RESUMO A baixa produtividade de grãos do feijão-caupi é influenciada por vários fatores do processo produtivo, principalmente a inadequada fertilização do solo, em especial a fosfatagem. Os solos tropicais apresentam baixos teores de fósforo e de zinco, seja em função do material de origem ou pela ausência de adubação, o que restringe a produtividade do feijão-caupi. A deficiência de zinco se acentua em função da aplicação de fósforo. Este trabalho objetivou avaliar o efeito da adubação com doses de fósforo e zinco na produção de feijão-caupi. Foram conduzidos dois experimentos, sendo um com a cultivar ‘BRS Guariba’ e o outro com a cultivar ‘BRS Aracê’, ambos em um Latossolo Amarelo Distrófico de textura média, no município de Magalhães de Almeida, Maranhão, ano 2015, em delineamento experimental de blocos casualizados, em esquema fatorial 4 x 4, utilizando quatro doses de fósforo (0; 40; 80 e 120 kg de P2O5 ha-1) e quatro de zinco (0; 2; 4 e 6 kg de zinco ha-1). Houve interação entre esses minerais (p < 0,01) e foram obtidas produtividades máximas de 1.376 kg ha-1 e de 2.165 kg ha-1 com aplicações de doses de 118 kg de P2O5 ha-1 e de 0,9 kg de zinco ha-1, para a cultivar ‘BRS Guariba’ e 120 kg de P2O5 e de 3,1 kg de zinco ha-1 para a cultivar ‘BRS Aracê’, respectivamente. O componente de produção que mais influenciou a produtividade de grãos foi o número de vagens por planta, com valores médios de 6 e 10 para as cultivares ‘BRS Guariba’ e ‘BRS Aracê’, respectivamente, e coeficiente de correlação médio de 0,82 (p < 0,01). | ABSTRACT Low grain yield of cowpea is influenced by several production factors, especially inadequate soil fertilization, in particular, phosphorus application. Tropical soils have low phosphorus and zinc levels due to either the source material or the absence of fertilization, which restricts cowpea grain yield; besides of that, zinc deficiency is accentuated with phosphor application. This study aimed to evaluate the effect of fertilization with phosphorus and zinc on cowpea yield. Two experiments were conducted, one with ‘BRS Guariba’ cultivar and another with ‘BRS Aracê’ cultivar. Both of them were performed on a medium-texture dystrophic Yellow Latosol (Oxisol), in the city of Magalhães de Almeida, Maranhão state (Brazil), in 2015. The experimental design was a randomized complete block in a 4 x 4 factorial scheme, using four doses of phosphorus (0, 40, 80, and 120 kg P2O5 ha-1), and four of zinc (0, 2, 4, and 6 kg of Zn ha-1). There was an interaction between these minerals (p<0.01). Maximum grain yields of 1,376 kg ha-1 and 2,165 kg ha-1 were obtained at doses of 118 kg P2O5 ha-1 and 0.9 kg zinc ha-1 for ‘BRS Guariba’, and 120 kg P2O5 ha-1 and 3.1 kg zinc ha-1 for ‘BRS Aracê’, respectively. The production component of greatest influence on grain yield was the number of pods per plant, with average values of 6 and 10 for ‘BRS Guariba’ and ‘BRS Aracê’ cultivars, respectively. The mean correlation coefficient was 0.82 (p < 0.01).

