Foram realizados dois experimentos, com os objetivos de estudar o efeito da correção do valor da condutividade elétrica da solução de embebição (mS cm-1 g¹) em função da condutividade da água e os efeitos do número de sementes e da quantidade de água sobre a condutividade elétrica da solução de embebição, visando o aprimoramento da metodologia deste teste na avaliação do vigor de sementes de milheto. Utilizaram-se três lotes de sementes, sendo o lote 1 representado pela cultivar Comum e os lotes 2 e 3 pela cultivar BN2. No experimento 1 foram avaliadas as condutividades elétricas de 10, 20, 30, 40, 50, 60, 70, 80, 90 e 100 sementes do lote 1, embebidas em 100 ml de água. No experimento 2 foram estudadas as combinações de 25, 50 e 100 sementes e 50, 75 e 100 ml de água para os três lotes. Os testes de condutividade foram conduzidos à temperatura de 25ºC, com 24h de embebição. Empregou-se o delineamento experimental inteiramente casualizado, com quatro repetições por tratamento. Pode-se concluir que: a condutividade da água exerce influência sobre o valor calculado da condutividade elétrica da solução de embebição de sementes de milheto, quando o valor da condutividade da solução é baixo; a utilização de 100 sementes e 100 ml de água foi a melhor combinação para a realização do teste de condutividade elétrica para as sementes de milheto, pois melhor identificou as diferenças entre os lotes. | Two experiments were carried out to study the correction effect of the electrical conductivity value of the imbibition solution (mS cm-1 g-1) as affected by the conductivity of the water used in the test and the effects seed number and volume of water on the electric conductivity of the imbibition solution, to improve the methodology for this test in the evaluation of pearl millet seed vigor. Three seed lots were used, lot 1 represented by cv. Comum and the lots 2 and 3 by cv. BN2. In experiment 1 the electrical conductivities of 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 seeds of lot 1 were evaluated and placed in 100 ml distilled water. In experiment 2 the combinations of 25, 50 and 100 seeds and 50, 75 and 100 ml of water were studied for the three lots. The conductivity tests were carried out at 25 Cº, with 24h imbibition. The statistical model was the complete randomized block, with four replications for all the treatments. The conductivity of the water used in the test influenced the calculated value of the electrical conductivity of the imbibition solution for pearl millet seeds, when the value of the conductivity of the solution is low. The best combination for the electrical conductivity test for pearl millet seeds was 100 seeds and 100 ml of water, because it identified best the differences among the lots.

Em relevo ondulado, a posição do solo na paisagem é importante quanto à quantidade de água armazenada e disponível para as plantas. A camada coesa dos solos dos Tabuleiros Costeiros do Nordeste do Brasil prejudica o fluxo de água no perfil. Em períodos mais chuvosos, pode ocorrer a formação de lençol freático suspenso acima dos horizontes coesos, em decorrência da restrição ao fluxo vertical descendente causada por tais horizontes. Dessa forma, em áreas declivosas, é possível ocorrer o interfluxo (fluxo lateral subsuperficial da água) no sentido morro abaixo sobre os horizontes coesos. Tal hipótese foi avaliada em uma toposseqüência com 190 m de comprimento e 0,097 m m-1 de declividade média, composta por Latossolo Amarelo argissólico coeso-LAx (terço superior), Argissolo Amarelo coeso-PAx (terço médio), solo transicional-PAx/PAC e Argissolo Acinzentado-PAC, não-coeso (terço inferior). Dados de umidade, medidos semanalmente durante o ano de 1996 (53 semanas), em 10 pontos ao longo da toposseqüência e em sete profundidades, permitiram comprovar a hipótese citada, com o interfluxo, acima dos horizontes coesos, proporcionando um aporte maior e mais contínuo de umidade ao longo do tempo, no sentido LAx → PAx → PAx/PAC → PAC. | Soil landscape position is important in relation to the amount of stored and available water for the plants. The cohesive layer in the tableland soil of the Northeast of Brazil hinders the water flow in the profile. During rainy periods, the formation of transitory water tables above cohesive horizons is possible, due to the restriction of descending vertical flow caused by such horizons. Therefore, the occurrence of interflow (downhill lateral subsuperficial water flow) on the cohesive horizons in slope areas is possible. This hypothesis was evaluated in a toposequence with a length of 190 m and a medium slope of 0.097 m m-1, composed by cohesive argisolic Yellow Latosol-LAx (upper third), cohesive Yellow Argisol-PAx (middle third), transitional soil-PAx/PAC, and non-cohesive Gray Argisol-PAC (lower third). Soil water data estimated weekly during the year of 1996 (53 weeks), in ten points along the toposequence and at seven depths, allowed to prove the mentioned hypothesis; interflow, on the cohesive horizons, caused a larger and more continuous moisture contribution on the long term, in the order LAx → PAx → PAx/PAC → PAC.

