Feedstock Development projects
Agave as a Feedstock Crop in the Southwestern U.S.
Agave spp. have been introduced as potential bioenergy crops that can be grown in semi-arid regions without competing with agricultural lands used for food crops. Because Agave plants have high water use efficiency, relatively low lignin, and potentially high yields, this genus has promise as a bioenergy crop that requires little inputs. Commercial production of Agave tequilana and A. fourcroydes has been demonstrated in Mexico, but there is little information about the potential to grow Agave commercially in the U.S. This project investigates the potential for Agave spp. to be grown for bioenergy in the semi-arid southwestern U.S.
The goal of this project is to determine if Agave species are viable bioenergy feedstocks in the semi-arid southwestern U.S. The experimental crops planted at the Maricopa Agricultural Center in Arizona were in their third growing season in 2014 and Agave americana remains the healthiest of the three species planted. Preliminary measurements indicate that A. americana yields 6 times greater biomass per unit of water input than cotton, an important crop in the semiarid southwest, when grown in similar conditions. New challenges for managing A. americana as a crop include an ongoing need to control the spread of the agave snout weevil (Scyphophorus acupunctatus). Insecticide has been applied by spraying and by dilution in irrigation water, but there have been extreme rainfall events this growing season that have led to flooding in the field that disrupted the irrigation treatments, thereby creating an opportunity for the snout weevil to spread. Plantings of A. americana in Ukiah, CA are in the second growing season and so far show no signs of the snout weevil.
The year 2013 was the second growing season of agave at the Maricopa Agricultural Center in Arizona. Although the plants are still immature, mortality and fecundity of the three species were assessed and preliminary measurements of gas exchange in Agave americana were completed in June. Agave americana is the healthiest of the three species planted, and physiological differences were evident in response to irrigation. An additional experimental site for Agave americana was established in Ukiah, CA. International interest in agave as a biofuel crop continues to be evident, and this work was presented at two conferences in August, a book chapter is in press, and a review article is in preparation.
In 2012, the first field-scale experiment to test the suitability of Agave spp. as bioenergy feedstocks in the U.S. was established on 3 acres of land in Maricopa, Arizona. At the end of the first growing season, mortality ranged from 0 to 8% with the greatest mortality observed in A. fourcroydes. The greatest survivorship and growth was observed in A. americana. These are preliminary results, serving only as an indication of establishment success, and there is not yet evidence for the suitability of these species for biofuel feedstock. A. americana was sourced from within the U.S. and thus was planted with a healthy root system and minimal leaf damage. A. fourcroydes and A. tequilana were sourced from Mexico and planted rootless due to importation requirements. Survivorship was high in all species despite the variable initial conditions. A greenhouse experiment was initiated to resolve the effect of fertilizer additions on plant growth; results from this experiment will be forthcoming in 2013.
Published in 2014
Light to Liquid Fuel: Theoretical and Realized Energy Conversion Efficiency of Plants Using Crassulacean Acid Metabolism (CAM) in Arid Conditions, S. C. Davis, D. LeBauer, S. Long, Journal of Experimental Botany (special issue: C4-CAM), 65, pp. 3471-3478, April 17, 2014.
Agave/Sisal in Industrial Crops: Breeding for Bioenergy & Bioproducts, S. C. Davis, S. P. Long, book chapter, M. Cruz and D. Dierig (Eds), Springer, New York, 2014.
Bioenergy Crop Greenhouse Gas Mitigation Potential Under a Range of Management Practices, T. Hudiburg, S. C. Davis, W. J. Parton and E. H. DeLucia, Global Change Biology—Bioenergy, doi: 10.1111/gcbb.12152. Biomass in the Energy Industry: an Introduction, S. C. Davis, W. Hay, J. Pierce, BP p.l.c., London, UK, March 7, 2014.
Published in 2012
Breeding for BioEnergy and Bioproducts, chapter for edited book in preparation: Sisal/Agave