José Tadeu Alves da Silva

Adubação com potássio e nitrogênio em três cíclos de produção da bananeira cv. prata-anã

Nitrogen, after potassium, is the chemical element most required by banana crop. This work evaluated the effect of nitrogen and potassium fertilization on irrigated banana crop (Prata-Ana, AAB) yield. Five rates of N (0 , 200 , 400 , 800 and 1600 kg ha-1 year-1) and five rates of K2O (0; 200; 400; 800 and 1600 kg ha-1 year-1), in a (5x5) factorial design were studied. The data were obtained during three yield cycles (second, third and four cycles), on an eutrofic Red-Yellow latosol, sandy-clay, in the North of Minas Gerais State, Brazil. The content of Mn have increased in the leaves with the increased amount of N applied in the soil. The banana yield reduced with the rise of the Mn content in the leaves, on the second and third cycle. The maximum yield was obtained with the application of 962,5 kg of K2O ha-1year-1, on the fourth cycle. No interaction between N and K was found.

Atributos químicos e físicos de solos cultivados com bananeiras 'Prata-Anã' (AAB), em três níveis de produtividade, no norte de Minas Gerais

In order to reach high productivity, banana crops must be cultivated in places with favorable climatic factors that present soil with good chemical and physical properties. The present work has the objective to evaluate the chemical and physical properties of soil cultivated with Prata dwarf banana crops (AAB) in three levels of productivity. A total of 96 commercial banana crops were selected in the North of Minas Gerais. The banana crops were divided in three levels of productivity: low productivity ( 32 t ha-1 year-1). In each selected banana crop, soil samples were collected for chemical and physical analyses. Leaf samples of each banana crop were collected in 20 plants. In the foliares samples were determined the N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn proportions. It was verified that the content of Ca, K, P, organic matter, the values of electric conductivity, CTC, the percentage of saturation per bases (V%), and the amount of clay and silte present were significantly greater in the banana crops of high productivity soil. It was verified that in the banana crops of high productivity soil the amounts of Ca, K and Mg corresponded to 82%, 5% and 13% of the base saturation, respectively. There was no difference among the foliar contents of nutrients in the three banana crops levels of productivity.

Adubação fosfatada em mudas de bananeira 'Prata anã'(AAB), cultivadas em dois Latossolos

Phosphorus fertilization in banana ‘Prata ana’ (AAB) cultivated in two latosols Data on the effect of phosphorus on the development of banana are scarce. The objectives of this work were to evaluate the effect of the application of phosphorus on the development of banana “Prata Ana” growing in a Red Latosol (RL) and a Red-Yellow Latosol (RYL), as well as to determine the phosphorus critical level. The treatments were arranged in a randomized design , using a 8 x 2 in factorial arrangement, with three replications . The factors corresponded to eight phosphorus doses (0; 50; 100; 150; 300; 450; 600; 750 mg.dm -3 ) and the two soil types. The dry mass production of banana seedlings increased with phosphorus application to both soils. Phosphorus soil critical levels in RL and RYL were 18.9 and 40.2 mg dm -3 , respectively. The phosphorus critical levels in the leaves of banana seedlings growing in RL and RYL were 0.20 and 0.31 dag kg -1 , respectively. Phosphorus was used more efficiently by banana seedlings

Critical levels for Brachiaria brizantha and Panicum maximum using different sources of phosphorus

El nivel critico de fosforo se ve influenciado por los atributos fisicos y quimicos del suelo y las caracteristicas de cada especie vegetal. El objetivo de este estudio fue determinar los niveles criticos de fosforo en el suelo y las plantas de Bracharia brizantha cv. Marandu y Panicum maximum cv. Tanzânia, utilizando diferentes dosis y fuentes de P. El trabajo se llevo a cabo bajo condiciones de invernadero utilizando muestras de suelo con diferentes contenidos de arcilla. En el experimento con la hierba Marandu, 20 tratamientos se aplicaron en un diseno factorial (5 x 4), correspondiente a cinco niveles de fosforo (0, 100, 200, 400 y 800 mg dm�3) y cuatro fuentes de fosforo (fosfato monoamonico, superfosfato triple, simple superfosfato y fosfato natural de Gafsa). En el experimento con la hierba Tanzânia, se aplico tambien termofosfato magnesiano. Los tratamientos se dispusieron en un diseno de bloques al azar con cuatro repeticiones. No se observaron diferencias entre los efectos de fosfato monoamonico, superfosfato triple, simple superfosfato, fosfato natural de Gafsa y termofosfato magnesiano en la produccion de materia seca de gramineas Marandu y Tanzânia. El super triple proporciona valores mas bajos de nivel critico de P en el suelo, al paso que el fosfato natural de Gafsa proporciono mas bajos niveles criticos de P en los brotes de hierbas.