Low grain yield of cowpea is influenced by several production factors, especially inadequate soil fertilization, in particular, phosphorus application. Tropical soils have low phosphorus and zinc levels due to either the source material or the absence of fertilization, which restricts cowpea grain yield; besides of that, zinc deficiency is accentuated with phosphor application. This study aimed to evaluate the effect of fertilization with phosphorus and zinc on cowpea yield. Two experiments were conducted, one with ‘BRS Guariba’ cultivar and another with ‘BRS Aracê’ cultivar. Both of them were performed on a medium-texture dystrophic Yellow Latosol (Oxisol), in the city of Magalhães de Almeida, Maranhão state (Brazil), in 2015. The experimental design was a randomized complete block in a 4 x 4 factorial scheme, using four doses of phosphorus (0, 40, 80, and 120 kg P2O5 ha-1), and four of zinc (0, 2, 4, and 6 kg of Zn ha-1). There was an interaction between these minerals (p<0.01). Maximum grain yields of 1,376 kg ha-1 and 2,165 kg ha-1 were obtained at doses of 118 kg P2O5 ha-1 and 0.9 kg zinc ha-1 for ‘BRS Guariba’, and 120 kg P2O5 ha-1 and 3.1 kg zinc ha-1 for ‘BRS Aracê’, respectively. The production component of greatest influence on grain yield was the number of pods per plant, with average values of 6 and 10 for ‘BRS Guariba’ and ‘BRS Aracê’ cultivars, respectively. The mean correlation coefficient was 0.82 (p < 0.01).

ABSTRACT Considering the relevance of the reduction or replacement of fresh water supplies for irrigation, to mitigate the use of agricultural fertilizers and to improve sustainability, this study aimed to evaluate water and nutritional efficiency of treated sewage in cowpea plots. The experiment was conducted in the city of Tianguá-CE, on land belonging to the Water and Sewage Treatment Company of Ceará. It used a randomized block design for the arrangement of split plots. The plots contained two water sources (treated sewage and well water). The subplots contained four irrigation levels based on potential evapotranspiration (50%, 75%, 100%, and 125% of ETc) and the sub-subplots contained four nitrogen, phosphorous, and potassium (NPK) levels (0%, 33%, 66%, and 99% of the nutritional recommendations for cowpea cultivation). The yield variables, number of pods per plant, bean numbers per pod, and bean production, were improved with increased irrigation, regardless of the water source. Examining NPK levels in particular, yields differed depending on the water source. The use of treated domestic wastewater for bean irrigation can replace up to 100% of commercial fertilizers. | RESUMO Objetivou-se com o presente trabalho quantificar os componentes de produtividade da cultura do feijão submetida a diferentes lâminas de irrigação com água de poço e esgoto doméstico tratado em solo com diferentes níveis de adubação NPK. O experimento foi conduzido em Tianguá - CE, na área da Estação de Tratamento de Esgoto da Companhia de Água e Esgoto do Ceará. Foi utilizado o delineamento em blocos casualizados, em parcelas subsubdivididas 2 x 4 x 4, referente à duas fontes hídricas (efluente de esgoto doméstico tratado e água de poço amazonas) nas parcelas, quatro lâminas de irrigação baseadas na evapotranspiração potencial (50, 75, 100 e 125% da ETc) nas subparcelas e nas subsubparcelas quatro níveis de NPK (0, 33, 66 e 99%) da recomendação nutricional para a cultura. As variáveis analisadas, número de vagens por planta, números de grãos por vagem e produtividade de grãos aumentaram em função do incremento da lâmina de irrigação, independente da fonte hídrica. Quanto ao tratamento níveis de NPK, os resultados produtivos divergiram em função da fonte hídrica. O uso do efluente esgoto doméstico tratado na irrigação do feijoeiro pode substituir até 100% dos fertilizantes comerciais.

Considering the relevance of the reduction or replacement of fresh water supplies for irrigation, to mitigate the use of agricultural fertilizers and to improve sustainability, this study aimed to evaluate water and nutritional efficiency of treated sewage in cowpea plots. The experiment was conducted in the city of Tianguá-CE, on land belonging to the Water and Sewage Treatment Company of Ceará. It used a randomized block design for the arrangement of split plots. The plots contained two water sources (treated sewage and well water). The subplots contained four irrigation levels based on potential evapotranspiration (50%, 75%, 100%, and 125% of ETc) and the sub-subplots contained four nitrogen, phosphorous, and potassium (NPK) levels (0%, 33%, 66%, and 99% of the nutritional recommendations for cowpea cultivation). The yield variables, number of pods per plant, bean numbers per pod, and bean production, were improved with increased irrigation, regardless of the water source. Examining NPK levels in particular, yields differed depending on the water source. The use of treated domestic wastewater for bean irrigation can replace up to 100% of commercial fertilizers.

