Waiting until soil temperature drops and stays below 50°F is crucial to safely apply fall anhydrous ammonia. It’s also critical to use the correct nitrogen stabilizer.
Narrow escape only emphasizes the importance of sound nitrogen management
Now would be a good time to thank Mother Nature. She saved many farmers from an environmental black eye by preventing what could have been a perfect storm of nitrogen pollution this past spring.
Next time we might not be so fortunate, warns Farm Journal Field Agronomist Ken Ferrie. The perfect storm that wasn’t shows how critical it is for farmers to be the best possible nitrogen stewards.
“The dangerous situation was caused by unusual weather from October 2015 through June 2016,” Ferrie explains. “Those conditions made it harder for some nitrogen inhibitors to do their job of holding nitrogen in the stable ammonium form. If ammonium converts to nitrate, it can move from fields to water supplies.”
Nitrate levels of 10 ppm or more in drinking water are hazardous for pregnant women and young children.
Here’s what happened: By the end of October 2015, many acres in the Midwest were abnormally dry or suffering moderate drought, according to the drought monitor maintained by the University of Nebraska-Lincoln, USDA and the National Oceanic and Atmospheric Administration.
Then soil temperatures refused to follow the usual pattern, such as 2014, of dropping below 50°F and staying there. “It was Nov. 22 before soil temperatures fell below 50°F in many areas,” Ferrie says. “By Nov. 26, they rose back up above 55°F. They continued to move up and down across that line until Dec. 27, when they finally stayed below 50°F.”
When soil temperature falls below 50°F and stays there it’s safe to apply anhydrous ammonia. At higher temperatures, soil microorganisms remain active and convert the stable ammonium form to nitrate, which can be leached out by water.
When soil temperatures reached 50°F, some farmers began to apply nitrogen. “No one anticipated soil temperatures above 50°F would return in November and December,” Ferrie says.
Responding to the warm soil temperature, microbes began converting the fall-applied ammonium into nitrate. The industrious microscopic creatures didn’t stop there—they also broke down and converted naturally-occurring organic nitrogen, which had been stored in the soil, into nitrate.
“Even fields where no nitrogen fertilizer had been applied showed an uptick in nitrate levels,” Ferrie says. “As we analyzed soil in various fields, we often found 7 ppm to 10 ppm nitrate levels in fields following either corn or soybeans.”
Next time we might not be so fortunate, warns Farm Journal Field Agronomist Ken Ferrie. The perfect storm that wasn’t shows how critical it is for farmers to be the best possible nitrogen stewards.
“The dangerous situation was caused by unusual weather from October 2015 through June 2016,” Ferrie explains. “Those conditions made it harder for some nitrogen inhibitors to do their job of holding nitrogen in the stable ammonium form. If ammonium converts to nitrate, it can move from fields to water supplies.”
Nitrate levels of 10 ppm or more in drinking water are hazardous for pregnant women and young children.
Here’s what happened: By the end of October 2015, many acres in the Midwest were abnormally dry or suffering moderate drought, according to the drought monitor maintained by the University of Nebraska-Lincoln, USDA and the National Oceanic and Atmospheric Administration.
Then soil temperatures refused to follow the usual pattern, such as 2014, of dropping below 50°F and staying there. “It was Nov. 22 before soil temperatures fell below 50°F in many areas,” Ferrie says. “By Nov. 26, they rose back up above 55°F. They continued to move up and down across that line until Dec. 27, when they finally stayed below 50°F.”
When soil temperature falls below 50°F and stays there it’s safe to apply anhydrous ammonia. At higher temperatures, soil microorganisms remain active and convert the stable ammonium form to nitrate, which can be leached out by water.
When soil temperatures reached 50°F, some farmers began to apply nitrogen. “No one anticipated soil temperatures above 50°F would return in November and December,” Ferrie says.
Responding to the warm soil temperature, microbes began converting the fall-applied ammonium into nitrate. The industrious microscopic creatures didn’t stop there—they also broke down and converted naturally-occurring organic nitrogen, which had been stored in the soil, into nitrate.
“Even fields where no nitrogen fertilizer had been applied showed an uptick in nitrate levels,” Ferrie says. “As we analyzed soil in various fields, we often found 7 ppm to 10 ppm nitrate levels in fields following either corn or soybeans.”
http://www.agweb.com/article/farmers-narrowly-dodge-environmental-storm-naa-darrell-smith/
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