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Yield Projections for Switchgrass as a Biofuel Crop Across the US

A team of researchers from Oak Ridge National Laboratory and Dartmouth College have compiled national data on switchgrass yield as it relates to site location, plot size, stand age, harvest frequency, fertilizer application, climate, and land quality. Their paper appears in the July-August 2010 Agronomy Journal, published by the American Society of Agronomy.

The scientists compiled a total of 1,190 biomass yield observations for both lowland and upland types of switchgrass grown from 39 field sites across the United States. Observations were pulled from 18 publications that reported results from field trials in 17 states, from Beeville, TX in the south, to Munich, ND in the Midwest, and Rock Springs, PA in the northeast.

Statistical analysis revealed that much of the variation in yield could be accounted for by variation in growing season precipitation, annual temperature, nitrogen fertilization, and they type of switchgrass.

Lowland switchgrass outperformed upland varieties at most locations, except at northern latitudes. Annual yields averaged 12.9 metric tons per hectare for lowland and 8.7 metric tons for upland ecotypes. Some field sites in Alabama, Texas and Oklahoma reported biomass yields greater than 28 metric tons per hectare using the lowland cultivars Kanlow and Alamo.

The research team did not observe any bias for higher yields associated with experimental plot size, row spacing, or with preferential establishment of stands on high quality lands. A model developed from the data, based on long-term climate records, projected maximum yields in a corridor westward from the mid-Atlantic coast to Kansas and Oklahoma. Low precipitation west of the Great Plans limited yields in that region.

This is the largest data base analyzed to date for energy crop productivity as a function of geographically distributed variables. The finding that there is no bias with respect to either plot size or land productivity is important. A promising future direction is to apply the modeling approaches taken here to additional bioenergy crops at a global scale in combination with various land use scenarios.

—Lee Lynd, co-author on the article and Steering Committee Chair of the Global Sustainable Bioenergy Project

Scientists at Oak Ridge National Laboratory and Dartmouth College continue to explore factors involved in the production of biomass from switchgrass and other dedicated energy crops. One of the lessons learned from the current analysis is that yield data from an even broader range of soil and climatic conditions will be useful in building better predictive models. Future studies should extend the geographic distribution of field trials and thus improve the understanding of biomass production for promising biofuels like switchgrass.

The full article is available for no charge for 30 days.


  • S. D. Wullschleger, E. B. Davis, M. E. Borsuk, C. A. Gunderson and L. R. Lynd (2010 Biomass Production in Switchgrass across the United States: Database Description and Determinants of Yield. Agron J 102:1158-1168 doi: 10.2134/agronj2010.0087



28 tons/hectare is huge.
novel enzymes to digest the switchgrass to sugar before the actual fermentation could also be used to transform the biomass to animal food. heterotrophic algae could also transform it to proteïn-rich animal food with very high efficiency. Compared to other crops, the productivity per hectare, pesticide use and soil degradation is very positive.


This may be a good compromise feed stock for animal food and agro-fuel. At 28 tonnes/hectare (about 12 tons/acre) it will be difficult (but not impossible) to beat. The variation between Low and High lands is more than expected.


~50 gallons of ethanol per ton of switgrass? At 12.5 tons per acre, that would produce 625 gallons per acre with lower stress on soil and fewer inputs into planting and cultivating. Not bad...


Does it compare to miscanthus ? I remember "" and I wonder...



50 gallons/hectare may be not that much to aim.

Just for a comparison with first generation sugar cane based ethanol, there are numbers like 85tc/ha, 70liters/tc, ~6000 liters/ha.

Numbers from:
Perspective: Potential for first-generation ethanol production from sugarcane, pg20

Introduction to Brazilian ethanol program:
The ethanol program in Brazil
Jose Goldemberg
Instituto de Eletrotecnica e Energia, Universidade de Sao Paulo, Brazil
Published 24 November 2006
Online at


The Syntec gasification process produces 100 gallons of mixed alcohols per ton and at 10 tons per acre that is 1000 gallons per acre. Put 100 million marginal acres into grass production and return the biochar to the land. All new cars being FFV would have 50 million on the road in 5 years, a good hedge against OPEC actions.


CelsoS: Japan has developed a new Sugar cane with 500% more sugar per given cultivated area. Using that new Cane in Brazil could produce 3x to 5x more ethanol per hectare. Converting baggasse to ethanol ( or to animal food) would raise production per hectare to higher level yet.

Improved Sugar Cane seems to be the best feed stock (to date)

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