ABSTRACT The objective of this work was to assess the agronomic performance of cowpea cultivars depending on sowing seasons in the Cerrado biome. Thus, an experiment was conducted in Uberaba, State of Minas Gerais, Brazil, in a complete randomized block design, in a 6x3 factorial arrangement, using six cowpea cultivars (BRS-Itaim, BRS-Guariba, BRS-Potengi, BRS-Cauamé, BRS-Novaera and BRS-Tumucumaque) and three sowing seasons (Dec 14, 2012; Jan 14, 2013; and Feb 14, 2013), with four replications. The interaction between the cultivars and sowing seasons was assessed regarding the number of days for full flowering, number of days for pod maturation, number of trifoliate leaves, height of the first pod -bearing node, pod length, number of pods per plant, final plant population, 100-grain weight and grain yield. The cowpea cultivars sown in December produced the lowest numbers of pods per plant and grains per pod, resulting in the lowest grain yields. The cultivar BRS-Tumucumaque had the highest grain yield in the January sowing. The highest grain yields were found in the February sowing, especially when the cultivars BRS-Itaim (3,439 kg ha-1), BRS-Novaera (3,435 kg ha-1), BRS-Guariba (3,168 kg ha-1) and BRS-Potengi (3,107 kg ha-1) was used. | RESUMO O objetivo do trabalho foi avaliar o desempenho agronômico de cultivares de feijão-caupi em função de épocas de semeadura no cerrado de Uberaba, MG. O experimento foi conduzido em Uberaba -MG, no delineamento de blocos casualizados, em arranjo fatorial 6 x 3, correspondendo a seis cultivares de feijão-caupi (BRS Itaim, BRS Guariba, BRS Potengi, BRS Cauamé, BRS Novaera e BRS Tumucumaque) e três épocas de semeadura (14/dez/2012 - E1, 14/jan/2013 - E2 e 14/fev/2013 - E3), com quatro repetições. Verificou-se interação cultivares x épocas de semeadura para o número de dias para o florescimento pleno, dias para a maturação das vagens, número de trifólios, altura de inserção da primeira vagem, comprimento de vagens, número de vagem por planta, população final de plantas, massa de 100 grãos e produtividade de grãos. Quando semeadas em dezembro, as cultivares de feijão- caupi produziram menor número de vagens por planta e de grãos por vagem, resultando em inferior produtividade de grãos. A cultivar BRS Tumucumaque apresentou maior produtividade de grãos quando semeada em janeiro. Produtividades de grãos superiores são obtidas na semeadura de fevereiro, sobressaindo-se as cultivares BRS Itaim, BRS Novaera, BRS Guariba e BRS Potengi, com 3.439, 3.435, 3.168 e 3.107 kg ha-1, respectivamente.

The objective of this work was to assess the agronomic performance of cowpea cultivars depending on sowing seasons in the Cerrado biome. Thus, an experiment was conducted in Uberaba, State of Minas Gerais, Brazil, in a complete randomized block design, in a 6x3 factorial arrangement, using six cowpea cultivars ( BRS - Itaim , BRS - Guariba , BRS - Potengi, BRS - Cauamé , BRS - Novaera and BRS - Tumucumaque ) and three sowing seasons (Dec 14, 2012; Jan 14, 2013; and Feb 14, 2013), with four replications. The interaction between the cultivars and sowing seasons was assessed regarding the number of days for full flowering, number of days for pod maturation, number of trifoliate leaves, height of the first pod - bearing node, pod length, number of pods per plant, final plant population, 100 - grain weight and grain yield. The cowpea cultivars sown in December produced the lowest numbers of pods per plant and grains per pod, resulting in the lowest grain yields. The cultivar BRS - Tumucumaque had the highest grain yield in the January sowing. The highest grain yields were found in the February sowing, especially when the cultivars BRS - Itaim (3,439 kg ha - 1 ), BRS - Novaera (3,435 kg ha - 1 ), BRS - Guariba (3,168 kg ha - 1 ) and BRS - Potengi (3,107 kg ha - 1 ) was used.

