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Modélisation de culture et diagnostic agronomique régional. Mise au point d'une méthode et application au cas du maïs chez les petits producteurs du Brésil Central

Abstract : In order to reduce locally the gap between potential and real yields, it is essential to diagnose its causes. The available methods, however, do not allow to assess the impact on yield of the identified constraints, but only evaluate their frequency of occurrence in a farmers' fields network. Furthermore, monitoring such network during a small set of years does not allow to take adequately into account the influence of inter-annual climate variability on the occurrence of these constraints.
This thesis develops a new method and tests it in a study case. Based on an on-farm survey and on the building and use of an ad hoc crop model, this method facilitates the detection of constraints and classifies them in a more objective hierarchy than with previous methods, although it does not suppress all subjectivity in the diagnosis. It allows to extrapolate, for a series of growing seasons representing the local climate, a diagnosis built for the few years of the survey.
In the case study, on maize crop of small-scale farmers in the Brazilian Cerrados region, the modeling performed resulted (i) in modifications in STICS model in order to improve its water balance module for the tropical context, and (ii) in new functions accounting for Aluminum toxicity, water excess and competition between crop and weeds for light, water and nitrogen. The local diagnosis showed that most of yield gap was due to incorrect crop establishment, itself resulting from shortcomings of associations of farmers in managing the collective farm machinery.
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Contributor : François Affholder <>
Submitted on : Friday, September 10, 2004 - 11:38:53 AM
Last modification on : Tuesday, February 11, 2020 - 10:10:06 AM
Long-term archiving on: : Friday, April 2, 2010 - 8:42:33 PM

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François Affholder. Modélisation de culture et diagnostic agronomique régional. Mise au point d'une méthode et application au cas du maïs chez les petits producteurs du Brésil Central. Physique [physics]. Institut national agronomique paris-grignon - INA P-G, 2001. Français. ⟨tel-00006864⟩

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