ABSTRACT This study aimed to determine how crop residue placement and composition would affect soil water content and temperature during the dry season in the central region of Espírito Santo state, Brazil. A 19-week field study was conducted from April to August 2017. A 2 x 4 factorial study with four replications was implemented using a randomized complete block design. Factors were soil management [conventional tillage (CT) and no soil disturbance (ND)] and residue amendment [maize (Zea mays L.), sunn hemp (Crotalaria juncea L.), a maize-sunn hemp mixture, and a no amendment control]. Soil water content and temperature were measured weekly at predetermined soil depth intervals. Soil water content was higher in ND plots amended with surface residues than under all other treatments in the 0 to 0.05 m depth range. All residue amendments in this range were equally effective in conserving soil water. Surface residues reduced soil temperature by up to 8.4 °C relative to the control in ND plots. Incorporating residue amendments by CT cancelled all temperature-moderating benefits provided by surface residues. These results indicate that surface residues from cereals, legumes, or cereal/legume mixtures are equally effective in conserving soil water and moderating soil temperature during the dry season. Additional research is needed to determine how improved soil environmental conditions, generated by surface residues, would affect nutrient acquisition and crop performance.

ABSTRACT Due to the predictions of climate change, there is a need to identify forage plants that can keep their productivity and nutritive value under hydric stress. The objective of this study was to evaluate the biomass and chemical responses of three Desmanthus spp. accessions under two water deprivation regimens (7 and 21-day). The experimental design used was randomized blocks in a 3 × 2 factorial arrangement (access and water deprivation) with four replications. There were reductions in the biomasses of leaf and stem fractions of 64% and 51%, respectively. The 43F accession showed greater leaf (1.86 g.plant-1) and stem (1.97 g.plant-1) biomasses under a total water restriction of 21 days, compared to the 89F and AusT accessions. In accessions 43F and 89F, there were carbohydrate accumulations in the leaves of 28% and 51%, respectively, under the 21-day water restriction, while AusT decreased 38% within a 7-day interval. Water deprivation affected the chemical characteristics of the accessions. Free proline was similar among accessions and accumulated 463% more in the leaves of plants submitted to 21-day water deprivation (90.22 mg.kg-1) compared to those subjected to water deprivation for 7 days (16.03 mg.kg-1). Proline and total soluble carbohydrate accumulation in 43F and 89F were insufficient to regulate crude protein, C content, and C:N ratios. These results demonstrate the variability in drought tolerance among accessions. Accessions 43F and 89F were more susceptible to 21-day water deprivation, while AusT showed greater drought tolerance.

ABSTRACT Fusarium wilt, caused by soil-borne Fusarium oxysporum f. sp. tracheiphilum (Fot), can reduce cowpea bean yield. Considering that genetic control through resistant genotypes is pivotal for Fusarium wilt control, the aim of the present study was to identify cowpea genotypes that are resistant to Fot from the Germplasm Bank of the Pernambuco Agronomic Institute, Embrapa Middle North, and other producing areas in the North and Northeast regions of Brazil. The cultivar BR-17 Gurguéia was used as a susceptible control and MNC01-649F-2-1 was used as a resistant control. Two experiments were carried out in a completely randomized design in the greenhouse of the Department of Agronomy of the University Federal Rural of Pernambuco. Plants with the first pair of expanded leaves were inoculated with a conidial suspension (106 conidia/mL) using the conidia root-immersion methodology. Fusarium wilt severity in plants was assessed 21 d after inoculation, with the aid of a descriptive scale. In the first experiment, we evaluated the resistance of 38 cowpea genotypes, of which 19 (5 moderately resistant and 14 resistant) were selected for the second experiment. In the first experiment, four genotypes (Canapu PE, Miranda IPA 207, Esperança, and BRS Pujante) did not show any symptoms of Fusarium wilt. In the second, 15 genotypes showed high resistance to Fot, including Canapu PE and Miranda IPA 207, which again had no symptoms of Fusarium wilt. In conclusion, this study identified that the genotypes, Canapu PE, Miranda IPA 207, Esperança, and BRS Pujante have greater resistance to Fusarium wilt.

