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

The majority of phosphorus (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 the Western Prairie provinces of Canada. This research study is assessing the effect of low and elevated rates of 16-20-0-13S compared to other P fertilizers available in the market. The fertilizer treatments were seed-row placed in experiments of both spring wheat and canola. The research was conducted by Hamman Research Inc., Lethbridge, Alberta.

In 2015, the P application rates ranged from a low of 20 lb P₂O₅/A up to 40 lb/A for the 16-20-0-13S, in 5 lb/A increments. There were additional 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, for comparison.

The higher application rates of 16-20-0-13S (30, 35, and 40 lb P₂O₅/A) did not decrease seedling emergence for spring wheat. The grain yields of spring wheat were very similar for both low P rates and high rates of all seed row-applied fertilizer. For the canola, a smaller-seeded crop that is more sensitive to seed row-applied fertilizer, higher application rates of 16-20-0-13S (35 and 40 lb P₂O₅/A) decreased emergence of canola seedlings by up to 33%, compared to a 20 lb/A rate of 11-52-0 fertilizer. However, since canola is a so-called "plastic crop", it is able to compensate in growth, by increasing stem branching to fill crop canopy and produced as much yield as with 20 lb P₂O₅/A of 11-52-0 fertilizer.

In 2016, there were direct comparisons between four different P fertilizers (16-20-0-13S0, 11-52-0, 40 Rock 12-40-0-6.5S-1Zn, and a 12-40-0-10S-1Zn) at application rates of 25, 35, and 50 lb P₂O₅/A. There was little difference between the four P-containing fertilizers at similar rates of P₂O₅/A for both plant stands and yields. There appeared to be a minor decrease in canola crop stands at the high rate of P₂O₅ (50 lb P₂O₅/A), but yields were not adversely affected. There will be an additional year of research conducted assessing the effect of rates of 20, 25, 30, 35, and 40 lb P₂O₅ on canola, and rates of 15, 20, 25, 30, and 35 lb P₂O₅/A on lentil, as it affects crop stand and yield, on a low-P soil near Lethbridge.