Microbial Enzyme Response to Biochar As a Soil Amendment for Corn (Zea mays L.) and Wheat (Triticum aestivum L.).

Biochar has been reported to improve crop yield, increase availability of plant nutrients, increase soil moisture retention, reduce greenhouse gas emission, and sequester carbon.  A greenhouse experiment was conducted at the University of Minnesota, Southwest Research and Outreach Center to evaluate soil and crop responses to biochar amendments. The objectives of this experiment were to: 1) measure biological activities in soil amended with pyrolysis, gasification and combustion biochar/ash products (Turkey Manure Combustion Ash, Corn Cob/Wood Gasification Biochar, and Switchgrass Pyrolysis Biochar); and 2) measure plant growth response to those same amendments. Treatments were applied at three rates (11.2, 22.4 and 44.8 Mg ha^-1) and a control (0 Mg Biochar ha^-1). Crops tested were corn (Zea mays L.), wheat (Triticum aestivum L.) and fallow treatment, and were kept in 2.1 L pots for 55 days. Soil series used were Hubbard loamy sand, Canisteo clay loam, and Barnes loam. Soil samples were collected from all pots at several planned intervals throughout the study. Plant growth was assessed on a weekly basis, starting 14 days after planting (DAP). Above ground plant material was collected, processed and analyzed for biomass yield and nutrient uptake. Biological analyses include Sulfatase, Urease, Phosphomonoesterase, Glycosidase, and FDA (Flourescein Diacetate Hydrolysis) measurements to reveal the enzyme activity of the amended soils. Initial analysis of data revealed no treatment effect on plant biomass in the loam and clay loam soils. The loamy sand had significant corn biomass reduction with the highest rate of Corn Cob/Wood Biochar, and yielded twice as much plant biomass when amended with Turkey Manure Combustion Ash compared to all other treatments. Continued analysis of enzyme activities with/without a crop should help further explain the biochemical interactions among soil, plants and by-products.