ARS | Publication request: Does spatial arrangement of 3D plants affect light transmission and extinction coefficient within maize crops?

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 2007
Publication Date: April 15, 2008
Citation: Drouet, J.L., Kiniry, J.R. 2008. Does spatial arrangement of 3D plants affect light transmission and extinction coefficient within maize crops? Field Crops Research. 107(1):62-69.

Interpretive Summary: When the row spacing changes for corn, there can be major changes in how effectively light is intercepted by the plants. The coefficient defining this efficiency of light interception is the extinction coefficient. Studies on the extinction coefficient have been inconsistent for corn when calculated with field measurements. To avoid inconsistencies due to variable light conditions and variable leaf canopies, we used a simulation model to describe three-dimensional (3D) shoot structures combined with a model of 3D light transfer. The MODICA model mimics 3D shoot structures of maize plants from digitizations in the field and makes it possible to simulate associated hypothetical canopies by re-arranging plants into different row spacings. All row spacings examined with the model had 10 plants m-2. By using the light model RIRI, simulations showed the relative importance of development stage and time integration on fraction of light transmitted and on the extinction coefficient. Narrow row spacings consistently had less transmitted light and greater values of extinction coefficient. This modelling tool shows promise to effectively evaluate row spacing to optimize light interception.

Technical Abstract: Row spacing effects on light interception and extinction coefficient have been inconsistent for maize (Zea mays L.) when calculated with field measurements. To avoid inconsistencies due to variable light conditions and variable leaf canopies, we used a model to describe three-dimensional (3D) shoot structures combined with a model of 3D light transfer. The MODICA model mimics 3D shoot structures of maize plants from digitizations in the field and makes it possible to simulate associated hypothetical canopies by re-arranging plants into different row spacings. All row spacings examined with the model had 10 plants m-2. By using the light model RIRI, simulations showed the relative importance of development stage and time integration on fraction of light transmitted and on the extinction coefficient. Narrow row spacings consistently had less transmitted light and greater values of extinction coefficient. This modelling tool shows promise to effectively evaluate row spacing to optimize light interception.