Evaluation of Phosphate and Nitrogen Fertilizers Treated with Polymer Additives to Increase Fertilizer Efficiency
The use of polymer additives to regular soluble fertilizers to increase the uptake of fertilizer nutrieIt is thought to slow down the reaction of the fertilizer nutrient ions and molecules with soil compounds.
IPNI-2008-CAN-AB26
15 Feb 2010
2009 Annual Interpretive Summary
Spring wheat was grown for the N experiment at Ellerslie, Alberta, but cool and dry conditions experienced from April to July affected yield potential in the region. This could not be compensated by more favorable moisture and temperatures that appeared later in the growing season. No significant differences in grain yield were observed between the selected N fertilizer forms [urea, urea treated with Nutrisphere-N® (a polymer coating), Super Urea (including both urease and nitrification inhibitors), and Environmentally Smart Nitrogen or ESN® (designed as a semi-permeable, polymer-coated urea source)]. Differences between fertilizer placement methods (banded at planting versus surface broadcast) or N rates (60 and 120 kg/ha) were also not observed.
In the P experiments, significantly higher yields were observed for dry granular monoammonium phosphate (MAP) compared to liquid ammonium polyphosphate (APP) at Ellerslie. In most years that are warmer and more moist, advantages for MAP over APP are not observed. Yields at Ellerslie responded to P rate as they increased from 3,659 to 4,839 kg/ha as P rate increased from 7.5 to 30 kg P2O5/ha. However, no significant difference was observed between regular P fertilizer compared to forms treated with the Avail® polymer additive. The Breton site was less responsive to P with no significant difference observed between the rates of P averaged for both form and with and without Avail®. However, a yield advantage was detected at the 30 kg/ha rate for MAP (3,350 kg/ha) compared to APP (2,728 kg/ha) and both forms resulted in greater yields with Avail® (3,664 kg/ha) than without Avail® (2,413 kg/ha). It is planned to repeat the experiments one more year at these two sites. AB-26F