Location: Southeast Watershed Research2013 Annual Report
1a. Objectives (from AD-416):
1. To develop low-input production methods for napiergrass, energycane, forage sorghum and sweet sorghum. 2. To develop efficient and economical harvesting, field drying, densification and storage methods for the studied crops. 3. To measure carbon sequestration in the soil and plant, soil carbon dynamics, nitrogen cycling including mineralization and N-fixation by legumes and emission of nitrous oxide from different cropping systems. 4. To develop comprehensive life cycle assessment models to quantify the economic and environmental value of the production systems.
1b. Approach (from AD-416):
Tifton-ARS scientists will contribute expertise in the area of perennial grass production, soil physical properties and greenhouse gas emission data collection. We supply research plots for field evaluations. Specifically, we will: Supply plant seed stock of energy cane and napiergrass to up to three experimental field sites. Contribute labor in data collection, harvest, as well as laboratory evaluations of soil and plant material. Assist in data analysis and publication of results. Collection of greenhouse gas samples.
3. Progress Report:
This project contributes to Objective 2 of the above in-house CRIS project: Quantify and assess the effects of agricultural conservation practices at multiple spatial and temporal scales in agricultural watersheds of the southeastern U.S. SEWRL scientist presented a summary of project results at the American Society of Agronomy Annual Meeting in Cincinnati, Ohio in October, 2012. Two sites in the southeastern Coastal Plain are being used for trials of two bioenergy grasses - elephant grass (Pennisetum purpureum (L.) Schum.) and energy cane (Saccharum officinarum L.) to obtain data for Life Cycle Analysis (LCA) of the crop production enterprise. The sites are located in Tift County, Georgia (Tifton loamy sand soil, eroded) and Peach County, Georgia (Orangeburg loamy fine sand soil) on marginal lands that were previously weed fallow. The grasses were established in a randomized complete block design (four replicates) in June, 2011. Treatments for the grasses include different winter covers (clover, lupine, or no winter cover) and different fertilizer nitrogen (N) rates (0, 75 kg N /ha and 150 kg N /ha). To provide specific data for the LCA, weekly sampling of greenhouse gas fluxes (methane, nitrous oxide, and carbon dioxide) using vented chambers were started shortly after planting for the clover cover treatments receiving the three N rates. The first year data (August 2011 – August 2012) showed that there were possible site differences for nitrous oxide flux and possible treatment differences for nitrous oxide flux on the Tifton site. Methane (negative) and carbon dioxide (positive) fluxes were not significantly different between the two sites or among treatments. Future research will provide data for LCA of these two bioenergy crops and provide data on the potential production of these crops under non-irrigated conditions with varying levels of N input.