Nitrogen stabilizers to enhance nitrogen use efficiency and reduce greenhouse gas emissions

Background
In Alberta, in fall, 2013 we initiated experiments in three Alberta locations on the effects of nitrogen stabilizers applied to spring wheat. Experiments were designed as factorials with 3 factors: 1. Nitrogen form (eNtrench impregnated urea (nitrification inhibitor); SuperU (nitrification and urease inhibitor on urea); polymer-coated urea (ESN); and urea); 2. Nitrogen rate (50, 77, 100 and 125% of soil test recommendations) and 3.Timing (spring and fall) in comparison with untreated check. In the Edmonton site only greenhouse N02 were monitored spring and fall. Carberry wheat was seeded at 400 plants m-2 all sites. Data included baseline soil nitrogen; nitrogen balance (NH4+, N03-) assessed with soil samples after seeding and post harvest, yield and grain quality. Results will be extended through the growing season and in meeting following data analysis.

Objective: To determine the effectiveness of three nitrogen stabilizer treatments applied with urea in the spring and fall on spring wheat yield, crop health, and grain quality

Sites (3):
Edmonton Research Station- Devon (Rory Degenhardt, Dow AgroSciences)
Edmonton F-62 (Keith Topinka, U of A)
Lethbridge- irrigated (Brian Beres, AAFC)

Spring application timing: After thaw, early May, pre-plant

Experimental Design:
Edmonton: Factorial design of 3 factors and 2 comparison treatments x 4 replicates (34 treatments, 136 plots)
1. Nitrogen form (4):

-eNtrench impregnated urea (nitrification inhibitor)
-SuperU (nitrification and urease inhibitor on urea)
-Polymer-coated urea (ESN)
-Untreated urea

2. Nitrogen Rate (4):

-50% of soil test N recommendations
-75% of soil test N recommendations
-100% of soil test N recommendations
-125% of soil test N recommendations

3. Timing (2):

-Early Fall
-Spring pre-plant

4. Comparison (2):

-0 N (early fall disturbed check)
-0 N (spring preplant disturbed check)

Lethbridge: Factorial design of 3 factors x 4 replicates (17 treatments, 68 plots)
1. Nitrogen form (4):

-eNtrench impregnated urea (nitrification inhibitor)
-SuperU (nitrification and urease inhibitor on urea)
-Polymer-coated urea (ESN)
-Untreated urea

2. Nitrogen Rate (4):

-50% of soil test N recommendations
-75% of soil test N recommendations
-100% of soil test N recommendations
-125% of soil test N recommendations

3.Comparison treatment (1):

-0 N (spring preplant disturbed check)

Agronomic Details:
Trial design: Each plot is 2m wide x 8.5-10m long. If required, plots will be trimmed before maturity to a uniform length. First rep will be non-randomized (Edmonton: group forms eNtrench, SuperU, ESN, Urea with fall and spring treatments side-by-side) (Lethbridge: group 50% treatments, 75% treatments, 100% treatments and 125% treatments). Randomize comparison treatment.

Seed: Certified Carberry wheat (Canadian Western Red Spring CWRS), treated with Raxil WW.

Seeding Rate: 400 seeds m-2

Seeder: New Fabro air seeder (no-till) with 20-30 em row spacing (Edmonton, Devon). Seeding depth 3-5 em to reach moisture.

Nitrogen application: The N is banded 5 cm below the seed. A pass must also be made through the untreated plots, acting as a disturbed check. Banded nitrogen to be marked with 4 flags as markers for where to take future soil samples. Flags to be placed 1 m apart in the centre of the plots with 2 flags on outside of rows 2 and 4. Wheat will be seeded perpendicular to the banded urea.

Other nutrients: Phosphate will be added to all plots based on soil test recommendations in the form of granular 0-45-0, placed in-furrow with the seed at the time of seeding. If K or S are needed, use K2S04 or MgS04. Do not seed apply K or S.

Herbicides: Preseed spring burn off with glyphosate at 900 g a.e. ha-1. Buctril M may be applied if necessary, at 1.0 L ha-1.

In-crop: Apply registered herbicides as necessary to control weeds.

