Could Virtual Plants be Considered as Lambertian Objects in Dense Canopies?

摘要

Light absorption by plant organs determines the development of a canopy directly through photobiological processes and indirectly through its action on organ temperature. Recent radiative models enable light absorption to be estimated for each individual organs within a canopy. A limitation of the development of these models is the difficulty of measuring and accounting for the bidirectional optical properties of phytoelements. Thus most of these models rely on the Lambertian approximation. In this paper we attempt to evaluate this approximation for dense canopies in the solar spectrum. Simulations were performed with Monte-Carlo ray tracing for three canopies, three sun positions, and two spectral domains (PAR and NIR). Results prove the validity of the Lambertian approximation for the simulation of the absorption of light by plants in the studied domain.