Impact of Oak Biochar On Maize-Soybean Yield and Soil Biochemical Properties On Alfisol In U.S. Midwest.

Biochar production and application has been proposed as a method for sequestering carbon in the pedosphere while increasing crop productivity.  Many studies have demonstrated large increases in crop yield on degraded soils particularly in the tropics, while relatively few studies have been conducted of agroecosystems in temperate climates.  Here we report first year data on the impact from application of biochar derived from an oak (Quercus) feedstock from a slow pyrolysis process at ~475 ⁰C to a corn (Zea mays L.) soybean (Glycine max) rotation in Ohio on a Miamian soil (fine, mixed, active, mesic, Oxyaquic Hapludalf).  Biochar was applied at two rates, 5 t ha^-1 and 25t ha^-1, plus control with 100% and 50% of recommended N fertilizer (146 kg ha^-1 and 72 kg ha^-1, respectively) in a full-factorial, 6-replicate field-scale experimental design.  Significant increases in both above ground biomass of the soybean crop by 8.0% and 14.8% for low and high rates of biochar, respectively, and in grain yield by 12.8% and 12.5%, respectively, are reported.  Mechanisms responsible for observed increases are likely due to both direct and indirect increases in plant available nutrients, as well as liming effect of biochar which had a measured pH of ~9.4.  Data was also collected for total microbial biomass, gaseous emissions (CO₂, CH₄, and N₂O), and general soil physical parameters including aggregate stability, moisture retention, and saturated hydraulic conductivity.