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Wheat Yield and Quality as Influenced by Coated Nitrogen (ESN Timings, Rates and Mixtures with Urea)

Start Date: 2012
Principal Investigator: Nancy Jo Ehlke
Organization: University of Minnesota, Department of Agronomy and Plant Genetics
Status: Complete

Background Info

Nitrogen (N) is the most expensive plant nutrient for farmers. In fact, 2012 crop budgets for spring wheat and perennial ryegrass indicated N alone was approximately 35 percent of the direct costs (Minnesota State Colleges and Universities Farm Business Management). Further, environmental issues, coupled with economics of today’s agricultural crop production, require a greater understanding of the use of N to minimize environmental impacts while maximizing crop production for Minnesota farmers. Research objectives are to compare the standard urea with a coated urea applied at various timings, rates and mixtures in a spring wheat under seeded to perennial ryegrass. Coated urea may allow increased rates of nitrogen to be applied “down the tube” at planting, when combined with phosphorus and potassium without injury to the wheat and ryegrass seedlings. This coated urea product may offer the potential to improve wheat yield and quality (protein), especially if the product is not released into the soil solution until later in the plant developmental stages of the spring wheat.


To compare various rates of ESN applied at planting to determine wheat and perennial ryegrass injury conducted as a small plot research trial.

To evaluate wheat yield and quality comparing the growers standard top dress urea treatment to a 50/50 blend of urea and ESN. These trials will be large plot, on-farm research to effectively evaluate the two fertilizer treatments using farm scale equipment.

To conduct a small plot research trial to determine the influence of ponded water and waterlogged soils on urea and ESN forms of nitrogen and their availability or loss to the wheat crop.

Key Findings

The in-furrow applications of phosphorus (P) and potassium (K) were more effective in improving wheat yields than the broadcast treatments. If soil tests indicated that P and K are significantly lower than recommended, higher application rates of P and K may increase wheat yields.

Significant differences for wheat yield were detected, with the 100 percent urea treatment producing lower seed yields than any of the other treatments with ESN (Environmentally Smart Nitrogen). This indicates that under wet conditions, which are common in this area of northern Minnesota, it may be beneficial to include ESN as a portion of your total N application.

It appears that having a portion of the N in a protected form such as ESN has the potential to increase seed yield, most likely from releasing N to the crop more slowly and at a later growth stage.

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