Infodoc : Sciences, Techniques et Culture

Annual dry matter production of two different clones of intensively cultured hybrid Populus in two locations was successfully simulated using a model which assumes that dry-matter production by plant communities is proportional to the radiant energy absorbed by the canopy. The model requires as inputs solar radiation and the leaf-area index at any time. Information on Populus growth parameters was obtained from experimental data from Pennsylvania State University (PSU) in College Station, Pennsylvania, and the United States Department of Agriculture (USDA) Forest Experimental Station at Rhinelander, Wisconsin. Long-term average daily values of incident solar radiation were used. The energy absorbed each year by each crop was calculated using Beer's law. The required information on tim[...]

Annual dry matter production of two different clones of intensively cultured hybrid Populus in two locations was successfully simulated using a model which assumes that dry-matter production by plant communities is proportional to the radiant energy absorbed by the canopy. The model requires as inputs solar radiation and the leaf-area index at any time. Information on Populus growth parameters was obtained from experimental data from Pennsylvania State University (PSU) in College Station, Pennsylvania, and the United States Department of Agriculture (USDA) Forest Experimental Station at Rhinelander, Wisconsin. Long-term average daily values of incident solar radiation were used. The energy absorbed each year by each crop was calculated using Beer's law. The required information on time-course of leaf-area index through a season was simulated using an equation constrained by maximum leaf area, the date of leaf emergence, and the end of leaf fall. Analysis of the PSU and USDA data was performed to evaluate how well it conformed to the energy-conversion model's assumptions and to derive parameter values for a computerized simulation model. Total above-ground production plotted against total absorbed energy gave the expected straight-line relationship for the data from both sites. The PSU data included 1-year production figures resulting in a slope (ϵ) of the dry-matter/absorbed-energy line of 0.00016 kg MJ−1. For 2-year-old and older crops, both PSU and USDA data indicated that ϵ = 0.0007 kg MJ−1 was a reasonable estimate for the clones being evaluated.