ABSTRACT Previous investigations showed that diverse varieties of melon may have different attractiveness for bees. Therefore, the objective of this study was to evaluate the composition, frequency and behavior of flower visitors of some melon (Cucumis melo) cultivars (Amarelo, Pele de Sapo, Cantaloupe, Gália) in different conditions (conventional and organic farming, dry and rainy seasons, with and without mulching and introduction or not of honey bee hives) in the main production poles in the Brazilian Northeast (Petrolina-PE/Juazeiro-BA, Pacajus-CE and Mossoro-RN). Observations and collections of flower visitors occurred from 5p.m. to 6p.m, in non-consecutive days. We recorded 12 species of insects, mostly bees. The most frequent was Apis mellifera (99.68%), but other species appeared sporadically (less than 0.5%): Xylocopa grisescens, Trigona spinipes, Plebeia sp., Melipona mandacaia, Frieseomelitta doedereleini, Halicitidae. Apis mellifera was present in all studied cultivars and sites. Xylocopa grisescens appeared in two poles, but not in Pacajus-CE, Amarelo cultivar. In addition, Trigona spinipes, although present in the three poles, was not recorded on Pele de Sapo. The Amarelo cultivar, under organic farming, without the use of mulching, and presence of honey bee hives, in the Petrolina-PE/Juazeiro-BA pole, in the dry season, was the combination of factors showing the largest number of Apis mellifera as the main visitor of melon flowers.

RESUMO O gênero Melocactus (cabeça-de-frade) possui 32 espécies no Brasil, das quais M. glaucescens e M. paucispinus estão ameaçadas de extinção. O objetivo deste trabalho foi analisar o efeito de diferentes concentrações de sais do meio Murashige e Skoog (MS, MS/2 e MS/4) e sacarose (15 g L-1 e 30 g L-1) na germinação de sementes e crescimento de plantas in vitro de M. glaucescens e a eficiência da esterilização do meio de cultura com hipoclorito de sódio (NaOCl) na germinação de sementes e crescimento de plantas in vitro de M. glaucescens ao utilizar sementes, M. glaucescens e M. paucispinus ao utilizar o segmento apical do cladódio. Para M. glaucescens a germinação final nas diferentes concentrações de MS e sacarose, variou de 53,5 a 68.1% e os melhores resultados para o crescimento in vitro foram observados nas menores concentrações de sais (MS/2 e MS/4) e de sacarose (15 g L-1) com valores de comprimento da parte aérea de 9,70 e 10,76 mm, respectivamente. Não houve diferença na germinação das sementes e crescimento das plantas em meio químico e autoclavado. Conclui-se que, o uso da esterilização química com NaOCl em baixas concentrações de sais (MS/2 e MS/4) e sacarose (15 g L-1) são as mais indicadas para produção de plantas ornamentais germinadas in vitro e /ou segmento apical do cladódio de M. glaucescens e M. paucispinus, o que representa uma redução de custo no cultivo in vitro dessas espécies. | ABSTRACT The genus Melocactus (“cabeça-de-frade”) comprises 32 species in Brazil, of which M. glaucescens and M. paucispinus are threatened with extinction. The present work evaluated the effects of different concentrations of Murashige & Skoog (MS, MS/2 and MS/4) culture medium and sucrose (15 g L-1 and 30 g L-1) on in vitro seed germination and plant growth of M. glaucescens and the efficiency of sterilization with sodium hypochlorite (NaOCl) on in vitro seed germination and plant growth of M. glaucescens when using seeds and M. glaucescens and M. paucispinus when using apical segment of cladode. In M. glaucescens, the final germination at the different MS and sucrose concentrations varied between 53.5 and 68.1% and the best results for in vitro growth were observed with the lowest mineral salt (MS/2 and MS/4) and sucrose (15 g L-1) concentrations, with lengths of the aerial portion of 9.70 and 10.76 mm, respectively. There was no difference in seed germination and plant growth in chemical and autoclave medium. It is concluded that the use of chemical sterilization with NaOCl at low concentrations of salts (MS/2 and MS/4) and sucrose (15 g L-1) are quite advantageous for producing ornamental plants germinated in vitro and/or apical segment of cladode of M. glaucescens andM. paucispinus, representing a reduction of costs for in vitro cultivation of this species.

