Soybean Canopy Coverage and Light Interception Measurements Using Digital Imagery

Abstract

Canopy light interception (LI) is important for yield and crop growth, but LI is often not measured because measurements must be made close to solar noon in unobstructed, direct-beam sunlight. Digital imagery may allow measurements of canopy coverage that are independent of solar radiation and solar angle restrictions. The objectives of this research were to determine the proportion of ground area covered by a soybean (Glycine max L. [Merr.]) canopy from digital images taken from above, and to compare the canopy-coverage measurements with LI measurements. Software limited the scanned areas of digital images to leaves, which allowed calculation of fractional canopy coverage. Similar values of canopy coverage were obtained throughout the day using digital imagery. Furthermore, comparisons of canopy coverage values with LI measured near solar noon indicated that there was a one-to-one relationship. Digital imagery, coupled with appropriate software, offers a simple and effective method of determining canopy coverage and LI.