O presente trabalho teve como objetivo principal, a avaliação do uso dos recursos naturais da microbacia do Córrego dos Araújos, com vista ao aumento da produção de água e melhoria de sua qualidade. Esta Microbacia localiza-se na porção média da bacia do Ribeirão São Bartolomeu, no município de Viçosa, Estado de Minas Gerais. Foi realizado um diagnóstico de sete elementos da Microbacia: água, solo, pastagens, culturas agrícolas, cobertura florestal, estradas e comunidade. Posteriormente, foram identificadas técnicas de recuperação e/ou conservação para cada um destes elementos. Foi simulada a alteração de vazão e da qualidade da água proporcionadas ao Ribeirão São Bartolomeu, caso as ações de recuperação e/ou conservação identificadas para os elementos da microbacia do Córrego dos Araújos, fossem aplicadas em todas outras sub-bacias do Ribeirão. De posse da nova vazão e da qualidade da água, possível de se obter para o Ribeirão São Bartolomeu, procedeu-se um estudo dos benefícios sócio-econômicos que poderiam ser gerados. Utilizou-se para isto, questionário aos produtores da Microbacia, ao Serviço Autônomo de Água e Esgoto e consultas a técnicos e a trabalhos de hidrologistas. O resultado deste estudo mostrou que a Microbacia encontra-se em estado de degradação do ponto de vista da quantidade da água. Quanto a qualidade, apesar da constatação de fontes contaminadoras, esta se constituiu, para o período de seca, como boa no final da Microbacia, dado o poder de purificação que as quedas d água e a vegetação hidrófila possui. Para todos os elementos diagnosticados na Microbacia, pelo menos uma técnica de recuperação e/ou conservação foi proposta. Verificou-se que as técnicas de recuperação e/ou conservação identificadas para a microbacia do Córrego dos Araújos, se forem aplicadas nas demais sub-bacias do Ribeirão São Bartolomeu, podem proporcionar aumento de vazão e melhoria da qualidade da água, gerando assim, benefícios sócio-econômicos (diminuição de custos com energia elétrica e com o tratamento da água bruta, além da diminuição de riscos à saúde dos usuários de água). Conclui-se principalmente que: as áreas de preservação permanente que estão ocupando os solos férteis de uso da comunidade local, prejudicam a sustentabilidade desta comunidade; que muitas ações de degradação são devido à falta de instrução da comunidade; e que, qualquer ação de melhoria da qualidade da água nas bacias de cabeceira serão sentidas pelos seus usuários à jusante, devendo, portanto, os manejadores de bacias hidrográficas, agirem localmente e pensarem globalmente. | The main objective of the present work was to evaluate the use of natural resources of the dos Araújos Creek micro basin viewing the increase in water supply and quality. This micro basin is located in the mean part of the São Bartolomeu Stream basin, in the municipality of Viçosa, Minas Gerais state, Brazil. A diagnosis of seven parameters of the micro basin was made: water, soil, pasture, crops, forest cover, roads and communities. Later, recuperation and, or conservation techniques were identified for each one of these parameters. A change in the flow and water quality for the São Bartolomeu Stream was simulated in the case that recuperation and, or conservation measures identified for the dos Araújos Creek micro basin were applied to all of the other sub basins of the Stream. With the new flow and water quality, which were obtained from the São Bartolomeu Stream a study was made of the social and economic benefits hat could be generated. To reach this objective, a questionnaire was given to the producers of the basin, to the Water and Sewers Autonomous Service as well as questions for technicians and hydrologists. The result of this study was that the micro basin shoved a decrease in water quantity. As to quality, in spite of the contaminant sources observed, it was considered as good, at the end of the micro basin, in the drought period, because of the purifying action of waterfalls and hydrophylous