ABSTRACT This study aimed to evaluate combinations of cowpea-vegetable cultivars with carrot cultivars in a strip-intercropping system fertilized with roostertree. The work was conducted at the Experimental Farm "Rafael Fernandes" of the Universidade Federal Rural do Semi-Árido (UFERSA) during September 2013 to March 2014. The experimental design was a randomized complete block with four replications and treatments arranged in a factorial 4 x 2 scheme, resulting from the combination of four cowpea -vegetable cultivars (BRS Tumucumaque, BRS Cauamé, BRS Guariba and BRS Itaim) with two carrot cultivars (Brasilia and Alvorada). The characteristics evaluated in cowpea-vegetables were: number of green pods per area, productivity and dry weight of green pods, number of grains per pod, productivity of grains, weight of 100 grains, and dry weight of green grains. In the carrot cultivars, we evaluated total, commercial, and classified productivity of roots. The cultivar combinations were evaluated in terms of land equivalent ratio, productive efficiency index, score of the canonical variable, as well as indicators of gross and net income, rate of return, profit margin, and modified monetary advantage. The intercropping system using the cultivars BRS Guariba (cowpea) and Alvorada (carrot) achieved highest agronomic/biological efficiency. Highest economic efficiency was achieved with the combination BRS Tumucumaque (cowpea) and Brasilia (carrot). | RESUMO Este estudo teve como objetivo avaliar combinações de cultivares de caupi-horaliça com cultivares de cenoura em sistema consorciado em faixas adubadas com flor-de-seda. O trabalho foi conduzido na Fazenda Experimental “Rafael Fernandes” da Universidade Federal Rural do Semi-Árido (UFERSA), durante o período de setembro de 2013 a março de 2014. O delineamento experimental utilizado foi o de blocos completos casualizados com 4 repetições e os tratamentos arranjados em esquema fatorial 4 x 2, resultante da combinação de quatro cultivares de caupi (BRS Tumucumaque, BRS Cauamé, BRS Guariba e BRS Itaim) com duas cultivares de cenoura (Brasília e Alvorada). As características avaliadas no caupi-hortaliça foram: número de vagens verdes por área, produtividade e peso seco de vagens verdes, número de grãos por vagem, produtividade de grãos, peso de 100 grãos e peso seco de grãos verdes. Nas cultivares de cenoura foram avaliadas: as produtividades total, comercial e classificada de raízes. As combinações de cultivares foram avaliadas pelo índice de uso eficiente da terra, índice de eficiência produtiva, escore da variável canônica e pelos indicadores rendas bruta e líquida, taxa de retorno, índice de lucratividade e vantagem monetária corrigida. O sistema de consórcio utilizando as cultivares de caupi BRS Guariba e a de cenoura Alvorada obteve maior eficiência agronômica/biológica. A maior eficiência econômica foi obtida com a combinação de caupi BRS Tumucumaque e cenoura Brasília.

This study aimed to evaluate combinations of cowpea-vegetable cultivars with carrot cultivars in a strip-intercropping system fertilized with roostertree. The work was conducted at the Experimental Farm "Rafael Fernandes" of the Universidade Federal Rural do Semi-Árido (UFERSA) during September 2013 to March 2014. The experimental design was a randomized complete block with four replications and treatments arranged in a factorial 4 x 2 scheme, resulting from the combination of four cowpea -vegetable cultivars (BRS Tumucumaque, BRS Cauamé, BRS Guariba and BRS Itaim) with two carrot cultivars (Brasilia and Alvorada). The characteristics evaluated in cowpea-vegetables were: number of green pods per area, productivity and dry weight of green pods, number of grains per pod, productivity of grains, weight of 100 grains, and dry weight of green grains. In the carrot cultivars, we evaluated total, commercial, and classified productivity of roots. The cultivar combinations were evaluated in terms of land equivalent ratio, productive efficiency index, score of the canonical variable, as well as indicators of gross and net income, rate of return, profit margin, and modified monetary advantage. The intercropping system using the cultivars BRS Guariba (cowpea) and Alvorada (carrot) achieved highest agronomic/biological efficiency. Highest economic efficiency was achieved with the combination BRS Tumucumaque (cowpea) and Brasilia (carrot).

