聚合物包膜肥料硝态氮释放特征研究

Release Characteristics of Nitrate from Polymer-Coated Fertilizers

采用不同养分组成(单一组分和复合组分)聚合物包膜肥料(Multicote)和水中静态溶出的方法,研究了不同温度和半径处理下聚合物包膜肥料NO3--N释放特征。结果表明,温度升高显著促进NO3--N的释放;肥料颗粒半径差异显著影响NO3--N释放,小半径的肥料颗粒NO3--N释放明显比大半径颗粒快,且小半径肥料颗粒NO3--N释放的活化能较低;肥料颗粒内离子间存在明显的交互作用,与单一组分聚合物包膜肥料相比,复合组分聚合物包膜肥料NO3--N释放的线性期明显缩短,NO3--N释放速率增加,且NO3--N释放的活化能明显增大。聚合物包膜肥料中NO3--N的释放特征直接与聚合物膜的扩散系数、扩散面积、膜厚度以及伴随离子的种类和浓度相关。养分释放时期以及活化能的定量化表征为全面评估聚合物包膜肥料养分释放特征提供了参考。

The release characteristics of nitrate in the static water were checked by mono-component and multi-component coated controlled release fertilizers treated with different temperatures and granule radii. The results showed that the nitrate release rate increased at higher temperature; and was promoted under smaller granule radius. Comparing with mono-component coated fertilizer,the linear period of multi-component coated fertilizer turned shorter, the nitrate release rate increased significantly, and the activation energy increased accordingly. The nitrate release rate was directly related with the variety and concentration of ion in granule, diffusion coefficient, coating thickness and diffusion area. The release profiles of coated fertilizer can be evaluated by the lag period, the linear period, the decay period and the activation energy, which gives a new way for the development and application of coated fertilizer.