Erosão entre sulcos em diferentes condições de cobertura do solo, sob cultivo da cana-de-açúcar

A erosão entressulcos acontece pela desagregação originada do impacto das gotas de chuva e pelo transporte do escoamento superficial, por arraste e suspensão das partículas superficiais do solo desagregadas, onde se encontram a matéria orgânica e os nutrientes fundamentais para a produção agrícola. O trabalho objetivou avaliar o efeito de diferentes coberturas do solo em área de cultivo de cana-de-açúcar sob o escoamento superficial na erosão entressulcos. As condições avaliadas foram: solo descoberto; resíduo em contato direto com o solo; dossel da cana-de-açúcar e efeito somado do dossel da cana-de-açúcar e do resíduo em contato com o solo, para três e 12 meses após o corte da cana-planta. Os regimes de escoamento na erosão entressulcos foram laminar lento, e a erodibilidade para o Argissolo Vermelho-Amarelo foi de 1,87 x 10(6) kg s m-4, por conta da presença de mica e caulinita. O resíduo da cana em contato direto com o solo destacou-se no aumento da rugosidade hidráulica, e o dossel pela interceptação da chuva que retardou o início do escoamento superficial, possibilitando maiores taxas de infiltração de água no solo e menores taxas da erosão entressulcos

INFLUÊNCIA DA COBERTURA DO SOLO NAS PERDAS DE ÁGUA E DESAGREGAÇÃO DO SOLO EM ENTRESSULCOS

The process of water erosion soil involves the detachment of particles soil by raindrop impact, the transport and consequently your deposition, by overland flow of water on the soil. This drainage happens in the flow form to laminate shallow what characterizes the interrill erosion. The work evaluated the efficiency in the different ways of soil cover provided by the sugarcane in the control of the losses of water and of the rates of detachment of the soil. The appraised treatments were: bary soil, residue under surface; dossal of the sugarcane and the added effect of the residue + dossal. The regime of found drainage, to laminate slow, it characterizes the interril erosion. The vegetable covering promoted by the culture of the sugarcane it promoted reduction in the rates of detachment of the soil. The residue in direct contact with soil and with the drainage it was responsible for the increment of the rugosidade, however, it provided low infiltration rates with consequent increase of the rates of loss of water, for constituting in a vegetable layer that hindered the infiltration. The dossal of the cane of suugarcane promoted a larger interception of the rain, delaying the beginning of the drainage, checking the largest infiltration rates obtained

EFEITO DA COMPACTAÇÃO EM DOIS SOLOS DE CLASSES TEXTURAIS DIFERENTES NA CULTURA DO RABANETE

The decrease in pore that are submitted to the certain pressure, causes an increase soil bulk density, causing the compactação process, affecting the ideal development of crop root system. Consequently the present study has as obejective to evaluate the effects of different compaction levels in two soils with differrent textural classes on the yilol of aerial biomass and root of radish. The experiment was carried out in a green house at the, UFRPE, where two samples of soils from 0-20 cm with the following textural classes: sand clay loan (NITOSSOLO) compacted to bulk densities of 1,05; 1,26 and 1,47 g cm-3 and sandy (PLANOSSOLO) compacted to densities of 1,54; 1,76 and 1,98 g cm-3. A severe reduction was observed in the production of bulbs a function of the levels compaction where in the sand clay loan texture there was no development of the bulbs in the density of 1,47 g cm-3, differing from at observed in the sandy texture soil, where the largest density (1,98 g cm-3), showed development of the bulbs. The compaction in subsurface alters the distribution of the root system of he crop along the profile of the soils, without decrease in the production of roots

HIDRÁULICA E TAXAS DE EROSÃO EM ENTRESSULCOS SOB DIFERENTES DECLIVIDADE E DOSES DE COBERTURA MORTA

The interrill erosion can be the most harmful form water erosion, due it drags of the superficial layer of the soil, where it essential elements to the crop development. This work had the objective of evaluating the soil losses for different slopes and doses of residue of sugar-cane straw. The experiment was led at Soil Conservation laboratory of UFRPE, it was constituted in the evaluation of the water erosion obtained under simulate rains in experimental portions (1,0 m x 0,5 m x 0,1 m). It was observed that there was difference for the applied doses of 0,4 and 0,6 kg m-2 of soil cover, in relation to the bare soil, so much for the soil losses as for it rates them of soil detachment, demonstrating the effectiveness of the cover of the soil in the reduction of the erosion rates. With relationship to the applied slopes, therewas an increase of the soil losses and of the rates of soil detachment, with the elevation of the slopes among all the cover doses. The residues in the surface of the soil reduce the rates of soil detachment and they increase the resistance to the surface water, provoking decrease of the Numbers of Reynolds and of Froude, evidencing the interrill erosion. The laminar slow regime of surface water to attest the interrill erosion

LINHAS ISOEROSIVAS DO ESTADO DE PERNAMBUCO - 1ª APROXIMAÇÃO

Erosivity is the potential ability of rain to cause erosion on somewhere. With the objective of mapping the rainfall erosivity in the entire State of Pernambuco, the average monthly values of the EI30 index with were correlated with Fournier rainfall coefficient and the average monthly precipitation, as well as the yearly values of the index EI with average yearly precipitation values. Data from 11 localities representative of their distinct climatic regions were utilized. From the best regression equations found for each region, the average yearly values of the EI30 index were calculated ( Factor R of Universal Soil Loss Equation - USLE) for 96 localities in the State, based on periods of 14 to 75 years of rainfall records. The values of erosivity found varied from 1,500 to 10,000 (Mj mm ha-1 h-1 year-1), where the Zona da Mata, Agreste and Sertão regions presented a moderate erosive potential, with values from 1,500 to 3,500 (Mj mm ha-1 h-1 year-1). The litoral region, was characterized by high erosivity, with annual average values of the index EI bethween 5.500 to 10.000 (Mj mm ha-1 h-1 year-1)

