ABSTRACT In the present study, we evaluated the influence of agroforestry systems and traditional agriculture on the physical attributes and biologicals of soil, using as reference a native forest area in Paraty, RJ. Levels of total soil organic carbon, as well as oxidizable fractions and aggregate stability, were analyzed, in addition to the activity and carbon and nitrogen content in the soil microbial biomass, in the 0-5 cm layer, in two distinct seasons (dry and rainy seasons). The agroforestry systems and traditional agriculture maintain high levels of total organic carbon and its storage in more stable fractions. These systems provide the same conditions as those of the forest area for the aggregation of the soil. The microbial biomass was more responsive to variations in management and seasonality. The deployment of agroforestry systems contributes to the formation of a more diversified agricultural matrix, promoting improvements in the soil quality and connection with the remaining adjacent forest. | RESUMO Esse estudo avaliou a influência dos sistemas agroflorestais e da agricultura tradicional sobre os atributos físicos e biológicos do solo, utilizando como referência uma área de floresta nativa em Paraty, RJ. Foram analisados os teores do carbono orgânico total do solo e suas frações oxidáveis, a estabilidade dos agregados, além da atividade e os teores de carbono e nitrogênio da biomassa microbiana do solo, na camada de 0-5 cm, em duas épocas (seca e chuvosa) distintas. Os sistemas agroflorestais e a agricultura tradicional mantêm níveis elevados de carbono orgânico total e seu armazenamento em frações mais estáveis. Quando comparados à área de Floresta, esses sistemas proporcionam as mesmas condições para a agregação do solo. A biomassa microbiana foi mais responsiva as variações de manejo e sazonalidade. A implantação de sistemas agroflorestais contribui para a formação de uma matriz agrícola mais diversificada, promovendo melhorias na qualidade do solo e conexão com os remanescentes florestais próximos.

In the present study, we evaluated the influence of agroforestry systems and traditional agriculture on the physical attributes and biologicals of soil, using as reference a native forest area in Paraty, RJ. Levels of total soil organic carbon, as well as oxidizable fractions and aggregate stability, were analyzed, in addition to the activity and carbon and nitrogen content in the soil microbial biomass, in the 0-5 cm layer, in two distinct seasons (dry and rainy seasons). The agroforestry systems and traditional agriculture maintain high levels of total organic carbon and its storage in more stable fractions. These systems provide the same conditions as those of the forest area for the aggregation of the soil. The microbial biomass was more responsive to variations in management and seasonality. The deployment of agroforestry systems contributes to the formation of a more diversified agricultural matrix, promoting improvements in the soil quality and connection with the remaining adjacent forest.

ABSTRACT Biochar is a solid material formed during biomass thermochemical decomposition processes. This organic compound has particular properties that may cause effects on soils depending on its feedstock and processing conditions. Thus, the characteristics and purpose of use of this material must be recognized prior to its use. Two types of biochar, derived from different wood sources, were compared, one from caatinga biome species and another from cashew trees. Two species from caatinga biome were used, jurema-preta (Mimosa tenuiflora Willd. Poir.), and marmeleiro (Croton sonderianus Müll. Arg.). This study aimed to identify the best biochar material regionally available to increase water-holding capacity in the soil, based on laboratory tests and microstructural porosity evaluation. Biochar from Caatinga wood demonstrated an improved water-holding capacity if compared to cashew wood biochar. The particle diameters of 2 and 4 mm showed the highest levels, which were 2,268 g.g-1 for caatinga wood and 0.574 g.g-1 for cashew wood biochars, respectively. While the smaller quantities of macropores and a larger number of micropores (smaller radius) could explain the higher water-holding capacity for biochar from caatinga wood, the thick lignified cell walls of biochar from cashew wood support the idea of a hydrophobic effect contributing to water lower holding capacity. | RESUMO Biocarvão é o material sólido formado durante a decomposição termoquímica da biomassa. Suas propriedades e efeitos no solo variam amplamente com o material de origem e condições de precessamento. Desta forma, é reconhecida a importância de sua caracterização e desempenho para o que se propõe, antes do uso. Foram comparados dois tipos de biochar, de acordo com o material de origem, espécies do bioma Caatinga, Jurema-Preta (Mimosa tenuiflora (Willd.) Poir. associada com Marmeleiro (Croton sonderianus Müll.) Arg. e lenha de cajueiro (Annacardium occidentale L.). O objetivo deste estudo foi identificar biocarvão com melhor desempenho de promover o aumento da capacidade de retenção de água no solo, com base em evidências de laboratório e avaliação de porosidade microestructural. O biocarvão oriundo das espécies da Caatinga demonstrou maior capacidade de retenção de água quando comparado com o biocarvão de lenha de cajueiro, para todos os diâmetros avaliados. Com relação ao tamanho de partículas, níveis maiores de retenção de água foram observados aos 2 mm e 4 mm, 2,268 g g-1 para o biocarvão de madeira das espécies da Caatinga e 0,574 g g-1 para o biocarvão de madeira de cajueiro, respectivamente. Menores quantidades de macroporos e maior número de microporos (raio menor) foram observados no biocarvão de madeira das espécies da Caatinga, provavelmente relacionado à mais alta capacidade de retenção de água, enquanto densamente lignificadas, as paredes celulares de madeira de cajueiro, sustenta a ideia de que um efeito hidrofóbico pode contribuir para sua menor capacidade de retenção hídrica.

