Spectral reflectance in the near‐infrared (NIR) and short‐wave–infrared (SWIR) regions shows decreasing water absorption troughs upon crop water stress. In this study, decreasing water absorption troughs were identified from reflectance of irrigated wheat crop. The crop was grown under two different irrigation methods, sprinkler and flood irrigation. Crop reflectance was measured using an ASD FieldSpec 3 (350–2,500 nm) hand‐held spectroradiometer at 1 week before the critical growth stages. Among different growth stages, wheat crop was found to be under stress in crown root initiation, jointing, and flowering. Results based on crop yield, and raw and first derivative spectral analysis indicated that flood‐irrigated wheat had more stress compared with sprinkler‐irrigated wheat. Five water stress‐sensitive wavelengths (974; 1,195; 1,455; 1,791; and 1,935 nm) were identified from flood‐irrigated wheat. Among them, two wavelengths (974 and 1,195 nm) were found to be highly water sensitive and good indicators for water stress. Detecting crop water stress prior to the critical growth stages of wheat helps in proper irrigation scheduling.

中文翻译：

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冠层光谱反射率，用于评估小麦的作物水分胁迫（Triticum aestivum，L。）*

在近红外（NIR）和短波红外（SWIR）区域中的光谱反射率表明，在作物水分胁迫下，吸水谷减少了。在这项研究中，从灌溉的小麦作物的反射率中确定了减少的吸水槽。作物是通过两种不同的灌溉方式种植的：喷灌和洪水灌溉。在关键生长阶段之前的1周，使用ASD FieldSpec 3（350–2,500 nm）手持式光谱仪测量了作物的反射率。在不同的生长阶段中，发现小麦作物在冠根萌芽，拔节和开花过程中处于胁迫状态。基于作物产量以及原始和一阶导数光谱分析的结果表明，与喷灌小麦相比，喷灌小麦承受的压力更大。五个对水分胁迫敏感的波长（974; 1,195; 1,455; 1,791; 从洪水灌溉的小麦中鉴定出了1935 nm和1935 nm）。其中，发现两个波长（974和1195 nm）对水非常敏感，并且是水分胁迫的良好指标。在小麦的关键生长阶段之前检测作物水分胁迫有助于适当的灌溉计划。