Modelagem da erosão como subsídio a implantação do Programa Produtor de Águas na Bacia do Ribeirão Pipiripau.

Abstract: Payment for Environmental Services (PES) has assumed increasing importance in discussions about sustainable development strategies. Many of the PES programs are based on water erosion control and the corresponding environmental and economic benefits generated in the basins where they are implemented. The main objective of this study was to show how erosion susceptibility models can support PES programs. The application of the Universal Soil Loss Equation (USLE) in the Pipiripau River Basin was used as study case. The USLE application in a spatially distributed form proved to be an important support tool for land management and the implementation of PSE policies. The results show that a large part of the studied basin presents 'Low' susceptibility to erosion, what is great in terms of use and conservation of ecosystem services, as well as a limitation regarding the need for implantation of PES programs for erosion control. Incentives for maintaining the natural vegetation in areas with higher erosion susceptibility and conserving rural roads justify PES programs in the basin. Soil and water conservation practices should be implemented in agricultural areas, but, as they occupy, in general, regions with low susceptibility to erosion, it is expected that their impacts will be realized mainly because of the high percentage of the area under this use

Multivariate analyses to establish reference values for soils in Médio Paraíba, state of Rio de Janeiro, Brazil.

Quality Reference Values (QRVs) for potentially toxic elements are obtained from background levels in soils. However, this determination from mean values or percentiles is not appropriate given the variability in the natural distribution of these elements in soils. Therefore, the objective of this study was to propose a new methodology to establish the QRVs, using the Médio Paraíba region (RJ, Brazil) as an example, from groups of soils defined based on the pseudo-total levels of B, Ba, Co, Cr, Cu, Ni, Pb, and Zn through the use of multivariate analyses and discriminant functions. A total of 40 points, collected at depths of 0-20 and 20-40 cm, were used for the determination of pseudo-total contents, according to the EPA 3051A methodology. The samples were separated into three groups to better represent the variability of the soils of the region. The classification functions were obtained based on the variables Mn, Fe, and Mg. In general, the groups G1 and G2 presented lower values than the ones obtained when the sample universe was used, whereas G3 presented higher values. The QRVs obtained from the soil groups presented substantial differences that translate into advantages for the management of the contaminated areas of the region. Valores de Referência de Qualidade (VRQ) para elementos potencialmente tóxicos são obtidos através dos teores naturais nos solos. No entanto, esta determinação a partir de valores médios ou de percentis não é adequada, diante da variabilidade existente na distribuição natural desses elementos nos solos. Diante disso, o objetivo do estudo foi propor uma nova metodologia de estabelecimento dos VRQs, usando como exemplo a Região do Médio Paraíba - RJ, a partir de grupos de solos definidos com base nos teores pseudo-totais de B, Ba, Co, Cr, Cu, Ni, Pb e Zn, mediante a utilização de análises multivariadas e de funções discriminantes. Foram utilizados 40 pontos, coletados nas profundidades 0-20 e 20-40 cm, para a determinação dos teores pseudo-totais, conforme a metodologia EPA 3051A. As amostras foram separadas em três grupos, para melhor representar a variabilidade existente nos solos da região. As funções de classificação foram obtidas com base nas variáveis Mn, Fe e Mg. Em geral, os grupos G1 e G2 apresentaram valores inferiores, em relação aos obtidos quando se utilizou o universo amostral. Enquanto que, G3 apresentou valores superiores. Os VRQs obtidos a partir de grupos de solos apresentaram diferenças substanciais que traduzem vantagens para o gerenciamento de áreas contaminadas da região

Comparing methods for extracting heavy metals from Histosols for establishing quality reference values.

The diversity of methods for heavy metal extraction from soils complicates comparison of results used by environmental agencies to establish quality reference values. The aim of this study was to evaluate three soil digestion methods regarding the solubilizing capacity of Ba, Cr, Cu, Fe, Mn, Ni, Pb and Zn, and to propose a standard method to establish Quality Reference Values (QRVs) for Brazilian Histosols. Twenty soil samples were selected to evaluate the USEPA 3051, USEPA 3051A and Aqua Regia methods in a closed system. The methods tested were statistically similar regarding Cu, Fe and Mn extraction from soils. However, the methods can not be considered similar for Ba, Cr, Ni, Pb and Zn; Aqua Regia recorded the highest levels, except for Ba. The Aqua Regia method proved suitable for metal extraction from soils with organic characteristics and can be used to establish QRVs

Alguns aspectos fisiológicos da mangueira em condições irrigadas e estresse hídrico.

