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Carvalho D.F.,Federal Rural University of Rio de Janeiro | De Oliveira A.D.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuaria | Pereira J.B.A.,Fitotecnia
Semina:Ciencias Agrarias | Year: 2011

This study was carried out at SIPA (Integrated Agroecological Production System), in Seropédica, RJ, Brazil, with the objective of generating models for characterizing variation and evolution of leaf area index (LAI) and total dry mass of Bell pepper as a function of degree days. Experimental design was of plots split in time, with three replications. The matematical models obtained by regression analysis on the basis of the significance of the coefficients, the F value in the variance analysis of regression, and higher determination coefficient (R 2). Based on adjusted curves for LAI and dry mass and in their respective maximum values degree days is a viable methodology for determination of crop phenological stages. The values of LAI and biomass accumulated by the plants were not significantly different between tillage systems. Bell pepper needed a total of 1533 degree days for completing its productive cycle, with maximum dry mass accumulation occurring at 1059 and 1148 degree days for conventional and no till cropping, respectively. Source

Rubim R.F.,Fitotecnia | Vieira H.D.,Centro Ciencias e Tecnologia Agropecuaria | Araujo E.F.,Federal University of Vicosa | Viana A.P.,Centro Ciencias e Tecnologia Agropecuaria | Coelho F.C.,Centro Ciencias e Tecnologia Agropecuaria
Revista Brasileira de Sementes | Year: 2010

The objective of this study was to evaluate the effect of sodium hypochlorite on the removal of the parchment and the acceleration of conilon coffee seed germination. Seeds of the Vitoria cultivar were obtained from fruits harvested at the cherry stage and pulped by hand. They were dried in a forced ventilation oven until 35, 30 and 25% moisture content on a wet basis. Sodium hypochlorite solution in concentrations of 4, 5, 6 and 7% active chlorine was appliedto those seeds with parchment for periods of 3 and 6 hours. For each moisture content, there were three additional treatments consisting of seeds with parchment and seeds whose parchments had been removed mechanically and manually. The seeds were evaluated for: moisture content, germination, first count of the germination test and speed of the germination index. The experiment was a completely randomized design in a factorial 3 (degrees of water content) × 4 (concentrations of sodium hypochlorite) × 2 (time of immersion) + 9 (additional treatments) with four replications. Sodium hypochlorite at a concentration of 6% for 3 hours caused germination and a speed of germination index similar to the method of manual removal of the parchment, which is used in the laboratory. The mechanical removal of the parchment damaged coffee seeds, reducing their germination. Source

Madalao J.C.,Federal University of Vicosa | Pires F.R.,Federal University of Espirito Santo | Filho A.C.,Federal University of Santa Maria | Nascimento A.F.,Campus CEUNES | And 5 more authors.
Semina:Ciencias Agrarias | Year: 2012

This paper aimed to select species with potential for phytoremediation of soils contaminated with the herbicide sulfentrazone. Eight species were evaluated: Arachis pintoi, Eleusine coracana, Crotalaria spectabilis, Crotalaria ochroleuca, Cajanus cajan, Leucaena leucocephala, Stizolobium cinereum, and Raphanus sativus. The experiment was set-up inside a greenhouse, using pots with a capacity of 6dm3 filled with soil samples collected at a depth of 0-20cm. The experimental design was arranged into randomised blocks in a factorial scheme (8 × 5) with four replications, which consisted of the combination between the species and five doses of sulfentrazone (0, 200, 400, 800, and 1,600g ha-1). The herbicide phytotoxicity, plant heights, and dry masses of shoots and roots were evaluated. The species Cajanus cajan and Leucaena leucocephala had a higher tolerance to sulfentrazone up to a dose of 400g ha-1, showing minor symptoms of phytotoxicity and smaller decreases in plant heights and in dry matter accumulation, both in the shoots and roots, when compared to the control treatment, indicating, thus, the potential to be used for further studies on phytoremediation of sulfentrazone in soil. Source

Petter F.A.,Federal University of Mato Grosso | Alves A.U.,Federal University of Piaui | Da Silva J.A.,Fitotecnia | De Almeida Cardoso E.,Federal University of Paraiba | And 3 more authors.
Semina:Ciencias Agrarias | Year: 2014

Cultural practices affect the production and physiological quality of soybean seeds, however the Cerrado these studies are still scarce. Therefore, this study aimed to evaluate the production and physiological quality of soybean seeds (cv. Monsoy 9350) in Piauí Cerrado under the influence of times and doses of potassium. We used a randomized block design in a factorial design, the treatments consisted of the combination of five doses of potassium (30 60, 90, 120 and 150 kg K2O ha-1) + aditional treatment (zero kg ha-1) applied four times: I. 100% at planting; II. 50 % at planting and 50% at 30 days after sowing (DAS); III. 100% at 30 DAS; IV. 50% at 20 DAS and 50% at 40 DAS, with four replications. The yield and harvest index of grain, thousand seed weight, seedling length, seedling dry weight, rate of germination, germination and first count. Regardless of the applied dose, there was no effect of application times on the parameters evaluated. Except for the germination and germination speed index, all other parameters were significantly influenced by K rates. The length and seedling dry weight increased with the increasing use of K, showing greater seed vigor. Doses of 80 to 95 kg ha -1 K2O provide the best results for all parameters evaluated. Source

da Silva E.C.,Federal University of Sao Joao del Rei | Maciel G.M.,Fitotecnia | da Alvarenga P.P.M.,Federal University of Alfenas | de Paula A.C.C.F.F.,Instituto Federal Of Educacao
Bioscience Journal | Year: 2011

This work was carried out at the Horticultural Section and Experimentation of the José do Rosário Vellano University - UNIFENAS, during the year of 2005. The objective was to evaluate carotenoid content in tomato fruit of industrial tomato plants in relation to potassium and phosphorus concentrations. The experimental design was randomized complete blocks distributed on a 2 x 3 x 3 factorial model containing three replicates: two tomato plant genotypes (1095 and 1570), three K2O concentrations (45, 90 and 180 kg ha-1) and three P2O5 concentrations (40, 80 and 160 kg ha-1). The characteristics evaluated were: lycopene and carotene contents and total sugar in the ripe fruits. The phosphorus and potassium concentrations did not influence significantly B-carotene, lycopene and total sugar in genotypes. Significant differences in the tenors of B-carotene between the genotypes had occurred. Source

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