Technology is key to managing and reducing the energy requirements of agricultural irrigation, says David Zoldoske, director for the Center for Irrigation Technology at California State University–Fresno, during a recent webinar sponsored by the Irrigation Association (IA). The center aims to establish full-scale irrigation and water demonstration sites at the campus’ 800-acre farm, covering every major crop grown in the San Joaquin Valley. In the future, they hope folks will be able to watch irrigation, and the resulting data, accumulate live from their computer.
Wireless sensors and cheaper controllers are entering the market, allowing farmers to measure soil temperature, pH and more. "We think information is key to managing your energy-water input," Zoldoske says.
Smart meters and pumps respond to demands on regional utilities, shutting down as needed to ensure power is distributed efficiently.
The challenge is vast: Between 1997 and 2002, per capita energy usage in the U.S. declined 1.8%, while per capita food-related energy use grew by 16.4%, says John Farner, government affairs director at IA. A 2005 report found that electricity used for water represented more than 90% of the total electricity used for crop production in California’s agriculture sector, primarily for field crops but also fruit and nut trees and vineyards.
Also, it’s important to re-examine some conventional wisdom and government policy about water and energy savings, says Rob Sampson, national water management engineer, USDA–NRCS.
Low-pressure pivots allow for more precise water application but might use more energy than other setups. A gravity-pressurized pipeline with enough force for sprinkler application, for example, might be an energy-efficient alternative.
Sampson recommends getting a good flow meter and keeping records. Next, use pressure gauges across your irrigation system and read them regularly. Finally, consider whether a
variable-speed drive makes sense for you, and realize minor changes to system performance can alter efficiency. "If you do go messing around with flow or head, you could easily change the efficiency point on your pump, and that could contradict what you’re trying to do to improve the pump efficiency," Sampson says.
It’s also important to keep irrigation savings in context, he says. That’s because water losses at the field level can be masked by looking at a larger area, such as multiple fields within a basin. Visit www.youtube.com/SmartIrrigationMonth to watch the webinar in its entirety.
Ag Group Studies Water
Irrigation research is the top research priority of the Mississippi Soybean Promotion Board, which dedicated $600,000 to that emphasis area this year. Topics explored from 2012-13 will include irrigation timing, methods of irrigation scheduling, deficit irrigation, furrow irrigation efficiency and the RISER project (Row-crop Irrigation Science and Extension Research). The latter project aims to identify and validate best management practices, including the best use of flow meters, scientifically developed scheduling tools and a software program known as PHAUCET, which optimizes furrow irrigation.