Carlos Alberto Vieira de Azevedo

Resposta da cana-de-açúcar, primeira soca, a níveis de irrigação e adubação de cobertura

This research was accomplished in the Capim Farm of the Distillery Miriri located in the municipality of Capim city in Paraiba state, Brazil, with the objective of identifying the behavior of sugarcane crop, second leaf, for different irrigation water depths and levels of topdressing manuring with a mixture containing N and K2O in 1:0.94 proportion. With this purpose, an experiment was conducted using the variety SP79-1011, in completely randomized blocks in a factorial scheme of 4 x 2 (four irrigation depths and two levels of topdressing manuring), with three replications. The total water applied in the respective treatments was 807, 986, 1164 and 1343 mm and the levels of topdressing manuring were 85 and 305 kg ha-1. The growth, quality and yield parameters of sugarcane were analyzed. The irrigations prevailed in the initial growth phase of the second leaf and at the beginning of maximum development. The manuring dose influenced more the analyzed parameters than the water depth. The water depth influenced significantly, according to a positive linear behavior, the parameters of growth; while the sucrose (POL) of the cane showed a quadratic behavior.

Doses de adubação nitrogenada e potássica em cobertura na cultura da cana-de-açúcar, primeira soca, com e sem irrigação

O presente trabalho teve como objetivo avaliar os efeitos de diferentes doses de N e K2O, aplicados em cobertura, no desenvolvimento e rendimento de colmos, acucar e alcool da cana-soca (Saccharum spp, cultivar SP79 1011) cultivada com e sem irrigacao, em area da Destilaria Miriri, municipio de Capim, PB. O arranjo experimental foi um fatorial 2 x 4 (com e sem irrigacao, e quatro doses de adubacao de cobertura de N e K2O) com tres repeticoes. A lâmina de irrigacao usada, 27,5 mm, foi aplicada em intervalos de irrigacao de 12 dias. As adubacoes de cobertura foram compostas dos elementos N e K2 O aplicando-se respectivamente: AC1 = 44 e 41, AC2 = 86 e 81, AC3 = 157 e 148; e AC4 = 236 e 222 kg ha-1. As interacoes estudadas regime de irrigacao x doses de adubacao de cobertura foram nao-significativas. Quando submetida a irrigacao, a cultura apresentou melhores rendimentos em todas as variaveis avaliadas, exceto peso medio do colmo, quando comparada a nao irrigada. Nas parcelas irrigadas, a dose de adubacao influenciou significativamente, segundo um comportamento linear positivo, os rendimentos de colmos, acucar e alcool, enquanto que nas parcelas nao irrigadas esse efeito so foi evidenciado no rendimento dos colmos. A maxima dose de adubacao de cobertura utilizada no presente trabalho nao foi suficiente para se atingir picos maximos de rendimentos, seja no regime irrigado ou nao.

Comportamento morfofisiológico da mamoneira BRS Energia submetida à irrigação com água salina

An experiment was conducted at the experimental station of Irrigation and Drainage of the Instituto Federal Baiano, to evaluate the growth variables of the castor bean BRS Energia as a function of salinity of irrigation water in lysimeters. The treatments were constituted of water salinity levels of 0.12; 0.8; 1.6; 2.4; 3.2; 4.0 and 4.8 dS m-1, disposed in a completely randomized design, with three replications and four plants per treatment. Fortnightly from 20 to 80 days after emergence, the growth variables and the absolute and relative growth rates of plant height, stem diameter and leaf area of plants were evaluated. The growth measured by height, stem diameter, leaf area and the rates of absolute and relative growth of each variable, decreased with increase in irrigation water salinity in all periods. The restrictions were in response to increase in soil salinity levels from non saline soil to slightly, moderately and strongly saline soil.

Características vegetativas do coentro submetido a doses do polímero hidroabsorvente e lâminas de irrigação

This study had the objective of evaluating the effect of five doses of the hidratassolo® hydrogel polymer 0, 4, 8, 12 and 16 dg kg-1 of dry soil, and two irrigation water depths, 60 and 120% of the reference evapotranspiration, on the vegetative characteristics of coriander. A completely randomized experimental design was adopted in split-plots, with four replications. At two stages of coriander growth the water use efficiency, the yield of green and dry matter, and the number of plants increased linearly with the elevation of dose of the polymer, when the smallest water depth was applied, except in the prediction of the height of plants at the first stage of planting according to quadratic model. With application of higher water depth (120%), the estimates of the appraised characteristics with significant interaction were maximized with ideal doses in the range of 6 to 11 dg kg-1 , and also the employment of the maximum dose of 16 dg kg-1 provided a fall in relation to the control.

Índice de área foliar e produtividade do tomate sob condições de ambiente protegido

The tomato cultivation in the greenhouse has been expanded in the last years, mainly, in the South and Southeast regions of Brazil, whose purpose is to improve the productivity and the quality of the agricultural products, offering regularity in the production. The present study aimed to determine, along the crop cycle, the relationship between the leaf area index and the productivity, and at the end of the cycle, the components of production of the tomato in the greenhouse. The models were generated through polynomial equations of 1st and 2nd order, having as independent variable the number of days after the transplanting. It was verified that it is possible to determine, in the greenhouse, through mathematical models, the leaf area index of the tomato crop considering the days after the transplanting. Basing on values of leaf area index, the productivity of the crop and the period of the maximum productivity can be determined, aiding the farmers to determine the best sowing and transplanting time of the tomato crop.

