Rick Engel, associate professor in the Department of Land Resources and Environmental Sciences at Montana State University, carried out the research and said while it is still ongoing results from the first five campaigns have been unexpected.

“What we have been seeing are some very large losses,” said 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 over five campaigns 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.

In three of the first five of these cold-weather studies, more than 30 per cent 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 three or four per cent up to 40 per cent,” Engel said. “The conditions that really seem to promote these ammonia losses from urea are prolonged damp conditions.”