Biochar is a solid material formed during biomass thermochemical decomposition processes. This organic compound has particular properties that may cause effects on soils depending on its feedstock and processing conditions. Thus, the characteristics and purpose of use of this material must be recognized prior to its use. Two types of biochar, derived from different wood sources, were compared, one from caatinga biome species and another from cashew trees. Two species from caatinga biome were used, jurema-preta (Mimosa tenuiflora Willd. Poir.), and marmeleiro (Croton sonderianus Müll. Arg.). This study aimed to identify the best biochar material regionally available to increase water-holding capacity in the soil, based on laboratory tests and microstructural porosity evaluation. Biochar from Caatinga wood demonstrated an improved water-holding capacity if compared to cashew wood biochar. The particle diameters of 2 and 4 mm showed the highest levels, which were 2,268 g.g-1 for caatinga wood and 0.574 g.g-1 for cashew wood biochars, respectively. While the smaller quantities of macropores and a larger number of micropores (smaller radius) could explain the higher water-holding capacity for biochar from caatinga wood, the thick lignified cell walls of biochar from cashew wood support the idea of a hydrophobic effect contributing to water lower holding capacity.

ABSTRACT Drip irrigation with diluted sanitary landfill leachate favors the development of grasses on the landfill surface, however, the clogging of emitters of the irrigation systems is the major obstacle for this practice. The objective of this study was to select empirical models of the Christiansen's uniformity coefficient, distribution uniformity coefficient, and statistical uniformity coefficient of drip irrigation sets applying sanitary landfill leachate diluted in water as a function of time of operation, and quality of the effluent. An experiment was conducted in a completely randomized experimental design with three replicates, using a split-split plot arrangement, with operating pressures (70, 140, 210, and 280 kPa) in the plots, types of drippers (G1, 1.65 L h-1; G2, 2.0 L h-1; and G3, 4.0 L h-1) in the subplots, and operating time of the drip irrigation sets (0, 20, 40, 60, 80, 100, 120, 140, and 160 hours) in the sub-subplots. Data regarding hydraulic performance and effluent quality were acquired every 20 hours during 160 hours of operation and subjected to simple and multiple regression analyses. The G3 dripper operating at pressures of 70 and 140 kPa were the combinations that best attenuated biofilm clogging. The linear regression and square root were the models that best represented the reduction in the uniformity of the effluent application as a function of the operating time of the drip irrigation sets. The linear correlations denoted that calcium contents and total coliform population rates were the characteristics of the sanitary landfill leachate that most affected the drip clogging process. | RESUMO A aplicação localizada de percolado diluído permite o desenvolvimento de gramíneas na superfície das células dos aterros sanitários, entretanto a obstrução dos emissores dos sistemas de irrigação consiste no maior obstáculo desta atividade. Objetivou-se com a realização do presente trabalho selecionar modelos empíricos do coeficiente de uniformidade de Christiansen, coeficiente de uniformidade de distribuição e coeficiente de uniformidade estatístico de unidades gotejadoras aplicando percolado diluído em função do tempo de operação e da qualidade do efluente. Para isso, montou-se um experimento em parcelas subsubdivididas. Nas parcelas tem-se as pressões de serviço (70, 140, 210 e 280 kPa), nas subparcelas os tipos de gotejadores (G1 - 1,65 L h-1; G2 - 2,0 L h-1; e 4,0 L h-1) e nas subsubparcelas os tempos de operação das unidades gotejadoras (0, 20, 40, 60, 80, 100, 120, 140 e 160 h). O delineamento experimental foi o inteiramente casualizado com três repetições. Os dados dos indicadores de desempenho hidráulico e da qualidade do efluente foram obtidos a cada 20 h, até completar 160 h de funcionamento, sendo posteriormente submetidos às análises de regressão simples e múltipla. Os resultados indicaram que o gotejador G3 operando nas pressões de serviço 70 e 140 kPa foram as combinações que melhor atenuaram o entupimento com biofilme. Os modelos de regressão linear e raiz quadrada foram os que melhor representaram a redução da uniformidade de aplicação do efluente em função do tempo de operação nas unidades gotejadoras. As relações lineares revelaram que os teores de cálcio e os níveis populacionais de coliformes totais foram as características do percolado de aterro diluído que mais interferiram no processo de obstrução dos gotejadores.

