Modelling the effect of diffuse light on canopy photosynthesis in controlled environments

James Cavazzoni, Tyler Volk, Francesco Tubiello, Oscar Monje

Research output: Chapter in Book/Report/Conference proceedingConference contribution


A layered canopy model was used to analyze the effects of diffuse light on canopy gross photosynthesis in controlled environment plant growth chambers, where, in contrast to the field, highly diffuse light can occur at high irradiance. The model suggests that high diffuse light fractions (∼ 0.7) and irradiance (1400 μmol m-2 s-1) may enhance crop life-cycle canopy gross photosynthesis for hydroponic wheat by about 20% compared to direct light at the same irradiance. Our simulations suggest that high accuracy is not needed in specifying diffuse light fractions in chambers between ∼ 0.7 and 1, because simulated photosynthesis for closed canopies plateau in this range. We also examined the effect of leaf angle distribution on canopy photosynthesis under growth chamber conditions, as these distributions determine canopy extinction coefficients for direct and diffuse light. We show that the spherical leaf angle distribution is not suitable for modeling photosynthesis of planophile canopies (e.g., soybean and peanut) in growth chambers. Also, the absorption of the light reflected from the surface below the canopy should generally be included in model simulations, as the corresponding albedo values in the photosynthetically active range may be quite high in growth chambers (e.g., ∼ 0.5). In addition to the modeling implications, our results suggest that diffuse light conditions should be considered when drawing conclusions from experiments in controlled environments.

Original languageEnglish (US)
Title of host publicationIV International Symposium on Models for Plant Growth and Control in Greenhoues
Subtitle of host publicationModeling for the 21st Century - Agronomic and Greenhouse Crop Models
PublisherInternational Society for Horticultural Science
Number of pages7
ISBN (Print)9789066058460
StatePublished - 2002

Publication series

NameActa Horticulturae
ISSN (Print)0567-7572


  • CERES-Wheat
  • Growth chamber
  • Leaf-angle distribution
  • Triticum aestivum L

ASJC Scopus subject areas

  • Horticulture


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