Estimating Light Interception by Cotton Using a Digital Imaging Technique

Radiation intercepted by the crop canopy is directly correlated to dry matter accumulation. Calculation of fractional light interception by the crop is commonly performed by measuring photosynthetically active radiation above and below the canopy using a line-source quantum sensor. However, this method is limited by the time of measurement and the presence of clouds. For soybeans grown in 19-cm rows, ground coverage values estimated from digital images taken above the canopy have been correlated to light interception measurements, but there have been no reports of using this method in cotton or in other crops on wide rows. In this study, a digital imaging technique was used to establish a relationship between fractional canopy coverage and fractional light interception for cotton. This study suggests that digital imagining may be used as an alternative technique for estimating light interception by cotton.