O presente trabalho objetiva analisar o comportamento do ciclo diurno da transpiração, resistência estomática, energia fotossinteticamente ativa, temperatura do ar e das folhas da mangueira,variedade Tommy Atkins,em condições irrigada e de estress ehídrico.Coordenado por Abel Rebouças São José, Tiyoko Nair HOJO Rebouças, Daniel Nieto Angel, Ivan Vilas Bôas Souza, Nilma Oliveira Dias, Marinês Pereira Bomfim. Trabalhos apresentados no I Simpósio Latino Americano sobre Produção de Manga, 1999, Vitória da Conquista, BA

Qualitative Characteristics of Meat from Lambs Fed Hydrolyzed Sugarcane

We used 24 Ile de France lambs, weighing between 15 and 32 kg (BW). Treatments were supplemented with concentrate: "in nature" sugarcane (IN), sugarcane hydrolyzed using 0.6% calcium oxide (CaO) under aerobic condition (AER), and sugarcane hydrolyzed using 0.6% CaO under anaerobic condition (ANA), constituting a completely randomized design with eight repetitions per treatment. Lambs were housed in individual stalls and fed into the through, allowing 10% of leftovers. Lambs were slaughtered when body weight reached 32 kg. The following parameters were determined on Longissimus lumborum muscle of hot and cold carcasses: pH and color, 45 minutes and 24 hours after slaughtering. Qualitative analysis of the meat were performed in the loins, water-holding capacity (WHC), cooking loss (CL), and shear force (SF). We used a completely randomized design with three treatments and eight repetitions. Means were compared by Tukey test at 5% significance. A higher value for redness (a*) 45 minutes after slaughter (10.48) was found for lambs fed sugarcane hydrolyzed under anaerobic conditions. The other qualitative characteristics of meat were not affected by treatments (P >0.05). The comparison of meat quality resulting from the treatments shows that it is possible to feed in nature sugarcane to lambs, thus waiving hydrolyses process and the spending with alkalizing agent

Alguns aspectos fisiologicos da mangueira em condicoes irrigada e de estresse hidrico.

Este estudo analisou medidas porométricas feitas em um pomar de manga, variedade Tommy Atkins, plantado em Fevereiro de 1993, e irrigado por gotejamento no campo experimental da Embrapa Semi-Árido em Petrolina, PE, Brasil (Latitude: 090 09`S, Longitude: 400 22`W; altitude: 365,5m), usando um porômetro de difusão, LI - 1600 (Licor, EUA)

Instalação de calhas de monitoramento da enxurrada para apoio a estudos hidrológicos no Bioma Cerrado.

A Equação Universal de Perda de Solo (EUPS), apesar de suas reconhecidas limitações, continua sendo uma ferramenta muito utilizada na modelagem do potencial e da taxa de erosão em vertentes e bacias hidrográficas de todo o Brasil. Contudo, destaca-se o fato de que em grande parte dessas aplicações, por falta de levantamentos dos valores dos parâmetros específicos para nossas regiões, são utilizados dados de áreas com características distintas ou obtidos por meio do uso de equações empíricas não validadas para o local, suscitando incerteza aos resultados das simulações. O objetivo deste trabalho é apresentar a experiência no processo de instalação de calhas de monitoramento da enxurrada na Embrapa Cerrados, como forma de motivar outros grupos de pesquisa na busca por valores de parâmetros fundamentais para o adequado uso de modelos hidrológicos, hidrossedimentológicos e de qualidade da água nas diferentes regiões do país. Foram construídas oito calhas com chapas galvanizadas e dimensões de 21 x 3m, em dois tipos de solo. As informações apresentadas no trabalho fornecem subsídios em relação aos materiais, custos e procedimentos para a implantação de calhas de monitoramento de enxurrada. Abstract: Universal Soil Loss Equation (USLE), despite its recognized limitations, remains a very useful tool in modeling the potential and the rate of erosion on hillslopes and watersheds throughout Brazil. However, in most of these applications, due to lack of surveys of specific parameter values to our regions, data from areas with different characteristics or obtained through the use of non-validated empirical equations for the local has been used, bringing uncertainties to the results of the simulations. The objective of this paper is to present the experience in the process of installing runoff monitoring plots at Embrapa Cerrados as a way to motivate other groups in the search for key parameters values required for the appropriate use of hydrologic, hydro-sedimentologic and water quality models in different regions of the country. Eight monitoring plots of 21 x 3m were constructed using galvanized steel sheets, in two different soil types. The information presented in this paper provides subsidies in relation to materials, costs and procedures for installing runoff monitoring plots