Fungicides, insecticides: Applied as necessary

Treatment List:

Edmonton
Treatment	Form	Rate	Timing
1	eNtrench	50%	Fall
2	eNtrench	50%	Spring
3	eNtrench	75%	Fall
4	eNtrench	75%	Spring
5	eNtrench	100%	Fall
6	eNtrench	100%	Spring
7	eNtrench	125%	Fall
8	eNtrench	125%	Spring
9	SuperU	50%	Fall
10	SuperU	50%	Spring
11	SuperU	75%	Fall
12	SuperU	75%	Spring
13	SuperU	100%	Fall
14	SuperU	100%	Spring
15	SuperU	125%	Fall
16	SuperU	125%	Spring
17	ESN	50%	Fall
18	ESN	50%	Spring
19	ESN	75%	Fall
20	ESN	75%	Spring
21	ESN	100%	Fall
22	ESN	100%	Spring
23	ESN	125%	Fall
24	ESN	125%	Spring
25	Urea	50%	Fall
26	Urea	50%	Spring
27	Urea	75%	Fall
28	Urea	75%	Spring
29	Urea	100%	Fall
30	Urea	100%	Spring
31	Urea	125%	Fall
32	Urea	125%	Spring
33	Fall disturbed check	0%	Fall
34	Spring disturbed check	0%	Spring

Lethbridge
Treatment	Form	Rate
1	eNtrench	50%
2	eNtrench	75%
3	eNtrench	100%
4	eNtrench	125%
5	SuperU	50%
6	SuperU	75%
7	SuperU	100%
8	SuperU	125%
9	ESN	50%
10	ESN	75%
11	ESN	100%
12	ESN	125%
13	Urea	50%
14	Urea	75%
15	Urea	100%
16	Urea	125%
17	Spring disturbed check	0%

Data Collection:

Baseline Soil fertility levels: (Complete nutrient, NH4+, pH, CEC, PSA, OM): Take 4-8 (1-2 per rep) 0-24" samples and divide into 0-6", 6-12" and 12-24" profiles prior to seeding. Submit a composite sample of 0-6", 6-12" and 12-24" for analyses.

Nitrogen balance (NH4+, N03-): Prior to planting in the spring, 2, 4 and 6 weeks after crop emergence, and after harvest. Take two 0-24" samples per and divide into 0-6", 6-12" and 12-24" profiles. Submit one composite of each depth profile per plot for nitrogen balance analysis. Samples should be kept frozen until they are analyzed.

Soil Moisture and temperature: For rain-fed trials identify local weather stations to access rainfall and air temperature data. For irrigated sites, obtain supplemental information on irrigation dates and application volumes. Record soil temperature using a soil temperature logger. Place probe at depth of approximately 2".

GHG emission: Edmonton only. Install GHG chambers in the 0 N and 100% N treatments to collect N20 emissions. Collect gas samples once a week after fertilizer application until harvest.

Stand establishment: Four weeks after seeding, emergence counts will be taken on 50 em of a) rows 2 and 3 at a distance 2 m from the front of the plots, and b) rows 4 and 5 2 m from the rear of the plots. Both areas will be flagged.

Early season vigor: Three-four weeks after emergence (3-4 leaf stage), all plants counted for stand establishment will be cut at ground level, bagged, oven dried and dry weight m-2 determined. Take a visual assessment of crop vigor (1-5 scale, 1 is very poor, 5 is very good).

Crop Height: Measure spring wheat height at the early milk stage (maximum height, to the top of the head).

Head counts: Prior to harvest, count all wheat heads on 50 em of a) rows 2 and 3 at a distance 3 m from the front of the plots, and b) rows 4 and 53 m from the rear of the plots.

Normalized difference vegetative index (NDVI): Using an NDVI meter, record NDVI at jointing and at mid-anthesis. Convert to percentage of highest plot reading in each rep in a separate data column.

Stubble nitrogen: Biomass cut immediately prior to harvest.

Grain yield: Plots will harvested using a Wintersteiger combine. Take only the center 1.5 m from each plot. Record moisture and test weight from every plot. Seed will be dried uniformly, then weighed.

Grain quality (protein): 1000 g of clean seed from each plot will be sent to a seed lab for protein analysis and grading. The amount of retained above-ground N will be calculated.