Redistribuição de nutrientes em folhas de pinhão-manso entre estádios fenológicos

Nutrient redistribution from mature leaves to growing structures is an important process in plant physiology. Each nutrient is redistributed in a different rate and time. This study aimed to quantify redistribution of macronutriens and minor nutrients in Jatropha curcas leaves through five phenological phases (expanding leaf, young leaf, mature leaf, senescing leaf, and dry leaf). It was observed that the nutrients P, K, Cu, and Zn are intensively redistributed from older to younger jatropha leaves, while N, Ca, Mg, Fe, and Mn are poorly redistributed. Leaf senescence causes a loss of the nutrients that are not redistributed because they will need to be re-absorbed for supporting the growth of new structures in the plant.

Posição da folha e estádio fenológico do ramo para análise foliar do pinhão-manso

ABSTRACT Leaf analysis is an important tool for prediction of nutritional disorders and evaluation of nutritionalstatus of plants. This procedure only can be effective if samples are standardized regarding leaf positionand phenological stage of the branch. This study had the objective of defining the most appropriate leafposition and type of branch for nutritional diagnosis of Jatropha plants. A factorial combination of fiveleaf positions (1 st , 2 nd , 3 rd , 5 th , and 10 node from apex to base) and two types of branch (vegetative andflowering) was adopted in a completely randomized design with four replications. Each leaf sample wascollected in 4 secondary branches of 20 plants in the flowering phase. Leaves in the position 2 and 3 arethe most adequate for analyzing N, P, K, S, Cu, Fe, Mn, and Zn, because they present mean values morestable when compared to the other studied positions. Leaves in the position 5 and 10 are more adequatefor analyzing Ca and Mg. The phenological stage of the branch does not influence nutrient content,except of Cu and Fe.

Displacement of solutes in soil columns with domestic and swine raising wastewater

With the objective of evaluating the parameters of transport retardation factor, dispersion-diffusion coefficient and effluent curves of the ions calcium, magnesium, sodium and potassium, present in domestic and swine raising wastewater, an experiment was conducted in laboratory with columns of Red Yellow Argisol and Regolithic Fluvisol. With the aid of flasks of Mariotte around two pore volumes of distilled water were passed in the columns; soon after, another flask was interconnected containing the wastewaters which leached 3.75 volume of pores divided in 25 aliqnot, totaling 600 samples. The obtained results lead to the conclussion that the retardation factors were higher for the sodium in the Red Yellow Argisol and for the magnesium in Regolithic Fluvisol leached with treated domestic wastewater. In reference to the swine raising wastewater, the largest values were calculated for the ion magnesium, in the two soils; as for the dispersion-diffusion coefficients, the highest values were observed for Regolithic Fluvisol, independent of the type of water.

Yield of bell pepper cultivated in greenhouse under different doses of nitrogen through fertirrigation

Aiming to evaluate the effect of doses of nitrogen applied via fertirrigation on the yield of bell pepper cultivated in greenhouse, this work was conducted at the Center of Agrarian Sciences - UFPB. The experiment consisted of five treatments (0, 100, 200, 300 and 400 kg ha-1 of N) and 4 repetitions. Total, commercial and non-commercial fruit yields were evaluated, and the relationship between the leaf area and the leaf area index with the yields were determined. The doses of nitrogen influenced linearly and positively the total (commercial plus non-commercial fruits) and for the commercial yield of fruits, and for non-commercial fruits of the bell pepper a quadratic function was observed. The thermal accumulation of the bell pepper to reach the phase of larger yield was of 1.668 oC, and to complete its whole phenologic cycle, 2.155 GDA were necessary. The leaf area and the leaf area index affected the total yield of fruits of bell pepper, in a linear and positive way. The leaf area index showed itself to be satisfactory for the conditions of this experiment, demonstrating that the density of the plants used was adequate.

Evapotranspiration and crop coefficient of Kaki tomato cultivated in greenhouse

The aerodynamic parameters of a crop cultivated in greenhouse can be considered dependent upon the level of global radiation, air temperature and relative humidity, based on exponential laws. Consequently, this work intends to estimate the evapotranspiration and the crop coefficient of Kaki tomato in greenhouse, under drip irrigation, using the Penman-Monteith model. The aerodynamic parameters were measured with sensors connected to the automatic station installed inside the greenhouse. The ETc was determined experimentally through drainage lysimeters and the soil water content was measured through sensors installed at a depth of 20 cm. The performance of the Penman-Monteith model was compared to decennial values of the water balance in the lysimeters, while the reference evapotranspiration was calculated with external data and used for calculation of crop Kc. The results indicated that the Penman-Monteith model underestimates the evapotranspiration values found by the water balance in the lysimeters.