Dr. Florence Cassel Sharma, Fresno State - Physiological performance and nutritional quality of forages irrigated with oilfield waters.

Co-investigators: Dave Goorahoo (CSU Fresno), Tim Jacobsen (CSU Fresno), Luis Cabrales (CSU Bakersfield), Shankar Sharma (UC Merced).

ARI funding commitment: $450,000 over three years; match funding $514,000.

Oil and gas production, including hydraulic fracturing, typically requires the injection of a few million gallons of water into the well or formation. A portion of this water, termed “produced water”, is brought back to the surface and must be managed. Recent estimates indicate about 11 billion gallons of produced water is generated annually in California. Produced water varies considerably, but typically contains dissolved salts, hydrocarbons, inorganic and organic compounds and naturally occurring radioactive material. Although some of this water is used to irrigate crops, surprisingly little is known about the short and long term consequences on soil properties and crop responses. A team headed by Dr. Florence Cassel Sharma will examine the effects on soil and forage crops irrigated with a blend of fresh and produced water. Produced water will be characterized and treated to remove some of the contaminants. The treated water will be blended with high quality irrigation water and applied to sorghum grown both in the greenhouse and field. Soil physical and chemical properties, as well as crop growth responses will be assessed.

Dr. Cassel believes the water treatment and blending approach is easily scalable and can be performed by growers and irrigation districts on large volumes of water and remain cost effective. The results of this study will allow the team to develop long-term studies to determine levels of produced water usage that are safe for agriculture and will produce science-based guidelines that will be beneficial to the petroleum industry while stretching water resources for agriculture during periods of water scarcity.