Mapping Crop Fractional Green Canopy Cover Using High Spatial Resolution Thermal and Optical Remote Sensing in Southern Ontario, Canada

Fractional green canopy cover (FGCC) is a commonly used diagnostic parameter to describe plant growth and vitality. Remote sensing estimates of crop FGCC have been used to support a wide range of agricultural applications, including assessing management practices designed to promote crop productivity and maintain environmental sustainability. This study investigated the potential of using affordable thermal and optical remote sensing sensors to map FGCC at the Agriculture Agri-Food Canada experimental farm located in Woodslee, Ontario, Canada. Airborne RGB (Red-Green-Blue) colour and thermal images and ground-level red-edge images were collected in August 2019 over crop fields with different treatment plots. The 20 cm resolution RGB images and 5 cm red-edge images were used to extract reference data for FGCC, which were then linked to thermal data and red-edge vegetation indices. We found that the airborne thermal data explained 77% of the variation in FGCC at a range of 0-100%. However, the airborne thermal image could only explain 17% of the variation within the cornfields, which have low FGCC values ranging from 20% to 40%. In contrast, the simple ratio derived from the ground-level red-edge image could explain 81% of the FGCC variation in the cornfields. These results suggest that both the thermal and red-edge images are capable of estimating crop FGCC, with the red-edge outperforms the thermal images in estimating low FGCC for single-crop fields. In conclusion, this study demonstrates an efficient and affordable means to map crop FGCC, and these maps could play an essential role in generating insights relating to crop canopy development, light interception, and evapotranspiration partitioning, which can be used as indicators for soil health and nutrient status.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author