Evaluation of Phosphate and Nitrogen Fertilizers Treated with Polymer Additives to Increase Fertilizer Efficiency

This study is in the fourth and final year of planned research. The growing season was slightly better than average due to greater than normal precipitation in the spring and early summer, followed by warm dry weather the rest of the July, August, and through harvest in September. Research experiments evaluating polymer additives for both P and N fertilizers were conducted at two University of Alberta (AB) research farms. One on a Black high organic matter (8%) clay soil near Edmonton, and the other 120 km south west of Edmonton on a Grey low organic matter (1.5%) clay loam soil near Breton, AB.

There was an excellent response to P for barley at the Breton site with an almost three-fold increase in yield from the zero-P (check) plot to 15 kg P₂O₅/ha (13 lb P₂O₅/A). At the Ellerslie site, the moist spring and early summer conditions followed by warm temperatures appeared to result in sufficient P mineralization from organic matter and no significant response to P fertilizer was found. At all the P research sites, there was no significant difference between P fertilizer with or without addition of polymer additives.

For the N experiments, there was a a significant response to added N fertilizer with the highest yields from the highest N rate (120 kg N/ha). The weather conditions did not appear to favor loss of N due to ammonia volatilization or denitrification, and the regular urea yielded similarly to when polymer additives, or urease and denitrification inhibitors were used. The four years of research data will be grouped and analyzed, and a final report will be completed in 2013. AB-26F