Dynamics of soil exploration by fine roots down to a depth of 10 m throughout the entire rotation in Eucalyptus grandis plantations

Although highly weathered soils cover considerable areas in tropical regions, little is known about exploration by roots in deep soil layers. Intensively managed Eucalyptus plantations are simple forest ecosystems that can provide an insight into the belowground growth strategy of fast-growing tropical trees. Fast exploration of deep soil layers by eucalypt fine roots may contribute to achieving a gross primary production that is among the highest in the world for forests. Soil exploration by fine roots down to a depth of 10 m was studied throughout the complete cycle in Eucalyptus grandis plantations managed in short rotation. Intersects of fine roots, less than 1 mm in diameter, and medium-sized roots, 1-3 mm in diameter, were counted on trench walls in a chronosequence of 1-, 2-, 3.5-, and 6-year-old plantations on a sandy soil, as well as in an adjacent 6-year-old stand growing in a clayey soil. Two soil profiles were studied down to a depth of 10 m in each stand (down to 6 m at ages 1 and 2 years) and 4 soil profiles down to 1.5-3.0 m deep. The root intersects were counted on 224 m(2) of trench walls in 15 pits. Monitoring the soil water content showed that, after clear cutting, almost all the available water stored down to a depth of 7 m was taken up by tree roots within 1.1 year of planting. The soil space was explored intensively by fine roots down to a depth of 3 m from 1 year after planting, with an increase in anisotropy in the upper layers throughout the rotation. About 60% of fine root intersects were found at a depth of more than 1 m, irrespective of stand age. The root distribution was isotropic in deep soil layers and kriged maps showed fine root clumping. A considerable volume of soil was explored by fine roots in eucalypt plantations on deep tropical soils, which might prevent water and nutrient losses by deep drainage after canopy closure and contribute to maximizing resource uses.

Theoretical and experimental study of agricultural spraying using CFD

This paper presents a computational fluid dynamics (CFD) application about the axial fan design used in an agricultural spraying system with a theoretical and experimental analysis of comparative results between the characteristic curves of a fan for several rotations and numerical results for the influence of blade attack angle variation and optimization of the spraying system, both for a same rotation. Flow was considered three-dimensional, turbulent, isothermal, viscous and non-compressible in a steady state, disregarding any influence of the gravity field. The average turbulent field was obtained from the application of time average where the turbulence model required for closing the set of equations was the k-E model. Resolution of all connected phenomena was achieved with the help of a fluid dynamics computer, CFX, which uses the finite volumes technique as a numerical method. In order to validate the theoretical analysis, an experiment was conducted in a circular section of a horizontal wind tunnel, using a Pitot tube for pressure readings. The main results demonstrate that the methodology used, based on CFD techniques, is able to reproduce the phenomenological behavior of an axial fan in a spraying system because results were very reliable and similar to experimentally measured ones.

Congo grass grown in rotation with soybean affects phosphorus bound to soil carbon

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aspectos da furação do titânio 6Al4V com broca de aço rápido sinterizado e broca de metal duro

Pós-graduação em Engenharia Mecânica - FEG

Using ecological thresholds to evaluate the costs and benefits of set-asides in a biodiversity hotspot

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sobre a dinâmica de rotação de um planeta através de um sistema médio

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Involutions whose fixed set has three or four components: a small codimension phenomenon

Let T : M → M be a smooth involution on a closed smooth manifold and F = n j=0 F j the fixed point set of T, where F j denotes the union of those components of F having dimension j and thus n is the dimension of the component of F of largest dimension. In this paper we prove the following result, which characterizes a small codimension phenomenon: suppose that n ≥ 4 is even and F has one of the following forms: 1) F = F n ∪ F 3 ∪ F 2 ∪ {point}; 2) F = F n ∪ F 3 ∪ F 2 ; 3) F = F n ∪ F 3 ∪ {point}; or 4) F = F n ∪ F 3 . Also, suppose that the normal bundles of F n, F 3 and F 2 in M do not bound. If k denote the codimension of F n, then k ≤ 4. Further, we construct involutions showing that this bound is best possible in the cases 2) and 4), and in the cases 1) and 3) when n is of the form n = 4t, with t ≥ 1.

Sistema eletrohidráulico para acionamento da esteira vibratória do arrancador-invertedor de amendoim

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Confecção e montagem do set-up ortodôntico

Diagnosis and planning stages are critical to the success of orthodontic treatment, in which the orthodontist should have many elements that contribute to the most appropriate decision-making. The orthodontic set-up is an important resource in the planning of corrective orthodontics therapy. It consists of the repositioning of the teeth previously removed from the study dental casts and reassembled on its remaining basis. When properly made, the set-up allows a three-dimensional preview of problems and limitations of the case, assisting in decision-making regarding tooth extractions in cases with problems of space, amount of anchorage loss extent and type of tooth movement, discrepancy of dental arch perimeter, discrepancy of inter-arch tooth volume, among others, indicating the best option for treatment. This paper outlines the most important steps for its confection, an evaluation system and its application in the preparation of orthodontic treatment planning.

Montagem e confecção do set up ortodôntico

Diagnosis and planning stages are critical to the success of orthodontic treatment, in which the orthodontist should have many elements that contribute to the most appropriate decision-making. The orthodontic set-up is an important resource in the planning of corrective orthodontics therapy. It consists of the repositioning of the teeth previously removed from the study dental casts and reassembled on its remaining basis. When properly made, the set-up allows a three-dimensional preview of problems and limitations of the case, assisting in decision-making regarding tooth extractions in cases with problems of space, amount of anchorage loss extent and type of tooth movement, discrepancy of dental arch perimeter, discrepancy of inter-arch tooth volume, among others, indicating the best option for treatment. This paper outlines the most important steps for its confection, an evaluation system and its application in the preparation of orthodontic treatment planning.

Effects of surface application of dolomitic limestone and calcium-magnesium silicate on soybean and maize in rotation with green manure in a tropical region

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Response to comment on "Using ecological thresholds to evaluate the costs and benefits of set-asides in a biodiversity hotspot"

Finney claims that we did not include transaction costs while assessing the economic costs of a set-aside program in Brazil and that accounting for them could potentially render large payments for environmental services (PES) projects unfeasible. We agree with the need for a better understanding of transaction costs but provide evidence that they do not alter the feasibility of the set-aside scheme we proposed.

Diploid chromosome set of kissing bug Triatoma baratai (Hemiptera, Triatominae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A survey on the set of periods of the graph homeomorphisms

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estimativas dos parâmetros genéticos para seleção de árvores de Eucalyptus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)