Round two of soil testing looking good for Yuma producers
By Laurie DiBattista, Colorado NPS Connection associate editor
A second round of soil testing shows that producers in the Yuma Conservation District continue to do a good job agronomically.
Most of the nutrients applied to their fields are being used by the crops and are not escaping below the root zone, where they could become a potential threat to groundwater quality in the underlying Ogallala Aquifer.
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| Scientist takes soil samples from Yuma County crop field. Yuma Conservation District |
The testing is part of Yuma Conservation District’s ongoing Water and Nutrient Management 319 Project. (Section 319 nonpoint source management programs are funded by the Colorado Department of Public Health and Environment through grants from the U.S. Environmental Protection Agency that support a variety of programs to protect water quality.)
The district’s soil test findings were not unexpected, according to Michael Petersen, who worked on the project as a soil scientist with the U. S. Department of Agriculture, Natural Resources Conservation Service (NRCS).
“We found what we thought we’d find. Western Yuma County farmers are doing a good job of meeting crop needs and are not overfertilizing,” he said.
It was a different story two decades ago. The old rule of thumb was to apply 1.3 pounds of nitrate nitrogen per bushel, Petersen said, “but good research and fieldwork showed that was erroneous. Now growers are using .8 pound of nitrate nitrogen for every bushel. They’ve become more judicious with nitrogen fertilizer.”
Last year and earlier this year, Petersen and another NRCS soil scientist, Andy Steinert, returned to the same 180 sites they sampled in 2003 and 2004. Each site was sampled at depths of six feet and nine feet to get an indication of whether producers were doing a good job of nutrient management, or if applied nitrogen was escaping below the root zone where it could possibly affect the Ogallala Aquifer.
The bottom line: “Producers are doing a good job agronomically, with most of the applied nutrients being used by the crops. Only eight test results out of 180 were a concern. GIS technology will be used to locate and flag those eight sites so the landowner will know their locations,” said Lynda Harper, district manager of the Yuma Conservation District.
“We’ll visit with the landowner about what may have happened to cause the problem. For example, the crop may have been damaged by hail and unable to use the available nitrogen. Any sites of concern that can’t be explained in this way will be re-tested,” she said.
The nonpoint source project started mid-2002 and was to run through 2005. However, the Colorado Department of Public Health and Environment granted an extension and the program will continue through the end of 2006. Producers enrolled 12,000 acres in the program for 2006.
During the entire project, 120 irrigations systems will have been checked – using well tests and sprinkler system efficiency evaluations – and Best Management Practices (BMPs) will have been implemented on over 45,000 acres. BMPs include irrigation water management, nutrient management and pest management practices. About 2,500 acres in the nonpoint source program were enrolled in the Environmental Quality Incentives Program to increase irrigation system efficiency in order to save water and energy, and reduce runoff.
“We expect the program will raise awareness of the connection between BMPs and groundwater quality,” Harper said.
As the study winds down, Petersen said that he and Harper consider soil testing to be “vital, and a good fertility management program is part of that. Soil testing is important to head off future problems, improve farmers’ bottom lines and keep the quality of the environment as good as possible.”
For more about the project contact Lynda Harper at 970-848-5605 or visit www.plains.net/~ycd. For a related story see http://www.ourwater.org/econnection/connection14/soiltest.html.
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