Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

3 ( 1 )

2020 ( 7 )

2019 ( 53 )

2018 ( 64 )

Custom range...

Search Results: 1 - 10 of 36752 matches for " Antonio Celso Dantas Antonino "
All listed articles are free for downloading (OA Articles)
Page 1 /36752
Display every page Item
Calibration of Hargreaves-Samani Equation for Estimating Reference Evapotranspiration in Sub-Humid Region of Brazil  [PDF]
José Romualdo de Sousa Lima, Antonio Celso Dantas Antonino, Eduardo Soares de Souza, Claude Hammecker, Suzana Maria Gico Lima Montenegro, Carlos Alberto Brayner de Oliveira Lira
Journal of Water Resource and Protection (JWARP) , 2013, DOI: 10.4236/jwarp.2013.512A001

Reference evapotranspiration (ETo) is an important parameter used in numerous applications, such as climatological and hydrological studies, as well as for water resources planning and management. There are several methods to estimate ETo, being that the FAO Penman-Monteith (EToPM) method is considered standard. This method needs many parameters (solar radiation, air temperature, humidity and wind speed), however there are still many uncovered areas, suggesting the need for methods of calculating evapotranspiration based on few meteorological elements, such as air temperature. Therefore, this study aimed to determine the ETo by Hargreaves-Samani method in the experimental watershed of the “Riacho do Papagaio” farm, in county of Sao Joao, in north-eastern Brazil, using data of 2011 and 2012. Reference evapotranspiration estimated by non-calibrated Hargreaves-Samani method (EToHS) was overestimated in all months (RMSE = 1.43 mm·d-1), mainly in months of lower evaporative demand (from May to July). Because of these tendencies, this method cannot be used in its original form to estimate ET for this region; therefore, a calibration of radiation adjustment coefficient (kRs) was performed. The calibrated Hargreaves-Samani method (EToHSc) had better performance (RMSE = 0.52 mm·d-1), being suitable for predicting ETo in this region.

