Seed Row Tolerance of 16-20-0-13 and 12-40-0-6.5S-1Zn in Western Canada

The majority of P-based fertilizers are either applied directly in the seed furrow (seed row) or side-banded close to the seed row, for the growing of small grain cereals and canola, in Western Canada. Farmers using ammonium phosphate-sulfate (16-20-0-13S) fertilizer have reported that they can safely apply greater rates of phosphate in the form of 16-20-0-13S in the seed row compared to regular monoammonium phosphate (11-52-0). To determine if this is accurate, a research study assessing the effect of low and elevated rates of 16-20-0-13S placed in the seed row of both spring wheat and canola was arranged with the regional applied research association, the Chinook Applied Research Association (CARA) based out of Oyen, Alberta. The experimental design was a randomized complete block experiment with 13 treatments, replicated four times. The application P rates ranged from a low rate of 20 lb P₂O₅/A in 5 lb increments up to 40 lb/A. For comparison, there were treatments using 11-52-0 and Rock 40 (12-40-0-6.5S-1Zn) at selected P rates the same as some of the 16-20-0-13S treatments. The crop year 2015 was the first of a planned two-year study.

The weather was extremely dry after planting in early May and through June at the site near Oyen. No significant amounts of precipitation were received until early July. The similar and higher rate of 16-20-0-13S up to 40 lb P₂O₅/A did not decrease plant emergence counts for spring wheat compared to the 20 lb P₂O₅/A rate using 11-52-0. There were some differences in spring wheat yield when comparing P fertilizer forms, but no consistent pattern of an effect of forms and rate of application observed. Canola, a smaller-seeded crop that is planted at a shallower depth (for example 0.75 to 1-inch depth compared to a 2.5 inches for wheat), was very susceptible to poor germination and reduced emergence after experiencing the extremely dry post-planting conditions. This resulted in very poor crop emergence for all experimental treatments, and poor crop growth, even after rains were received in early July. There were no observed treatment differences in plant stands or crop growth and potential yields estimated using biomass measurements.

Another year of research at this site will hopefully help to show whether or not 16-20-0-13S is less prone to reducing spring wheat and canola emergence and yield than 11-52-0.