Long-term effects of controlled release urea application on crop yields and soil fertility under rice-oilseed rape rotation system

Improving crop yields, nitrogen use efficiencies, and profits by using mixtures of coated controlled-released and uncoated urea in a wheat-maize system

Controlled Release Urea Improved Nitrogen Use Efficiency and Yield of Wheat and Corn

Comparison of Enhanced-Efficiency Nitrogen Fertilizers for Reducing Ammonia Loss and Improving Bermudagrass Forage Production

Seedrow-placed urea minimizes soil disturbance in reduced tillage systems, but it generally decreases emergence at nitrogen (N) rates adequate for optimum crop yield. The objective of this study was to determine the influence of coating urea fertilizer granules with a urease inhibitor or a polymer on the emergence and seed yield of durum wheat (Triticum turgidum L.) and canola (Brassica napus L.) with seedrow-placed urea, and to determine the appropriate rate of Agrotain™ coating for seedrow-placement. Protein content and N uptake in wheat seed were also determined. Field experiments were conducted at three locations using durum wheat (Aneroid) and canola (Scott and Swift Current) in Saskatchewan, Canada. The combinations of N rates (28, 56, 84, 112, and 140 kg N ha−1 for durum wheat and 34, 68, 102, and 136 kg N ha−1 for canola) and urea coatings [non-coated urea (NCU)], urea coated with Agrotain™ at full rate (Agr1, 5.2 L t−1), 2/3 rate (Agr2/3) and 1/3 rate (Agr1/3), and with polymer (Plmr, at 3% by we...

Improving Effectiveness Of Seedrow-placed Urea With Urease Inhibitor And Polymer Coating For Durum Wheat And Canola

Controlled release urea as a nitrogen source for spring wheat in Western Canada: yield, grain N content, and N use efficiency.

Controlled release nitrogen (N) fertilizers have been commonly used in horticultural applications such as turf grasses and container-grown woody perennials. Agrium, a major N manufacturer in North and South America, is developing a low-cost controlled release urea (CRU) product for use in field crops such as grain corn, canola, wheat, and other small grain cereals. From 1998 to 2000, 11 field trials were conducted across western Canada to determine if seed-placed CRU could maintain crop yields and increase grain N and N use efficiency when compared to the practice of side-banding of urea N fertilizer. CRU was designed to release timely and adequate, but not excessive, amounts of N to the crop. Crop uptake of N from seed-placed CRU was sufficient to provide yields similar to those of side-banded urea N. Grain N concentrations of the CRU treatments were higher, on average, than those from side-banded urea, resulting in 4.2% higher N use efficiency across the entire N application range from 25 to 100 kg ha(-1). Higher levels of removal of N in grain from CRU compared to side-banded urea can result in less residual N remaining in the soil, and limit the possibility of N losses due to denitrification and leaching.

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A. D. Blaylock

Papers

Controlled release urea as a nitrogen source for spring wheat in Western Canada: yield, grain N content, and N use efficiency.

Controlled Release Urea as a Nitrogen Source for Spring Wheat in Western Canada: Yield, Grain N Content, and N Use Efficiency