Vadose Zone Heterogeneity Effect on Unsaturated Water Flow Modeling at Meso-Scale  [PDF]
Artur Paiva Coutinho, Laurent Lassabatere, Thierry Winiarski, Jaime Joaquim da Silva Pereira Cabral, Antonio Celso Dantas Antonino, Rafael Angulo-Jaramillo
Journal of Water Resource and Protection (JWARP) , 2015, DOI: 10.4236/jwarp.2015.74028
Abstract: The understanding of unsaturated flow in heterogeneous formations is a prerequisite to the understanding of pollutant transfer in the vadose zone and the proper management of infiltration basins settled over such heterogeneous formations. This study addresses the effect of lithological heterogeneity of a glaciofluvial deposit on flow in the vadose zone underneath an infiltration basin settled in the Lyon suburbs. The basin had already been the subject of several previous studies, some of which demonstrated the impact of soil heterogeneity. But all of them were only based on the sedimentological study of a trench and no study addressed the potential spatial variability of results due to the spatial variability of soil heterogeneity. In this study, we model flow in the vadose zone for several case studies, including drainage, water infiltration during a rainfall event, and a complete meteorological chronic. These calculations were conducted for several sections, previously characterized in the basin using GPR and sedimentological study and compared with a blank (homogeneous section). The results clearly show that heterogeneity impacts unsaturated flow and that these impacts depend upon the section considered. Some geometrical architectural and textural parameters were proposed to explain the spatial variability and effect of the soil heterogeneity on unsaturated flow, thus establishing the first step towards modeling unsaturated flow in the basin at the meso-scale.
Pesquisa Agropecuária Brasileira , 1999, DOI: 10.1590/S0100-204X1999001100015
Abstract: sorptivity and hydraulic conductivity were determined by two methods using disc permeameters. infiltration experiments were carried out on three horizons of a representative soil of the semi-arid region, located in santa maria da boa vista, state of pernambuco, brazil. water was supplied to this soil by disc permeameters at potentials of 0, -2.5, -5 and -10 cm of water. in the first method, hydraulic conductivity was measured using estimates of sorptivity and steady state fluxes. in the second, sorptivity and hydraulic conductivity were determined using measurements of steady state fluxes with two disc permeameters of different radius. results of the second method, regarding characteristic times and characteristic pore radius, were more consistent than those of the first one. sorptivity was as important as hydraulic conductivity to characterize the infiltration process. the abrupt reduction of the characteristic pore radius in the horizon a2/b with changes in the water supply potential indicates the structure heterogeneity of this horizon and allows the identification of the role of the clay compact volumes on the infiltration process.
Balan?o hídrico em solo com cultivos de subsistência no semi-árido do nordeste do Brasil
Antonino, Antonio Celso Dantas;Sampaio, Everardo V. S. B.;Dall'Olio, Attilio;Salcedo, Ignácio Hernan;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2000, DOI: 10.1590/S1415-43662000000100006
Abstract: considering that water is a limiting factor and there are few studies on water balance in the semi-arid northeastern brazil, an experiment was established at coxixola, pb, brazil, with four treatments (corn and beans crops, bare soil and soil covered with mulch), in plots of 7.7 x 10 m and plant spacing of 1.1 x 1.0 m. rainfall, evaporation (class a tank) and soil water (neutron probe) were monitored. low (212 mm) and irregular rainfall resulted in water deficit towards the final period of the experiment and was responsible for the low water use efficiencies and low productivity of corn (grain and total biomass, 282 and 1141 kg ha-1) and beans (166 and 558 kg ha-1). bare soil and mulch had similar results, with high water losses, 1.57 and 1.48 mm day-1, respectively, and only small increases in stored soil water (28 and 35 mm, respectively) were observed at the end of experiment. mulching does not seem to be a promising practice in the area due to this small increase and the difficulty in obtaining plant residues.
Condutividade hidráulica n o saturada de um podzólico amarelo da zona da mata norte de Pernambuco
Pesquisa Agropecuária Brasileira , 2000,
Abstract: A determina o da condutividade hidráulica de um Podzólico Amarelo foi obtida a partir de experimento montado em uma parcela de 3,5 m x 3,5 m, localizada na Esta o Experimental da Empresa Pernambucana de Pesquisa Agropecuária (IPA), de Itapirema, Goiana, PE. Foi utilizado o método de drenagem interna para calcular a condutividade hidráulica (K(q)) como fun o da umidade do solo, nos três horizontes característicos do solo. Os perfis de umidade e de potencial matricial, em fun o do tempo, obtidos no experimento de drenagem interna mostram claramente a existência de um joelho que marca a transi o entre as fases de drenagem rápida e lenta. Várias fun es do tipo potência, soma de duas e três exponenciais, foram usadas para modelar essa transi o entre a fase rápida e a fase lenta de drenagem. O horizonte A, arenoso, com poros maiores, é um horizonte de elevada condutividade hidráulica, enquanto o horizonte BA, de estrutura maci a com poros pouco visíveis, é um horizonte de impedimento para a infiltra o. A dinamica hídrica do horizonte Bt é mais complexa em virtude de sua heterogeneidade. A caracteriza o dos horizontes A e BA pode trazer subsídios significativos para a elabora o de modelos de simula o numérica dos processos de transferência de água nos horizontes superficiais, que s o os mais condicionantes para a explora o agrícola e a conserva o dos solos.
Condutividade hidráulica n?o saturada de um podzólico amarelo da zona da mata norte de Pernambuco
Pesquisa Agropecuária Brasileira , 2000, DOI: 10.1590/S0100-204X2000000600019
