基于茎直径变化诊断番茄水分状况的机理与应用

The precision irrigation system generally including the precise water flow measurement, water supply, crop drought forecast, crop water requirement estimation and etc, a better method of crop water content diagnosis would aid them making scientific decisions. At present, there are 2 methods of crop water content diagnosis in our country, the direct and indirect measurements, and they both have some faults as too many professional knowledge to be operated easily, special equipments needed, labour intensive and etc, so they can’t be used continuously and efficiently to crop water content diagnosis. On the contrary, using crop stem diameter variation method to diagnose crop water content has some virtues like easy use, low cost, no destruction to tested plants, continuous supervising and self-recording, and these virtues would facilitate the researchs of environmental factors’ influences on crop water content. This item will be carried out by barrels and plots experiments in greenhouses. The main research contents are (1) the law of tomato stem diameter variation and its relationship with soil water content, (2) the influences of meteorological factors on the tomato stem diameter variation and the determination of reference equation under full irrigation, (3) the choosing of water content diagnosing indexes based on stem diameter variation and their relationships with water content within tomato, (4) the data processing technology and the analysis of their coefficient variations, (5) the research of the application of guiding irrigation methods based on stem diameter variation. This study is of significance for improving the scientific, modernization agricultural water management in China.

现代精准灌溉体系一般包括精确量水、送水、作物旱情预报、需水估算等几部分组成，其中做好作物水分诊断将为其他几个环节的科学决策起到指引作用。目前国内对作物水分状况的诊断主要有直接测定和间接测定2种方法，它们因专业性太强，对设备有严格的要求，劳动强度过大等缺点，难以对作物水分进行实时、有效的监控。应用茎直径微变化诊断作物水分状况具有劳动强度小、操作简单、不破坏被测植株的完整性、可实时监测连续记录作物水分状况等优点，对于综合研究环境因子对作物水分状况的影响很有帮助。本项目拟采取温室内桶栽、小区试验联合进行。主要研究：（1）茎直径变化一般规律及其与土壤水分的关系；（2）气象因子对茎直径变化的影响及其参考值的确定；（3）茎直径变化诊断指标的选取及其与体内水分状况的对应关系；（4）数据处理技术与变异性分析；（5）基于茎直径变化指导灌溉的应用分析。该研究对提高我国农业水管理的科学化、现代化很有意义。

现代精准灌溉体系一般包括精确量水、送水、作物旱情预报、需水估算等几部分组成，其中做好作物水分诊断将为其他几个环节的科学决策起到指引作用。而应用茎直径微变化诊断作物水分状况具有劳动强度小、操作简单、不破坏被测植株的完整性、可实时监测连续记录作物水分状况等优点。本课题通过对温室作物番茄桶栽及小区全生育期茎直径变化研究发现：（1）气象因子、土壤含水量共同对番茄茎直径变化产生影响，气象因子决定着蒸腾强度，而土壤含水量则决定着根区土壤的供水水平，二者是导致茎直径收缩、恢复的主要外因。（2）番茄茎直径微变化指标MDS能够灵敏的反映植株体内水分状况，具有较高的稳定性和可靠性，可以作为指导灌溉的指标加以利用。（3）为消除气象因子对番茄茎直径变化指标MDS数据的干扰，本次研究提出了将MDS数值标准化的计算方法，利用该计算方法得出了番茄水分诊断的合理阈值范围。（4）株间叶面积差异是导致番茄茎直径变化指标MDS产生变异的主要原因，因此茎直径变化传感器在安装时应尽量挑选株型一致的番茄以减少株间变异。（5）应用统计学原理，本次研究得出了应用茎直径变化诊断番茄水分状况传感器的合理布设数量。该研究成果对提高我国农业水管理的科学化、信息化很有意义。