Biomass Feedstock Production and Carbon Sequestration in Native Warm-Season Perennials.

A combination of increased energy security, CO₂ mitigations, and impact on the rural economy through expanded production of agricultural crops for biofuels has focused the attention on renewable energy. Using our prime agricultural land to grow agronomic or bioenergy crops only for the production of biofuels is not a logical choice. A randomized complete block experiment was established on marginal land in 1999 to evaluate the impact of N fertilization (0, 10, 20, 40, and 80 lbs N/A) on mixed stands of Switchgrass, Indian grass, Big and Little Bluestem and Eastern Gamma grass as part of the Conservation Reserve Program at the Ohio State University South Centers at Piketon. The shoot  biomass (SBM) of the grass species was collected, processed, and oven-dried to calculate biofeedstock production. The root biomass (RBM) and soil samples were collected at 0-20, 20-50, and 50-100 cm depth, respectively. Roots were processed and analyzed for total C and N contents. Soils were analyzed for total and active C, total N, and bulk density. Results showed that N fertilization significantly but non-linearly increased the SBM but decreased RBM production. Highest SBM production recorded in N40 treatment. Total C and N contents of RBM was not significantly impacted by N fertilization. However, deeper RBM had less N but higher C content. Root C and N have shown a significant linear relationship to justify the stoichiometry of C and N in organic matter. N fertilization and soil depth had a significant interaction on bulk density. Total and active C content did not change consistently by N fertilization. Active C content followed a similar pattern like total C and N contents. Irrespective of N fertilization treatments, total C, N and active C decreased with increasing soil depth. Like root C and N, soil total C and N contents showed a significant relationship to enhance N sequestration or vice-versa.