In Montana, farmers often fertilize wheat by applying urea to the soil surface during the fall, winter,  or early spring.  The question of how much nitrogen is lost from this application strategy seems to be raised by growers and fertilizer dealers every season. Surface urea applications are known to be susceptible to nitrogen losses as a result of ammonia volatilization (lost to the air).  However, the importance of this process in cold soils is not known and is the focus of an investigation I am currently leading. To answer this question, I am using a micrometeorological system referred to as the integrated horizontal flux (pictured in photograph below) method to quantify ammonia losses from the soil.   Micrometeorological are widely recognized as providing the most accurate measures of gas losses from soils. This method is not disruptive of the soil environment and provides for continuous collection of ammonia gas over time. This is a first of its kind study in Montana. From 2008 to 2015 I conducted 21 field trials or campaigns at six different farms in Montana.  I have constructed this web site to keep people up-to-date on the progress of this study.



For additional presentations on urea volatilization, including management to minimize N loss, browse "Presentations" on the Soil Fertility Extension Website