Effect of Various Forms of Enhanced Efficiency Fertilizers in the Development and Yield of Wheat

Funded by Alberta Grains

Introduction and Objective

Intensified agricultural strategies and novel genetic varieties can improve Spring Wheat yield production, but questions persist about optimal soil nitrogen (N) release and precise nitrogen (N) uptake by crops. At Agriculture and Agri-Food Canada in Lethbridge, Dr. Brian Beres has a research program evaluating different fertilizers designed to provide better nitrogen (N) availability to wheat crops than through traditional banded urea. This experiment explores N-Enhanced Efficiency Fertilizers (EEF) set at different N application rates and yield estimates. The goal is to investigate the agronomic benefits of using EEFs on wheat.

What We Did

The project was implemented at the Fairview Research Farm (FRF). Table 1 gives site history, soil information, treatments, field operations, and data collected for this trial. The experimental design included a randomized complete block design using three replications on small plots measuring 8m x 1.14m. Seeding was carried out using a 6-row Fabro Small Plot Drill with disc-type openers on 23 cm row spacing, complete with side banding. 

The efficiency fertilizers used for this experiment were Urea, Environmentally Smart Nitrogen (ESN), and SuperU. Fertilizer rates were set at 100% and 70% of the recommended rate and adjusted to meet 1x and 1.5x of the grain target yield. The site received 10" of rainfall for the growing season (April 1 – Sept 30) and about 1,414 Growth Degree Days. Data was subjected to the One-Way Analysis of Variance (ANOVA) procedure with treatment as the only fixed factor, and significance was declared at p ≤ 0.05. Also, we used Principal Component Analysis (PCA), a multivariate statistical approach to simplify and represent patterns in the dataset in fewer dimensions or factors.

Results

Table 2 gives the fertilizer treatments, plant counts, heights, yields, and grain attributes.

Wheat Counts

Plant counts determined 3 weeks after seeding ranged from 226 – 299 plants/m² and did not vary significantly between fertilizer treatments.

Wheat Heights and Lodging

Plant heights ranged from 47–57cm and varied significantly among treatments. On average, ESN and Urea treatments were taller than Super U treatments. No lodging was observed amongst any treatments.

Wheat Yields

The yields ranged from 23–29 bu/ac and varied insignificantly between fertilizer treatments. On average, ESN treatments had higher yields than Urea and Super U treatments.

Wheat Thousand Kernel Weights (TWK) and Bushel Weights (BW)

For TKW and BW, 23–27 g/1000 and 53–59 lbs/bu were obtained, respectively. No significant differences were observed between treatments.

Wheat Grain Quality

The Crude Protein (CP) content of wheat ranged between 15% and 18% and varied significantly between treatments. ESN treatments generally had lower protein contents than the SuperU and Urea treatments.

Principal Component Analysis (PCA)

The results of the PCA are shown in Figure 1. The first two principal components explained 76% of the variation in the dataset, with Grain Yield, TKW, BW after drying, Crude Protein, and BW at harvest mainly on PC1, while Plant Height and Plant Counts loading primarily on PC2. Grain Yield was inversely proportional (R = 0.60; p = 0.03) to Protein Content.

Figure 1: Score plot of the dataset's first two principal components score vectors.

Conclusion and Implications

These findings highlight that fertilizer treatments, at the rates used in this trial, had limited impact on wheat plant establishment (i.e., no detrimental impact on emergence - important for early vigour), yield, or kernel weights. However, the significant differences in plant height and protein content suggest that specific fertilizer types, such as ESN, may influence wheat growth dynamics. There is a trade-off between yield and protein, as yield increases, protein tends to decrease. This reflects a dilution effect, common in cereals.

Overall, the study suggests that while fertilizer type minimally impacts yield and kernel weights, it significantly affects protein content and plant height.

Figure 2. Alberta Grain Slow Release Fertilizer plots approaching field day at Fairview Research Farm.