保水剂包膜尿素的特征与性能

保水肥料是缓/控释肥料研究的新方向,本文利用聚合化学反应制备出了一种保水剂包膜尿素肥料,并对该肥料的包膜特征、养分控释性能及其对土壤水分的影响进行了研究。结果表明:保水剂包膜尿素的实际包膜量低于设计包膜量,一般低10%～12%。扫描电镜成像图显示:保水剂包膜尿素包膜上存在纤维网状孔隙,膜厚度为0.15～0.25mm。7d水溶出率的实验结果表明,保水剂包膜尿素养分控释效果低于塑料包膜尿素,保水剂包膜尿素的养分缓释作用主要来自包膜对尿素的吸附作用。保水剂包膜尿素处理土壤的土壤水分脱水曲线测定结果说明,保水剂包膜尿素可提高土壤水分含量,增加土壤水分的有效性,改善土壤的保水、释水性能。因此,保水剂包膜尿素肥料是具有开发应用前景的新型缓/控释肥料。

Characteristics and performance of water-adsorbent polymer coated urea

Absorbed fertilizers is new trend to research and development of slow/controlled release fertilizers(SRFs/CRFs). In this article, the author prepared water absorbent polymer coated urea (WACU) by using chemical polymerization reaction, and study coatings characteristics, performance of nutrient-controlling release, and effects of the coated urea on soil water. Test results of WACU show that the actual coating rate is lower than that of the designed coating rate of WACU, generally 10%—12%. The photograph of SEM(Scanning Electronic Microscopy) show that there are lot of fiber-network-like porosity in coatings of fertilizers, the coatings is 0.15mm—0.25 mm in thickness. The results of "7d water solution rate" experiment indicate that the capability of nutrient-controlling release of WACU is inferior to that of plastic coated, or water adsorbent plus plastic coated urea, the slow release effect of WACU is mainly attributed to the absorption of urea by water absorbent. The measurement results of soil water characteristic curve show that WACU can increase water content and availability in soils treated by WACU, improve water-holding and releasing properties of soil. Thus, WACU is one of new slow/controlled release fertilizers that have the potential of development and application.