Long-Term Assessment of Nitrogen Stabilizers Effect On Urea Volatilization Quantified By Acid Trap and Soil Nitrate/Ammonium Content.

An ammonia volatilization experiment was conducted by David Dunn during June and July of 2012 at the University of Missouri-Delta Center assessing nitrogen stabilizers. Untreated urea and urea treated with NBPT or two formulations of maleic-itaconic copolymers (MIC) were compared to an untreated check on bare soil assessing levels of ammonification. The plots consisted of four randomized replications with an untreated check and 112 kg/ha or 100 lbs. of urea (N/A) per replication with the following treatments: 4 qt. NBPT per ton of urea (4.2mL/kg), 0.25% (w/w) MIC, and 0.25% (w/w) MICO (color indicated quick dry formulation). Nitrogen was applied to assigned plots on June 4, 2012 to moist soil with limited rainfall over the duration of the study. Ammonia measurements were gathered through 50mL of 0.10m sulfuric acid traps collected at staggered intervals of one to five days. Once the experiment was completed, soil samples were collected on July 20 at depths of 0-6 inches, 6-12 inches and 12-24 inches and analyzed for NO₃ and NH₄. During the 41-day period, the results showed untreated urea lost two times more nitrogen than NBPT-treated urea and three times more nitrogen than MIC-treated urea. NBPT-treated urea lost less nitrogen during the first 5-7 days of sampling. However, past 5-7 days MIC-treated urea lost less ammonia. The cumulative results for the trial period showed volatilization was lower for both MIC products and NBPT versus urea alone.