What is in this article?:
- California agriculture in groundwater controversy over nitrate contamination.
- Dairy, almonds and citrus growers are taking steps to cut down on unnecessary nitrogen use and improved efficiency in irrigation delivery systems for nitrogen and other nutrients.
A Tulare meeting was pretty much expected to be a rubber-meets-the-road gathering on how growers can handle the challenge of cutting down on the amount of nitrates contaminating the groundwater below their fields while maintaining crop yields.
More precisely, it was a nitrogen-meets-the-root zone meeting, a look at what growers and dairy operators can do to maximize their use of nitrogen fertilizers, whether organic or inorganic, at the same time that they curb contamination of groundwater.
Industry presenters representing dairy, almonds and citrus talked of steps already being taken to cut down on unnecessary nitrogen use and improved efficiency in irrigation delivery systems for nitrogen and other nutrients.
Others, including the head of a coalition of growers facing tighter groundwater restrictions, discussed a need for more monitoring to establish base points that will show whether farmers are doing a better job of keeping nitrates from contaminating drinking water.
(For more, see: California groundwater nitrate report more about past than present)
The program included some basic pointers on what needs to be done, along with some haunting questions on how agriculture can get to where its regulators – and itself — want to be when it comes to use of nitrogen to produce crops, milk and meat.
Here’s what some of the speakers had to say:
• “Nitrogen is slippery; it easily changes form and moves between environmental reservoirs,” said Paul Martin, director of environmental services, Western United Dairymen.
Dairies in the state have been active in adopting waste management and nutrient management plans, along with well monitoring at more than 4,000 sites, he said, and got an early start on groundwater protection.
Still, he said, the target of arriving at applying no more than 1.4 times the amount of crop removal, is “extremely difficult ... all has to go perfectly. Poor weather or bugs in crops can reduce yields and ruin the ability to hit the mark.”
Martin favors evaluating nitrogen efficiency as a “trend analysis over a period of years” rather than annually because of those kinds of setbacks.
He would like to see more research on ways to mineralize organic nitrogen as a way to making it more rapidly available to plants and sees that as a way to make it easier to transform manure into material that could be hauled away more economically.
Martin drew laughter as he said, “We could send it back to Nebraska where it came from.”
He also advocates testing for nitrogen in soils, irrigation water, crops and manure to properly balance nitrogen applications.
• “Spoon feeding nitrogen in multiple low doses” through delivery systems that include fertigation can be key, said Bob Curtis, associate director of agricultural affairs with the Almond Board of California.
Like Martin, he pointed to success in the almond industry as it has moved to more efficient delivery of nutrients with use of micro irrigation, timely leaf sampling, fertigation and application of nitrogen during periods of peak plant demand: “matching demand during tree growth and crop development.”
Curtis said self-assessment by growers can include quantifying how much nitrogen and other nutrients are used in production of a crop and what forms they take.
• “You can’t manage what you don’t measure,” said Andrew Brown, a Fresno County citrus grower and member of the California Citrus Mutual Executive Committee.
With a wife and two small children, Brown said it is in his personal interest to monitor water from the wells on his farm.
Brown said he turns to sources of information on “how to get more out of less” from the universities of Florida and Arizona, along with the University of California.