A Direct Field Measurement of Ammonia Emission After Injection of Anhydrous Ammonia

Abstract

Studies of the efficiency of applications of anhydrous ammonia fertilizer require a measurement of ammonia retention or loss at the time of application. Because of sampling problems, conventional measurements based on soil analysis are difficult to make in the field. A new method is described, based on calculating the aerial transport of ammonia across the downwind edge of the treated field from measurements of wind speed, wind direction, and atmospheric ammonia concentration. Ammonia losses as small as 1 kg N/ha can be easily detected. Maximum errors are reckoned at no more than 20%. In a field experiment in which anhydrous ammonia was applied at 107 kg N/ha, aerial sampling gave a loss of 1 kg N/ha. Soil sampling detected no loss because of a large sampling error (SE 15 kg N/ha).