AMMONIA VOLATILIZATION FROM AMMONIUM-SULFATE, AMMONIUM-NITRATE, AND UREA SURFACE-APPLIED TO WINTER-WHEAT ON A CALCAREOUS SOIL

Ammonia (NH3) volatilization losses from surface-applied ammonium sulphate (AS), ammonium nitrate (AN), and urea to winter wheat and the effects of the NBPT [N-(n-butyl) thiophosphoric triamide], PG (Phosphogypsum), and PR (byproduct-Pyrite) were determined in a field experiment. Effects on grain yield and protein content of the grain were also measured. Total NH3 losses from AS, AN, and urea varied from 13.6-19.5%, 4.4-6.4%, and 3.9-12.0% depending on the compounds and their levels added to nitrogen (N) fertilizers, respectively. The compounds added to AS and AN increased NH3-N losses with respect to unamended fertilizers (control). On the other hand, while urea treatments with two tons of PG/ha increased NH3 losses, the other compounds decreased the losses. The highest reductions of NH3 loss were observed with NBPT 0.50% and NBPT 0.25% by 63.4% and 52.8%, respectively. Although the effect of nitrogeneous fertilizers on total N losses and protein content of wheat grain was found statistically significant (p<0.01), as the compounds applied with N fertilizers have had no significant effect. Also, a negative and highly significant correlation (r = -0.69***) was found between total N loss and protein content of the grain.