vegetation along the stream. For all the diagnosed parameters in the micro basin, at least one recuperation and, or conservation measures was proposed. It was observed that the recuperation and, or conservation measure identified for the dos Araújos creek micro basin, if applied to the other sub basins of the São Bartolomeu Stream, could provide an increase of flow and improvement of water quality, thus producing social and economic benefits (decrease in costs with electric power and water treatment, and also a decrease in health risks for the water users). The main conclusions were: that the permanent preservation areas located at fertile soils used by the local communities impair the sustainability of the community; that many degradation actions are done due to lack of information of the community; and that any measures taken to improve water quality at the head basin will be felt at end basin by the water users, and, therefore, the basin manager should act locally and think globally. | Conselho Nacional de Desenvolvimento Científico e Tecnológico

A medium-term forecast of the challenges and needs of agriculture at global and regional levels shows that to achieve significant increases in agricultural productivity in the developing countries not only intensification, diversification and specialization of agricultural production systems will be needed but also sustainable use and conservation of the natural resources. In response to this situation, the Joint FAO/IAEA Programme through its Soil and Water Management & Crop Nutrition sub-program, promotes the development and adoption of integrated soil, water and nutrient management practices in well-defined agro-ecosystems and cropping systems through the use of nuclear and related techniques. In the Latin American region there is an operational IAEA Technical Co-operation Project carried out in the frame of the regional program ARCAL (Regional Co-operative Agreement for the Promotion of Nuclear Science and Technology in Latin America and the Caribbean). The main features, activities and outputs/achievements of the project ARCAL XXII "Plant Nutrition, Soil and Water Management" are described. The results obtained in the regional network of field trials illustrate the use of nuclear techniques to generate technologies of integrated and efficient use of water, fertilizers, and alternative nutrient sources and their contribution to increasing agricultural productivity. A logical continuation of the ongoing project will be the formulation of a new one on sustainable management of agricultural production systems and conservation of land resources in Latin America.

4 ilus. 2 tab. 7 ref. 5 pág. | Desde marzo hasta octubre del 2001, se estudió el efecto de la fertilización química nitrogenada en la contaminación del agua con nitratos en dos fincas que poseen sistemas de café (Coffea arabica) con sombra de eucalipto (Eucalyptus deglupta) en la zona Pacífica Sur de Pérez Zeledón, Costa Rica. Las dos fincas recibieron 260 kg N ha-1año-1 hasta el 2000 pero solamente 120 kg N ha-1 en el 2001. Los promedios de N-NO3 registrados en las nacientes son de 0,21mg l-1 bajo bosque y 1 - 1,6 mg l-1 en las dos fincas cafetaleras valores más bajos que los reportados en zonas cafetaleras del Valle Central de Costa Rica (2,1 a 4 mg l-1). Esto podría ser debido al mayor nivel de lluvias, al aporte más bajo de fertilizante y a la baja fertilidad de los suelos en Pérez Zeledón. También el nivel máximo de N-NO3 encontrado en este estudio (5,8 mg l-1) está debajo del valor máximo permisible establecido por la Organización Mundial de la Salud (10 mg l-1). En la estación lluviosa (junio), los contenidos de nitratos en el suelo y en el agua de lixiviación indicaron una acumulación alta de nitratos en el primer metro de suelo (130 kg ha-1) y una concentración media en el agua libre a 1,2 m (6,2 mg l-1). Los niveles más bajos en las nacientes sugirieron adsorción de nitratos o desnitrificación a profundidades más bajas que 1,2 m.

