Biodegradable oil-based polymeric coatings on urea fertilizer: N release kinetics transformations of urea N in soil

Reference	Presenter	Authors (Institution)	Abstract
05-013	Ricardo Bortoletto-Santos	Bortoletto-Santos, R.(Embrapa Instrumentação); Guimarães, G.G.(Embrapa Instrumentação); Junior, V.R.(Universidade de São Paulo); Cruz, D.F.(Universidade de São Paulo); Polito, W.L.(Universidade de São Paulo); Ribeiro, C.(Brazilian Agricultural Research Corporation, São Carlos, SP, Brazil);	Polymer coatings are used to control the rate of release of plant available nutrients from fertilizers as well as reduce nutrient losses such as NH3 volatilization. Although the literature presents several examples of materials used to coat urea, little is known about nitrogen (N) release properties such as the mechanism involved and phenomena (e.g., pore opening) in the polymer coating. Thus, this work investigates urea release from polyurethane (PU) derived from two renewable raw materials (castor oil and soybean oil), to explain how the oil structure and coating microstructure influence release and urea-N dynamics in soil. The results demonstrated that the profile of urea release and the urea-N mineralization in the soil could be controlled by altering the thickness of the coating on the urea granules. Coating by eco-friendly polymer was efficient to control of urea release in soil, to reduce volatilization of ammonia and increase of the availability of N in the soil.
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