化学反应型保水缓释氮肥调控水肥的行为特征与机制

化学反应型保水缓释氮肥（CSR-WN）是基于尿素改性制备的低成本新型多功能肥料，具有氮含量高、保水强、制备成本低的优点，能够同时实现对水和肥双调控，低成本优势势必会促进其成为农田水肥调控技术的一条新途径。通过前期制备工艺和性能研究发现：CSR-WN中的亲水基团及尿素形态对吸水、释水和氮素释放有显著影响，但调控水肥的机制不清楚。本项目拟从CSR-WN吸水、释水和氮素释放三个方面研究其对水和肥的调控，探明亲水基团和尿素分布对水分吸收和释放以及网络孔隙结构的变化作用，进而明确亲水基团和尿素形态对氮素释放调控的作用机制；结合溶液和土壤培养确定CSR-WN外界条件对其水分吸水、水分释放和氮素释放的作用，最终揭示CSR-WN本身特性和外界条件综合调控水肥的机制；建立CSR-WN特性与水分和氮素释放特征曲线间的数学关系式，为化学反应型保水缓释氮肥的生产应用提供理论和技术支撑。

Chemical reactive water-retaining slow-release nitrogen fertilizer (CSR-WN) is a new type of low-cost multi-functional fertilizer based on urea modification. It has the advantages of high nitrogen content, strong water retention capacity and low preparation cost. It can realize the dual regulation of water and fertilizer at the same time. The low-cost advantage will certainly promote it to become a new way of water and fertilizer regulation technology in farmland. Through previous preliminary preparation process and performance studies, it can be found that the types, quantity and urea form of hydrophilic groups in CSR-WN had significant effects on water absorption, water release and nitrogen release, but the specific mechanism of regulating water and fertilizer was not clear. This project intends to study the regulation of water and fertilizer from water absorption, water release and nitrogen release of CSR-WN fertilizer, and to find out how hydrophilic groups and urea morphological distribution affect water absorption and release, and how to influence the change of network pore structure, so as to clarify the regulatory mechanism of hydrophilic groups and urea form on nitrogen release. Soil culture method determined the effect of external conditions of CSR-WN fertilizer on water absorption, water release and nitrogen release, and ultimately revealed the function mechanism of CSR-WN itself and external conditions to regulate water and fertilizer comprehensively. The mathematical relationship between CSR-WN characteristics and water and nitrogen release characteristics curve was established to provide theoretical and technical support for the production and application of chemical reactive water-retaining slow-release nitrogen fertilizer.