Drip irrigation with diluted sanitary landfill leachate favors the development of grasses on the landfill surface, however, the clogging of emitters of the irrigation systems is the major obstacle for this practice. The objective of this study was to select empirical models of the Christiansen's uniformity coefficient, distribution uniformity coefficient, and statistical uniformity coefficient of drip irrigation sets applying sanitary landfill leachate diluted in water as a function of time of operation, and quality of the effluent. An experiment was conducted in a completely randomized experimental design with three replicates, using a split-split plot arrangement, with operating pressures (70, 140, 210, and 280 kPa) in the plots, types of drippers (G1, 1.65 L h-1; G2, 2.0 L h-1; and G3, 4.0 L h-1) in the subplots, and operating time of the drip irrigation sets (0, 20, 40, 60, 80, 100, 120, 140, and 160 hours) in the sub-subplots. Data regarding hydraulic performance and effluent quality were acquired every 20 hours during 160 hours of operation and subjected to simple and multiple regression analyses. The G3 dripper operating at pressures of 70 and 140 kPa were the combinations that best attenuated biofilm clogging. The linear regression and square root were the models that best represented the reduction in the uniformity of the effluent application as a function of the operating time of the drip irrigation sets. The linear correlations denoted that calcium contents and total coliform population rates were the characteristics of the sanitary landfill leachate that most affected the drip clogging process.

RESUMO O semiárido representa cerca de 70% da superfície do Nordeste brasileiro e o recurso forrageiro de maior expressão é a Caatinga, cobrindo aproximadamente 54% desta região. Porém, cerca de 40% dessa vegetação encontra-se em sucessão secundária e as áreas em processo de degradação de intensidade baixa a severa, já somam mais de 20 milhões de hectares, reflexo do uso intenso da terra, dentre elas o superpastejo. Objetivou-se avaliar a influência de diferentes doses de fósforo (0, 50 e 100 kg de P2O5 ha-1 ano), em área de Caatinga manipulada, sem pastejo por quatro anos, sobre a dinâmica da vegetação herbácea em diferentes épocas do ano. O experimento foi conduzido na Unidade Acadêmica de Serra Talhada-UFRPE, durante os anos de 2015 a 2016. Foi utilizado delineamento em blocos casualizados, com três blocos e quatro repetições por bloco. A adubação fosfatada em áreas de exclusão ao pastejo promoveu aumento da massa de forragem do estrato herbáceo da Caatinga enriquecida, em todas as épocas de avaliação, com destaque para a época seca de 2016, que obeteve valores acima da média de 7950 kg de MS ha-1. Promoveu aumento da participação do capim-buffel na composição florística, elevando sua participação na área em torno de 74% para a dose máxima de fósforo utilizada. Neste sentido, a adubação fosfatada até 100 kg de P2O5 ha-1 ano, juntamente com a exclusão ao pastejo, pode ajudar na recuperação da Caatinga enriquecida com capim-buffel e otimizar a sua utilização diminuindo a formação de novas áreas de pastejo na Caatinga. | ABSTRACT The semi-arid region accounts for about 70% of the surface area of the Brazilian northeast, and the most important forage resource is the Caatinga, covering approximately 54% of this region. However, about 40% of this vegetation is in secondary succession. The areas in the process of degradation range from low to severe intensity, and total more than 20 million hectares, reflecting the intense use of the land, such as the overgrazing. The objective of this study was to evaluate the influence of different doses of phosphorus (0, 50 and 100 kg P2O5 ha-1 year-1) on the dynamics of herbaceous vegetation at different times of the year, in a Caatinga area manipulated without grazing for four years. The experiment was conducted at the Serra Talhada-UFRPE Academic Unit during the years 2015 and 2016. We used a randomised block design with three blocks and four replicates per block. Phosphate fertilisation in grazing exclusion areas promoted an increase in forage mass of the enriched Caatinga herbaceous stratum at all evaluation times, especially in the dry season of 2016, which showed values above the average of 7950 kg DM ha-1. In addition, it promoted an increase in the participation of buffelgrass in the floristic composition, increasing its involvement in the area to around 74% at the maximum dose of phosphorus used. Thus, phosphate fertilisation at up to 100 kg of P2O5 ha-1 year-1, together with grazing exclusion, can help to recover the Caatinga enriched with buffelgrass and optimise its use by reducing the formation of new grazing areas in the Caatinga.