The recent dynamics of agribusiness sector from the west of Pará (Brazil): soybean expansion and logistical corridors

A expansão da soja no Brasil tem transformado áreas rurais e fomentado a instalação de estruturas logísticas, sobretudo na região amazônica. O objetivo deste artigo é compreender a dinâmica de expansão da soja e de estruturação de corredores logísticos nesta região e seus impactos sobre a mercantilização da terra. A partir de levantamento bibliográfico, dados secundários e da realização de trabalho de campo, se problematiza as formas pelas quais esse processo vem se dando na área do Oeste do Pará, uma das principais e recentes “fronteiras agrícolas e de estruturação de corredores logísticos” no Brasil. Os resultados indicam uma intensa expansão da soja na região, bem como a consolidação deste corredor logístico, fruto de um conjunto de estratégias, nem sempre convergentes, implementadas por diferentes atores sociais.The expantion of soybean in Brazil has transformed rural landscapes and fostered the installation of large logistical structures, especially in the Amazon region. The aim of this paper is to understand the dynamics of soybean expansion and the structuring of logistical corridors in this region and its impacts on land commodification. Based on a bibliographic survey and secondary data, and the realization of fieldwork, in this article we seek to problematize the ways in which this process has been taking place in the Western Pará region, one of the main and recent “agricultural borders and structuring of logistical corridors” in Brazil. The results indicate an intense expansion of soy in the region, as well as the consolidation of this logistical corridor, the result of a set of strategies, not always convergent, implemented by different social actors.Instituto de Investigaciones en Humanidades y Ciencias Sociale

Dinâmicas recentes do agronegócio no Oeste do Pará (Brasil): expansão da soja e estruturação de corredores logísticos

The expantion of soybean in Brazil has transformed rural landscapes and fostered the installation of large logistical structures, especially in the Amazon region. The aim of this paper is to understand the dynamics of soybean expansion and the structuring of logistical corridors in this region and its impacts on land commodification. Based on a bibliographic survey and secondary data, and the realization of fieldwork, in this article we seek to problematize the ways in which this process has been taking place in the Western Pará region, one of the main and recent “agricultural borders and structuring of logistical corridors” in Brazil. The results indicate an intense expansion of soy in the region, as well as the consolidation of this logistical corridor, the result of a set of strategies, not always convergent, implemented by different social actors.A expansão da soja no Brasil tem transformado áreas rurais e fomentado a instalação de estruturas logísticas, sobretudo na região amazônica. O objetivo deste artigo é compreender a dinâmica de expansão da soja e de estruturação de corredores logísticos nesta região e seus impactos sobre a mercantilização da terra. A partir de levantamento bibliográfico, dados secundários e da realização de trabalho de campo, se problematiza as formas pelas quais esse processo vem se dando na área do Oeste do Pará, uma das principais e recentes “fronteiras agrícolas e de estruturação de corredores logísticos” no Brasil. Os resultados indicam uma intensa expansão da soja na região, bem como a consolidação deste corredor logístico, fruto de um conjunto de estratégias, nem sempre convergentes, implementadas por diferentes atores sociais.A expansão da soja no Brasil tem transformado áreas rurais e fomentado a instalação de estruturas logísticas, sobretudo na região amazônica. O objetivo deste artigo é compreender a dinâmica de expansão da soja e de estruturação de corredores logísticos nesta região e seus impactos sobre a mercantilização da terra. A partir de levantamento bibliográfico, dados secundários e da realização de trabalho de campo, se problematiza as formas pelas quais esse processo vem se dando na área do Oeste do Pará, uma das principais e recentes “fronteiras agrícolas e de estruturação de corredores logísticos” no Brasil. Os resultados indicam uma intensa expansão da soja na região, bem como a consolidação deste corredor logístico, fruto de um conjunto de estratégias, nem sempre convergentes, implementadas por diferentes atores sociais

RESPOSTAS DE BIOMARCADORES MUSCULARES A UMA PARTIDA DE FUTEBOL

Exhausting physical exercise damages muscular tissue. Among other factors, damage depends on training load and intensity. The aim of this study was to determine changes in enzymatic biomarkers in response to a football match. The study sample was composed of 30 football players aged between 18–35 years and male, divided into experimental (GE; N = 15) and control (GC; N = 15) groups. Blood samples from GE and GC individuals were withdrawn before and 24 hours after the match. The following enzymes were examined: total creatine kinase (CKt), cardiac muscle creatine kinase (CKMB), lactate dehydrogenase (LDH), and gamma-glutamyl transpeptidase (GGT). In GE individuals, there were significant changes (p<0.05) in CKt (334±203 and 860±553 U/L), CKMB (30±7 and 42±11 U/L), and LDH (417±86 and 547±84 U/L) between before and after the match, respectively; GGT remained unchanged. In GC individuals, levels were similar at the two time points. A football game is sufficiently aggressive to induce tissue damage, as evidenced by increased plasma levels of various enzymes. Enzyme clearance assessment might be a valuable tool for development of training programs