聚合物包膜控释肥料氮素释放的数学模拟  

Mathematical model for N release from polymer-coated controlled-release fertilizers

作　　者：陈可可[1,2] 张保林[1] 

机构地区：[1]郑州大学化工与能源学院,郑州450002 [2]新乡学院化学与化工学院,新乡453002

出　　处：《农业工程学报》2013年第9期123-130,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家"十一五"科技支撑计划课题(2007BAE58B07)

摘　　要：为了研究聚合物包膜控释肥料的养分释放机制,以Fick扩散第二定律为理论基础,运用数学物理和数值分析方法建立了聚合物包膜控释肥料氮素释放的数学模型,并对其进行了解析,通过25℃的水浸提试验验证该模型的适用性。研究表明,包膜材质和膜层厚度能显著影响聚合物包膜控释肥料的氮素释放速率,该数学模型能够对醇酸树脂和热塑性树脂包膜控释肥料的氮素释放过程进行有效的模拟,可为控释肥料的研发、生产及施用提供参考。Controlled release of nutrients from coated fertilizer granules is desired for optimal uptake by plants and crops. We studied the release of amide nitrogen, a non-electrolyte, from a polymer-coated spherical fertilizer granule, having varying influence factors. The release course was divided into three stages： the lag period, the linear stage and the decay stage. An exact mathematical model based on Fick’s Second Diffusion Law was developed to predict the release rate of a polymer-coated controlled-release fertilizer using equations of mathematical physics and numerical analysis methods, and Laplace transform and Residue theory were used to solve the equations. From the explicit mathematical model, an approximate solution for the nitrogen release was obtained. The model showed that nitrogen release was mainly controlled by the types of coating materials and their membrane thickness. The models can be used to describe the release rate under different operating conditions. Detailed and approximate solutions were developed and compared with the nutrient release experiments, and different fertilizers were used to verify the approximate release model. Four polymer-coated controlled-release fertilizers, the thermoplastic resin coated fertilizer （1#, l=0.0586 cm; 3#, l=0.0065 cm）, and alkyd resin coated fertilizer （2#, l=0.0463 cm; 4#, l=0.0058 cm）, were used in nitrogen release experiments. Release experiments were conducted using the methods of water extraction from GB/T 23348—2009, at 25℃. The effective diffusion coefficient of amide nitrogen was fixed. The experiments showed the nitrogen was mainly released in the linear stage. The release period of alkyd resin coated fertilizers was shorter than the thermoplastic resin coated fertilizers under almost the same membrane thickness. The cumulative percentage of nitrogen release decreased when the membrane thickness increased. The cumulative release profile of nitrogen from the thermoplastic resin coated fertilizer and alkyd resin coated fertilizer into

关 键 词：数学模型 浸提 肥料 

分 类 号：S131.2[农业科学—农业基础科学] TQ021.4[化学工程]