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Primo D.C.,Federal University of Pernambuco | Menezes R.S.C.,Federal University of Pernambuco | de Sa Barretto Sampaio E.V.,Federal University of Pernambuco | da Silva Garrido M.,Federal University of Vale do São Francisco | And 2 more authors.
Nutrient Cycling in Agroecosystems | Year: 2014

Proper management of N applied in fertilizers is important to optimize crop production and to avoid negative environmental impacts. The best way to study N dynamics in the soil plant system is to use fertilizers labeled with 15N. Recoveries of nitrogen following fertilization with 15N-labeled goat (Capra hircus L.) manure and gliricidia (Gliricidia sepium Jacq. Walp) biomass were evaluated in a greenhouse experiment with three successive planting cycles of three crops: maize (Zea mays L.), cotton (Gossypium hirsutum L.), and cowpea (Vigna unguiculata (L.) Walp.). Each 1 kg soil pot received 8 g (equivalent to 20 Mg ha−1) of either manure (12.3 mg g−1 of N) or gliricidia (37.8 mg g−1 of N). Plants were harvested 50 days after germination and real (15N) and apparent recoveries of the applied N were determined. Biomass and N amounts in the cotton and maize crops in all three cycles were higher with gliricidia application than with manure, except for cotton in the first cycle. The biomass of cowpea was also higher with gliricídia in the first and second cycles but the amount of N was significantly higher only in the second cycle. In the first cycle, the largest recoveries of 15N were obtained with gliricidia, for all three crops, but in the second and third cycles recoveries were greater with manure, so that the real recoveries of gliricidia and manure were similar (cotton, 35 and 37 %; maize, 27 and 26 %; and cowpea, 41 and 38 % of the applied N, respectively). Estimates of apparent recoveries were different from the real ones and therefore inadequate for cotton and cowpea. The fast release of N from gliricidia prunings and, on the other hand, the strong residual effect of goat manure-N to subsequent cropping cycles should be considered by farmers in their fertilization strategies. © 2014, Springer Science+Business Media Dordrecht.

Teixeira F.A.,State University of Southwest Bahia | Bonomo P.,State University of Southwest Bahia | Pires A.J.V.,State University of Southwest Bahia | da Silva F.F.,State University of Southwest Bahia | And 2 more authors.
Revista Brasileira de Zootecnia | Year: 2011

This study was conducted to evaluate the displacement and permanency patterns of grazing cattle on Brachiaria decumbens deferred during 95 days under four strategies of nitrogen application (0-0, 0-100, 50-50, 100-0 kg N.ha-1), at the beginning and at the end of the rainy season. During the deferred period, in the dry season, forage yield, canopy structural characteristics, and displacement pattern were evaluated. Four steers were used in Ten grazing tests of 45 minutes and 14 heifers Girolanda, monitored every 10 minutes during 24 hours, were used to evaluate the permanency time. Pastures fertilized with 100 kg N at the end of the rainy season had higher herbage and leaf blade, sward surface height, extended leaf height, sward leaf blade bulk density and stem mass in all canopy layers. The lodging rates were higher for pastures fertilized at the end of the rainy season (0-100 and 50-50). More feeding stations and steps per minute were found in 0-100 and 50-50 fertilization strategies, due to greater difficulty in forage selection with higher degree of lodging. On the other hand, the numbers of bites per feeding station and per minute were lower for these strategies. The permanency time was greater on pastures where the fertilization was 100 kg N.ha-1 at the end of the rainy season (0-100). Fertilization close to sealing period modify the displacement pattern of animals because the higher plants lodging making the animals to spend more time on pasture with greater density of leaf blade. © 2011 Sociedade Brasileira de Zootecnia.

Costa S.N.,University Estadual Of Santa Cruz | Alves R.M.,Federal University of Bahia | de Carvalho C.A.L.,University Federal do Reconcavo Baiano | Conceicao P.J.,University Federal do Reconcavo Baiano
Ciencia Animal Brasileira | Year: 2015

This study aimed at identifying the pollen sources used by Apis mellifera L. in the municipality of Itaberaba, State of Bahia. Pollen samples were obtained through collectors installed at the entrance of ten A. mellifera bee colonies, implanted in an apiary at a savanna area, in the months of December of 2006, January, March and December of 2007, period in which high blooming was observed in the area. The quantitative and qualitative analyses were accomplished at the laboratory of Entomology of the Center of Agrarian, Environmental and Biological Sciences of Universidade Federal do Recôncavo da Bahia, County of Cruz das Almas, State of Bahia, Brazil. Through the analysis of the obtained results, we verified the presence of 78 pollen types, belonging to 24 families. The family Mimosaceae presented the greatest number of pollen types. The results demonstrated the species A. mellifera L. presents generalist habit, and the families Fabaceae-Mimosoidea, Asteraceae, Commelinaceae and Poaceae are the main pollen sources for A. mellifera in region.

