Biomass feedstock harvest from conservation reserve program land in northwestern Oklahoma

Authors: Venuto, Bradley; Daniel, John

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/22/2009
Publication Date: 1/27/2010
Citation: Venuto, B.C., Daniel, J.A. 2010. Biomass feedstock harvest from conservation reserve program land in northwestern Oklahoma. Crop Science. 50:737-743.

Interpretive Summary: Development of a large scale biofuel industry based upon plant biomass will require large quantities of cellulosic feedstock. Among the proposals for acquiring this feedstock, without impacting other land uses such as food or forage, is the use of up to 50% of Conservation Reserve Program (CRP) land. The objective of this study was to estimate annual biomass production capability of CRP land in northwestern Oklahoma and record the impact of an annual biomass harvest on plant species composition, plant growth, and soil characteristics. Six CRP sites at three locations were harvested on three annual dates, August, October and post-frost, for three consecutive years, 2004, 2005, and 2006. Within locations, one site was established to Old World bluestem, an introduced grass species, and one site was established native mixed species. Across all years, locations, and harvest dates Old World bluestem produced an average of 3380 lbs/acre and NM produced 1710 lbs/acre of dry biomass feedstock. Maximum yields were obtained at the October harvest for both Old World bluestem (3720 lbs/acre) and the native mixed species (1950 lbs/acre). At the native mixed species sites, there was no observed change in species composition. Soil characteristics, as a result of annual harvest for three years, were not altered. Among all species evaluated, nitrogen, neutral detergent fiber, carbon and ash contents varied significantly. Within the native mixed species, production of dry biomass among native grass species also differed considerably. Biomass production consistently declined at all sites and for all harvest dates over the three harvest years. If sustained biomass feedstock production is to be feasible from CRP land in this region of Oklahoma, harvest management and nutrient replacement will be important considerations.

Technical Abstract: Development of a large scale biofuel industry based upon plant biomass will require large quantities of cellulosic feedstock. Among the proposals for acquiring this feedstock, without impacting other land uses such as food or forage, is the use of up to 50% of Conservation Reserve Program (CRP) land. The objective of this study was to estimate annual biomass production capability of CRP land in northwestern Oklahoma and record the impact of an annual biomass harvest on plant species composition, plant growth, and soil characteristics. Six CRP sites at three locations were harvested on three annual dates, August, October and post-frost, for three consecutive years, 2004, 2005, and 2006. Within locations, one site was established Old World bluestem, Bothriochloa spp. (OWB) and one site was established native mixed species (NM). Across all years, locations, and harvest dates OWB produced an average of 3790 kg ha-1 and NM produced 1920 kg ha-1 of dry biomass. Maximum yields were obtained at the October harvest for both OWB (4170 kg ha-1) and NM (2180 kg ha-1). There was no observed change in species composition or soil characteristics as a result of annual harvest for three years. Among all species evaluated, nitrogen, neutral detergent fiber, carbon and ash contents varied significantly. Within NM, production of dry biomass among native grass species differed and ranged from 213 g plant-1 for big bluestem, Andropogon gerardii Vitman, to 14 g plant-1 for sand lovegrass Eragrostris trichoides (Nut.) A.W. Wood. Biomass production consistently declined at all sites and for all harvest dates over the three harvest years.