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UNIVERSIDADE FEDERAL DO CEARÁ (2014)

Disponibilidade hídrica para a cultura do feijão-de-corda em função do manejo de solo no Semiárido Cearense

FERNANDES, F. B. P

Titre : Disponibilidade hídrica para a cultura do feijão-de-corda em função do manejo de solo no Semiárido Cearense

Water availability for cowpea crops as a function of soil management in the semi-arid region of Ceará

Auteur : FERNANDES, F. B. P

Université de soutenance : UNIVERSIDADE FEDERAL DO CEARÁ

Grade : Doutor em Engenharia Agrícola 2014

Résumé
The research was beginning to collect climate data in order to generate information on the specialization and frequency of dry spells as a basis for understanding their effects on water storage in soil under the intervention of different managements and on the responses of plants to these variables, in the search to reduce the vulnerability of rainfed agriculture to the climatic uncertainties of the semi-arid region of the state of Ceará, Brazil. The study was carried out in the municipality of Quixeramobim, in the central region of the state, which is representative of the semi-arid zone in Ceará. To generate information on the distribution of the classes of dry spells (number of continuous days without rain) across the homogeneous regions of the state of Ceará, and on the categories of rainfall (dry years, normal years, rainy years, very dry and very wet years), a 39-year rainfall time series was reviewed (source : FUNCEME). The following classes of dry spells were studied : 5-10 (1) ; 11-15 (2) ; 16-20 (3) ; 21-25 (4) ; 25-30 (5) ; >30 (6). In order to understand the response of the cowpea crop to the dry spells, an experimental area consisting of five different soil managements was set up, where soil humidity throughout the crop cycle was studied. Sampling in the field was completed with measurements of the foliar gas exchange of the bean plants using a model LI 6400 IRGA. The results showed that the Central and Inhamuns regions, as well as Jaguaribana, had more prolonged dry spells, indicating the greater agricultural vulnerability of these regions to the rainfall regime. February and May proved to be the months with the greatest occurrence of dry spells. The soil management which included subsoiling with in situ catchment, mulching and organic compost proved to be, throughout the crop cycle of the beans, the one having the greatest capacity for the storage and retention of water, especially during dry spells. Plant response confirmed the effects of this management as having a greater capacity for collecting and holding the water available to the plants for a longer period of time, increasing yield when compared to the other treatments, in ascending order (first to fourth) by 41% , 28%, 47% and 12%.

Mots clés  : Semi-Arid. Dry Spells-Vulnerability. Water Storage. Gas Exchange. Yield — Semiárido. Veranicos. Vulnerabilidade. Armazenamento da Água. Trocas Gasosas. Rendimento.

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Page publiée le 3 décembre 2015, mise à jour le 5 juillet 2017