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Результаты 161-165 из 165
ABSORÇÃO DE NUTRIENTES E SÓDIO PELO CAUPI EM SOLOS SALINO-SÓDICOS CORRIGIDOS COM GESSO
2008
Francisco de Sousa Lima | Maria de Fátima Cavalcanti Barros | Fábio Barbosa Ferraz | Sebastião da Silva Junior | Leandra Brito de Oliveira
The use of mine gypsum in reclamation of soils with high levels of exchangeable sodium is viable by its effectiveness, and although this product show others advantages as low price and easy applicability in field. The product is finding in great amount at the Araripe Highland, located across (between) the division of the Ceará and Pernambuco states. The aim of the research work is to evaluate the shoot dry biomass and Ca+2, Mg+2, K+, P and Na+ accumulation on cowpea plants grown in two saline sodic soils recently amended with gypsum. The experiment was carried out in a completely randomized factorial design with three replications, applying 6 levels of gypsum in two soils. The statistical calculations were achieved using the Program SAEG 9.0 and the standard deviations and the averages were compared by the Tukey test at probability P < 0.05. The effects of gypsum levels and the relationships between the variables were analyzed by the Pearson correlation test. Application of gypsum in different levels reduced sodium uptake and increased shoot dry biomass of cowpea plants grown in the Neossolo Flúvico Eutrófico Saline Sodic soil with medium texture. Higher levels of gypsum promoted reduction in phosphorus accumulation on cowpea plants grown in the Neossolo Fluvico Eutrófico saline sodic soil with medium texture.
Показать больше [+] Меньше [-]PRODUÇÃO DE MILHO (Zea mays L.) EM CONSÓRCIOS COM GRAMÍNEAS FORRAGEIRAS
2008
Edson Tenório da Silva | Jorge Luiz Xavier Lins Cunha | José Antônio da Silva Madalena | José Andre Custódio da Silva | Wéliton Tenório da Silva
The objective of the present experiment was evaluate the effect inter cropping systems with the culture of the maize on the production components, aiming at to maximize the grain production and to increase availability of pastures for animal feeding. The treatments had consisted of the culture of DKB-950 maize (Hybrid Simple Modified), on three grassy species of (Brachiaria decumbens, Brachiaria brizantha and Panicum maximum cv. Tanzania) inter cropping systems and conventional tillege of soil. In foundation one applied 0, 35, 50 and 4 kg ha-1 of N, P, K and Zn respectively in the sulphate form of ammonium, simple superphosphate, potassium sulphate and zinc Sulphate. In covering it applied if 120 kg ha-1 of N. the used espaçamento was of 0,80 x 0,20 m, The experiment was arranged in a randomized complete block design, with four repetitions. The components of the production of the maize had not been affected by the studied systems of inter cropping, except for the number of spikes and production of grains, where the maize cultivated inter cropping systems with Brachiaria decumbens (4.787 kg ha-1) was better that the Tanzania (3.683 kg ha-1). The accumulation of dry mater presented significant difference between the treatments, in the which Tanzânia presented greater accumulates of dry mater.
Показать больше [+] Меньше [-]POTENCIAL GENÉTICO DAS POPULAÇÕES DE MILHO UFVM 100 E UFVM 200 AVALIADAS EM SOLOS COM DEFICIÊNCIA DE NITROGÊNIO
2008
Ricardo Gonçalves Silva | Glauco Vieira Miranda | Cosme Damião Cruz | João Carlos Cardoso Galvão | Débora Gonçalves Silva
The objective of this study was to estimate the genetic potential of two maize populations, in order to verify their genetic potential under two production systems (with and without nitrogen stress). So, 49 half-sib families (FMI) of the population UFVM 100 and 49 FMI of the population UFVM 200 were randomly taken. The 7 x 7 lattice design was used, with two replicates. The high nitrogen level was established with planting fertilization more two side-dressing fertilizations, so totaling 120 kg/ha N (40 kg/ha N in planting fertilization; 40 kg/ha N at the 15 days after emergency - DAE; 40 kg/ha N at 30 DAE). The low nitrogen level was only 20 kg/ha N in planting fertilization. The experimental plot consisted of one row with 5m length and 0.90m spacing between rows and 0.20m among plants inside the rows. All experiments were subjected to water deficit (irrigation interruption) at flowering stage, during 7-day period, until soil water potential was between -0.09 to -0.1 MPa. The grain yield was evaluated in each plot. The variance analysis relative to those 49 FMI of each population in each production system was accomplished according to recommendation by Cochran and Cox (1957), whereas the estimates of the genetic parameters were performed according to method 1 presented by Silva et al. (1999), when considering the lattice experiments. After the individual analyses, those 15% more productive FMI were selected in each production system to estimate the expected selection gain when recombining them. It was found that only the population UFVM 100 shows genetic variability to be explored by selection based on half-sib families, for grain production under low N availability conditions; the estimates of the genetic parameters associated to grain yield were similar as for high and low nitrogen; the consistence of the agreement level between the families´ performances under low and high availability of nitrogen was low, therefore pointing out the need for conducting a specific improvement program when the objective is to obtain material adapted to nitrogen stress conditions.
Показать больше [+] Меньше [-]ESTRUTURA E FLORÍSTICA DE UM REMANESCENTE FLORESTAL NA FAZENDA RIBEIRÃO, MUNICÍPIO DE JUVENÍLIA, MG, BRASIL
2008
Rubens Manoel dos Santos | Fábio de Almeida Vieira | Paola Ferreira Santos | Verlândia de Medeiros Morais | Maria Aparecida de Medeiros
The area of the extreme North of Minas, due to your character ecotone, involves a large number of physiognomies and floristic complexes, but presumably unknown. Thus, the aim of this research was to determine the structure and the floristic composition of an area of arboreal caatinga in Juvenília, Minas Gerais. Hopes to contribute with information that allow, in the future, that is arrived to a classification it aims at and coherent of this vegetation. A sample of 10 (20x20m) plots was allocated (400m2), distributed on a parallel transect to the largest axis of the fragment, and to each 20 meters in this transect two plots were allocated, distanced 10 meters to each other, totaling 0.4ha. All the individuals were registered with CBH (circumference at breast height) > 10cm. In the structure, 36 species with diversity of H' = 2.4 and eqüability of J' = 0.67 were sampled, values middlemen if compared with results of other works developed at Brazilian deciduous seasonal forests. Acacia martii, Caesalpinia pluviosa, Eugenia uniflora and Tabebuia impetiginosa presented the largest values in all the structural parameters analyzed. This links with the high abundance of those species. The community's diameter distributions tended to the normality with smaller amount of individuals in the classes smaller and larger diametric.
Показать больше [+] Меньше [-]CONDICIONAMENTO OSMÓTICO DE SEMENTES
2008
Maria Célia Aroucha Santos | Edna Maria Mendes Aroucha | Marcelo Sobreira de Souza | Roberto Ferreira da Silva | Pahlevi Augusto de Sousa
The osmotic conditioning is a technique that uses inert chemically substances with the aim to begin the essential biochemical processes to embryo growth without there is seedling protrusion. This revision refer the several factors that interfere in the osmotic conditioning technique, as well as the use of chemistries, temperature, conditioning period, drying, storage and seeds revigoration. Other aspects as reduced time to obtain seedling, dormance overcome and seed revigoration.
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