[show abstract][hide abstract] ABSTRACT: Objetivou-se determinar a viabilidade econômica e o risco do cultivo do mamão na Região Norte do Espírito Santo e comparar os índices econômicos com dados experimentais de irrigação e doses de sulfato de amônio. O experimento foi conduzido na Fazenda Caliman Agrícola S.A., em Linhares, Estado do Espírito Santo. Foram avaliadas, separadamente, duas variedades de mamão, Golden e UENF Caliman 01, em cinco níveis de irrigação (50, 70, 90, 110 e 130% da evapotranspiração de referência), combinados com quatro doses de sulfato de amônio (90, 188, 288 e 377 kg ha-1 mês-1). Na determinação dos riscos e índices da cultura do mamão utilizou-se o cálculo do Valor Presente Líquido, a Taxa Interna de Retorno, a análise de sensibilidade e o método de Monte Carlo. Os tratamentos de irrigação apresentaram diferenças estatísticas significativas (p < 0,05) emrelação à produtividade. Contudo, as doses de sulfato de amônio e suas interações com as lâminas aplicadas não apresentaram diferenças significativas (p < 0,05) para a produtividade. Mediante a simulação de Monte Carlo (simulação triangular), a probabilidade de obterValor Presente Líquido negativo é de 63,2 e 81,4%, para Golden e UENF Caliman 01, respectivamente.
The aim of this paper was to determine the economic viability and cultivation risk in northern Espírito Santo State and compare theeconomic indices with experimental irrigation data and ammonium sulfate doses. The experiment was carried out at Calima Agricola S.A. farm, in Linhares, ES. Two varieties were evaluated separately, Golden and UENF Caliman 01, in five irrigation levels, combined withfour ammonium sulfate doses. The determination of indices and risks of papaya cultivation utilized the calculation of net present value, internal rate of return, sensitivity analysis and Monte Carlo method. The irrigation treatments showed significant statistical differences (p < 0.05) in relation to productivity. The ammonium sulfate and its interactions with applied irrigation depths did not present significant differences (p < 0.05) for the same variable. By means of a Monte Carlo simulation (triangular simulation), the probability of obtaining negative net present value is 63.2 and 81.4% for Golden and UENF Caliman 01, respectively.
Acta Scientiarum Agronomy 01/2010; · 0.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: Leaf area estimation is an important feature in physiological research involving predominantly photosynthesis, transpiration and growth. This study was carried out to develop a practical and nondestructive empirical mathematical model to estimate the area of one leaf and the total leaf area for papaya trees (Carica papaya L.). Two irrigated commercial orchards were evaluated over a period of 50 to 550 days after transplanting, during which the length of the leaf midrib (LM) varied from 0.04 to 0.60 m. A mathematical model was developed to estimate the area of one leaf for the papaya tree, taking into account LM and the age of the plant measured in days after transplanting. The model was considered satisfactory. Based on the average length of the last two leaves of the crown and the total leaf number of the plant, it was possible to satisfactorily estimate the total leaf area of the papaya tree.
[show abstract][hide abstract] ABSTRACT: This paper aimed in identifying great levels of irrigation and nitrogen fertilization that provide the greatest physical and economical productivity of papaya tree Golden cultivar. In the identification of the great levels it was used production function. The experimental study was conducted at Caliman S.A. farm, in the city of Linhares, State of Espírito Santo, Brazil. The experimental design was randomized blocks in a 5x4 factorial scheme in split-plot. Five irrigation water depths (0.5; 0.7; 0.9; 1.1 e 1.3 of the evapotranspiration of reference) were used with daily irrigation frequency and four rates of ammonium sulphate (90, 188, 288 e 377 kg ha-1 month-1). The productivity estimation (t ha-1) as a function of the applied total water depth obtained a significant statistical adjustment (p < 0.05) from the model of second order. The great economical productivity was 94.83 t ha-1, with the maximum depth of 1546.50 mm. Operational net incomes for domestic and international markets were R$ 313.19 e R$ 929.57 ha-1 month-1, respectively.
Revista Brasileira De Fruticultura - REV BRAS FRUTIC. 01/2008; 30(2).