Abstract: the determination of the hydraulic conductivity of a yellow podzolic soil was carried out during an experiment in a plot measuring 3.5 m x 3.5 m, at the esta??o experimental de itapirema, goiana, in the state of pernambuco, brazil. the internal drainage method was used to obtain the hydraulic conductivity (k(q)) as a function of soil water content, in the three main horizons of the soil. in relation to the methodological aspects, processing of data from internal drainage experiments, including the initial phase of fast drainage, the adjustment of the required parameters, it is necessary to use functions that reproduce the distinct transition between the fast and slow phases of drainage. from all five tested functions, those of power, sum of two exponentials and sum of three exponentials, especially this last one, adjusted well to this distinct transition. three main horizons of the yellow podzolic soil were investigated for hydraulic conductivity. the sandy a horizon, with large pores, has a high conductivity while the ba horizon, with massive structure and few visible pores, has a low infiltration rate. the hydraulic dynamics of the bt horizon is more complex due to its heterogeneity. the precise characterization of the a and ba horizons, which are the most important to agriculture and soil conservation, makes it possible to elaborate numeric simulation models of the water transference process in the surface horizons of this type of soil.
Modelagem da cinética de biodegrada??o de paclobutrazol em dois solos do semiárido do nordeste brasileiro
Vaz, Fernanda Leit?o;Maciel Netto, André;Antonino, Antonio Celso Dantas;Afonso, Antonio Cláudio Marques;Martins, Jean Manuel Fonseca;Gouveia, Ester Ribeiro;
Química Nova , 2012, DOI: 10.1590/S0100-40422012000100015
Abstract: mathematical models can help to prevent high levels of toxic substances in soil or fruits of plants treated with pesticides and indicate that such substances should be systematically monitored. the aim of this research was to study the kinetics of paclobutrazol biodegradation by soil native bacteria using mathematical models. three models were used to assess the kinetics of paclobutrazol biodegradation obtained experimentally. excellent fits were obtained using dual kinetic and logistic models. the use of glycerol as additional carbon source increased the biodegradation of pbz and consequently decreased the time required for a given pbz initial concentration be halved.
Variabilidade espacial dos parametros hidrodinamicos de duas parcelas agrícolas no estado da Paraíba
Souza, Eduardo Soares de;Antonino, Antonio Celso Dantas;Jaramillo, Rafael Angulo;Netto, Andre Maciel;Montenegro, Suzana Maria Gico Lima;Silva, Edvane Borges da;
Revista Brasileira de Ciência do Solo , 2008, DOI: 10.1590/S0100-06832008000500001
Abstract: knowledge on soil hydraulic properties such as water retention and hydraulic conductivity curves is indispensable for water and pollutant transport modeling of agricultural systems. this soil hydraulic properties are affected by numerous sources of variability, mostly associated with spatial, temporal, and management-related factors. the objective of this study was to analyze the spatial variability of parameters of water retention (van genuchten) and hydraulic conductivity (brooks & corey) curves obtained with the "beerkan" method based on simple infiltration experiments and soil texture data. these parameters are related to shape or texture (fitting parameters that shape the curves) and normalization or structure (saturated water content, saturated hydraulic conductivity and air entry potential). the field tests were carried out in a 25 x 25 m grid in a fluvent soil and in an oxisoil planted with beans (vigna unguiculata (l.) walp.). for both soils, spatial dependence was verified in the values of parameters of shape, saturated water content, logarithms of the saturated hydraulic conductivity and air entry potential. the values of saturated water content and air entry potential were more sensitive to variation at short distances in the fluvent than in the oxisoil. the spatial dependence in the variograms was weak.
Desenvolvimento de um modelo fractal para a estimativa da condutividade hidráulica de solos n?o saturados
Fuentes, Carlos;Antonino, Antonio Celso Dantas;Netto, André Maciel;Lira, Carlos Alberto Brayner de Oliveira;Cabral, Jaime Joaquim da Silva Pereira;
Revista Brasileira de Ciência do Solo , 2005, DOI: 10.1590/S0100-06832005000100006
Abstract: from a conceptual model based on fractal geometry and laplace's and poiseuille's laws, a versatile and general fractal model for the hydraulic conductivity to be used in the soils was developed. the soil-moisture retention curve is derived from a power model. due to the fact that the proposed model of hydraulic conductivity introduces a still unknown interpolation parameter, which in turn is a function of soil properties, its limiting values were considered for the analysis. to apply the model in the soil, the form parameters of the soil-moisture retention curve were chosen so as to reproduce van genuchten's equation. in order to obtain a closed-form equation for the hydraulic conductivity, relationships between the form parameters were imposed. the comparison between the predicted and experimental hydraulic conductivity from two soils, oxisol and yellow utilsol, demonstrated that the proposed model is flexible and that it can be used to predict the unsaturated hydraulic conductivity of soils with good accuracy.
Transporte do paclobutrazol em colunas de solos
Milfont, M?nica Lúcia;Antonino, Antonio Celso Dantas;Martins, Jean Manuel Fonseca;Netto, André Maciel;Gouveia, Ester Ribeiro;Correa, Marcus Metri;
Revista Brasileira de Ciência do Solo , 2008, DOI: 10.1590/S0100-06832008000500037
Abstract: paclobutrazol (pbz) is a post-emergence plant growth regulator used in agricultural systems with the objective of vegetative control growth, thereby increasing the reproductive capacity of the plant. this growth regulator remains active in the soil for several years being detrimental to subsequent tillage and contamination of groundwater through leaching. the objective of this work was to study the mechanisms involved in the transport and sorption of pbz in an ultisol and a vertisol, both of the s?o francisco valley, brazil. column breakthrough experiments were performed with a water tracer (bromide) and with pbz at 0.4 e 1.6 cm3.min-1 in the two soils. hydrodispersive parameters of both soils were obtained by fitting the tracer breakthrough curves (btc) with the convection-dispersion (cde) model, whereas the parameters of pbz reactive transport were obtained with the cde-2 sorption sites model, through the cxtfit code. pbz presents a lower retardation factor in the vertisol than in the ultisol. the water flow was found to strongly affect pbz mass balance, mainly because of sorption/desorption hysteresis, suggesting partial irreversible sorption of the chemical. the two sites model fitted well the tracer and pbz breakthrough curves. the results showed that pbz transport is strongly influenced by its interactions with the soil matrix through rate-limited sorption. the determined transport parameters indicate that pbz applied to the two tropical soils cultivated with mango presents an important leaching potential and contamination risk of the groundwater of the s?o francisco valley.
Page 1 /36752
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.