农药对靶标作物定向沉积与剂量转移的界面过程与机制

The run-off of pesticide deposition on target crop brings about adverse effect on the food quality、eco-environmental security and human health risk. Based on the most frequently used "water-based spraying" method, in-depth study about the pesticide formulation,water-dilluted solution,droplets and deposition performance on target crops has been launched. However, up to now, the interfacial process and mechanism of the interaction between dispersed microparticle in pesticide droplet and the leaves of target crop, which are the dominated factor to affect the bio-efficiency and pesticide lasting, are unclear. Based on the micro-structure and characteristics of the leaves of the representative target crop during the pest occurrence and damage, dispersed pattern with different particle size and deposition profile with different interface of the typical pesticides will be designed. On the microscopic view, the "size effect" and "action effect" present in the interface action between the dispersed pesticide microparticle and the leaves of target crop, which are relevant to pesticide run-off, will be explored in depth. Finally, the micro-mechanism and control factors of the furthest loading of target crop to dispersed microparticle and the most effective dosage released by dispersed microparticle will be illustrated. The implement of this project will provide new idea to establish the precise pesticide application system and enhance the innovate capacity of new pesticide formulation, which decreases comprehensively the pesticide run-off.

农药对靶沉积过程中的流失是导致农产品质量、环境生态安全与人类健康风险问题的重要因素。基于农药施用最广为采用的"对水喷雾"方式，业界已深入开展了药剂与药液、雾滴与沉积性能的研究，但最终决定农药对靶有效沉积与持留和发挥防控作用的关键，药液中农药载药微粒与靶标作物叶面之间相互作用的界面过程与机制尚不明确，是本学科发展亟需解决的科学问题。本项目基于典型靶标作物生长过程中，有害生物集中为害期叶面微观结构与组分特性，选择典型农药代表品种，设计对水分散形式（不同粒径）与对靶沉积形态（不同界面）；从微观层面上，重点研究靶标作物叶面与农药载药微粒界面之间存在的、与农药流失相关的"尺度效应"与"作用力效应"，探索农药载药微粒对靶标作物叶面定向高效沉积与剂量转移的调控因子与微观机制，控制农药流失，为农药对靶高效剂型设计提供理论依据。

本项目基于靶标作物叶面微观结构与组分特性、有害生物发生与为害特征，设计农药对水分散形式（不同粒径）与对靶沉积形态（不同界面），从微观层面上，重点研究农药载药微粒与靶标作物叶面界面之间存在的、与农药流失相关的“尺度效应”与“作用力效应”，探索使靶标作物叶面能够最大限度地承载农药载药微粒，并在有害生物防控最需要的时候提供最有效剂量的微观机制。.基于靶标作物叶面微观结构与有害生物发生与为害特性，采用小尺寸的纳米材料制备高效对靶沉积与持留性能的可控释放载药体系，并对载药颗粒粒径及分布、控制释放行为及生物活性进行表征。结果表明，不同粒径及表面性能的载药颗粒表现出优异的可控释放性能和生物活性，纳米材料有效负载的2,4-D钠盐载药颗粒表现出了酸碱度、温度和离子敏感调控释放特性，在保持良好生物活性的同时对非靶标植物安全，与传统剂型相比大幅减小了土壤淋溶风险。.基于有害生物发生及为害时空规律，利用介孔二氧化硅等载体材料有效负载农药，并对其表面进行靶向修饰，制备了具有靶向传输性能的载药体系，并开展了其在黄瓜植株中的传输性能及剂量分布规律研究。结果表明，依靠纳米材料的小尺度效应及界面修饰改性，制备的纳米载药颗粒可以在植株中进行传输与分布。与传统剂型相比，纳米材料在提高农药传输性能的同时，降低了农药在植株体内的降解速率，且可食部分的残留检出量低于残留限量标准。该项研究为农药对靶高效剂型设计提供理论依据。