Estimation of radiation interception and intercepted photosynthetically active radiation in soybean using smartphone images

ABSTRACT The acquisition of parameters such as canopy cover, leaf area index, radiation interception, and intercepted photosynthetically active radiation (iPAR) in crops such as soybean often relies on methods that are costly and time-consuming. This study aimed to identify the most suitable smartphone-based image acquisition method for estimating the percentage of radiation interception, iPAR, and radiation-use efficiency in soybean crop. The images were collected using a smartphone positioned at different heights, angles, and orientations relative to the canopy, including nadir (vertical), upward-facing, and video-based acquisitions. The images and videos were analyzed using the Canopeo application to obtain the fractional green canopy cover (FGCC). The video-based and smartphone camera images acquired at distances of 0.8 and 1.0 m from the crop canopy, respectively, were the most effective approaches for estimating radiation interception and iPAR through FGCC.