When California Governor Jerry Brown announced a mandatory 25 percent cut in water consumption in the coming year for urban areas, many people protested that the state’s agricultural industry, which is responsible for the lion’s share of human water consumption, was not included in the restrictions.
The governor countered that farms, which lap up about 80 percent of the water used in the state, have already made sacrifices and will likely have to make more.
Some Central Valley Project water contractors will face a second year of receiving no water and some San Joaquin Valley irrigation districts are delivering no more than 25 percent of normal supplies, according to the University of California Davis. As more farmers face dwindling supplies, there are variety of high tech tools, including GPS, sensors and big data analytics, to help them manage water supply; if they can get them at the right price.
“It’s not as though they’re getting off Scot free,” says Ed Osann, senior water policy analyst with Natural Resources Defense Council (NRDC).
As water allocations dwindle, more farmers are drilling down to tap groundwater supplies, which should be regulated more strictly, says Osann. If the drought continues, however, tapping more groundwater is not a sustainable approach. So increased conservation will have to come to California’s farms and the irrigation districts that serve them.
California’s farmers have made strides in water efficiency, but there is still considerable headroom. NRDC found that economic productivity of water [pdf] in California rose from US $420 per acre-foot in the 1960s to more than $700 per acre-foot in 2009. From 1990 to 2010, micro sprinkler and drip irrigation use increased from 15 percent to nearly 40 percent in California.
Many California water districts deliver water through a series of open canals and pipelines that use gravity to deliver water. Far more farmers would use precision irrigation methods if they could get pressurized water on demand, says Osann. “It makes it hard to irrigate with any precision if you’re on a fixed schedule that’s determined on the physical capability of the delivery system,” he says. “If we want a more sustainable future for California agriculture, this is a direction to go.”
Demonstration projects funded by the federal government found that on-demand pressurized systems improve water use efficiency by an average of 25 percent. In South San Joaquin Irrigation District, the combination of pressurized irrigation system with controls and measurement technology for individual farms allowed farmers to grow 30 percent more food using 30 percent less water.
There is even more room for improvement if GPS, sensors, and data analytics are put to use.
A 2009 study from the Pacific Institute found that “despite the promise of technology-based irrigation scheduling, many California farmers still primarily rely on visual inspection or personal experience to determine when to irrigate.” Sensors, computer modeling, and evapotranspiration reports are fairly uncommon, the study found.
The burgeoning field of precision farming, also called site specific management, allows farmers to map their farms down to the meter and understand in detail how soil conditions vary across the field. That information is uploaded, analyzed and then used to help farmers apply the right amount of nutrients and water to each piece of land. Although it’s still early days, it is an industry that is attracting both startups, like OnFarm, legacy computing companies, such as IBM, and Big Ag stalwars, such as Monsanto.
Precision agriculture can boost yields and save money, but the USDA has found that most farmers are not flocking to the technology yet. High value crops, such as almonds and walnuts, are some of the early adopters.
Some California orchard farmers are using variable rate irrigation, which uses mobile soil sensors to map a field and sense its soil depth. Once different soil zones are defined, they can be irrigated and fertilized to their specific needs.
Allan Fulton, an irrigation and water resource advisor for the University of California, estimated only a few thousands acres in California are using it. He says the additional cost could be up to $200 to $250 per acre to design and implement the systems. In one study, however, he found that the investment in variable rate irrigation could be paid back in two to three years depending on water costs.
Even with a relatively strong payback for high-value crops, the ongoing drought in California still might not be enough to push farmers towards these cutting-edge solutions.
Osann says that the farmers who do invest in data analytics and sensors usually invest in the technology for other purposes, such as better yields while using less fertilizer and pesticides, rather than water savings.
Still, if yields are down due to reduced water allocation, it could make precision agriculture more attractive. One study from 2001 on precision agriculture found that water management was the major determinant of yield in nearly all agricultural settings.
There is a need not only for changes to water pricing and farmer education, but also innovation in financing options to adopt the latest technology, Osann says. “They pay market prices for seed, land, labor, fertilizer,” he says, “but somehow way back when, some people got it in their head that irrigators shouldn’t have to pay for water.”