By Dr. John D. Bailey, PhD, and Jim Thomas, Director of Specialty Products
Nitrogen stabilizers have been studied for many, many years and there have been some improvements to our knowledge in how to use them to manage the risk of nitrogen loss.
Urease inhibitors have had positive effects on yield where rainfall around fertilizer application was less than 0.25 inches, which is not enough to move fertilizer into the soil. On the contrary, small amounts of rain (less than 0.25 inches) can actually cause more urea hydrolysis on the surface, and thus, promote loss. It is not uncommon in the scientific literature to see losses of 5%-30% of nitrogen from surface applied urea and(or) UAN. I’ve personally ran trials in extreme conditions where the loss was closer to 50%…extremely detrimental to crop yields.
Nitrification inhibitors also can have a positive impact on yield especially when weather during the next four-six weeks after application includes moderately high volumes of rain that are well-distributed are coupled with high temperatures, especially on sandy soils. These conditions promote nitrification and leaching, where it is not uncommon to see estimates in the scientific literature from 5%-20% loss.
Independent research spanning several decades from both industry and universities shows that the effects of nitrogen stabilizers depend upon the formulation, the type and timing of application, and, above all else, the weather.