It was studied the distribution patterns of the native European white-clawed crayfish (Austropotamobius pallipes) and the introduced signal crayfish (Pacifastacus leniusculus), and looked at the water chemistry in several streams in the north of the Iberian Peninsula (Cantabrian watershed). Fifty fluvial reaches which were currently or previously inhabited by crayfish and had physical attributes similar to the known habitat requirements of crayfish were sampled. P. leniusculus was the most common species encountered (54 percent of the samples), A. pallipes was found in 19 percent and neither species was recorded in the remaining reaches. In this paper it was determined the relationship between crayfish presence and water chemistry. As neither species inhabits waters with the highest NO2- concentrations found, it seems both species are sensitive to NO2-. Mg+2 and S04-2 concentrations are the factors separating sites with and without crayfish (crayfish inhabit water with higher concentrations of both cations). The main differences between reaches inhabited by native and signal crayfish lies in SO4-2 concentration: higher concentrations favour signal crayfish. Applications to management based on the river water chemistry are proposed

Four «self-built» travertine canals located in the vecinity of the Alicún hydrothermal springs CS Spain) were studied. Two canals are presently functional and their growth patterns have shown that their existences require human maintenance. The ancient canals have been dated by diferent methods (C-14, U-series, and AMS-radiocarbon) and their radiocarbon polen dating are 3660 and 2660 yr B.P. respectively. These data make possible to confirm the existence of an European Neolithic culture, in this area, with water control and management. Finally, the palynologie studies on the travertine canals, reveals the existence of mediterranean-like climatic conditions, at least since 3660 yr B.P. in southern Spain. | Esta investigación ha sido financiada por los proyectos 448 del PCG de la UNESCO, BTE2000-0299 y CLI95-1905 de la DGICYT y el proyecto PIR 9447 de la DGIA.

RESUMEN Utilizando la propuesta de tipología de ríos de la Directiva Marco del Agua en su anexo 2 se realiza un ensayo tipológico de los puntos de muestreo del proyecto GUADALMED. Según el sistema A, se presentan 16 ecotipos, lo que se juzga poco adecuado para la gestión de los mismos y sin una base ecológica que lo justifique. De acuerdo con la selección previa hecha por los miembros del grupo GUADALMED para 5 de estos ecotipos no habría estaciones de referencia. Con algunas variables medidas en los puntos de muestreo y otras de tipo geológico e hidromorfológico, se realiza un ensayo tipológico usando el sistema B. El método implica un análisis de la correlación entre variables, un cluster de las estaciones utilizando el método K-means y un análisis discriminante de cuáles son las variables que distinguen estos grupos. El estudio da como resultado la caracterización de 6 ecotipos que sin embargo, a juicio de los miembros del proyecto GUADALMED, no recogen la variedad de tipos de ríos mediterráneos. Valorando cualitativamente parámetros no introducidos (por falta de datos) en el análisis K-means, se propone una tipología provisional en 9 grupos. Un análisis de las comunidades de macroinvertebrados (a nivel taxonómico de familia) revela un grado importante de coherencia entre las familias asociadas a cada tipo y sus preferencias ecológicas conocidas. ABSTRACT A preliminary analysis was conducted of the river types in the GUADALMED project using the river typology proposed in the Water Framework Directive (WFD) in its annex 2. Using System A, 16 different types were found, a number too high for water management purposes and such typology lacks a supportive ecological basis. For 5 of these 16 ecotypes, no