ABSTRACT Estimation of canopy cover (CC) can be replaced with measurement of dry matter (DM) during the growing season, which leads to saving cost and time. A variety of software programs, such as Canopeo, have recently been launched for estimating CC by processing digital images. The main objective of the present study was to validate whether the CC estimated by Canopeo could be used to determine the critical nitrogen dilution curve (CNDC) of maize. DM and critical nitrogen concentration (%Nc) of summer maize were measured during the growing seasons in 2015 and 2016. On the same dates, CC was estimated by digital images and Canopeo. The CNDC based on DM (Nc, DM) was accurately described by the equation Nc, DM = 2.9DM−0.27. Furthermore, an exponential relationship was observed between CC and DM (R2 = 0.934) that resulted in the estimation of DM based on CC (DMcc). A new CNDC based on CC was determined (Nc,CC = 4e −1.17CC) by replacing DMcc in the Nc,DM which has an acceptable accuracy in estimating Nitrogen Nutrition Index. These results demonstrate that Canopeo can be applied as a useful tool to develop CNDC and Nitrogen management for different varieties of plants under various climatic conditions.

中文翻译：

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基于冠层数据的夏玉米临界氮稀释曲线的确定

摘要 在生长季节，冠层盖度 (CC) 的估计可以用干物质 (DM) 的测量代替，从而节省成本和时间。最近推出了各种软件程序，例如 Canopeo，用于通过处理数字图像来估计 CC。本研究的主要目的是验证 Canopeo 估计的 CC 是否可用于确定玉米的临界氮稀释曲线 (CNDC)。在 2015 年和 2016 年的生长季节测量了夏玉米的 DM 和临界氮浓度 (%Nc)。在同一日期，通过数字图像和 Canopeo 估计了 CC。基于 DM (Nc, DM) 的 CNDC 由方程 Nc, DM = 2.9DM-0.27 准确描述。此外，在 CC 和 DM 之间观察到指数关系（R2 = 0。934) 导致基于 CC (DMcc) 的 DM 估计。通过替换 Nc,DM 中的 DMcc 确定了基于 CC 的新 CNDC（Nc,CC = 4e -1.17CC），其在估算氮营养指数时具有可接受的准确性。这些结果表明 Canopeo 可用作在各种气候条件下为不同植物品种开发 CNDC 和氮管理的有用工具。