Soil and crop residue CO2-C emission under tillage systems in sugarcane-producing areas of southern Brazil

Appropriate management of agricultural crop residues could result in increases on soil organic carbon (SOC) and help to mitigate gas effect. To distinguish the contributions of SOC and sugarcane (Saccharum spp.) residues to the short-term CO2-C loss, we studied the infl uence of several tillage systems: heavy offset disk harrow (HO), chisel plow (CP), rotary tiller (RT), and sugarcane mill tiller (SM) in 2008, and CP, RT, SM, moldboard (MP), and subsoiler (SUB) in 2009, with and without sugarcane residues relative to no-till (NT) in the sugarcane producing region of Brazil. Soil CO2-C emissions were measured daily for two weeks after tillage using portable soil respiration systems. Daily CO2-C emissions declined after tillage regardless of tillage system. In 2008, total CO2-C from SOC and/or residue decomposition was greater for RT and lowest for CP. In 2009, emission was greatest for MP and CP with residues, and smallest for NT. SOC and residue contributed 47% and 41%, respectively, to total CO2-C emissions. Regarding the estimated emissions from sugarcane residue and SOC decomposition within the measurement period, CO2-C factor was similar to sugarcane residue and soil organic carbon decomposition, depending on the tillage system applied. Our approach may define new emission factors that are associated to tillage operations on bare or sugarcane-residue-covered soils to estimate the total carbon loss.

Algunas reflexiones sobre los censos del 90: posibles áreas de colaboración = Some thoughts concerning the 1990 censuses: possible areas for co-operation

Incluye Bibliografía

Integrated quality assessment of sediments from harbour areas in Santos-São Vicente Estuarine System, Southern Brazil

Santos-São Vicente Estuarine System is a highly populated coastal zone in Brazil and where it is located the major port of Latin America. Historically, port activities, industrial and domestic effluents discharges have constituted the main sources of contaminants to estuarine system. This study aimed to assess the recent status of sediment quality from 5 zones of Port of Santos by applying a lines-of-evidence approach through integrating results of: (1) acute toxicity of whole sediment and chronic toxicity of liquid phases; (2) grain size, organic matter, organic carbon, nitrogen, phosphorus, trace metals, polycyclic aromatic hydrocarbons, linear alkylbenzenes and butyltins; (3) benthic community descriptors. Results revealed a gradient of increasing contamination for metals and organic compounds, alongside with their geochemical carriers. Sediment liquid phases were more toxic compared to whole sediment. Low number of species and individuals indicated the impoverishment of benthic community. The use of site-specific sediment quality guidelines was more appropriate to predict sediment toxicity. The integration of results through Sediment Quality Triad approach and principal component analysis allowed observing the effects of natural stressors and dredging on sediment quality and benthic distribution. Even with recent governmental efforts to control, pollution is still relevant in Port of Santos and a threat to local ecosystems. © 2013 Elsevier Ltd.

El régimen de salarios y su influencia en la selección de la mano de obra rural: estudio de algunas comunas rurales de la periferia de la ciudad de Santiago = Wage structure and its influence on the selection of rural labour: survey of a number of rural communes in the Santiago areas

Los documentos del Seminario fueron publicados por UNESCO en 1961 con el título: La urbanización en América Latina/Urbanization in Latin America

Aplicabilidad del desarrollo de la comunidad a las zonas rurales = Aplicability of community development to urban areas

Los documentos del Seminario fueron publicados por UNESCO en 1961 con el título: La urbanización en América Latina/Urbanization in Latin America

La protección y el manejo de océanos, mares y zonas costeras en la Plataforma de Tlatelolco sobre Medio Ambiente y Desarrollo: un análisis práctico de sus alcances = The protection and management of oceans, seas and coastal areas under the Tlatelolco Platform on Environment and Development: a practical analysis of its implications

Incluye Bibliografía

El manejo del agua en las áreas metropolitanas de América Latina = Water management in metropolitan areas of Latin America

Incluye Bibliografía

Urban poor and productivity: keys to action. Public programmes aimed at raising productivity of poor sectors in urban areas of Jamaica

Includes bibliography

Apoyo a la productividad de los pobres rurales: nuevas experiencias en América Latina y el Caribe: current experience in increasing the productivity level among the poor sector in rural areas of Dominica: the case of Petite Savanne

Includes bibliography

Informe del Seminario Nacional sobre Gestión del Desarrollo Agrícola Sustentable en Areas Marginales de Chile

Incluye Bibliografía

Extração semi-automática de rodovias no espaço-objeto: uso integrado de um estéreo par de imagens aéreas e um MDT

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ajuste radiométrico de imagens aéreas digitais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)