The semi-arid region accounts for about 70% of the surface area of the Brazilian northeast, and the most important forage resource is the Caatinga, covering approximately 54% of this region. However, about 40% of this vegetation is in secondary succession. The areas in the process of degradation range from low to severe intensity, and total more than 20 million hectares, reflecting the intense use of the land, such as the overgrazing. The objective of this study was to evaluate the influence of different doses of phosphorus (0, 50 and 100 kg P2O5 ha-1 year-1) on the dynamics of herbaceous vegetation at different times of the year, in a Caatinga area manipulated without grazing for four years. The experiment was conducted at the Serra Talhada-UFRPE Academic Unit during the years 2015 and 2016. We used a randomised block design with three blocks and four replicates per block. Phosphate fertilisation in grazing exclusion areas promoted an increase in forage mass of the enriched Caatinga herbaceous stratum at all evaluation times, especially in the dry season of 2016, which showed values above the average of 7950 kg DM ha-1. In addition, it promoted an increase in the participation of buffelgrass in the floristic composition, increasing its involvement in the area to around 74% at the maximum dose of phosphorus used. Thus, phosphate fertilisation at up to 100 kg of P2O5 ha-1 year-1, together with grazing exclusion, can help to recover the Caatinga enriched with buffelgrass and optimise its use by reducing the formation of new grazing areas in the Caatinga.

RESUMO O feijão comum (Phaseolus vulgaris L.) é uma das fontes proteicas mais importantes em todo o mundo. Todavia, o ataque de bruquídeos inviabiliza o armazenamento do produto após a colheita. O objetivo deste trabalho foi determinar a taxa de emergência de Zabrotes subfasciatus (Coleoptera: Chrysomelidae) em quatro variedades de feijão P. vulgaris (Carioca Pitoco, Enxofre, Gorgutuba Vermelho e Rosinha) cultivadas na Amazônia sul-ocidental (Acre, Brasil). Os grãos de cada variedade foram infestados com 50 adultos não-sexados e após 13 dias do início dos bioensaios, os insetos foram removidos. A progênie adulta obtida nas variedades foi contabilizada e removida em dias alternados, a partir da primeira emergência, até o final do período de emergência (n° de insetos/frasco). A soma da emergência de insetos foi acumulada a partir da emergência inicial e resultou na soma da emergência acumulada (SEa, % dia), calculada por SEa = ∑SEd. Foram constadas diferenças nas taxas de emergência de Z. subfasciatus entre as variedades de feijão, sendo que a variedade Gorgutuba Vermelho apresentou menor taxa de emergência. Embora esta variedade de feijão tenha apresentado menor emergência de adultos, o tempo de desenvolvimento dos insetos não se estendeu nesta variedade, em comparação com as outras variedades. Em geral, a variedade Gorgutuba Vermelho apresentou indícios de fontes resistência a Z. subfasciatus. | ABSTRACT Common beans (Phaseolus vulgaris L.) are one of the most important protein sources worldwide. However, infestation by bruchids compromises the storage of these beans after harvest. The objective of this study was to determine the emergence rate of Zabrotes subfasciatus (Coleoptera: Chrysomelidae) in four P. vulgaris varieties (Carioca Pitoco, Enxofre, Gorgutuba Vermelho, and Rosinha) cultivated in the southwestern Amazon (State of Acre, Brazil). The grains from each variety were infested with 50 non-sexed adult Z. subfasciatus, and the insects were collected 13 days after initiating the bioassays. The adult progeny was collected from each plant variety on alternate days from the beginning to the end of the emergence period, and they were counted (number of insects/jar). The sum of emerged insects per day (SEd) was determined from the beginning of the emergence period, from which the accumulated emergence was calculated (SEa= ΣSEd, % day). There were differences in the emergence rates of Z. subfasciatus among the bean varieties, with the rates being lower in the Gorgutuba Vermelho variety. Although this bean variety had the lowest peak of adult insect emergence, the period of insect development was not of increased length in this variety compared to the other varieties. In general, the Gorgutuba Vermelho variety appears to be resistant to Z. subfasciatus.

