N loss during cold higher than thought
For years, growers and other experts have believed that nitrogen losses to the air (volatility) from
surface-applied urea could not occur in the cold, but innovative new research has recorded significant losses in those very conditions.
Rick Engel, associate professor in the Department of Land Resources and Environmental Sciences at Montana State University, carried out the research. He says results from the first five campaigns have been unexpected.
“What we have been seeing are some very large losses,” says Engel. “We’ve actually seen some of our largest losses when our urea applications are during the late-fall or early-spring period, even when the soil temperatures are near freezing.”
Engel conducted his study in the hill country of northern Montana. He uses a unique micrometeorological system in the field, which collects ammonia gas over time without disrupting the soil environment. The study was designed to duplicate the common practice of fertilizer application used by wheat growers.
In three of the first five of these cold-weather studies, more than 30% of the applied nitrogen was lost. These losses can add up quickly, especially when conditions are damp as well as cold.
“In the five campaigns we’ve conducted to date, our losses have ranged anywhere from 3% or 4% up to 40%,” Engel says. “The conditions that really seem to promote these ammonia losses from urea are prolonged damp conditions.”
A new way of thinking
John Hassell, research and agronomic development manager for Agrotain International, recognizes the importance of this groundbreaking research. “The fertilizer industry has made assumptions in the past, not based on scientific proof, but rather long-held beliefs,” he says. “With these advanced techniques, Dr. Engel has documented that our previous way of thinking is basically incorrect ... that enzymes continue to work in freezing conditions and that urea loss can and will occur at significant levels. This will change the way textbooks are written and students are taught in the future.”
For now the study demonstrates wheat growers can offset much of this potential for loss by using a nitrogen stabilizer, which already is a standard practice for many growers in warmer climates. The Montana study compared untreated urea with urea that had been stabilized with Agrotain nitrogen stabilizer. “What we’re finding with Agrotain is that it’s giving us two weeks of protection from volatilization losses,” Engel says. “And over an eight-week campaign, we’ll see a reduction in the amount of ammonia lost of about 60% over an untreated product.”
Source: Agrotain International
This article published in the April, 2010 edition of MICHIGAN FARMER.