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

The use of polymer additives to regular soluble fertilizers has been shown to increase the uptake of fertilizer nutrients into target crops. The mechanism of activity of the polymers is thought to slow down the reaction of the fertilizer nutrient ions and molecules with soil compounds.


Justification

The use of polymer additives to regular soluble fertilizers has been shown to increase the uptake of fertilizer nutrients into target crops. The mechanism of activity of the polymers is thought to slow down the reaction of the fertilizer nutrient ions and molecules with soil compounds. In the case of phosphorous (P) the Avail polymer applied to mono-ammonium phosphate is thought to slow down the reaction of phosphate ions (H2PO4^- or HPO4^-2) with cations (i.e Ca⁺² and Mg⁺² under neutral to alkaline soil pH, and Fe⁺³ and Al⁺³ under acidic soil pH). For urea-nitrogen the Nutrisphere polymer is thought to have urease inhibiting and nitrification inhibiting properties that reduce ammonia volatilization, and N2O and N2 emissions respectively.


Objectives

This research initiative will assess the efficacy of the Avail-P and Nutri-N technologies under a wide range of western Canada soil and cropping conditions. Research results under Canadian conditions are required for submission to the Canadian Food Inspection Agency (CFIA) - Fertilizer Division to register the Avail technology for use with liquid ammonium polyphosphate (10-34-0) fertilizer, and Nutrisphere technology for use with urea (46-0-0) fertilizer.


Methodology

The study will be located on Grey Luvisolic soils near Dawson Creek, BC and Breton, AB with clay loam textured soils; and Black Chernozemic soils near Edmonton, AB, Indian Head, SK and Howden, MB with clay, loam, and clay textured soils respectively.

The Avail-P experiments will consist of a randomized complete block (RCB) design replicated four times at each site and include the seed row fertilizer treatments listed in the Table 1 below. All plots will receive an N application of 100 kg N/ha as banded or side-banded urea.

Table 1. Avail P Experimental Treatments

Treatment Number	P Form	Kg P2O5/ha
1	11-52-0	15
2	11-52-0	30
3	11-52-0 + Avail	15
4	11-52-0 + Avail	30
5	10-34-0	15
6	10-34-0	30
7	10-34-0 + Avail	15
8	10-34-0 + Avail	30
9	Check	0

The Nutrisphere experiments will consist of a randomized complete block (RCB) design replicated four times at each site and include N treatments as pre-plant banded or at planting side-banded, or surface broadcast treatments as listed in Table 2 below. Seed row fertilizer will include P, K and S fertilizer as required based on soil test results.

Table 2. Nutrisphere N Experimental Treatments

Treatment Number	N Form	N Placement	N kg/ha
1	Urea	Banded	60
2	Urea	Banded	120
3	Urea	Surface Broadcast	60
4	Urea	Surface Broadcast	120
5	Nutrisphere treated Urea	Banded	60
6	Nutrisphere treated Urea	Banded	120
7	Nutrisphere treated Urea	Surface Broadcast	60
8	Nutrisphere treated Urea	Surface Broadcast	120
9	Super Urea	Banded	60
10	Super Urea	Banded	120
11	Super Urea	Surface Broadcast	60
12	Super Urea	Surface Broadcast	120
13	Check	NA	0