Large Urea Granules for Broadcast Application for No-till Cropping in Alberta Spring Wheat

The field work at this experiment progressed very well, all the fall N fertilizer broadcast applications (18-Oct-2010) and the spring broadcast applications (20-Mar-2011) were completed as planned. The crop was planted on 20-May-2011, after some delays because of cool wet weather. The crop year 2011 was an excellent growth year with 8.8 in. of precipitation after planting and warm dry weather in July and August to ripen the spring wheat crop sufficiently so that harvest was done on 8-Sept-2011, close to an average harvest date for the area. The challenge about having a moist warm growing season is that even though the site was initially rated as deficient in N, there was probably above average mineralization of N soil organic matter by the soil microbial population. The above average N mineralization caused the check or zero N treatment to yield well, 68 bu/A, compared to the N fertilizer treatments all applied at 63 lb N/A, that ranged from 66 to 74 bu/A. Yields in this area are more commonly around 40 to 45 bu/A. Measurements of grain height at harvest showed that the majority, 16 out of 18, of the 18 fertilizer treatments had significantly taller wheat (at 90% confidence) than the check treatment. That being 30 in. height for the check treatment compared to a range from 31 to 34 in. height for the fertilizer N treatments. Variability at the site was very low for both yield and crop height, i.e. 7% and 3% coefficients of variation (CV) respectively. All fertilizer treatments yielded well with no significant differences between granule size (1/8 in. compared to 1/2 in.), time of application (fall or spring), and with or without urease and nitrification inhibitors. It is hoped that with a more normal precipitation year in 2012 that there will be a greater response to fertilizer N compared to the check treatment, and that differences between N fertilizer treatments will be observed. It is planned to conduct the experiments for two more years on a field near the location. AB-29