Having an accurate yet simple method to estimate crop evapotranspiration (ET_C) is a vital component of reliable irrigation scheduling. In this study, two versions of the two-source energy balance (TSEB) model: the TSEB model with the Priestley–Taylor equation (TSEB-PT) and the Penman–Monteith equation (TSEB-PM), were used to estimate ET_C of dry edible beans in western Nebraska. Compared with previous studies, this study is unique in that a Visual Basic software—Crop Canopy Image Analyzer (CCIA) was developed to process digitally captured RGB canopy images to obtain necessary canopy cover (CC) parameters for the TSEB models such as CC percentage and leaf shape factor (leaf area divided by its perimeter). Software-estimated CC percentage was closely correlated with commercial sensor-derived CC percentage with an R² of 0.96. Additionally, estimated leaf shape factor was closely correlated with measured leaf shape factor with R² of 0.99. Both TSEB-PT and TSEB-PM models estimated ET_C well for fully irrigated dry edible beans with a root-mean-square error (RMSE) that ranged from 0.95 to 1.63 mm day⁻¹ in 2018, and 0.75 to 1.35 mm day⁻¹ in 2019, as compared to ET_C estimated from FAO56. Furthermore, ET_C from TSEB-PT and TSEB-PM were compared with a soil water balance-derived ET_C and the RMSE ranged from 2.03 to 9.65 mm in an approximate 1-week period under four irrigation treatments ranging from dry land to fully irrigated. The proposed methods in this study, by integrating digital image processing with TSEB models, have great potential to be automated and used in field-scale operations for various irrigation management scenarios of many crops.

拥有一种准确而简单的方法来估算作物蒸散量（ET _C）是可靠的灌溉计划的重要组成部分。在这项研究中，使用两种版本的双源能量平衡（TSEB）模型：带有Priestley-Taylor方程（TSEB-PT）和Penman-Monteith方程（TSEB-PM）的TSEB模型用于估算ET _C内布拉斯加州西部的干食用豆品种。与以前的研究相比，该研究的独特之处在于，开发了Visual Basic软件-作物冠层图像分析器（CCIA）来处理数字捕获的RGB冠层图像，以获得TSEB模型所需的冠层覆盖（CC）参数，例如CC百分比和叶片形状因子（叶面积除以周长）。软件估计的CC百分比与商用传感器衍生的CC百分比密切相关，R ²为0.96。另外，估计的叶片形状因子与测得的叶片形状因子紧密相关，R ²为0.99。TSEB-PT和TSEB-PM模型均估算了ET _C相对于FAO56估计的ET _C，均方根误差（RMSE）在2018年为0.95至1.63 mm天^-1，在2019年为0.75至1.35 mm天^-1的完全灌溉的干食用豆。另外，ET _Ç从TSEB-PT和TSEB-PM用土壤水分平衡衍生的ET相比_Ç和RMSE从2.03范围到9.65毫米以约1周的时间下4个灌溉处理范围从陆地到充分灌溉。本研究中提出的方法，通过将数字图像处理与TSEB模型集成在一起，具有很大的潜力，可以自动化并用于田间规模操作，以应对多种农作物的各种灌溉管理方案。