Common beans (Phaseolus vulgaris L.) are one of the most important protein sources worldwide. However, infestation by bruchids compromises the storage of these beans after harvest. The objective of this study was to determine the emergence rate of Zabrotes subfasciatus (Coleoptera: Chrysomelidae) in four P. vulgaris varieties (Carioca Pitoco, Enxofre, Gorgutuba Vermelho, and Rosinha) cultivated in the southwestern Amazon (State of Acre, Brazil). The grains from each variety were infested with 50 non-sexed adult Z. subfasciatus, and the insects were collected 13 days after initiating the bioassays. The adult progeny was collected from each plant variety on alternate days from the beginning to the end of the emergence period, and they were counted (number of insects/jar). The sum of emerged insects per day (SEd) was determined from the beginning of the emergence period, from which the accumulated emergence was calculated (SEa= ΣSEd, % day). There were differences in the emergence rates of Z. subfasciatus among the bean varieties, with the rates being lower in the Gorgutuba Vermelho variety. Although this bean variety had the lowest peak of adult insect emergence, the period of insect development was not of increased length in this variety compared to the other varieties. In general, the Gorgutuba Vermelho variety appears to be resistant to Z. subfasciatus.

RESUMO O objetivo deste trabalho foi avaliar a eficiência, fitotoxicidade e efeito residual do extrato aquoso de folhas de Prosopis juliflora (Sw.) DC. (Fabaceae) para Tetranychus bastosi Tuttle, Baker & Sales (Acari: Tetranychidae) em Jatropha curcas L. (Euphorbiaceae). Para a avaliação da eficiência de controle plantas de pinhão-manso foram infestadas com 30 fêmeas adultas do ácaro e após 12 dias, foram pulverizadas com as concentrações letais (m/v) do extrato (CL50 = 53,45% ou CL90 = 85,35%) e com água destilada (testemunha), correspondendo aos tratamentos. Decorridas 24, 48, 72 e 96 e 120 horas após a aplicação do extrato, duas folhas do terço inferior, médio e superior das plantas foram amostradas e contabilizou-se os ácaros vivos por tratamento. A avaliação do efeito residual foi feita três, 24, 48, 96, 192 e 288 horas após a pulverização. Para avaliação do efeito fitotóxico do extrato foram atribuídas notas de acordo com a intensidade dos sintomas nas plantas. Constatou-se eficiência de controle por todo período avaliado, com média de 81,67% para a CL50 e 73,05% para CL90, sem diferença significativa entre os intervalos de avaliação. O extrato apresentou baixo efeito residual sobre T. bastosi, mas ao final de 12 dias a porcentagem média de redução da oviposição do ácaro foi de 49,21% e 68,86% para a CL50 e CL90, respectivamente. As plantas não apresentaram fitotoxicidade. O extrato de algarobeira apresenta potencial para o controle alternativo de T. bastosi em pinhão-manso em razão de sua eficiência sobre a mortalidade deste ácaro, redução da oviposição de fêmeas e ausência de efeito fitotóxico nas plantas. | ABSTRACT The objective of this study was to evaluate the efficiency, phytotoxicity and residual effect of the aqueous extract of leaves of Prosopis juliflora (Sw.) DC (Fabaceae) for Tetranychus bastosi Tuttle, Baker & Sales (Acari: Tetranychidae) on Jatropha curcas L. (Euphorbiaceae). For the evaluation of the control efficiency, physic nut plants were infested with 30 adult mite females and after 12 days were sprayed with the lethal concentrations (m/v) of the extract (LC50 = 53.45% or CL90 = 85.35%) and with distilled water (control), which corresponded to the treatments. After 24, 48, 72, 96 and 120 hours after application of the extract, two leaves of the lower, middle and upper third of the plants were sampled and the live mites were counted per treatment. The evaluation of the residual effect was done three, 24, 48, 96, 192 and 288 hours after spraying. To evaluate the phytotoxic effect of the extract, scores were given according to the intensity of the symptoms in the plants. Control efficiency was verified throughout the evaluated period, with an average of 81.67% for LC50 and 73.05% for LC90, with no significant difference between the evaluation intervals. The extract had a low residual effect on T. bastosi, but at the end of 12 days the average percentage of oviposition reduction of mite was 49.21% and 68.86% for LC50 and LC90, respectively. The plants did not present phytotoxicity. P. juliflora extract presents potential for the alternative control of T. bastosi in physic nut due to its efficiency on the mortality of this mite, oviposition reduction of females and absence of phytotoxic effect in the plants.

