Supplemental videos for "Diurnal Trends of Maize Canopy Cover Under Water Stress"

These videos quantify and demonstrate the diurnal fluctuations of maize canopy cover under full and limited irrigation. These datasets were taken in 2016 at the USDA-ARS Limited Irrigation Research Farm, in conjunction with an overarching project that evaluated crop yield response with varying irrigation levels. These videos will be referenced in an upcoming journal article which features deeper experimental detail and analysis.

Images were collected by digital trailcams with 5.0 megapixel resolution, with images taken every 15 minutes. The cameras were mounted to a customized metal frame which cantilevered above the crop canopy, mounted nadir at height of 12 ft above the ground. Nighttime images were illuminated by LED lights mounted on the camera. Images were processed using a custom Python language script that delineates green pixels from each RGB image, and defines the ratio of green pixels to total pixels as the fractional canopy cover (fc, %). Due to overexposure from low sunlight angle at dawn and dusk, as well as occasional fog, some images were eliminated from analysis. 

The single day video shows images and associated graphs for July 8, 2016, for fully and deficit irrigated maize. The multiday video shows the same, but for six consecutive days from July 13 until July 19, which includes an irrigation event on July 15 (40 mm for full irrigation and 26 mm for limited irrigation) and an 18 mm rainfall event on the night of July 17.