Effect of biochar application on soil water availability and hydraulic conductivity

Biochar has been widely promoted as a means to improve a range of soil properties including water holding capacity and infiltration. In this study we investigated the effect of applying 47 Mg ha^-1 Acacia green waste biochar to a sandy loam texture contrast soil in a commercial apple production system. Thirty one months after incorporation the biochar amended soil had significantly lower bulk density, higher saturated water content and higher near saturated hydraulic conductivity compared to the unamended control. However, biochar application had no significant effect on water holding capacity, field capacity, permanent wilting point, aggregate stability or infiltration at matric potentials below -0.05 kPa. This study casts doubt on the widely cited belief that biochar generally improves soil water movement and soil water holding capacity.