ABSTRACT Sugarcane is considered as one of the prominent agricultural crops in Brazil, with Goiás being the second largest national producer. During the processing of sugarcane, waste is generated, and one of these is vinasse. The objective of this study was to evaluate the biometric and technological performances of two varieties of sugarcane for different depths and vinasse parceling. Experiments were conducted at Fazenda Boa Sorte, located in the municipality of Carmo do Rio Verde-GO. A randomized block design was used with a subdivided plot containing two varieties of sugarcane (RB 86-7515 and SP 80-1816) and each subplot having three management types for the application of vinasse (M1 20-20 mm, M2 40-0 mm, and M3 30-30 mm) and four repetitions. The applications were performed in the months of May and June (dry period). The variables analyzed were the plant height, number of photosynthetically active green leaves, stem diameter, leaf area, stalk productivity, soluble solids content, broth pol, apparent sucrose content, fiber content, total reducing sugars, and reducing sugars. Analysis of variance was performed on the results obtained using the F test; subsequently, for the significant data, the test of means was performed. The SP 80-1816 variety showed superiority for both the biometric and technological variables. The ethanol yield and total recoverable sugar content were higher for the SP 80-1816 variety, with no difference between the vinasse application management. The vinasse application installment did not show viability. | RESUMO A cana-de-açúcar é considerada uma das culturas agrícolas de maior destaque no Brasil, sendo o Goiás o segundo maior produtor nacional. Durante o processo de beneficiamento da cana-de-açúcar são gerados resíduos e um deles é a vinhaça. Objetivou-se avaliar o desempenho biométrico e tecnológico de duas variedades de cana-de-açúcar, sob aplicação de diferentes lâminas e parcelamento de vinhaça. O experimento foi conduzido na Fazenda Boa Sorte, localizada no município de Carmo do Rio Verde - GO. Foi utilizado o delineamento experimental de blocos casualizados, com parcela subdividida, sendo as parcelas duas variedades de cana-de-açúcar (RB 86-7515 e SP 80-1816) e as subparcelas três manejos da aplicação de vinhaça (M1 2020 mm, M2 40-0 mm e M3 30-30 mm), com quatro repetições. As aplicações ocorreram nos meses de maio e junho (período seco). As variáveis analisadas foram altura de planta, número de folhas verdes fotosinteticamente ativas, diâmetro do colmo, área foliar, produtividade de colmos, teor de sólidos solúveis, Pol do caldo, teor de sacarose aparente, teor de fibra, açúcares redutores totais, açúcares redutores. Para os resultados encontrados foi feita análise de variância pelo teste F e, posteriormente, para os dados significativos, foi feito o teste de média. A variedade SP80 - 1816 mostrou superioridade tanto para as variáveis biométricas, quanto para as variáveis tecnológicas. O rendimento de etanol e o teor de açúcares totais recuperáveis foram superiores para a variedade SP80 - 1816, não havendo diferença entre os manejos de aplicação de vinhaça. O parcelamento da aplicação de vinhaça não mostrou viabilidade.

ABSTRACT Information on the different species that compose a weed community is essential for plant protection managements in production systems, which should include not only flora identification and diversity assessments, but morphological and ecophysiological aspects that can to show the potential effect of the agrosystem and guide the conduction of weed control strategies. Therefore, the objective of this work was to conduct a floristic and phytosociological surveying to identify the grouping patterns of weed populations in vineyards in the Petrolina-Juazeiro irrigated perimeter, in the Sub-Mid São Francisco River Valley, Brazil. The absolute and relative values of weed frequency, density, abundance, importance value index, population distribution level, and similarity between areas were evaluated in five properties. A high diversity of species of the families Poaceae, Malvaceae, and Asteraceae were found. The most important species found were Commelina benghalensis, Euphorbia hirta, and Cyperus aggregatus. The distribution of populations was mainly in aggregate and highly aggregate forms. | RESUMO O conhecimento sobre as diferentes espécies que compõem uma comunidade infestante torna-se fundamental no manejo fitossanitário dos sistemas de produção vegetal, não somente pela identificação da flora e diagnóstico da diversidade, mas também pelos aspectos morfológicos e ecofisiológicos, o que pode revelar o potencial de interferência ao agrossistema e nortear a condução das estratégias de controle. Neste sentido, o objetivo deste trabalho foi realizar o levantamento florístico e estudo fitossociológico, assim como conhecer o padrão de agrupamento das populações infestantes em áreas de videira no perímetro irrigado do polo Petrolina -PE/Juazeiro-BA, submédio do Vale do Rio São Francisco. As avaliações ocorreram em cinco propriedades, sendo analisados os parâmetros de: frequência, densidade, abundância e índice de valor de importância absolutos e relativos, assim como o grau de distribuição das populações e a similaridade entre as propriedades. As famílias Poaceae, Malvaceae e Asteraceae apresentaram maior diversidade de espécies. E as espécies com maiores níveis de importância foram Commelina benghalensis, Euphorbia hirta e Cyperus aggregatus. De maneira majoritária, a distribuição das populações apresentou-se de forma agregada ou altamente agregada.

