG) served as controls. Water infiltration, water flow rate, cumulative leached cations, anions, and exchangeable cations (Ca2+, Mg2+, K+, and Na+) were determined. Biochar increased the water infiltration and water flow rate by 80% and 71%, respectively. The SB and CB treatments increased the ion removal from the soil by 48%, whereas the OB increased the removal by 19%. The OB´s lower surface area and water holding capacity likely influenced its performance. Biochar reduced the Ca2+ and Mg2+ concentration on the soil exchange complex by 44% and 76%, respectively, and increased K+ by 233%. However, the most exciting result was the reduction of exchangeable Na+, 90% in the SB and CB treatments and 50% in the OB treatment. Considering that a high concentration of Na+ on the exchange complex contributes to soil structural degradation, biochar application, especially SB and CB, can potentially improve soil quality and mitigate salt-affected soils. [Display omitted] •All biochars increased the water infiltration and distribution in the clayey soil.•Biochar showed a selective affinity for cations and anions in the soil.•All biochars promoted Ca2+ and K+ leaching.•Sugarcane biochar increased Na+ removal from the soil.•Biochar can potentially improve the soil´s mechanical and hydraulic properties.