Fertilizers losses due to leaching, volatilization and the activated risk of Fertilizers leaching after addition to the soil may be reduced through the use of slow release fertilizers. These membranes often consist of permeable polymers, waxes or sulfur. The aim of this project is to find a suitable material and method for coating of nitrogen fertilizer to achieve controlled release and also to evaluate the coating and the coating method in laboratory scale. The reason for choosing natural and synthetic rubbers that has been used as coating materials for the controlled release fertilizers to decrease the release rate. To evaluate the coating material a conductivity meter was used to measure the conductivity as a function of time. The conductivity was changed as the ammonium and nitrate ions were released through the membrane to the surrounding water. The results shows that it was possible to coat fertilizer particles with styrene butadiene (SBR), natural rubber(NR), butadiene rubber (BRcis) and butyl rubber. The release rate of ammonium nitrate from SBR and Butyl rubbers are higher than NR and BRcis rubbers.

Abstract

Thin films of SnS and chlorine doped SnS were prepared utilizing chemical spraypyrolysis.The electronic transition was found to be direct and indirect for all the samplesunder investigation. The Urbach tail values were increased as the doping percentageincrease while the energy gap takes the behavior of reverse. The single oscillatormodel proposed by Wimple and Didomoico were applied to the obtained samplewhich certainly obey single oscillator model.