Large Urea Granules for Broadcast Application in No-till Cropping - Alberta Agriculture - Lethbridge AB

This is the second site-year for this experiment. In 2010, the experiment was severely flooded, and this is the first year of analyzable data. The control zero N treatment yielded 43 bu/A, with the highest fertilizer treatment yielding 71 bu/A. The site was quite variable with a coefficient of variation (CV) of 15%. All of the fertilizer treatments were applied with a sub-optimal N rate (63 lb N/A) because emphasis of this experiment was to compare timing, i.e. fall versus spring; size of urea granule, i.e. regular sized urea (1/8 in.) vs. large of the urea granule (1/2 in.); and whether or not adding an urease inhibitor (Agrotain®) resulted in greater yields. All of the N fertilizer treatments resulted in similar yields statistically. There didn’t appear to be any advantage or disadvantage of using a larger sized granule as the 1/2 in. granules performed just as well as the regular 1/8 in. granules. There was no statistical yield disadvantage to fall application compared to spring application, or adding Agrotain to the urea, but there did appear to be a trend towards higher yields in the spring applications, and with application of Agrotain. There was 3 in. of precipitation received after spring broadcast applications on 13-May-2012 until planting on 1-June-2012. This precipitation and cooler than normal temperatures delayed planting, and probably didn’t result in conditions suitable for ammonia volatilization losses from surface applications of urea, thus the use of Agrotain didn’t seem to make much difference. AB-28