reference stations exist. Reference stations were selected a priori in project GUADALMED for each of the 12 basins sampled. An ecotypological analysis was performed using System B of the WFD using several variables measured during the study, and other variables obtained from maps or data bases (e.g., geology). The method included the analysis of the calibration between variables, the clustering of stations by the K-means method and a discriminant analysis. The latter revealed which factors were distinctive of each group. Six ecotypes were established for the GUADALMED study sites. These, however, do not include all the mediterranean-type streams of the region. This is mainly due to the absence in the data base of some important features of streams in the data base such as temporality or the dependence of flow on the presence of karstic aquifers, attributes

A standardized ecotoxicological evaluation of soil pesticides such as lindane, chlorpyrifos and metamidofos was realized at Federico Villarreal University, Lima, Peru, employing the freshwater snail Physa venustula as a tool for environmental risk assessment. The values determined for mean lethal concentration (LC50) for the lethal effect of the pesticides evaluated were at 24, 48 and 96 h of exposure respectively: lindane 811.89, 715.30 and 415 m g L-1; chlorpyrifos 379.13, 154 and 66.01 m g L-1 and metamidofos 1 791, 391.33 and 194 m g L-1. Sublethal effects were observed with chlorpyrifos and metamidofos. The CE50 values determined for disadherence at 24, 48 and 96 h respectively were chlorpyrifos 197.14, 89.14 and 36.23 m g L-1, and metamidofos 600.81, 361.69 and 150.75 m g L-1. The values for cephalic detachment at 24, 48 and 96 h of exposure respectively were chlorpyrifos 323.69, 109.02 and 60.01m g L-1, and metamidofos 738.4, 314.4 and 155.93 m g L-1. Of the three evaluated pesticides, the decreasing order of ecotoxicity for the lethal effects, at 24 h of exposure was chlorpyrifos > lindane > metamidofos; and at 48 h and 96 h was chlorpyrifos> metamidofos > lindane. For sub-lethal effects the decreasing order of ecotoxicity at 24, 48 and 96 h was chlorpyrifos > metamidofos. This protocol of ecotoxicological assays using P. venustula is proposed as a tool for the evaluation of environmental risks of soil pesticides. | Se realizó una evaluación ecotoxicológica estandarizada de plaguicidas del suelo: lindano, clorpirifos y metamidofos, en la Universidad Federico Villarreal, Lima, Perú, empleando al caracol dulceacuícola Physa venustula como herramienta para la evaluación de riesgos ambientales. Los valores determinados de la concentración letal media (CL50) para el efecto letal de los plaguicidas evaluados fueron a 24, 48 y 96 h de exposición respectivamente: lindano 811,89; 715,30 y 415 m g L-1; clorpirifos 379,13; 154,18 y 66,01 m g L-1 y metamidofos 1 791, 391,33 y 194 m g L-1. Se observaron efectos subletales con clorpirifos y metamidofos. Los valores determinados de concentración efectiva media (CE50) para la desadherencia a 24, 48 y 96 h fueron respectivamente: clorpirifos 197,14; 89,14 y 36,23 m g L-1, y metamidofos 600,81; 361,69 y 150,75 m g L-1. Los valores de CE50 para el desprendimiento cefálico a 24, 48 y 96 h de exposición respectivamente fueron: clorpirifos 323,69; 109,02 y 60,01 m g L-1 y metamidofos 738,4; 314,4 y 155,93 m g L-1. De los tres plaguicidas evaluados el orden de ecotoxicidad decreciente a 24 h de exposición fue: clorpirifos > lindano > metamidofos y a 48 y 96 h fue: clorpirifos > metamidofos > lindano para el efecto letal. En efectos subletales el orden de ecotoxicidad decreciente a 24, 48 y 96h fue clorpirifos > metamidofos. Se propone este protocolo de ensayo ecotoxicológico empleando a P. venustula como una herramienta para la evaluación de riesgos ambientales por plaguicidas de suelo.