[show abstract][hide abstract] ABSTRACT: This study aimed to determine the crop evapotranspiration (ETc) and the crop coefficient (Kc) for of UENF/CALIMAN01 papaya hybrid (Carica papaya L.). The experiment was conducted in an area of UENF/PESAGRO-RIO, in Campos dos Goytacazes, RJ, Brazil, from 4-25-2006 to 8-20-2007. To determine the ETc and Kc, a weighing lysimeter (6 m2) was used. The reference evapotranspiration (ETo) was determined by the Penmam-Monteith (FAO) method. The maximum crop evapotranspiration was of 2.9 mm day-1, 229 days after the transplant (DAT), and the medium crop evapotranspiration during the experiment was of 1.8 mm day-1. The value of crop coefficient (Kc) varied linearly from 0.63 to 1.05, the transplant to 206 DAT. After this period, the variation of Kc presented inversely relation with the canopy diameter, being reduced to a value medium minimum of 0.81, to 300 DAT. Considering the whole period of study, it was obtained an average Kc of 0.87.
[show abstract][hide abstract] ABSTRACT: Entomopathogenic nematodes (EPNs) are currently being used as successful biological control agents of soil-dwelling insect pests. Previous field and greenhouse studies demonstrated that application techniques and non-biotic factors (temperature and pressure) have a significant effect on EPNs efficacy. The objective of this study was to evaluate the influence of an irrigation spray application system on the viability, infectivity and host search capability of Heterorhabditis baujardi LPP7 (Nematoda: Heterorhabditidae) infective juveniles (IJ). Two assays were proposed. Their viability was evaluated under the microscope after the IJ passed through the irrigation system. Infectivity on Galleria mellonella larvae, and host search capability, as evidenced by larval mortality, were evaluated in containers (Experiment 1). In the field (Experiment 2), mortality of G. mellonella larvae was evaluated under different nematode concentrations (0, 100,000, 300,000 and 500,000 IJ per tree). No differences were recorded on the viability, infectivity and host search capability of the IJ in Experiment 1. In Experiment 2, differences were recorded among the different concentrations used (p < 0.05), and a higher mortality was observed at the highest nematode concentration (28.3% and 37% in each one of the two experiment repetitions). This irrigation system did not affected adversely the viability, infectivity and host search capability of H. baujardi LPP7.
[show abstract][hide abstract] ABSTRACT: The objective of the present work was to study the effect of number of productive branches on the leaf area development and green fig tree yield of Roxo de Valinhos cultivar. The experiment using six year-old plants was carried out between November/2002 and April/2003 at Pesagro-RJ, Campos dos Goytacazes, RJ (21º19'23" South latitude, 41º19'40", West longitude, altitude of 20 a 30 m and Aw Koppen climate). The treatments consisted of plants conducted with 16, 20, 24, 28 and 32 productive branches in a randomized block design with five replicates. The LAI incresead linearly in function of productive branches, whereas the yield showed a quadratic response pattern to the treatments, probably, limited by shading in canopy that decrease the fruit bud formation. The highest green fig yield was observed in the treatment which had plants conducted with twenty four branches, where the mean leaf area was 6,2 m2.
Revista Brasileira De Fruticultura - REV BRAS FRUTIC. 01/2005; 27(3).
[show abstract][hide abstract] ABSTRACT: This paper discusses the variation of relative permittivity, dielectric loss factor and loss tangent, and the a.c. conductivity of three varieties of parchment coffee (Coffea arabica L.) in the frequency range from 75 kHz to 5 MHz, at 21·0±0·9°C and 63±1% relative humidity. Included are curves showing the variation of these four dielectric properties on moisture (11·0 to 23·1% w.b.), bulk density (326–455 kg m−3), and variety (Catuaı́ Vermelho, Catuaı́ Amarelo and Mundo Novo). The importance of the determination of the dielectric properties of parchment coffee for the indirect measurement of its moisture content, and the use of on-line moisture meters in automatic control of coffee dryers, are discussed briefly. Also included are definitions of the dielectric properties of interest in measuring the moisture content of granular materials. The variation of relative permittivity on frequency, moisture content, density and variety was more regular compared to the behaviour of the other dielectric properties in that it continuously increases with moisture and bulk density and decreases with frequency. Dielectric dispersion and its relation to water binding mechanisms in grain are also discussed. The conclusion, based on experimental values and data found in literature, is that of all dielectric properties the relative permittivity should provide less error in parchment coffee moisture content determination.
Journal of Agricultural Engineering Research. 09/2001;