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Accueil du site → Doctorat → Portugal → Modificação das características agrometeorológicas do sorgo pela adubação azotada/Modification os sorghum agrometeorological characteristics by different nitrogen fertilization rates

Instituto Politecnico de Braganca (2009)

Modificação das características agrometeorológicas do sorgo pela adubação azotada/Modification os sorghum agrometeorological characteristics by different nitrogen fertilization rates

Costa, Luís de Sousa

Titre : Modificação das características agrometeorológicas do sorgo pela adubação azotada/Modification os sorghum agrometeorological characteristics by different nitrogen fertilization rates

Auteur : Costa, Luís de Sousa

Université de soutenance : Instituto Politecnico de Braganca

Grade : Doutoramento 2009

Résumé
The aim of this work is to evaluate the influence of distinct levels of soil nitrogen fertilization on the agrometeorological characteristics of development and growth of irrigated fodder sorghum in the Nordeste Transmontano (Northeastern Portugal). The effects of four levels of soil nitrogen fertilization on the responses of sorghum development and to temperature and solar radiation were analysed, namely crop height, leaf number, leaf area, biomass and nitrogen uptake. This assessment is based on the thermal time for development, on the radiation use efficiency for dry mater production and on the efficiency of nitrogen utilization. The experiments were carried out in Quinta de Sta. Apolónia, Bragança, in 1997, 1998 and 1999, with the hybrid fodder sorghum variety Sweet Sioux IV. Nitrogen fertilization increased leaf area, radiation interception and biomass production. However, nitrogen fertilization rates above 400 kg ha-1 should not be used because they do not lead to a significant increases of both yield and radiation use efficiency, and they reduce the efficiencies of nitrogen recovery and utilization.

Mots clés : Sorgo ; Azoto ; Temperatura ; Radiação ; Germinação ; Área foliar ; Produtividade ; Intercepção da radiação ; Eficiência de utilização da radiação ; Eficiência de utilização do azoto ; Sorghum ; Nitrogen ; Temperature ; Radiation ; Germination ; Leaf area ; Yield ; Radiation interception ; Radiation use efficiency ; Nitrogen use efficiency

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Page publiée le 23 octobre 2013, mise à jour le 12 juin 2017