ABSTRACT The objective of this study was to evaluate the symbiotic efficiency of three novel nitrogen-fixing bacterial strains with cowpea cv. BRS Guariba as forage. Two experiments were carried out in the field in Balsas and São Raimundo das Mangabeiras, MA, in a randomized block design with seven treatments and four replications: three novel strains efficient in symbiotic nitrogen fixation with cowpea (UFLA 3 -153, UFLA 3-154 and UFLA 3-164), two strains already approved as inoculants by MAPA (UFLA 3-84/SEMIA 6461 and INPA 3-11B/SEMIA 6462), and two controls without inoculation, with and without mineral N. Symbiotic efficiency of strains was determined by the number of nodules, nodules dry matter, shoot dry matter, relative efficiency, crude protein content and shoot N content. Strains UFLA 3-154 and UFLA 3-164 were the most efficient in Balsas, whereas UFLA 3-153 and UFLA 3-164 were the most efficient in São Raimundo das Mangabeiras. Strains UFLA 3-153, UFLA 3-154 and UFLA 3-164 were more efficient in symbiotic nitrogen fixation with cowpea than the strains already approved as inoculants UFLA 3-84 and INPA 3-11B in the climatic and edaphic conditions of southern Maranhão. UFLA 3-164 is the most efficient strain in this region. | RESUMO O objetivo deste trabalho foi avaliar a eficiência simbiótica de três novas estirpes de bactérias fixadoras de N2 em feijão-caupi cv. BRS Guariba como forrageira. Foram conduzidos dois experimentos em campo, em Balsas e São Raimundo das Mangabeiras, MA, em delineamento em blocos casualizados com sete tratamentos e quatro repetições, sendo: três novas estirpes eficientes em feijão-caupi (UFLA 3-153, UFLA 3-154 e UFLA 3-164), duas estirpes já aprovadas como inoculantes pelo MAPA (UFLA 3-84/SEMIA 6461 e INPA 3-11B/SEMIA 6462) e dois controles sem inoculação, com e sem N mineral. A eficiência simbiótica das estirpes foi determinada pelo número e massa seca de nódulos, produção de matéria seca da parte aérea, eficiência relativa, teor e acúmulo de proteína bruta e nitrogênio na parte aérea. As estirpes UFLA 03 -154 e UFLA 3-164 destacaram-se na eficiência simbiótica de N2 em Balsas e a UFLA 3-153 e UFLA 3-164 em São Raimundo das Mangabeiras. As estirpes UFLA 3-153, UFLA 3-154 e UFLA 3-164 são mais eficientes em fixar nitrogênio do que as estirpes aprovadas como inoculantes UFLA 3-84 e INPA 3-11B nas condições edafoclimáticas do sul do Maranhão. A UFLA 3-164 é a estirpe mais eficiente em fixar nitrogênio na região estudada.

The objective of this study was to evaluate the symbiotic efficiency of three novel nitrogen-fixing bacterial strains with cowpea cv. BRS Guariba as forage. Two experiments were carried out in the field in Balsas and São Raimundo das Mangabeiras, MA, in a randomized block design with seven treatments and four replications: three novel strains efficient in symbiotic nitrogen fixation with cowpea (UFLA 3-153, UFLA 3-154 and UFLA 3-164), two strains already approved as inoculants by MAPA (UFLA 3-84/SEMIA 6461 and INPA 3-11B/SEMIA 6462), and two controls without inoculation, with and without mineral N. Symbiotic efficiency of strains was determined by the number of nodules, nodules dry matter, shoot dry matter, relative efficiency, crude protein content and shoot N content. Strains UFLA 3-154 and UFLA 3-164 were the most efficient in Balsas, whereas UFLA 3-153 and UFLA 3-164 were the most efficient in São Raimundo das Mangabeiras. Strains UFLA 3-153, UFLA 3-154 and UFLA 3-164 were more efficient in symbiotic nitrogen fixation with cowpea than the strains already approved as inoculants UFLA 3-84 and INPA 3-11B in the climatic and edaphic conditions of southern Maranhão. UFLA 3-164 is the most efficient strain in this region.