Abstract The crop water stress index (CWSI) is usually used to normalize crop temperature for efficient irrigation management. For CWSI computation, the temperature of a non-transpiring crop (Tdry) and that of a crop transpiring at its potential rate (Twet) are required. Alternatively, the use of artificial reference surfaces (ARS) that mimic Tdry and Twet has been proposed. However, to date, little effort has been made on the development of such surfaces, and there is still much uncertainty concerning what is measured. The aim of this research was to design, develop and evaluate the feasibility of new artificial reference surfaces for real time CWSI computation in maize. Hemispherical cellulose paper-based surfaces were constructed using three shades of green. The paper-based hemispheric surfaces were placed in a 3D-printed plastic structure that allows water storage and the placement of an upward-looking infrared thermometer at the bottom of the ARS. An experimental array comprising 18 randomly located ARS was designed, of which 9 were wet ARS (3 replicates per colour) and 9 were dry ARS (3 replicates per colour). The prototypic ARS were able to accurately determine Tdry and Twet in maize canopies. The CWSI values determined using the ARS developed in this research were validated in a commercial maize breeding trial against leaf gas exchange variables. The shade of green that provided the best results in both cases was the RGB colour R32, G66, B34. While Tdry could be obtained directly from a dry ARS temperature, a solar radiation-based transformation is required to determine Twet from the wet ARS temperature.

中文翻译：

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用于实时监测玉米作物水分胁迫指数的新型人工参考面的设计与评估

摘要 作物水分胁迫指数（CWSI）通常用于使作物温度正常化，以实现高效灌溉管理。对于 CWSI 计算，需要非蒸腾作物的温度 (Tdry) 和以其潜在速率 (Twet) 蒸腾的作物的温度。或者，已经提议使用模拟 Tdry 和 Twet 的人工参考表面 (ARS)。然而，迄今为止，对此类表面的开发几乎没有做出任何努力，并且关于测量的内容仍然存在很多不确定性。本研究的目的是设计、开发和评估用于玉米实时 CWSI 计算的新型人工参考面的可行性。半球形纤维素纸基表面使用三种绿色色调构建。纸质半球表面被放置在一个 3D 打印的塑料结构中，该结构允许储水并在 ARS 底部放置一个向上看的红外温度计。设计了一个包含 18 个随机定位的 ARS 的实验阵列，其中 9 个是湿 ARS（每种颜色 3 个重复）和 9 个干 ARS（每个颜色 3 个重复）。原型 ARS 能够准确确定玉米冠层中的 Tdry 和 Twet。使用本研究中开发的 ARS 确定的 CWSI 值在商业玉米育种试验中针对叶片气体交换变量进行了验证。在这两种情况下提供最佳结果的绿色阴影是 RGB 颜色 R32、G66、B34。虽然 Tdry 可以直接从干燥的 ARS 温度获得，