RESUMO Em florestas tropicais sazonalmente secas, como a Caatinga brasileira, fatores como tipo de solo e luminosidade são conhecidos por causar alterações nos tecidos foliares que possibilitam a sobrevivência de espécies nesses locais. O presente estudo teve como objetivo descrever a morfoanatomia foliar de Senna cana e observar a plasticidade em tecidos foliares que recebem radiação de luz direta e indireta. O estudo foi realizado no Parque Nacional do Catimbau em Buíque, PE, Brasil. Amostras de folhas maduras foram coletadas sob plena luz do sol e plena sombra em três áreas com solos de cores diferentes. Lâminas histológicas foram preparadas para visualização das faces epidérmicas, estrutura foliar interna e testes histoquímicos. A plasticidade foi notada no tipo de tricoma que recobriu as faces epidérmicas, e no número de camadas dos parênquimas paliçádico e esponjoso, mesmo sob efeito indireto da radiação. Compostos fenólicos e lipídios também apresentaram plasticidade. Esses resultados demonstram que Senna cana é uma espécie com alta plasticidade para o fator de luminosidade. Além disso, percebeu-se que a luz indireta também promove alterações anatômicas e deve ser considerada em análises futuras. | ABSTRACT In seasonally dry tropical forests such as the Brazilian Caatinga, factors such as soil type and luminosity are known to cause changes in foliar tissues that enable the survival of species in such places. The present study aimed to describe the leaf morphoanatomy of Senna cana and to observe the plasticity in leaf tissues receiving both direct and indirect light radiation. The study was carried out in the Catimbau National Park in Buíque, PE, Brazil. Mature leaf samples were collected from under full sunlight and full shade in three areas with soils of different colors. Histological slides were prepared for visualization of epidermal faces, internal leaf structure, and histochemical tests. Plasticity was noted in the type of trichome that covered the epidermal faces, and in the number of layers of the palisade and spongy parenchymas, even under the indirect effect of radiation. Phenolic compounds and lipids also showed plasticity. These results demonstrate that Senna cana is a species with high plasticity for the luminosity factor. Further, it was noticed that indirect light also promotes anatomical changes and should be considered in future analyses.

ABSTRACT The soils of the Semiarid region of Brazil lack studies regarding sorption processes and availability of phosphorus (P). Therefore, the objective of this work was to quantify the sorption of P in ten soils representative of the Semiarid region of Brazil and correlate them with the soil phosphorus storage capacity. The P concentrations in the equilibrium solutions used to model the sorption isotherms were: 0, 5, 10, 15, 20, 30, 40, 55, 70, and 80 mg L-1 for the soils Typic Quartzipsamment (Neossolo Quartzarenico), Typic Hapludox (Latossolo Vermelho Amarelo), Typic Hapludult (Argissolo Vermelho Amarelo), Typic Quartzipsamment (Neossolo Flúvico), and Typic Dystrudept (Cambissolo Haplico); and 0, 10, 15, 25, 40, 55, 80, 100, 130, and 150 mg L-1 for the soils Typic Calciudolls (Chernossolo Rendzico), Typic Dystrudept (Cambissolo Haplico), Typic Dystrudept (Cambissolo Haplico), Typic Hapludult (Argissolo Vermelho Amarelo), and Typic Hapludert (Vertissolo Haplico). The Langmuir and Freundlich sorption isotherms were fitted to non-linear regression models and the values of the model parameters were estimated. The sorption isotherms were adequate to quantify the sorption of P in the soils of the Semiarid region of Brazil, with maximum P sorption capacity varying from 50.4 mg kg-1 to 883.5 mg kg-1. The sorption of P was higher in soils with more clayey textures, alkaline, and rich in iron and calcium, denoting the importance of evaluating the effect of these characteristics on the sorption of P in these soils. | RESUMO Os solos do semiárido brasileiro ainda não foram suficientemente estudados quanto aos processos de sorção e de disponibilidade de fósforo (P). Nesse sentido objetivou-se com este trabalho quantificar a sorção de P em dez solos representativos da região semiárida e correlacioná-las com o Fator Capacidade de Fósforo do Solo (FCP). As concentrações de P das soluções de equilíbrio utilizadas para o ajuste dessas isotermas corresponderam a 0; 5; 10; 15; 20; 30; 40; 55; 70 e 80 mg L-1 de P para os solos Neossolo Quartzarênico (Entisol), Latossolo Vermelho Amarelo (Oxisol), Argissolo Vermelho Amarelo (Ultisol), Neossolo Flúvico (Entisol) e Cambissolo Háplico (Inceptsol); e a 0; 10; 15; 25; 40; 55; 80; 100; 130 e 150 mg L-1 para os solos Chernossolo Rêndzico (Mollisol), Cambissolo Háplico (Inceptsol), Cambissolo Háplico (Inceptsol), Argissolo Vermelho Amarelo (Ultisol) e Vertissolo Háplico (Vertisol). As isotermas de Langmuir e de Freundlich foram ajustadas por meio da técnica de regressão não-linear e estimados os valores dos parâmetros desses modelos. As isotermas mostraram-se adequadas para quantificar a sorção de P nos solos do semiárido, com valores de capacidade máxima de sorção de P (CMSP) variando de 50,4 mg kg-1 a 883,5 mg kg-1. O P foi sorvido em maior quantidade nos solos mais argilosos, alcalinos e ricos em ferro e cálcio, evidenciando a importância da avaliação dessas características na sorção de P nesses solos.

