设施基质培水肥运移模拟及灌溉决策系统研究

Substrate cultivation develops very quickly these years in facilities, the mineralization phenomenon occurs in substrate recycling has great effect on the physical and chemical properties, moisture holding capacity and fertilizer retention capacity of substrate. Relying on the experience to management must lead to excessive irrigation and fertilization, and effect the crop yield and quality. This study aims to explore the effect of substrate mineralization and add new substrate to mineralization substrate on” the substrate fertilizer and water transport, the detection accuracy of moisture and electrical conductivity sensors, and the distribution of crop root”. Models were proposed simulating the transport of water and fertilizer, and the substrate moist wetting body based on the change of substrate physical and chemical properties, the moisture/electrical conductivity sensor calibration models and crop root distribution model were proposed based on the degree of mineralization, the condition of substrate environment, and the production of thermal effectiveness and photosynthesis active radiation, the crop biomass allocation respectively. A control strategy and a decision system of irrigation and fertilization using in substrate cultivation are presented by man-machine interface combined with menu choose, the information of moisture and electrical conductivity sensors, the meteorological information in facilities and the information of crop root with the ZigBee network technology as the core. It has a very important theoretical value and practical significance to achieve precision irrigation and promote the healthy development of substrate cultivation in facilities.

设施基质培近年来在我国发展迅猛，基质循环利用中发生的矿化现象对基质理化特性及其持水和保肥能力均有较大影响，依常规水肥经验管理必然导致过量灌溉和施肥，影响作物产量和品质。本课题探索基质矿化及在其表层添加新基质对“基质水肥运移、水分/电导率传感器检测精度以及作物根系生长分布规律”的影响，建立“基于基质理化特性变化的水肥动态运移模型和基质湿润体特征值模型、基于基质矿化程度及基质环境条件补偿的水分/电导率传感器标定模型以及建立以辐热积、根际环境和作物生物量分配为基础的根系生长分布模型”。以ZigBee网络技术为核心，采用人机对话与菜单选择相结合的方式，结合基质水分传感器和电导率传感器检测信息、设施气象信息、作物根系生长信息，提出设施基质栽培水肥灌溉控制策略，开发设施基质栽培的水肥灌溉决策系统，对实现设施基质栽培精准化灌溉，促进我国设施基质培行业持续稳定健康发展具有非常重要理论价值和现实意义。

本项目以发酵的稻壳、蛭石、珍珠岩和泥炭等复配的栽培基质为研究对象，研究设施基质栽培条件下灌溉用水的最优调控与管理策略。主要研究成果包括：（1）研究了张力计、中子仪、TDR、FD、电容法和高光谱等水分检测方法用于检测基质含水率的可行性，分析了基质温度、容重和电导率等对电容传感器（EC-5）检测基质含水率精度的影响，建立了基于温度补偿的基质含水率检测模型；分析了基质破碎度对高光谱检测基质含水率精度的影响，采用PLSR法建立了基于高光谱技术的基质含水率快速检测模型，为栽培基质含水率的快速检测提供了有效的方法和技术支持；（2）研究了基质不同初始含水率、不同流量和不同灌水量对基质湿润体形状、湿润锋的变化规律以及湿润体内水分分布规律的影响，采用无量纲法建立了基质水分运移模型；（3）以意大利耐抽薹生菜为试验对象，研究了灌溉方式和基质种类对生菜根系的生长发育规律和生菜产量的影响，建立基于辐热积的生菜及其根系动态生长模型；（4）提出了基于生菜根系与基质湿润区的匹配原则和灌溉控制策略，确定了灌溉开启和停止的具体指标，结合建立的作物根系模型和基质湿润体模型，开发了基于Zigbee无线传感网络的灌溉控制系统，实现基质栽培灌溉的科学化和合理化。