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Accueil | Français » Publications » DEA et Masters » Proposition de modèle d’estimation de la densité de longueur racinaire chez (...)

Proposition de modèle d’estimation de la densité de longueur racinaire chez le mil (Pennisetum glaucum (L.) R. Br.) par des impacts racinaires sur profil des sols

Mémoire de fin d’études soutenu par KOUAKOU Kouadio Paul-Martial, le 10 Septembre 2010 à l’UCAD, Département de Biologie Végétale

ABSTRACT

Root length density (RLD) is the most important parameter to quantify the capacity of a plant in supplying its water and nutrients needs. RLD is also used as an indicator in selecting drought resistant plants. Yet, its accessibility is costly and requires destructives methods. Therefore, the present study, carried out at Bambey (Senegal), aimed to build a mathematical model to facilitate the estimation of RLD on pearl millet (Pennisetum glaucum (L.) R. Br.) by taking into account root intersection density (RID) and root orientation. RID was determined on three perpendicular soil planes of cubic samples and RLD was measured for the enclosed volume at different dates and positions in the soil. Those samples have been taken from soil profiles perpendicularly to the sowing plane. Results showed a quasi isotropic orientation for all roots without diameter distinction and this orientation was not influenced by the experimentation factors (pearl millet varieties, sowing densities, plant age and depth). A geometric model has therefore been built and its robustness has been highlighted for low values of root impacts. Nevertheless, further analyses must be performed in order to take into account high values of root impacts.

Key words : root length density, root intersection density, pearl millet (Pennisetum glaucum (L.) R. Br.), model, soil profile, roots.