Time filter

Source Type

Montes Claros, Brazil

de Queiroz W.T.,Institute Ciencias Agrarias | Netto S.P.,PUCPR | Valente M.D.R.,Federal University of Para | Pinheiro J.G.,Programa de Pos Graduacao em Ciencias Florestais
Floresta | Year: 2011

This work studied the structural form of the Maltese cross cluster, considering three variables to quantify wood volume, using 25 different sizes of sub-sampling, to define the cluster ideal size through the Maximum Curvature Method and, from this, to study 17 different distances from the subsampling to the cluster central point. The results indicated a size equal to 0,32 ha for a distance of 100 m. When used a sub-sampling size of 0,25 ha, the distance between them and the central point can not be less than 50 m. It was observed that the number of sub-sampling necessary to structuralize a cluster increases when the size decreases, which was verified when the magnitude reached 0,12 ha, where the values of the intracluster correlation coefficients for the three studied variables varied between 0,055 to 0,087 and, consequently, the number of sub-sampling varied from 5,596 to 7,193, denoting to be more efficient a cluster structure in crossed shape, but showing eight sub-sampling. Source

Teles R.F.,Faculdade da Terra de Brasilia | del Menezzi C.H.S.,University of Brasilia | de Souza M.R.,Laboratorio Of Produtos Florestais | de Souza F.,Institute Ciencias Agrarias
Cerne | Year: 2010

This work aims to assess the bending properties of glued laminated timber beams (glulam) manufactured with species louro-vermelho (Sextonia rubra). Laminations were nondestructively tested using the transverse vibration method (EMlam). Then 10 glulam beams were manufactured and tested in static bending according to ASTM D 198 standard, having modulus of elasticity (EM), modulus of rupture (fM), and bending moment (M) determined. The finished beams were also tested by the transverse vibration method (EMvt). It was noted that the EMvt value was only 2% lower than the EM value. Using laminations with a high modulus of elasticity did allow effective gain in stiffness. Therefore, results indicate that the transverse vibration method is a valid, reliable technique both for testing glulam laminations and for assessing stiffness in finished beams. Bending properties in glulam beams were influenced by the stiffness of constituent laminations. Source

de Faria G.,Federal University of Lavras | Guimaraes R.M.,Federal University of Lavras | Carvalho E.R.,Institute Ciencias Agrarias | de Sousa D.P.,Federal University of Lavras
Journal of Seed Science | Year: 2015

Enzyme activity detection in seeds allows the assessment of the deterioration process in the early stages. In this context, the objective was to assess the effectiveness and the degree of similarity between the results of izoenzymes activity using different methods, as follows: spectrophotometry, visual analysis after electrophoresis, evaluation of the bands nodes gels with software GelAnalyzer. 250 hybrid seeds were submitted to artificial aging to form four lots with differences in physiological quality. In addition to the enzymatic determinations, physiological germination tests, emergence and emergence speed index were performed. It was concluded that there are differences in results according to the methods used; the results were consistent between test methods and correlated with physiological results when the catalase enzyme was evaluated; and in the isozyme analysis of superoxide dismutase and alcohol dehydrogenase there was a divergence among the results of the methodologies, and according to such, the relationship to seeds physiological quality. © 2015, Associacao Brasileira de Tecnologia de Sementes. All rights reserved. Source

Lana R.M.Q.,Federal University of Uberlandia | de Oliveira S.A.,University of Brasilia | Lana A.M.Q.,Federal University of Minas Gerais | de Faria M.V.,Institute Ciencias Agrarias
Revista Brasileira de Ciencia do Solo | Year: 2010

A striking characteristic of soils under savanna vegetation is the low natural fertility, as in soils in the Upper Paranaíba region - MG. This characteristic is aggravated by the use of low fertilizer quantities, which may cause nutritional imbalance in plants. The objective of this study was to evaluate the nutritional status of coffee plants in the Upper Paranaíba region - MG, using the integrated system for diagnose and recommendation (DRIS) to interpret leaf analyses and apply the fertilization response potential to the DRIS index and analyze the correlations and interactions between leaf nutrient concentrations and DRIS index. Coffee leaf samples were collected in the initial fruit growth stage, removing two pairs of leaves from each plant in 20 random plants, in 59 commercial plantations of the region. Nutrient levels were determined and interpreted by the DRIS. DRIS indicated that the yield-limiting nutrients were: P, Fe, K = Mn, and Zn = B. The nutrients to which coffee plants tended to respond positively were: P, B, Fe, K, and Mn. The positives correlations between the DRIS index were: N(P, K and S), P(K, Mg and S) and K(Mg and S), and the negatives correlations: N(Ca, B, Fe, and Zn), P(Ca, B, Fe, Mn, and Zn) and K(Ca, B, Fe, Mn, and Zn). Source

Rabelo C.H.S.,Sao Paulo State University | de Rezende A.V.,Institute Ciencias Agrarias | Rabelo F.H.S.,University of Sao Paulo | Basso F.C.,Sao Paulo State University | And 2 more authors.
Revista Caatinga | Year: 2015

The objective of this study was to evaluate the effect of corn plant harvested in diferente ma-turity stages on the chemical composition, digestibility and aerobic stability of silages. The corn used in the study was the hybrid BM3061 harvested after 114, 121, 126, 133 and 140 days of sowing at five maturity stag-es based on the advancement of the grain milk line (early dent (ED), 1/3 of milk line (ML), 1/2 ML, 2/3 ML and black layer (BL)). A variation from 242.7 to 377.4 g of dry matter (DM) kg-1as fed was observed between the ED and BL stages; however, the measurements performed in this study did not exhibited major changes in the composition of these silages. The silages produced with plants that were harvested at the 1/2 ML, 2/3 ML and BL stages showed lower DM loss during the fermentative process. The silages produced with plants that were harvested at the ED and 1/3 ML stages showed higher in vitro organic matter digestibility (IVOMD) (0.584 and 0.631 g g-1 of OM, respectively). The corn silages produced at the maturity stage of 2/3 ML showed a higher aerobic stability (104 hours) during the aerobic exposure. The 1/3 and 2/3 ML maturity stages seem to be the best harvest stages for the production of corn silage in tropical climates. © 2015, Universidade Federal Rural do Semi-Arid. All rights reserved. Source

Discover hidden collaborations