ABSTRACT Pulse irrigation may be more advantageous for peanut crops than continuous irrigation, when using brackish water. However, studies on pulse irrigation with brackish water considering the environmental conditions of the Northeast region of Brazil using are incipient. Therefore, the objective of this study was to evaluate the effect of using brackish water for pulse and continuous dripping irrigations on the grain yield and production characteristics of peanut (Arachis hypogaea L.) crops. A completely randomized block design with four repetitions was used, in a 6*2 factorial arrangement consisted of six electrical conductivities of the irrigation water (EC; 0.2, 1.6, 2.8, 4.0, 5.2, and 6.4 dS m-1) set by adding NaCl to the irrigation water, which originally had 0.2 dS m-1, until reaching the respective EC; and two irrigation methods (pulse and continuous). The evaluated variables were fresh and dry weights of shoot, 10 grains, pods, grains, and production; number of pods and grains; and percentages of empty pods (EP%) and perfect grains (PG%). The addition of salt to the irrigation water negatively affected all variables studied, except for EP% and PG%. The lowest EP% were found for the pulse irrigation, which increased the pod and grain yields, regardless of the EC of the irrigation water. Under the conditions of the present study, the use of brackish waters with electrical conductivities of up to 2.98 dS m-1 is viable for peanut production. | RESUMO A irrigação por pulsos pode proporcionar maiores rendimentos para a cultura do amendoim em comparação a irrigação contínua com a utilização de águas salobras, contudo, estudos para as condições do Nordeste brasileiro utilizando esta técnica de manejo da irrigação associada ao uso de águas salobras são incipientes. Diante disso, objetivou-se com o trabalho avaliar o efeito do uso de águas salobras e da irrigação por gotejamento pulsado e contínuo sobre a produção de grãos e características produtivas do amendoim (Arachis hypogaea L.). O delineamento experimental utilizado foi o de blocos casualizados, em esquema fatorial de 6 x 2, composto por seis condutividades elétricas da água de irrigação (CEa: 0,2; 1,6; 2,8; 4,0; 5,2 e 6,4 dS m-1), na qual foi adicionada NaCl a água de abastecimento (CEa: 0,2 dS m-1) até atingir as respectivas CEa, e duas formas de aplicação da irrigação por gotejamento (com pulsos e contínua), com quatro repetições. As variáveis analisadas foram: a massa fresca e seca da parte aérea de 10 grãos, das vagens, dos grãos e da produção, além do número de vagens, do número de grãos, da percentagem de vagens chochas (PerVC) e da percentagem de grãos perfeitos (PerGP). A salinidade influenciou negativamente todas as variáveis estudadas, com exceção do PerVC e da PerGP. As menores percentagens de vagens chochas foram obtidas com a irrigação pulsada que por sua vez demonstrou a maior produção de vagens e de grãos independentemente dos níveis de condutividade elétrica da água avaliados. Nas condições desta pesquisa, é viável produzir amendoim utilizando águas salobras com condutividade elétrica de até 2,98 dS m-1.