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International Journal of Photoenergy
Volume 2015, Article ID 705471, 6 pages
http://dx.doi.org/10.1155/2015/705471
Research Article

Solubility Characteristics and Slow-Release Mechanism of Nitrogen from Organic-Inorganic Compound Coated Urea

1College of Land and Environment, Shenyang Agricultural University, Northeast Key Open Laboratory of Soil and Environment, Ministry of Agriculture, State Engineering Laboratory of Efficient Use of Soil and Fertilizer Resources, Shenyang 110866, China
2School of Natural and Built Environments, University of South Australia, Adelaide, SA 5095, Australia

Received 9 August 2014; Revised 31 August 2014; Accepted 2 September 2014

Academic Editor: Qingrui Zhang

Copyright © 2015 Hongtao Zou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A soil incubation method was used to investigate the solubility characteristics and slow-release mechanism of organic-inorganic compound coated urea at temperature of 10, 20, and 30°C. The membrane microstructure with and without incubation was tested via scanning electron microscopy (SEM). Slow release of nitrogen (N) from different inorganic minerals was analysed by the activation energy from the nutrient solubility system. The rate of nitrogen solubility increased with temperature increasing. The first-order reaction kinetic equation described the solubility process of coated urea. The rate constant also increased with temperature increasing. Moreover, the SEM images showed that the microstructure of the coating layer changed into a flocculent structure and the number of tiny pores and holes on the membrane surface increased significantly with temperature increasing, which increased N solubility rate. The Arrhenius equation indicated that activation energy was closely related to during the solubility process; the activation energy was reduced with rising, which resulted in N solubility rate increasing. Overall, the N solubility rate of coated urea was affected by temperature.