Nitrogen management in most row crops can be a significant proportion of the overall production cost and can impact the bottom line. Keeping tabs on factors that can reduce the efficiency of N applications and deploying appropriate management strategies is one of the several ways to ensure a profitable production in this season. Nitrogen loss is one of the several factors that can reduce N application efficiency. The most common loss from broadcast or dribbled, unincorporated urea-containing fertilizers is ammonia volatilization losses, especially in no-till production systems. Ammonia volatilization occurs when ammonium ion from the breakdown of urea or fertilizer is subsequently converted to ammonia gas, which escapes to the atmosphere. The striking thing about ammonia volatilization losses is that nearly 90% of the total losses occurs within 3-5 days after fertilizer application. The potential and extent of ammonia loss is dictated by three key factors including soil properties, fertilizer management practices, and environmental conditions. This article focuses on how soil pH, clay content, soil organic matter, and soil moisture levels can influence ammonia loss from urea ammonium nitrate (UAN) applied onto the surface without incorporation.
