Effect of biochar application rate on soil physical and hydraulic properties of a sandy loam

Abstract

Biochar is used as a soil amendment for improving soil quality and enhancing carbon sequestration. In this study, a loamy sand soil was amended at different rates (0%, 25%, 50%, 75%, and 100% v/v) of biochar, and its physical and hydraulic properties were analyzed, including particle density, bulk density, porosity, infiltration, saturated hydraulic conductivity, and volumetric water content. The wilting rate of tomato (Solanum lycopersicum) grown in soil amended with various levels of biochar was evaluated on a scale of 0–10. Statistical analyses were conducted using linear regression. The results showed that bulk density decreased linearly (R² = 0.997) from 1.325 to 0.363 g cm⁻³ while the particle density decreased (R² = 0.915) from 2.65 to 1.60 g cm⁻³ with increased biochar amendment, with porosity increasing (R² = 0.994) from 0.500 to 0.773 cm³ cm⁻³. The mean volumetric water content ranged from 3.90 to 14.00 cm³ cm⁻³, while the wilting rate of tomato ranged from 4.67 to 9.50, respectively, for the non-amended soil and 100% biochar-amended soil. These results strongly suggest positive improvement of soil physical and hydraulic properties following addition of biochar amendment.

Keywords:

• biochar amendment
• soil quality
• soil hydraulic properties
• soil physical properties