The objective of this study was to evaluate the efficiency, phytotoxicity and residual effect of the aqueous extract of leaves of Prosopis juliflora (Sw.) DC (Fabaceae) for Tetranychus bastosi Tuttle, Baker & Sales (Acari: Tetranychidae) on Jatropha curcas L. (Euphorbiaceae). For the evaluation of the control efficiency, physic nut plants were infested with 30 adult mite females and after 12 days were sprayed with the lethal concentrations (m/v) of the extract (LC50 = 53.45% or CL90 = 85.35%) and with distilled water (control), which corresponded to the treatments. After 24, 48, 72, 96 and 120 hours after application of the extract, two leaves of the lower, middle and upper third of the plants were sampled and the live mites were counted per treatment. The evaluation of the residual effect was done three, 24, 48, 96, 192 and 288 hours after spraying. To evaluate the phytotoxic effect of the extract, scores were given according to the intensity of the symptoms in the plants. Control efficiency was verified throughout the evaluated period, with an average of 81.67% for LC50 and 73.05% for LC90, with no significant difference between the evaluation intervals. The extract had a low residual effect on T. bastosi, but at the end of 12 days the average percentage of oviposition reduction of mite was 49.21% and 68.86% for LC50 and LC90, respectively. The plants did not present phytotoxicity. P. juliflora extract presents potential for the alternative control of T. bastosi in physic nut due to its efficiency on the mortality of this mite, oviposition reduction of females and absence of phytotoxic effect in the plants.

The use of stimulants in the establishment of arbuscular mycorrhizal fungi has great potential in contributing to P uptake by plants. This study aimed to evaluate the effect of isoflavonoid formononetin as mycorrhization stimulant on soybean associated with phosphate fertilizer in Oxisols with intermediate (OPi) and low (OPl) phosphorus availability, in the Cerrado region of Piauí. The experiment in each soil consisted of randomized blocks design in a 4×4 factorial scheme, with four replications. The treatments comprised of four phosphorus doses (0, 26.66, 40 and 80 kg ha-1 P2O5), and four isoflavonoid formononetin doses (0, 0.5, 0.9 and 1.8 g kg-1 soybean seeds). The variables evaluated were soybean growth, yield, nodulation and mycorrhizal colonization rate. With the exception of mycorrhizal colonization rate in OPi, plant height and number of pods per plant in OPl, the other variables were not affected by the application of isoflavonoid formononetin, in both soils. Yield linearly increased with increase in the phosphorus doses in OPl, and presented agronomic efficiency of ~15 kg ha-1 grain for each kg ha-1 P2O5 applied to the soil.

RESUMO O uso de estimulantes para o estabelecimento de fungos micorrízicos arbusculares tem grande potencial em contribuir para a absorção de P pelas plantas. Objetivou-se avaliar a eficácia do isoflavonóide formononetina como estimulante da micorrização na cultura da soja, associada a adubação fosfatada, em dois Latossolos com teores de fósforo disponível médio (LPm) e baixo (LPb) no Cerrado piauiense. O delineamento experimental em cada solo foi em blocos casualizados no esquema fatorial 4×4, com quatro repetições. Os tratamentos foram constituídos por quatro doses de fósforo (0; 26,66; 40 e 80 kg ha-1 de P2O5) e quatro doses do isoflavonóide formononetina (0; 0,5; 0,9 e 1,8 g kg-1 de semente de soja). As variáveis avaliadas foram, o crescimento, a produção, a nodulação e taxa de colonização micorrízica da soja. Com exceção da taxa de colonização micorrízica no LPm, altura e número de vagens por planta de soja no LPb, as demais variáveis, não foram influenciados pela aplicação do isoflavonóide formononetina, em ambos os solos. A produtividade cresceu linearmente ao incremento das doses de fósforo no LPb, apresentando uma eficiência agronômica de ~15 kg ha-1 de grãos para cada kg ha-1 de P2O5 aplicado no solo. | ABSTRACT The use of stimulants in the establishment of arbuscular mycorrhizal fungi has great potential in contributing to P uptake by plants. This study aimed to evaluate the effect of isoflavonoid formononetin as mycorrhization stimulant on soybean associated with phosphate fertilizer in Oxisols with intermediate (OPi) and low (OPl) phosphorus availability, in the Cerrado region of Piauí. The experiment in each soil consisted of randomized blocks design in a 4×4 factorial scheme, with four replications. The treatments comprised of four phosphorus doses (0, 26.66, 40 and 80 kg ha-1 P2O5), and four isoflavonoid formononetin doses (0, 0.5, 0.9 and 1.8 g kg-1 soybean seeds). The variables evaluated were soybean growth, yield, nodulation and mycorrhizal colonization rate. With the exception of mycorrhizal colonization rate in OPi, plant height and number of pods per plant in OPl, the other variables were not affected by the application of isoflavonoid formononetin, in both soils. Yield linearly increased with increase in the phosphorus doses in OPl, and presented agronomic efficiency of ~15 kg ha-1 grain for each kg ha-1 P2O5 applied to the soil.

