(672c) Engineering Biochars for Plant-Available Water Soil Applications

Water availability for agriculture is a serious challenge in many areas of the United States and around the world. This challenge is expected to become worse as precipitation events intensify and dry periods lengthen with climate change. Several studies have shown increased water holding capacity in soils amended with biochars. In this research, biochar properties were varied by varying biomass feedstocks and reaction conditions in order to identify production conditions that create biochars with favorable pore structures and surface chemistries for soil water retention. The biochars studied included corn stover slow pyrolysis biochars made over a 200-800°C temperature range under an inert or a 5% oxygen reaction environment, as well as biochars from fast pyrolysis. The methods used to evaluate biochar properties included proximate analysis, elemental analysis, nitrogen gas adsorption for BET surface area and micropore volume, solid-state ¹³C nuclear magnetic resonance spectroscopy (NMR), and soil water retention by both pressure plate and centrifuge.