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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Disponibilidade hÃdrica para a cultura do feijÃo-de-corda em funÃÃo do manejo de solo no semiÃrido cearense / Water availability for cowpea crops as a function of soil management in the semi-arid region of CearÃ

Francisco Bergson Parente Fernandes 11 April 2014 (has links)
A pesquisa teve como inÃcio, a coleta de dados climÃticos para a geraÃÃo de informaÃÃes sobre a espacializaÃÃo e a frequÃncia dos veranicos, como base fundamental para o entendimento dos seus efeitos no armazenamento da Ãgua no solo, sob a intervenÃÃo de diferentes manejos; e, as respostas das plantas a estas variÃveis na busca da reduÃÃo da vulnerabilidade da agricultura de sequeiro Ãs incertezas das condiÃÃes climÃticas do armazenamento da Ãgua cearense. O trabalho foi realizado no municÃpio de Quixeramobim, pertencente à regiÃo central do Estado do Cearà - representativa do semiÃrido cearense. Para gerar informaÃÃes sobre a distribuiÃÃo das classes de veranicos (n de dias contÃnuos sem chuva) entre as regiÃes homogÃneas do estado do Cearà e sobre as categorias de precipitaÃÃes pluviomÃtricas (anos secos, normais, chuvosos, muito secos e muito chuvosos) investigou-se uma sÃrie histÃrica pluviomÃtrica de 39 anos de precipitaÃÃes (fonte: Funceme). Foram estudadas as seguintes classes de veranicos (5-10 (1); 11-15 (2); 16-20 (3); 21-25 (4); 25-30 (5) e >30 (6)). Para se entender a resposta da cultura do feijÃo-de-corda aos veranicos instalou-se um campo experimental, composto por cinco manejos diferenciados de solo onde se investigou a umidade do solo durante todo o ciclo da cultura. As coletas de campo foram finalizadas com as mediÃÃes das trocas gasosas foliares das plantas do feijÃo-de-corda, utilizando-se um IRGA modelo LI 6400. Os resultados mostraram que a regiÃo central e Inhamuns, bem como a Jaguaribana apresentaram veranicos mais prolongados, expressando uma maior vulnerabilidade agrÃcola dessas regiÃes ao regime pluviomÃtrico. Os meses de fevereiro e maio mostraram-se como os de maior ocorrÃncia dos veranicos. O manejo (subsolagem + capitaÃÃo in situ + cobertura do solo+ composto orgÃnico) mostrou-se, durante todo o ciclo do cultivo do feijÃo-de-corda como o de maior capacidade no armazenamento e retenÃÃo da Ãgua, principalmente, na ocorrÃncia de veranicos. As respostas das plantas confirmaram os efeitos do manejo na maior capacidade de captar e reter a Ãgua disponÃvel para as plantas por um maior perÃodo de tempo, aumentando o rendimento em relaÃÃo aos demais tratamentos na ordem crescente (do primeiro ao quarto) de 41%; 28%; 47%, e 12%, respectivamente. / 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 CearÃ, 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 CearÃ. 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 CearÃ, 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%.

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