Nunes A.S.,Federal University of Bahia | Oliveira R.L.,Federal University of Bahia | Borja M.S.,Federal University of Bahia | Bagaldo A.R.,University Federal do Reconcavo Baiano | And 5 more authors.
Archivos de Zootecnia | Year: 2011

This study was conducted in order to verify the best level of palm kernel for sheep diet by intake, nutrient digestibility and blood parameters in terminated feedlot lambs. Twenty non-castrated Santa Inês lambs were fed diets with corn meal, soybean meal, Tifton 85 hay and palm kernel levels (0.0; 6.5; 13.00 and 19.5% in dry matter), as total mixed ration. The experiment lasted 24 days. For three consecutive days, feed, orts and faeces were sampled for determination of intake and nutrient digestibility. At the last day, blood was collected for plasma urea nitrogen and glucose. Dry matter (DM), organic matter (OM), crude protein (CP) and total digestive nutrients (TDN) expressed by g/day, body weight percentage (%BW) and grams per kg of metabolic weight (g/kg MW) intake were not influenced by palm kernel inclusion, while neutral detergent fiber (NDF), acid detergent fiber (ADF) and ether extract (EE) increased with palm kernel levels and non-fibrous carbohydrate decreased. Digestibility coefficient of noncarbohydrate decreased as levels of palm kernel increased. Blood urea nitrogen and glucose levels were not influenced by the diets, however, diets promoted quadratic effect at post feeding. Up to 19.5% of palm kernel can be included in diets for lambs, with no effects on studied variables.

Sousa A.E.C.,Federal University of Campina Grande | Gheyi H.R.,University Federal do Reconcavo Baiano | Soares F.A.L.,Instituto Federal Goiano | Nobre R.G.,Federal University of Campina Grande | Nascimento E.C.S.,Federal University of Campina Grande
Ciencia Rural | Year: 2012

The physic nut has attracted considerable interest in recent years because of the high potential to provide oil for biofuel production and this has caused the rapid expansion of cultivated area worldwide. This research aimed to evaluate the influence of irrigation with water of different electrical conductivity (ECw) and two doses of phosphorus on the production components of physic nut during the third year of production. A randomized block design in a factorial (5×2) was adopted with four repetitions, with five levels of salinity (ECw - 0.6 control; 1.2; 1.8; 2.4 and 3.0dS m-1) of the irrigation water and two doses of P2O5 (135 and 200g plant-1 year-1), in which the water of 0.6dS m-1 refers to municipal supply water and the dose of 135g plant-1 is the recommended dose for physic nut. Plants were cultivated in recipient of 200L and irrigated at intervals of three days. The number of days for inflorescence, number of clusters plant-1, grain yield and oil content of physic nut seeds were negatively affected by the increasing salinity of the irrigated water. The cultivation of physic nut irrigated with electrical conductivity of 1.3dS m-1 reduces the productivity by 10% and consequently the seed oil content. Only the number of days for inflorescence was affected by phosphorus doses. A positive and significant correlation between weight of 100 seeds and oil content of seeds was observed and in the treatment with the lowest ECw the values obtained were respectively 90.26g and 36.39%.

Lobo D.M.,University Federal do Reconcavo Baiano | Silva P.C.C.,UFRB | do Couto J.L.,Agrarias e Consultor da Fundacao Mokiti Okada | Silva M.A.M.,UFRB | dos Santos A.R.,Solos e Nutricao de Plantas da CCAAB
Bioscience Journal | Year: 2012

The groundnut is a great agricultural alternative for the Northeast region of Brazil, but few studies have been carried out for this crop in relation to its fertilization. Thus, a study was conducted to evaluate the performance and visual characteristics of nutritional deficiency in groundnut (Arachis hypogaea L.) submitted to the absence of N, P, and K. The experiment was conducted in a greenhouse at the Federal University of Bahia Recôncavo, at the Center for Agricultural, Environmental and Biological Sciences, located in Cruz das Almas, BA, from August to October 2010. The experimental design was in randomized blocks, consisting of seven treatments and four replications. The treatments were: T1 - Complete Solution; T2 - Omission of N; T3 - Omission of P; T4 - Omission of K; T5 - Omission of NP; T6 - Omission of PK; and T7 - Omission of NPK. Throughout the crop cycle possible visual aspects of deficiency were assessed. At the end of the experiment, the data were evaluated in height and chlorophyll content. At sixty days after emergence (DAE) plants were collected and partitioned into leaves, stem and root for drying in air forced oven at 65°C until constant weight was obtained to measure the dry mass of shoot and root. Under these experimental conditions the omission of K was not a limiting factor for dry mass of leaves and stem in peanut plants. Phosphorus is an element that proved to be enough for the required growth in height and accumulation of dry mass of leaves and stem. The chlorophyll content of the plant was lower in the treatment in which there was the omission of N. The treatment with omission of NPK was the most limiting, demonstrating the importance of applying these nutrients to the groundnut plants.