This study evaluated the effects of feeding frequency and feeding rate on productive performance of hybrid surubims reared in cages with automatic feeding. Three feeding frequencies (6, 12 and 24 meals day-1), and two feeding rates (4% and 8% of body weight per day, BW day-1) were evaluated. Hybrid surubims (Pseudoplatystoma corruscans × Pseudoplatystoma fasciatum) with average weights of 24.20 ± 0.80 g were distributed in 18 cages of 1.0 m³ at a density of 60 fish m-3. Fish were fed commercial ration containing 40% crude protein, and feeding took place at night using automatic feeders. The study lasted 47 days. With a feeding rate of 4% BW day-1, the final weight (FW) of the surubims was higher when feed was supplied as 24 meals day-1 (66.92 g). However, using 8% BW day-1, the FW was greater with a feeding frequency of 12 meals day-1 (106.90 g). Regardless of feed frequency, the values of daily weight gain and standard length of surubims were higher with the feeding rate of 8% BW day-1. Therefore, the feeding rate of 8% BW day-1, provided in 12 meals day-1, provided better productive performance for hybrid surubims (Pseudoplatystoma corruscans × Pseudoplatystoma fasciatum) reared in cages.

RESUMO Este estudo avaliou os efeitos da frequência e taxa de alimentação sobre o desempenho produtivo de surubins híbridos criados em tanque rede. Três frequências (6, 12 e 24 refeições dia-1) e duas taxas de alimentação (4% e 8% do peso vivo por dia, PV dia-1) foram avaliadas. Híbridos de surubim (Pseudoplatystoma corruscans x Pseudoplatystoma fasciatum), com peso médio de 24,20 ± 0,80 g, foram distribuídos em 18 tanques rede de 1,0 m³ com densidade de 60 peixes m-³. Os peixes foram alimentados no período noturno por alimentadores automáticos, com ração comercial contendo 40% de proteína bruta. O estudo teve duração de 47 dias. Com a frequência de 4% PV dia-1, o peso final (PF) dos surubins foi maior com o fornecimento da ração em 24 refeições dia-1 (66,92 g). Entretanto, usando 8% PV dia-1 o PF foi maior com a frequência de 12 refeições dia-1 (106,90 g). Independente da frequência alimentar, os valores de ganho de peso diário e comprimento padrão dos surubins foram maiores com a taxa de alimentação de 8% PV dia-1. Assim, o fornecimento da ração com taxa alimentar de 8% PV dia-1, dividida em 12 refeições dia-1, proporcionou melhor desempenho produtivo para surubins híbridos (Pseudoplatystoma corruscans × Pseudoplatystoma fasciatum) criados em tanque rede. | ABSTRACT This study evaluated the effects of feeding frequency and feeding rate on productive performance of hybrid surubims reared in cages with automatic feeding. Three feeding frequencies (6, 12 and 24 meals day-1), and two feeding rates (4% and 8% of body weight per day, BW day-1) were evaluated. Hybrid surubims (Pseudoplatystoma corruscans × Pseudoplatystoma fasciatum) with average weights of 24.20 ± 0.80 g were distributed in 18 cages of 1.0 m³ at a density of 60 fish m-3. Fish were fed commercial ration containing 40% crude protein, and feeding took place at night using automatic feeders. The study lasted 47 days. With a feeding rate of 4% BW day-1, the final weight (FW) of the surubims was higher when feed was supplied as 24 meals day-1 (66.92 g). However, using 8% BW day-1, the FW was greater with a feeding frequency of 12 meals day-1 (106.90 g). Regardless of feed frequency, the values of daily weight gain and standard length of surubims were higher with the feeding rate of 8% BW day-1. Therefore, the feeding rate of 8% BW day-1, provided in 12 meals day-1, provided better productive performance for hybrid surubims (Pseudoplatystoma corruscans × Pseudoplatystoma fasciatum) reared in cages.

