Guilherme Bastos Lyra

Avaliação da taxa de crescimento de frutos de mamão (Carica papaya L.) em função das épocas do ano e graus-dias acumulados

The monitoring of the vegetable organ development, as the fruit, is a great scientific interest. The knowledge of the different phases of growth of these fruits can indicate the critical points of nutritional requirements and water, and its relation with climatic factors effect, as the temperature. The aim of this work was to evaluate the growth rate of the hybrid papaya fruit UENF/CALIMAN 01 at different times of the year, in function of the number of degree-day (DD) accumulated. The fruits had reached the harvest point varying in accordance to the different times of development throughout the year. Fruits developed in periods with high temperatures had in smaller time its point of harvest, and it was inverse in fruits developed in colder periods. However, when reaching around 800 DD after anthesis, the fruits had tended to stabilize its growth invariably. After this growth period, the maturation process was as fast as the monthly temperature of the period is bigger.

Manning roughness coefficient for Paracatu river, Brazil

Pela teoria do escoamento em canais abertos, o coeficiente de rugosidade de Manning e um dos principais parâmetros para descricao da vazao sobre uma superficie. Uma das dificuldades da aplicacao da equacao de Manning e a definicao do seu coeficiente de rugosidade em rios e canais, razao pela qual o presente estudo tem como objetivo, estimar o coeficiente de rugosidade de Manning para os periodos de vazao minima e maxima media mensal, em alguns trechos do rio Paracatu, e propor um modelo baseado em redes neurais artificiais para estimar o coeficiente de rugosidade. O coeficiente foi determinado em funcao das caracteristicas geometricas do canal (area molhada, raio hidraulico e declividade do canal) e das series de vazao de seis postos fluviometricos do rio Paracatu. Utilizaram-se series de vazao de 21 anos (1976-1996). O coeficiente de rugosidade nao apresenta tendencia (maior ou menor) em funcao apenas do periodo seco ou de cheia. As caracteristicas da margem e do leito do rio influenciam diretamente nos valores de coeficiente de rugosidade. O modelo baseado em rede neural apresentou desempenho satisfatorio, o que possibilita estimar o coeficiente de rugosidade em funcao da cota, vazao, declividade e do raio hidraulico do rio.

Influência do nitrogênio e das lâminas de irrigação na qualidade fisiológica das sementes de mamoeiro

The objective of this study was to verify the physiologic quality of papaya tree seeds, in function of different levels of nitrogen application and irrigation levels. Papaya tree plants of the Golden cultivar (Solo group) were used set in double and single rows, in a total area of 5.04m² per plant and 120.96m² per plot. Treatments were consisted of five irrigation levels, equivalent to 70, 90, 110, 130 and 150% of the reference evapotranspiration, estimated by the Penman- Monteith (FAO-56) equation and four doses of nitrogen (10, 20, 30 and 40g/plant), provided monthly until the end of the experiment, with ammonia sulfate as source of this nutrient. Seeds were extracted

Média diária do déficit de pressão de saturação do vapor d'água do ar e sua influência na vapotranspiração de referência pelo modelo de penman-monteith (FAO 56) em Piracicaba - SP

The results of the evapotranspiration obtained with the Dair_avg proceeding from 14 methods were evaluated, by using the lysimetric measures of a sward. These comparisons allowed to separate the Dar_avg calculating methods into three groups: a group always resulted into an overestimate ETo; in other one always tended to underestimating the ETo; and in the last tended to overestimating the low values (<4.5 mm day-1), while underestimating the high values of ETo. No significant statistical differences were observed (t test; p <0.05) in ETo as a function of the Dair_avg methods, when using the hourly average of the temperature and/or the air relative humidity in relation to those determined with the average of the maximum and minimum values of these elements. Among the methods proposed by paper FAO56, just the one using the average relative humidity to calculate the actual pressure (ea) showed a satisfactory estimate. The best estimates of ETo were obtained with the Dair_avg methods using the average of the air temperature in the determination of the saturation pressure (es) and the average of the relative humidity for the actual pressure (ea). The use of saturation-vapor-pressure deficit of the air at a single time (from 9 or 10 a.m. local) as a representative of Dair_avg showed to be a satisfactory alternative in estimating the ETo under the climatic conditions of Piracicaba, SP, Brazil.

