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California groundwater nitrate report more about past than present

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  • The UC nitrate report did not reveal anything not already known, but it is causing quite a stir.
  • The report gave tacit recognition to changes in nitrogen fertilization and irrigation practices, but focused more on the past than the future.
  • Investigators seemed to lack an understanding of the well-known fact that much less water is now available to California agriculture and therefore there is far less percolation.

The first inclination upon delivery of bad news is to shoot the messenger. Many a farmer wants to hypothetically do that as a pair of UC professors and a covey of graduate students traverse California delivering a report entitled, “Addressing Nitrate in California’s Drinking Water.”

The State Water Resources Control Board commissioned the report in response to a legislative mandate to detail the problem of nitrates in groundwater and identify remediation solutions. The report did not reveal anything not already known, but it is causing quite a stir.

It was not a particularly elucidating study. The authors admitted that the two-year time frame for the study was insufficient for a thorough research effort. A modeling technique was used to estimate many of their findings in it. That did not set well within UC. Several agronomists opted out of participating, citing the need for real time data rather than modeling since fertilization and irrigating practices are far different than they were just 10 years ago.

The report gave tacit recognition to changes in nitrogen fertilization and irrigation practices, but focused more on the past than the future. The investigators seemed to lack an understanding of the well-known fact that much less water is now available to California agriculture and therefore there is far less percolation. Drip irrigation also has become the dominant irrigation method in row crops, thus reducing water use significantly and minimizing N leaching potential.

The well sampling information in the report left something to be desired. In Monterey County, for example, more than 5,100 samples were repeat tests of 4,700 wells, meaning that a substantial number of wells were double or triple counted.

The report also indicated well sampling had not been done on many agricultural wells. Farmers test well water constantly to determine what’s in it to determine how it will impact crops.

The report simple targeted sins of the past. Veteran farmers and consultants will readily admit that too much nitrogen was put on crops in the past. One farmer admitted when dairy manure was free for the hauling and diesel was 50 cents per gallon, it was not uncommon to spread dairy waste a foot deep on open ground.

Consultants also say that in the past when a farmer was concerned about his crop, an inexpensive shot of N to green it up quickly would make the client happy.

Since nitrogen prices have become a new gold standard and diesel is $4 per gallon, those practices are long past.

As controversial and onerous as the report is, there is no need to hypothetically shoot the messenger in this case. Maybe wing a little for being a bit sloppy and unrealistic about the chronological sources of N in the groundwater and failure to fully recognize significant advances in farm management.

The report has spawned more meetings in the past month than a Tupperware lady holds in a year. That’s good since sound nitrogen management and protecting water are absolutely essential, and the more research results and information given to farmers the better.

Information in this report and previous research in the hands of thoughtful, objective scientists can result in reasonable mitigation.

However, we fear that some of the almost anecdotal information in the report in the hands of term-limited politicians will result in ridiculous and costly regulations. With California’s dysfunctional legislature, it is almost like having a cache of loaded guns aboard a ship of fools.

Sins of the past should not spawn unreasonable regulations today.

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

Discuss this Blog Entry 2

Jay Lund (not verified)
on Jun 23, 2012

Much can be learned from reading the original reports at groundwaternitrate.ucdavis.edu There is a clear and growing safe drinking water problem in these basins. Agriculture is certainly involved (albeit not exclusively), in the past, the present, and the foreseeable future of this problem. This problem is not unique to California, and is common in many intensive agricultural regions nationwide and worldwide. It is not a problem likely to be resolved by source control in the near future.

Stuart Pettygrove (not verified)
on Jun 25, 2012

Mr. Cline repeats what several others have said, that the report authors biased their analysis because of double or triple counting wells. This is a misunderstanding of how the data were used. The repeats were for different years, and this allowed the authors to map trends over time.
Mr. Cline also does not mention the main conclusion of the report, which was that source control won't provide drinkable water to affected communities for a long time, and therefore treatment, blending, and alternative supply must be pursued. In the long run, more efficient use of N sources by agriculture will have an impact, but the report does not throw the whole problem onto agriculture.
It is likely that many farmers are managing water supplies more tightly than in the past -- mainly due to the switch to drip and microsprinkler irrigation systems. But for most commodities, the N rates used and the how they have changed with recent improvements in irrigation are unknown. To use Mr. Cline's terms, it would have been "a bit sloppy and unrealistic" to just assume that farm use of N is now in balance, so problem solved.

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