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 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.

Sweet corn is an important crop because of its seeds with high total sugar and low starch contents. As common corn, this group requires an adequate amount of nitrogen to reach high yields. However, the studies on nitrogen and sweet corn are performed for ear yield instead of seed yield. As seeds are the main propagation method for this species, we proposed to evaluate the effects of nitrogen rates as side-dressing at different plant stages of a sweet corn seed production. Sweet corn seeds (variety BR 400) were sown in Latosol (Oxisol), and a 3×2+1 factorial scheme was designed with three nitrogen rates (40, 80, and 120 kg ha-1) at two plant stages (V6 and R1) plus the control (no nitrogen side-dressing). The evaluated variables were seed yield, protein content, P and Zn contents, germination, and vigor rates. We concluded that nitrogen applied at a rate of 120 kg ha-1 at V6 increases seed yield and maintains unaltered the protein content in seeds of sweet corn (BR 400 variety). Neither germination nor seed vigor increases when nitrogen rates are increased or administered at different stages of plant development. We also noted a slight decrease in P content or an increase in Zn content of seeds at low nitrogen rates; however, they are insufficient to promote changes in the physiological potential of sweet corn seeds.

ABSTRACT Sweet corn is an important crop because of its seeds with high total sugar and low starch contents. As common corn, this group requires an adequate amount of nitrogen to reach high yields. However, the studies on nitrogen and sweet corn are performed for ear yield instead of seed yield. As seeds are the main propagation method for this species, we proposed to evaluate the effects of nitrogen rates as side-dressing at different plant stages of a sweet corn seed production. Sweet corn seeds (variety BR 400) were sown in Latosol (Oxisol), and a 3×2+1 factorial scheme was designed with three nitrogen rates (40, 80, and 120 kg ha-1) at two plant stages (V6 and R1) plus the control (no nitrogen side-dressing). The evaluated variables were seed yield, protein content, P and Zn contents, germination, and vigor rates. We concluded that nitrogen applied at a rate of 120 kg ha-1 at V6 increases seed yield and maintains unaltered the protein content in seeds of sweet corn (BR 400 variety). Neither germination nor seed vigor increases when nitrogen rates are increased or administered at different stages of plant development. We also noted a slight decrease in P content or an increase in Zn content of seeds at low nitrogen rates; however, they are insufficient to promote changes in the physiological potential of sweet corn seeds. | RESUMO O milho doce é uma cultura importante por causa do seu tipo de sementes com índice elevado dos açúcares totais e baixo índice do amido. Como o milho comum, este necessita de quantidade adequada de nitrogênio para atingir altas produtividades, no entanto, os estudos que envolvem nitrogênio e milho doce são realizados para o rendimento das espigas e não para a produção de sementes. Como a semente é o principal método de propagação dessa espécie, foi avaliado os efeitos das doses de nitrogênio em cobertura em diferentes estádios fenológicos para produção e potencial fisiológico de sementes de milho doce. As sementes de milho doce (variedade BR 400) foram semeadas em Latossolo e um esquema fatorial de tratamento 3 × 2 + 1 foi instalado com três doses de nitrogênio 40, 80 e 120 kg ha-1 e dois estádios fenológicos (V6 e R1) mais o controle (sem nitrogênio em cobertura). Foram avaliadas a produtividade de sementes, teores de proteína, P e Zn, germinação e vigor. Como conclusão, o nitrogênio fornecido em V6 a 120 kg ha-1 aumenta a produtividade de sementes e mantém os teores de proteína inalterados. A germinação da semente e o vigor não aumentam quando as taxas de nitrogênio são acrescidas ou fornecidas em diferentes estádios fenológicos. Diminuição ligeira do teor de P ou o aumento do teor de Zn nas sementes são observados a uma dose baixa de nitrogênio entretanto não suficientes para promover alterações no potencial fisiológico das sementes do milho doce.