Tuesday, 8 November 2005
179-5

This presentation is part of: Nitrogen

Slow Release Urea-Based Polymer Fertilizers for Agronomic, Turf, and Vegetable Crop Production.

M. M. Alley, James M. Wargo, Jorge Hernandez, A. Cothran, and Stacey Wertz.

Improving the efficiency of nitrogen use in crop production is increasingly important for economic and environmental reasons. The objective of this paper is to present information on a new group of slow release N fertilizers that may more closely match crop N uptake patterns than currently utilized water soluble N fertilizers. These new slow-release fertilizer N materials can be produced in both liquid and granular forms, and potentially at more economical prices than previously-developed slow-release N fertilizers. The liquid material contains 30% N, and is a blend of methylene ureas of varying molecular weight, urea, and triazone molecules. The granular fertilizer contains similar N forms as the liquid material, plus higher molecular weight methylene ureas and occluded urea. N contents vary with formulation but generally range from 40 to 43% N. Incubation of these new fertilizer N materials with selected soils at varying moisture contents and temperatures indicate that N release from these fertilizer materials ranges from 60 to 90 days depending on the nature of the N forms utilized in the fertilizer material. Laboratory and field experiments have been conducted in a number of locations to measure N release rate, crop response compared to standard N fertilization programs, and crop N utilization efficiencies.

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