Hydrocarbon production and growth of Euphorbia lathyris : a water use study

Abstract

Euphorbia lathyris, a hydrocarbon producing plant was field tested at the University of Arizona. Flood irrigation of small basins was used to determine the growth, percent of biocrude, total biocrude production, and field water use of E. lathyris as a function of soil moisture availability. Two ecotypes of E. lathyris from Palo Alto and Chico, California, were studied. Four distinct water regimes were used in this experiment. A high supply of water was available to plants in the wettest treatment. Plants in the driest treatment were under water stress during almost all the growing season. The other two treatments were irrigated as a fraction of the water applied in the wettest treatment to provide four distinct irrigated water treatments. The Palo Alto ecotype clearly outperformed the Chico in all parameters measured even though similar water use was observed for both ecotypes. A positive relationship was observed between soil moisture availability and plant growth, total biocrude production, and water use. However, no relationship was found between percent of biocrude and soil moisture availability. The highest yield recorded in this study was 8.4 barrels/ha of biocrude with a water use of 67 cm in the wettest treatment of the Palo Alto ecotype.