Abstract

This paper was focused on the use of allicin as inhibitor which binded with less valuable by-product, palm stearin on urea fertilizer as to increase its efficiency in soil. The coated urea was prepared in three models: urea + palm stearin (UPS), urea + allicin (UAL), urea + allicin + palm stearin (UALPS), whereas pure urea prills act as control (U) sample. The efficiency of the coating materials were investigated through characterization study and this followed by investigation on its N-transformation in soil through quantification of urea-N and ammonium-N remained in soil. Fourier Transformed Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) results proved palm stearin as a compatible binder for urea-allicin system as no significant chemical reaction or weight losses occurred compared to control sample, based on their spectrum respectively. Scanning Electron Microscope (SEM) images demonstrated that the micro-structure of UALPS resulted in a smoother coated layer besides hardness test exhibits higher crushing strength. All coated urea fertilizer showed significantly higher nitrogen in urea form (urea-N) in soil compared to control sample. Consequently, nitrogen in ammonium form (ammonium-N) in coated urea fertilizer was lower than uncoated urea as this has proved the coating material has delayed the urea-N release. Besides, UALPS and UAL possess lowest ammonium-N content since the presence of allicin in their coating material had reduced the urease activity in the soil. In overall UALPS, found to be more efficient in reducing the hydrolyzation rate due to the dual effects of material, which may inhibit urease activity and reduce nitrogen (N) releases rate from fertilizer microenvironment.

摘要

本文着重于大蒜素作为抑制剂的应用，该抑制剂与价值不高的副产品棕榈硬脂精结合在尿素肥料上，以提高其在土壤中的效率。包衣尿素有以下三种模型：尿素+棕榈硬脂（UPS），尿素+大蒜素（UAL），尿素+大蒜素+棕榈硬脂（UALPS），而纯尿素颗粒用作对照（U）样品。通过表征研究来研究涂层材料的效率，然后通过定量土壤中残留的尿素-N和铵态氮来研究其在土壤中的氮转化。傅里叶变换红外光谱（FTIR）和热重分析（TGA）结果证明，棕榈硬脂精是尿素-大蒜素体系的相容粘合剂，因为与对照样品相比，没有发生明显的化学反应或重量损失，分别基于它们的频谱。扫描电子显微镜（SEM）图像表明，除硬度测试外，UALPS的微观结构还导致涂层更光滑，显示出更高的抗压强度。与对照样品相比，所有涂覆的尿素肥料在土壤中的尿素形式（尿素-N）氮含量均显着较高。因此，包膜尿素肥料中铵态氮（铵态氮）低于未包膜尿素，因为这证明了包衣材料延迟了尿素氮的释放。此外，由于其涂层材料中存在大蒜素降低了土壤中的脲酶活性，因此UALPS和UAL的铵态氮含量最低。在整体UALPS中，由于材料的双重作用，在降低水解速率方面更为有效，