Water vapour and carbon dioxide fluxes in sugarcane grown in megathermal humid climate in Northeastern Brazil

The understanding about biophysical processes taking place between the crop and the atmosphere is essential to define the appropriate management practices in order to increase crop yield. The aim of the present study is to analyze water vapour and carbon dioxide (CO2) fluxes in sugarcane crop between the development and the mid-season as an environmental variables function, as well as to assess the correction effects on fluxes. Latent heat flux (lambdaE) and net ecosystem CO2 exchange (NEE) micrometeorological measurements were performed through the eddy covariance technique (EC), between June7th and November 17th, 2013 in a sugarcane crop grown in Northeastern Brazil. Days were characterized according to cloudiness conditions through the clearness index (Kt). The lambdaE and NEE, set through the EC technique, needed correction due to heat and water vapour transfer, because CO2 and lambdaE raw fluxes tend to overestimate and underestimate the values, respectively. Both lambdaE and NEE followed the daily photosynthetic solar irradiance course, but maximum values were not recorded at the same time. Apparent quantum yield and water use efficiency were higher under partly cloudy skies; both variables can be applied to simulation models in order to improve management practices and increase yield.

Observed and modelled solar radiation components in sugarcane crop grown under tropical conditions

Abstract The net radiation over vegetated surfaces is one of the major input variables in many models of soil evaporation, evapotranspiration as well as leaf wetness duration. In the literature there are relatively few studies on net radiation over sugarcane crop in tropical climates. The main objective of the present study was to assess the solar radiation components measured and modelled for two crop stages of a sugarcane crop in the region of Rio Largo, Alagoas, North-eastern Brazil. The measurements of the radiation components were made with a net radiometer during the dry and rainy seasons and two models were used to estimate net radiation: the Ortega-Farias model and the Monteith and Unsworth model. The highest values of net radiation were observed at the crop development stage, due mainly to the high indices of incoming solar radiation. The daily average albedos of sugarcane at the crop development and mid-season stages were 0.16 and 0.20, respectively. Both models showed a better fit for the crop development stage than for the mid-season stage. When they were inter-compared, Monteith and Unsworth model was more efficient than Ortega-Farias model, despite the dispersion of their simulated radiation components which was similar.

Crescimento e produtividade do milho, submetido a doses de nitrogênio nos Tabuleiros Costeiros de Alagoas

Maize growth and yield under nitrogen levels in Coastal Plains of Alagoas, Brazil The objective of this work was to evaluate the growth and yield of maize subjected to different nitrogen rates. The experiment was conducted with maize cultivar Pioneer 30F35 from 25/06 to 28/10/2009, in the region of Rio Largo-AL. The experiment was arranged in a randomized block design, with six nitrogen rates (0, 50, 100, 150, 200 and 250 kg ha 1 of N in the form of urea) and five repetitions per treatment. The models logistic and log normal peak showed statistically significant adjustments (p<0.05) and maximum coef ficient of determination of 0.994 and 0.990, respectively . The values observed and estimated by these models showed high association by the Willmot’s index of agreement, with values greater than 0.953. The plants showed statistically significant differences by the F teste (p<0.05) between the treatments for height (h) and leaf area index (LAI), with a maximum growth corresponding to the rate of 100 kg ha 1 N. The treatments showed significant differences (p<0.05) for yield, with the rate of 200 kg ha -1 providing the highest yield (5.45 t ha -1 ). The growth models can assist the growth analysis.

Influência da água e do potássio na qualidade da semente de mamoeiro

The purpose of this work is to verify the effect of potassium fertilizing and the different irrigation levels on the germination and vigor of papaya tree seeds. To do so, it was used seeds coming from hermaphrodites fruits of the papaya tree, belonging to the group of Solo (cv. Golden), harvested during the stage two of maturing, in Santa Terezinha Farm, which belongs to Caliman Agricola, localized in Linhares-ES. After harvesting, fruits were stored over eight days, in an open and aerated place. The treatments were constituted by five irrigation levels, equivalent to 70, 90, 110, 130 and 150% of the reference evapotranspiration and four doses of potassium (30, 42, 54, and 66g/plant), applied monthly, until the end of the experiment. The spacing used was, respectively, 3,6 meters and 2 meters for double-rows and single-rows, and the plants distance in the rows was 1,8 meters. The assessed characteristics were germination and vigor, which was determined by germination test first count and by seedling classification. The experimental design was completely randomized, having the data been submitted to variance and regression analysis. From the obtained results, it was possible to conclude that the 35g of potassium dose associated to irrigation, equivalent to 70% of evapotranspiration increased germination percentage, and that the suitable combination of potassium dose and irrigation levels contributed significantly to the increase of papaya tree seeds vigor.

Estimativa dos níveis ótimos e econômicos de irrigação no mamoeiro (Carica papaya L.) cultivar Golden nas condições do norte do Espírito Santo

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 Espirito 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

On modeling global solar irradiation using air temperature for Alagoas State, Northeastern Brazil

313.19 e R