Introduction

Background and Rational

Nitrogen fertilizer is an important agricultural input used to produce high crop yields for global food production. However, it is estimated that only 50% of the nitrogen fertilizer applied is taken up by the crops, with the remaining nitrogen lost in the form of greenhouse gases, or lost via leaching (3). By better matching nitrogen fertilizer supply with crop uptake, fertilizer use efficiency may be improved, increasing agricultural productivity and decreasing nitrogen losses. Environmentally Smart Nitrogen (ESN) is an enhanced efficiency, controlled release fertilizer and the first agronomic controlled release fertilizer available in Canada (5). Unlike conventional urea fertilizer, the Environmentally Smart Nitrogen urea granules are coated with a polymer coat to prevent nitrogen release until soil temperature and moisture are optimal for crop growth. By releasing nitrogen when conditions are optimal for crop growth, nitrogen supply is better matched with crop uptake, which provides opportunities for increased nitrogen recovery, reduced nitrogen losses to the atmosphere and waterways, and higher yields (5).

Yield gains with Environmentally Smart Nitrogen fertilizer vary depending on fertilizer management practices, and environmental conditions (1, 2, 4-7). When side banding Environmentally Smart Nitrogen and Urea fertilizers in the Canadian prairies, both fertilizers had similar impacts on canola and barley crop yields overall, with positive yield responses to Environmentally Smart Nitrogen over Urea at only a few sites (1, 2). C. A. Grant et al. also applied urea and Environmentally Smart Nitrogen fertilizer in side bands, and found no consistent or large improvements in wheat, canola, or barley yields at sites across the Canadian prairies (2012). Seed placed Environmentally Smart Nitrogen was found to provide higher yields at higher nitrogen fertilizer rates than seed placed Urea due to a lower risk for seedling toxicity (6). Yield benefits from Environmentally Smart Nitrogen also depend on environmental conditions such as soil moisture and precipitation, with Environmentally Smart Nitrogen providing higher yields under wetter conditions due to decreased nitrogen leaching losses (4, 7).

Objective

The objective of this study was to determine if Environmentally Smart Nitrogen provides yield increases over Urea fertilizer for barley, canola, and wheat crops in Lethbridge, Alberta under different fertilizer management practices. By comparing the performance of Environmentally Smart Nitrogen and Urea fertilizer for different fertilizer application timings and placements, fertilizer rates, and at dryland and irrigated sites, the management options which provide yield gains when using Environmentally Smart Nitrogen in Southern Alberta can be determined.

Expected Results

Environmentally Smart Nitrogen is expected to provide higher yields than conventional Urea fertilizer as nitrogen supply should be more closely matched with the crop need. However, yield gains for Environmentally Smart Nitrogen are not expected to be consistent across crop types, dryland and irrigated sites, fertilizer placement and timing, and fertilizer rates. Yield gains for Environmentally Smart Nitrogen are expected to vary according to the crop type, as different crops have different responses to nitrogen fertilization. Environmentally Smart Nitrogen may provide higher yield gains compared to urea on irrigated sites due to higher moisture conditions leading to increased nitrogen losses with conventional urea. Seed placed Environmentally Smart Nitrogen is expected to provide higher yield increases than seed placed Urea due to seedling toxicity, particularly at higher nitrogen rates. In addition, higher yield gains are expected with seed placed Environmentally Smart Nitrogen compared to fall and spring banded Environmentally Smart Nitrogen, based on results from previous studies (4, 7). Depending on the yield gains with Environmentally Smart Nitrogen under different fertilizer management options, the results can be used to determine optimal fertilizer management strategies for the use of Environmentally Smart Nitrogen fertilizers in Southern Alberta to provide agronomic and environmental benefits.

Disclaimer: This website is a project for REN R 690 at the University of Alberta, and was developed solely to fulfill the requirements for the course.