Modeling the spatial distribution of plants on the row for wheat crops: Consequences on the green fraction at the canopy level
Résumé
This work investigates the spatial distribution of wheat plants and its consequences on the canopy structure.
A set of RGB images were taken from nadir on a total 14 plots showing a range of sowing densities,
cultivars and environmental conditions. The coordinates of the plants were extracted from RGB images.
Results show that the distance between-plants along the row follows a gamma distribution law, with no
dependency between the distances. Conversely, the positions of the plants across rows follow a Gaussian
distribution, with strongly interdependent. A statistical model was thus proposed to simulate the possible
plant distribution pattern. Through coupling the statistical model with 3D Adel-Wheat model, the
impact of the plant distribution pattern on canopy structure was evaluated using emerging properties
such as the green fraction (GF) that drives the light interception efficiency. Simulations showed that
the effects varied over different development stages but were generally small. For the intermediate development
stages, large zenithal angles and directions parallel to the row, the deviations across the row of
plant position increased the GF by more than 0.1. These results were obtained with a wheat functionalstructural
model that does not account for the capacity of plants to adapt to their local environment.
Nevertheless, our work will extend the potential of functional-structural plant models to estimate the
optimal distribution pattern for given conditions and subsequently guide the field management practices.