Fields of leafy green vegetables and ripening strawberries in the Santa Maria Valley look innocent enough as the food crops get ready for dining tables around the country, their growth spurred by farmers’ addition of synthetic nitrogen fertilizer. But deep below the root zone lurks an unappetizing problem.
A new study by UC Davis scientists shows that plants only use half the nitrogen fertilizer that farmers apply. The other half hops a ride on water molecules and percolates down through the soil, eventually making its way into local drinking-water wells—where nitrate contamination can make the water unfit for human consumption. It’s a serious problem that’s getting worse, according to water quality officials.
Many local growers have been taking steps to reduce their use of costly nitrogen fertilizer in the last few years. Today’s farmers often apply the liquid boost along with irrigation water, using drip lines to feed the plants’ root zones. Some even have their own onsite laboratories, relying on plant science to fine-tune fertilizer application.
But nitrate pollution of groundwater is so widespread that these voluntary efforts aren’t enough for the Central Coast Regional Water Quality Control Board anymore. Now Central Coast farmers are the first in California to face a host of stringent new requirements designed to stem the flow.
“Nothing is more important than making sure people have clean drinking water,” explained Matthew Keeling, a water resources control engineer with the water board. “Many people are drinking water contaminated with nitrates and don’t know it, with associated health costs.”
Social-justice advocates first raised the alarm in the Salinas Valley, where people living in farmworker communities started experiencing various health problems associated with high nitrate levels in their drinking water—traced to heavy use of nitrogen fertilizer on crops.
Nitrogen flows through the environment in a dynamic natural cycle, but, according to the UC Davis report, the balance has been disrupted by the production of synthetic nitrogen fertilizer, made with natural gas.
“You can’t grow fresh produce without adding nitrogen,” said George Adam, owner-operator of Innovative Produce in Santa Maria.
In the past five years, Adam said, he’s been able to reduce the amount of nitrogen he uses on the 1,200 acres he farms.
Nitrogen-laden runoff from the fields today is about one-tenth of what it was a few years ago.
The company’s office on West Main Street now houses a laboratory, where specially selected samples of growing vegetable plants are analyzed to determine their exact nitrogen needs.
“We feel we are doing what’s right for the health of the plants,” Adam explained. “We’re all working on a solution [to the nitrate pollution problem]. But to keep nitrate completely out of groundwater is, quite frankly, unachievable with today’s technology.”
The Regional Water Quality Control Board wants to start taking steps to address the nitrate problem. In March, after two days of public hearings, board members unanimously adopted a contentious set of requirements for growers throughout the region, including Santa Barbara and San Luis Obispo counties, as well as the Salinas Valley.
The new rules apply to growers who irrigate their commercial crops—vegetables, wine grapes, orchards, or nursery stock. Each farm has been assigned to one of three tiers, with differing requirements depending on their perceived threat to water quality.
Adam was one of about 80 growers who attended a June 1 workshop in Santa Maria to learn more about how to comply with the strict requirements. About 4,000 farms in the Central Coast region are covered by the new rules, Lisa McCann, the water board’s watershed division manager, told the growers at the workshop.
All growers—referred to by water board staff as “dischargers”—are required to develop and implement a farm water quality management plan for irrigation efficiency, nutrients, pesticides, salinity, erosion control, and aquatic habitat protection.
All growers must monitor nearby creeks and estuaries that may receive farm runoff each month, and they must twice sample the groundwater from irrigation and drinking-water wells on their farms, with nitrate levels reported to the water board.
Tier 2 and 3 growers also have to calculate their farms’ risk of adding nitrate to groundwater and record and report the total nitrogen applied to crops of leafy greens and strawberries. Tier 3 growers also must prepare an irrigation and nutrient management plan and a water quality buffer plan, and monitor the runoff coming off their fields.
These new requirements, collectively known as the Agricultural Order, have been appealed by farmers’ groups. Farm bureaus in the Central Coast region, the Grower-Shipper Association of Santa Barbara and San Luis Obispo Counties, and other agricultural groups have petitioned the State Water Resources Control Board to halt the implementation of the new program and to overturn its adoption.
The Farm Bureau petition says the new plan will lead to “dramatic and severe impacts on the agricultural industry, which will have a significant effect on the economic and social environment of the region.”
Richard Quandt, president of the Grower-Shipper Association of Santa Barbara and San Luis Obispo Counties, said in an interview that the rules have “serious economic implications” for agriculture and the entire region. Tier 3 growers will have “great difficulty” complying with the rule, Quandt said.
The State Water Resources Control Board is “still evaluating” the petitions, Phil Wyels, assistant chief council for the state board, said in a phone interview from Sacramento. Due to staffing reductions, there’s a backlog of petitions to consider, he said, and he couldn’t predict when a decision would be made.
“Unless and until the state board issues a stay—which is rare—the order remains in effect, even with the petitions pending,” Wyels said.
“The order is unrealistic in its timetable,” Kevin Merrill, president of the Santa Barbara County Farm Bureau, said in an interview. “We need to work on nitrate levels. The big question is how do we do that in a way that works. We’re making progress in fixing the problem, but the issue is how fast. If we stopped farming today, there would still be nitrates in groundwater for hundreds of years.
“How can we make small steps without going out of business?”
Farming in the Santa Maria Valley is “a very precise industry now,” he said. “Growers don’t want to buy more nitrogen than they have to. They’re not just throwing fertilizer on the ground willy-nilly.”
Even organic growers like Jerry Rutiz are subject to the water board order. His 30-acre farm in Oceano has been assigned to Tier 2, probably because of its proximity to a nitrate-contaminated drinking-water well in Halcyon, he said. But he believes the organic fertilizer he uses to grow his produce takes a long time to break down and doesn’t leach quickly like synthetic nitrogen.
“This is going to be a lot of paperwork. Farmers hate paperwork,” Rutiz said.
“Most farmers are environmentalists. They know it’s not acceptable to be polluting groundwater. But if farmers are pressed too hard, nothing will be accomplished,” he added.
Contributing writer Kathy Johnston can be reached at email@example.com.