Produção da bananeira 'Prata anã'(AAB) em função de diferentes doses e fontes de potássio

Production of banana tree cv. Prata ana (AAB) as a function of different doses and sources of potassium Among the nutrients required by the banana tree, the potassium (K) is what most influences the production of the crop. This study aimed to compare the effects of two K sources, potassium chloride (KCl) and potassium sulfate (K 2 SO 4 ) on production, and estimate the dose of K for maximum physical efficiency (MPE) and maximum economic efficiency (MEE), besides determine the critical levels of leaf K for the banana tree, cultivar Prata ana (AAB) irrigated, cultivated in the semi-arid region of northern Minas Gerais State, Brazil. The experiment was conducted in an oxisol, medium texture. The treatments were derived from the factorial (4 x 2), being four rates of K (0, 400, 800 and 1200 kg ha1 yr-1 of K 2 O) and two K sources (KCl and K 2 SO 4 ), resulting in eight treatments. These were distributed in randomized blocks with four replications. There were no differences among the effects of KCl and K 2 SO 4 on the production of banana. The KCl showed greater economic viability to be used as a source of K. The estimated doses for MPE of banana in the 2nd and 3rd production cycles using the KCl were 827 and 835 kg ha -1 yr -1 of K 2 O, respectively, while for MEE, doses were 157 and 670 kg ha -1 yr -1 of K 2 O, respectively. The critical levels of leaf K obtained in the 2nd and 3rd production cycles were 2.85 dag kg -1 for the MPE and for MEE, the values were 2.41 and 2.80 dag kg -1 , respectively.

Desenvolvimento vegetativo e produção do pinhão-manso em resposta à adubação fosfatada

The industrial processing of mango generates by-products such as kernel and peel that are usually discarded without proper utilization. The objective of this study was to investigate the physicochemical and functional properties of native and acidified starch separated from mango kernels of variety Tommy Atkins, searching for a new source of starch, ways to improve it and contribute to the utilization of residues from the food industry. Kernels were removed manually and starch was extracted. The native starch was acidified with hydrochloric acid and its chemical composition was -determined. Functional and paste properties of native and acidified starch was also determined. The chemical composition of the native starch consisted of 71.56% starch, 7.30% lipids and 5.6% protein. Native and acidified starches showed low resistance to high temperature, with maximum swelling at 75oC of 9.395 and 6.861 g/g, respectively. The solubility increased with temperature achieving the maximum of 48.03% for acidified starch. The native starch had greater capacity to absorb water and oil and greater paste clarity. It also showed the highest peak viscosity, hold on, breakdown, final viscosity, setback and paste temperature than the acidified starch. The native starch can be indicated to make dehydrated soups and meat products, while the acidified starch can be used in frozen and chilled food and candy industry.

Phytotechnical Aspects of Jatropha Farming in Brazil

Surveys ofJatropha curcasL. are being pursued worldwide, but scientific compilations on Jatropha farming are still rare. Since 2008, significant efforts have been made to understand the biological parameters of this species, ranging from genetic diversity to genome sequencing, so that the basics of Jatropha are better known. Emphasis now needs to be placed on crop improvement through selective breeding and biotechnology. However, this effort only makes sense if a cultural system that optimizes the potential of the species has been previously defined. We report our experience over the years concerning the optimization of the propagation system, fertilization, plant nutrition, spacing, crop mechanization, irrigation and culture management, among other farming practices, for Jatropha cultivation. Our discussion applies to the semi-arid region of Brazil that corresponds to the Caatinga biome.

QUALITY OF ‘TAHITI’ ACID LIME FERTILIZED WITH NITROGEN AND POTASSIUM IN THE SEMIARID REGION OF MINAS GERAIS

this study aimed to evaluate external characteristics and juice obtained from ‘tahiti’ acid lime produced under nitrogen and potassium fertilization. this study had a completely randomized design with three replicates of four fruits of the two central plants, 4 x 5 factorial and four N doses (0, 25, 50 and 100 Kg ha-1 year1) and five K2O doses (0, 25, 50, 100 and 200 Kg ha -1 year1), totaling 20 treatments. In the postharvest period, external characteristics (size, color and skin thickness, firmness and fresh mass) and juice (content, percentage, soluble solids, technological index, pH, titratable acidity, ratio and ascorbic acid) of fruits were evaluated. Size, skin color, soluble solids content and pH of ‘tahiti’ acid lime juice were not affected by N and K2O fertilization. Skin thickness, juice percentage and technological index increased with the N and K2O doses applied to the soil. Juice content and fruit firmness decreased with application of K2O doses. titratable acidity and ascorbic acid content increased with K2O doses. the different nitrogen and potassium doses influenced more the juice quality than the external characteristics of ‘Tahiti’ acid lime in the postharvest period.