De Lima J.C.,Federal University of Ceará | Duarte Arraes F.D.,Instituto Federal Of Educaao | De Oliveira J.B.,Instituto Federal Of Educaao | Do Nascimento F.A.L.,University Federal do Reconcavo Baiano | De Macedo K.G.,Instituto Federal Of Educaao
Revista Ciencia Agronomica | Year: 2016

The Hargreaves-Samani model is used in estimating reference evapotranspiration, and is very useful for irrigation management; it is considered to be of practical use as it uses meteorological elements, which are easily obtained, such as temperature. However, the equation is in need of regional calibration in order to accurately estimate evapotranspiration. The aim of this work was to calibrate the Hargreaves-Samani model for the State of Ceará, using meteorological data from 12 cities. The empirical parameters α (0.0023) and β (0.5) were calibrated considering two processes: firstly, the simultaneous calibration of the two parameters, and then only the α coefficient. The simultaneous calibration returned a variation in the extreme values for three cities; α ranged from 0.0004 (Campos Sales and Crateús) to 0.0019 (Guaramiranga), and exponent β varied between 0.51 (Guaramiranga) to 1.1977 (Campos Sales). The correlation between the Hargreaves-Samani model calibrated with the Penman-Monteith equation, had a maximum value for the city of Jaguaruana, 0.934 when calibrated with the two parameters, and 0.942 when calibrated with the α coefficient only, demonstrating that calibration of the Hargreaves-Samani equation is viable, and is necessary for improving estimates of evapotranspiration.

Dos Santos J.C.,São Paulo State University | Carvalho J.P.S.,University Federal Do Reconcavo Baiano | Prado A.F.B.A.,National Institute for Space Research | De Moraes R.V.,National Institute for Space Research | De Moraes R.V.,Federal University of São Paulo
Journal of Physics: Conference Series | Year: 2015

Space missions intending to visit Europa, one of the famous Galilean's moons of Jupiter, are among the most important topics in space activities today. There is an increasing interest in the scientific community to send spacecrafts to be inserted into Europa's orbit, with goals like mapping its surface and gravitational field. From the quality of the observations until the orbital maneuvers, the required aspects for the success of the mission will depend on the orbits used by the spacecraft. The present work searches for less perturbed elliptical orbits around Europa, because they are very important, since these orbits are expected to be more stable to place the spacecraft. The development of the study is based on the net effects of the perturbing forces over the time, evaluated by the integral of those forces with respect to the time. The value of this integral depends both on the dynamical model and the orbit of the spacecraft. Jupiter's third-body perturbation and the J2 and J3 terms of the gravitational potential of Europa are the perturbing forces considered. The results presented here are obtained by performing numerical integrations of the perturbing forces, and they show the locations of the less perturbed orbits. © Published under licence by IOP Publishing Ltd.

de Andrade Neto T.M.,University Federal do Reconcavo Baiano | Coelho E.F.,Embrapa Mandioca e Fruticultura | Santana J.A.V.,University Federal do Reconcavo Baiano | Santana Junior E.B.,University Federal do Reconcavo Baiano | Alves M.S.,University Federal do Reconcavo Baiano
Revista Brasileira de Engenharia Agricola e Ambiental | Year: 2012

The objective of this work was to evaluate and to validate models for estimating potassium in the soil solution as a function of bulk electrical conductivity (ECw), soil water content (θ) and a soil solution electrical conductivity (ECss). Treatments consisted of using three concentrations of injecting solution of potassium chloride (1.0, 2.5 and 4.0 g L-1) which were applied by two trickle irrigation systems (microsprinkler and drip) during the first cycle of the banana crop cv. Terra Maranhão. Results showed that it is feasible to estimate potassium concentration in the soil solution from data of ECss and θ obtained by time domain reflectometry (TDR) using an equation that combined a linear and a potential model. The estimated values of potassium concentration were close to the ones measured along the crop cycle under field conditions, with a mean normalized deviation of 10.0%, maximum and minimum deviation of 5.0 and 13.0%, respectively.

De Melo J.L.,University Federal Do Reconcavo Baiano | Pedrosa I.A.,Federal University of Paraiba | Furtado C.,Federal University of Paraiba
International Journal of Modern Physics B | Year: 2016

In this paper, we study the coherent states of Landau-Aharonov-Casher (LAC) levels. These LAC levels are an analogue of the Landau quantization for neutral particles. Afterwards, we investigate some properties of the coherent states, evaluate the uncertainty product and derive the wave functions for our problem. We also discuss the coherent states for the Landau-He-McKellar-Wilkens (LHMW) levels by using the Maxwell duality. © 2016 World Scientific Publishing Company.

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