Impacts of biochar application rates and particle sizes on runoff and soil loss in small cultivated loess plots under simulated rainfall

Increasing literature suggests that biochar can be used to improve soil fertility and subsequently benefit crop yield. However, the effects of biochar application rates and particle sizes on soil erosion processes have yet to be fully identified. The objective of the present study was to evaluate the influence of biochar with different application rates and particle sizes on soil erosion. Addition of biochar to loess generally increased the mean time to runoff by 19.47% relative to the control. The time to runoff decreased with an increase in the biochar application rates and fluctuated with a decrease in biochar particle sizes. The combined 1% and 2 mm water-stable soil aggregates and saturated hydraulic conductivity (Ksat) in this study. We inferred that the positive effects on soil and water loss were potentially due to the improvement in >2 mm water-stable soil aggregates and Ksat. The results implied that soil-biochar additions could be a potential measure for conserving soil and water in the Loess Plateau. [Display omitted] •Biochar application reduced runoff production relative to soil without biochar.•>3% biochar addition accelerated soil loss relative to soil without biochar.•The effect of the biochar addition rate on runoff and sediment stronger than particle size•Reasonable addition of the biochar rate and particle size could control soil erosion.