Influence of Biochar Source On Soil Water Holding Capacity.

Biochar is the carbon–rich by-product of pyrolysis. Pyrolysis is a thermo-chemical process in which biomass goes through combustion either in the absence of oxygen or a partial oxygen supply.  Biochar due to its high charge density and surface area has been proposed as a soil amendment for use in improving soil water holding capacity, nutrient retention, and other soil properties critical for crop production. Biochar properties differ depending on feedstock source and manufacturing processes. The efficacy of biochar as an amendment may differ between soil series. Four unique biochars were produced and used in this study. Additionally a commercially produced biochar used in published studies was examined. We measured the effect of  biochars on water retention of two soil series from eastern South Dakota. Soil series used represent coarse and fine textured soils found in eastern South Dakota. Water retention between soil series was significantly different. Biochar from two processing methods (fast and slow pyrolysis) and two feedstock sources (corn stover and switchgrass) and the commercially produced biochar were applied to each soil series. Water retention was measured using sand table, ceramic plate, and WP4 water potential meter methods.  Preliminary results suggest that biochar produced as a by-product of bio-oil production modifies soil water retention curves depending on biochar type.