R E S U M ONeste trabalho objetivou-se avaliar os componentes de produção, produtividade e eficiência da irrigação do feijão-caupi em lâminas de irrigação no cerrado de Roraima. Conduziu-se o experimento no Campo experimental Água Boa, da Embrapa Roraima, em cultivo sobre palhada sob irrigação por aspersão convencional, de fevereiro a abril e de setembro a novembro de 2012. Foram testadas cinco lâminas de irrigação 30, 60, 90, 120 e 150% da evapotranspiração de referência (ETo) e três cultivares de caupi: BRS Guariba, BRS Novaera e BRS Pajeú. Foram estabelecidas as lâminas com base em frações da ETo diária do tanque classe A. O delineamento foi em blocos casualizados com tratamentos dispostos em faixas e parcelas subdivididas, com cinco repetições. Avaliaram-se o número de vagens por planta, número de grãos por vagem, massa de cem grãos, produtividade de grãos secos e a eficiência do uso da água. Concluiu-se que as variáveis do BRS Pajeú não foram influenciadas pelos tratamentos, os cultivares BRS Guariba e BRS Novaera obtiveram a máxima produtividade de grãos, 1.275,19 e 1.504,98 kg ha -1 , com as respectivas lâminas 74,3 e 94,02% da ETo. A máxima eficiência da irrigação foi obtida com a lâmina de 30% da ETo para os três cultivares.Components of production, productivity and efficiency of irrigation of bean-cowpea in the 'Cerrado' of Roraima A B S T R A C TThe objective of this study was to evaluate the components of production, productivity and irrigation efficiency of cowpea under irrigation in the 'Cerrado' of Roraima. The experiment was conducted at Experimental Farm ' Agua Boa'-EMBRAPA Roraima in cultivation on straw under irrigation by sprinkler from February to April and from September to November 2012. Five irrigation levels (30, 60, 90, 120 and 150% of the reference evapotranspirationETo) and three cowpea cultivars: (Guariba BRS, Novaera BRS and Pajeú BRS) were tested. The depths of irrigation established were based on fractions of the daily ETo (Pan Class A). The experimental design was in randomized blocks with treatments arranged in bands, split-plot, and five replications. The variables evaluated were: number of pods per plant, number of seeds per pod, weight of hundred grains, dry grain yield and efficiency of water use. It was observed that the variables of BRS Pajeú were not affected by treatments. Novaera BRS and BRS Guariba had the highest grain yield, 1275.19 and 1504.98 kg ha -1 , respectively, with irrigation depths equivalent to 74.3 and 94.02% of ETo. The maximum irrigation efficiency was obtained with 30% ETo for all three cultivars. Palavras-chave:Vigna unguiculata savana cultivares Key words:Vigna unguiculata savana cultivars ISSN 1807ISSN -1929ISSN v.18, n.6, p.574-580, 2014 Introdução No Brasil, principalmente nas regiões Norte e Nordeste, o feijão-caupi se apresenta como cultivo secundário visando garantir alimento por determinado período; seu excedente é comercializado em feiras de produtores nas áreas urbanas mais próximas. No estado de Roraima, o feijão-caupi é cultivado em ...

In order to study the effect of downgrade rate of water table in the growth of sugar cane (Saccharum spp, cultivate 867515), an experiment in was carried under randomized block design with factorial arrangement (3 × 5 + 1) and 4 replications, applying the flood irrigation system in 3 stages of development (67, 210 and 300 days after planting - DAP) with 5 downgrade rate of water table (3, 6, 9, 12 and 15 days) and the control (no flood). The plants were grown in soil columns of 240 liters, filled with Yellow Oxisol by 300 days after planting and monitored as the height of the stem, number of leaves, stem diameter, number of internodes, number of tillers, leaf area, growth increment, rate relative growth, leaf area index, leaf area ratio and specific leaf area. The stages of development that the flooding was applied at a rate of lowering of the groundwater level variables influenced the growth of cane sugar. The plants drenched at 210 days after planting for 12 days had higher growth of stem, leaf number, leaf area and leaf area index. Plants exposed to water logging after 67 and 210 days after planting obtain better physiological indices that the witness and those who received the 305 DAP waterlogging. It is recommended that the spacing between drains is estimated to be able to lower the water table, after a reloading project to 30 cm deep in 15 days.

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