Groundwater nitrate issue dumped in agriculture’s lap

Groundwater nitrate issue dumped in agriculture’s lap

In California, 250,000 people are at risk from nitrate contamination in their drinking water. A recent study said 96 percent of the nitrates in groundwater are traceable to agriculture. It is not surprising that the California groundwater nitrate issue was not just deposited on agriculture’s doorstep, it was heaped on agriculture’s back for blame and draconian mitigation recommendations to be paid for by agriculture. “With UN 32 at $442 per ton, I don’t think farmers are going to waste a lot of N,” said Kern County, Calif. pest control adviser Vern Crawford.

When Jim Sullins, director of Cooperative Extension for Tulare and Kings counties, asked for a show of hands of how many wanted the recent nitrogen workshop to continue after the appointed closing hour, the response was underwhelming.

Fewer than 10 raised their hands. It was obvious the packed meeting room had heard enough from the University of California experts reporting on their recent nitrate-in-groundwater findings.

What drew a crowd of about 200 to the UC Kearney Ag Center in Parlier, Calif., was a recently released UC study of nitrates in drinking water in the central San Joaquin Valley Tulare Lake Basin and the Salinas Valley in Monterey County.

The study has created a statewide media buzz since it says a quarter of a million Californians are hooked to unsafe drinking water wells and agriculture should pay for cleaning it up.

It’s no secret that nitrates in groundwater are a problem. As the study indicates, 250,000 people within the two basins are currently at risk from nitrate contamination in their drinking water. This is out of 2.6 million people who live in the four counties (Fresno, Kings, Tulare and Kern) Tulare Lake Basin and the Salinas Valley, the focal point of the study. Most of these people are on public water systems, not individual wells.

The population of the study area represents only about 7 percent of the state’s population; however, 40 percent of the state’s irrigated cropland is in the study area and over half the state’s dairy herds.

With those statistics, it is not surprising that the nitrate issue was not just deposited on agriculture’s doorstep, it was heaped on agriculture’s back for blame and draconian mitigation recommendations to be paid for by agriculture. Some of the regulatory measures researchers are recommending could reduce farming in the region and the production of food in two of the most productive farming areas in the world.

The study said 96 percent of the nitrates in groundwater are traceable to agriculture. Several in the audience challenged that, and principal investigator Thomas Harter, UC Davis groundwater hydrologist, acknowledged that figure may not be “precise.” However, chief investigator Jay Lund, director of the Center for Watershed Sciences at Davis, reiterated the overwhelming majority of the nitrates are from agriculture.

The study was ordered by the State Water Resources Control Board based on a legislative mandate in Senate Bill SBX2 passed in 2008 that ordered a study on nitrates in groundwater. Harter admitted that the two-year timeline for the study was a “relatively short research project.”

Controversial numbers

The study covered almost 4 million acres of irrigated agriculture and there are 1 million dairy cows within the study boundaries. Researchers claim 420,000 tons of nitrogen is applied annually, according to its models. Half of that is N applied to cropland, with only about 40 percent of the applied N harvested, suggesting that more than half the N applied is leached into the groundwater, a figure farmer’s find difficult to accept.

(For more, see: Fertilizer industry working to reduce groundwater pollution)

“With UN-32 at $442 per ton, I don’t think farmers are going to waste a lot of N,” said Kern County, Calif., pest control adviser Vern Crawford.

Tulare County, Calif., dairyman Tom Barcellos, a panelist at the workshop, also challenged the study’s tenor that farmers use more nitrogen than the crop needs by saying, “we have never made so much money that we can waste by putting on more than we need.”

Tulare County Board of Supervisors Chairman Allen Ishida urged caution in reacting to this study, calling for more scientific research to determine the exact source and age of the nitrogen in the groundwater.

Groundwater can be aged and some of the nitrate-tainted water could be 300 years old, contaminated by nitrates from foothill sediments washed into the groundwater basin by rainfall.

The model used to determine the source of nitrates seemed to be old and researchers acknowledged that they could not quantify the impact on such things as drip irrigation, conservation tillage and the fact that there is simply less water applied to crops today due to reduced surface water supplies. It is common knowledge that 100 percent of the processing tomatoes produced in the valley are grown with drip irrigation; 30 percent of the cotton is drip irrigated and virtually every new orchard or vineyard planted within the past 20 years is irrigated with low water volume micro-irrigation.

Barcellos said he is being forced to dig deeper wells due to the lack of surface water deliveries brought on by passage of laws giving farmers water for environmental uses. And, the deeper he goes, the higher the nitrate levels, suggesting that older farming practices are responsible for nitrate leaching, not today’s ag technology. This would imply over-regulating farmers now would do little to solve the age-old problem.

Ishida is a third-generation citrus farmer from the Lindsay-Strathmore area in Tulare County, the focal point of the study. He pointed out citrus growers no longer flood irrigate and therefore reduce leaching. They use micro-irrigation like drip and sprinklers to apply less water. “We (farmers) are already addressing the issue,” he said.

The researchers acknowledged advancement in farming, but did not seem to include them in outlining 50 management practices they claim could reduce nitrate use by 60 percent to 80 percent.

Private wells

One of the other contentions challenged was that the majority of the private wells in the study area are not tested. Public drinking water wells are tested by law.

“Guess we are just a bunch of dumb farmers,” Barcellos said after the meeting in reacting to the contention farmers do not test well water. Farmers test wells, Barcellos said, for not just nitrate levels, but other minerals as well because they can impact crops. It is common knowledge that minerals like boron in well water can have a major impact on almond production.  How would a farmer determine boron levels if they do not test the water? “Wells in the Hanford area are known to be high in sulfur. How do farmers know that if they do not have the water analyzed,” he said.

Wells are also tested for nitrates, and those numbers are plugged into fertilizer management programs.

There is a large area of Kern County around Shafter, Calif., where water is very high in nitrates, yet very little nitrogen is applied, said Crawford. The nitrates apparently come from foothill sediments.

“We drink the water in this valley, and our families drink this water,” says Barcellos, acknowledging that finding a solution to the nitrate issue is important to farmers, too. However, he urged researchers, legislators and regulators to be “patient” in mitigating the issue.

“This has been years in the making. Let’s think this through and not come up with a bunch of expensive mandates,” he said.

According to the study, it would cost up to a prohibitive $30 billion to clean up groundwater. Therefore, study writers say the way to solve the problem is to regulate it with water and fertilizer use fees and mandated management practices.

“I hate fees. I spend 40 percent of my time as a supervisor fighting fees and regulations. All the fees collected today wind up in the general fund,” he says. That is thievery, he contends, and “we need to put some of these guys in jail for stealing.”

Water is the key factor in the leaching process, and there are several agencies overseeing its use. Study authors suggest attacking the nitrate issue by coordinating it through the various agencies regulating water. There was also a notion to create a water use/quality agency like the California Department of Pesticide Regulation to oversee groundwater use.

(For more, see: What’s next for California groundwater?)

Lund attempted to mollify farmers and others in the room by saying that it will cost more to “fix the Delta” than to mitigate the nitrate in wells, and farmers should be glad they are not in Iowa, implying the groundwater nitrate issue is much worse there than in California.

That was little appeasement, since everyone seemed ready to go home.

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