Pyrolysis of biomass for hydrogen fuel produces a char byproduct that may be beneficial to plant growth, improve soil conditions, and contribute to stable soil carbon. We measured corn (Zea mays) growth response and CO₂ efflux in microplots (1.8 x 2.2 m) amended with peanut hull and pine chip pellet char produced at 400^o C. For each char type, the treatments were: 11.2 Mg char ha^-1, 11.2 Mg char ha^-1 plus fertilizer, 22.4 Mg char ha^-1, 22.4 Mg char ha^-1 plus fertilizer, a control, and a fertilizer check (4 replicates). Soil samples were taken before plots were amended, week 4, 16 after planting, and at harvest. Soils were analyzed for pH, nutrients and C. Soil moisture and CO₂ efflux from the soil surface were measured periodically during the growing season. Analyses of the char indicated that the peanut hull char at the 11.2 Mg ha^-1 rate added 213 kg total N ha^-1, 1.3 kg P ha^-1, and 56 kg K ha^-1. Nutrient additions with the pine chip char were low. Small increases in CO₂ evolution in the field were observed following char incorporation. Similar short-term increases in CO₂ were seen in related laboratory incubations. There was not a significant total biomass or yield response due to the pine chip pellet char. There was a significant response of stover to peanut hull pellet char alone, but total biomass and yield were not significantly higher with the char plus fertilizer treatment compared to fertilizer alone.