WHEAT, RICE AND CORN RESPONSE TO THE UREASE INHIBITOR N-(N-BUTYL THIOPHOSPHORIC TRIAMIDE) IN A DIMETHYL SULFOXIDE/PROPYLENE GLYCOL SOLUTION

Surface applied granular urea is a nitrogen fertilizer commonly used throughout the world. Unfortunately, a significant portion of the urea can be lost to the atmosphere through ammonia volatilization. Much research has been conducted in an attempt to reduce or stop this process and increase the efficiency of urea fertilizer. Urease inhibitors have been shown to be one possible method to reduce nitrogen volatilization. The chemical compound N-(n-butyl) thiophosphoric triamide (NBPT) has been shown to be an effective urease inhibitor. The purpose of this research was to test the effect that a new commercial NBPT containing product, N-Yield™, had on the growth of the common field crops including wheat, rice, and corn. Additionally, N-Yield was compared to the existing product, Agrotain Ultra©. Three studies were performed; a greenhouse study in Verde variety spring wheat, a greenhouse study of CL 111 variety rice, and a field study of dent corn. In the wheat study, three treatments, consisting of urea, urea with Agrotain (4.17 mL/kg), and urea with N-Yield (4.17 mL/kg) applied at 56, 84 and 112 kg nitrogen/ha, were compared to a no fertilizer treatment. The study was a CRD design, with three replications of each treatment. Above and below ground biomass were measured, and protein was analyzed using a Near Infrared Spectrometer (NIR). Significant differences were found in the mean above ground biomass for the Olton Clay Loam soil type (p=0.05). A significant difference between treatment means in protein content was found for both the Olton Clay Loam (p=0.08) and Amarillo Fine Sandy Loam soil types (p=0.001). In the rice study, three treatments consisting of urea, urea with Agrotain Ultra (4.17 mL/kg), and Urea with N-Yield™ (4.17 mL/kg) applied in either one or two applications of 22.41 kg nitrogen/ha, were compared to a no fertilizer treatment. The study was a CRD design, with four replications of each treatment. Above ground biomass and grain weight per plant was measured. Significant differences were observed between the treatment means of the grain weight (p=0.06) and for above ground biomass (p=0.09).The field corn study was set up in a RCBD design, using the prevailing south wind as a blocking factor. Three treatments and a no fertilizer control were used. Treatments consisted of urea, urea with Agrotain Ultra© (4.17 mL/kg), and urea with N-Yield™ (4.17 mg/kg) applied at a rate of 112 kg of nitrogen per hectare. There were three replications of each treatment for a total of 12 plots. Twenty plants were harvested from the middle of each plot and grain weight per ear was collected. Significant differences were found for the means of the grain weight per plant (p=0.008).