Résumé :
|
The expolinear equation for crop growth (Goudriaan and Monteith Annuals of Botany 66: 695-701, 1990) was fitted to measurements of above ground dry weight made on two cultivars of each of three species, faba bean (Vicia faba L.), peas (Pisum sativum L.) and lentils (Lens culinars Medic.), each grown at three densities at the University of Reading, UK in 1992 and 1993. The expolinear equation fitted the data well but required frequent sampling to obtain good estimates of the parameters. The equation has three parameters, R-m the maximum relative growth rate, C-m a maximum crop growth rate, and t(b) the time at which the crop effectively reaches a linear phase of growth. R-m did not differ between densities, cultivars or species but differed between years. C-m increased with increased density and was lower for lentils than for faba beans or peas. t(b) decreased with increased density for faba bean but not for the other species. Incorporating an extinction coefficient for solar radiation and the maximum fraction of radiation intercepted enabled reasonably accurate time courses of leaf area index to be derived, as suggested by Goudriaan (1994. In: Montieth JL, Scott RK, Unsworth MH, eds. Resource capture by crops. Nottingham: Nottingham University Press, 99-110). (C) 1998 Annals of Botany Company
|