Cowpea Yield Under Water Stress Scenarios

Cowpea is considered a subsistence crop, so it is generally cultivated by  family farming in the rainy season and, outside this season, with the aid of irrigation. Its yield is reduced if there is water stress due to the lack of rainfall or irrigation water. Objective of this study was to evaluate the influence of water stress in the rainy and dry seasons on grain yield, biomass, harvest index and water use efficiency in the ‘Costela de Vaca’ cowpea variety cultivated in no-tillage system using crop residues present in the experimental area. Experimental design used was randomized blocks, in a 2 x 5 factorial scheme (cropping season x water stress), with four replicates. Treatments consisted of two cropping seasons (rainy and dry) and five forms of water stress (without water stress, water suspension for 5, 10 and 15 days, and rainfed cultivation). Biomass was the only parameter influenced by the cropping season versus water stress interaction. Regardless of the cowpea cropping season, water stress reduced grain yield and biomass. Harvest index showed no sensitivity to water stress and cropping season. Water use efficiency was influenced by the cropping season. Soil cover promoted maintenance of soil moisture during cowpea cultivation in both periods.

WATER DEMAND AND TECHNICAL-ECONOMIC VIABILITY OF COWPEA GROWN IN DIFFERENT PRODUCTION SCENARIOS

Water demand and agronomic and economic efficiency of cowpea are strongly related to agricultural practices and climatic conditions. This study aimed to determine in which cropping season cowpea has the highest water demand and maximum agronomic and economic efficiency as a function of water stress under the edaphoclimatic conditions of the semi-arid region of northeastern Brazil. Cowpea was cultivated in two cropping seasons (rainy and dry) and subjected to five forms of water stress (without water stress, water suspension for 5, 10 and 15 days and rainfed cultivation) and four replicates, started in the flowering and grain filling stages, under no-tillage system. Agronomic (yield, biomass, harvest index and water use efficiency) and economic (gross revenue, net revenue, rate of return and profit margin) parameters were evaluated. The water demand of cowpea in the dry season was 20.2% higher than in the rainy season; consequently, the Kc values obtained were also higher in this period. The climatic conditions that occurred during the cropping seasons and water stress negatively influenced the agronomic performance and financial profitability of cowpea, being more evident in the rainfed cultivation. For the edaphoclimatic conditions of the study, cowpea can be grown without significant losses of yield and profitability in both cropping seasons, provided that the water stress does not last more than 10 days during its reproductive stage.ABSTRACT: Water demand and agronomic and economic efficiency of cowpea are strongly related to agricultural practices and climatic conditions. This study aimed to determine in which cropping season cowpea has the highest water demand and maximum agronomic and economic efficiency as a function of water stress under the edaphoclimatic conditions of the semi-arid region of northeastern Brazil. Cowpea was cultivated in two cropping seasons (rainy and dry) and subjected to five forms of water stress (without water stress, water suspension for 5, 10 and 15 days and rainfed cultivation) and four replicates, started in the flowering and grain filling stages, under no-tillage system. Agronomic (yield, biomass, harvest index and water use efficiency) and economic (gross revenue, net revenue, rate of return and profit margin) parameters were evaluated. The water demand of cowpea in the dry season was 20.2% higher than in the rainy season; consequently, the Kc values obtained were also higher in this period. The climatic conditions that occurred during the cropping seasons and water stress negatively influenced the agronomic performance and financial profitability of cowpea, being more evident in the rainfed cultivation. For the edaphoclimatic conditions of the study, cowpea can be grown without significant losses of yield and profitability in both cropping seasons, provided that the water stress does not last more than 10 days during its reproductive stage. Keywords: profitability; Vigna unguiculata; water stress; cropping season   Demanda hídrica e viabilidade técnico-econômica do feijão-caupi cultivado em diferentes cenários produtivos   RESUMO - A demanda hídrica e a eficiência agronômica e econômica do feijão-caupi estão fortemente relacionados com as práticas agrícolas e a condições climáticas. Este trabalho teve como objetivo determinar em qual época de cultivo o feijão-caupi apresenta maior demanda hídrica e máxima eficiência agronômica e econômica em função do estresse hídrico, nas condições edafoclimáticas da região semiárida do nordeste do Brasil. O feijão-caupi foi cultivado em dois períodos de cultivo (chuvoso e seco) e submetido a cinco formas de estresse hídrico (sem estresse hídrico, suspensão de água de 5, 10 e 15 dias e plantio de sequeiro) com quatro repetições, iniciado nas fases de floração e enchimento de grãos, em sistema de plantio direto. Foram avaliados parâmetros agronômicos (produtividade, biomassa, índice de colheita e eficiência do uso da água) e econômicos (renda bruta, renda líquida, taxa de retorno e margem de lucro). A demanda hídrica do feijão-caupi no período seco foi 20,2% superior a do período chuvoso, consequentemente, os valores de Kc obtidos também foram superiores nesse período. As condições climáticas ocorridas nos períodos de cultivos e o estresse hídrico influenciaram negativamente no desempenho agronômico e rentabilidade financeira do feijão-caupi, sendo mais evidenciada no cultivo de sequeiro. Para as condições edafoclimáticas do estudo, o feijão-caupi pode ser cultivado sem significativas perdas de produtividade e rentabilidade em ambos os períodos de cultivo, desde que o estresse hídrico não seja superior a 10 dias durante sua fase reprodutiva. Palavras-chave: rentabilidade; Vigna unguiculata; estresse hídrico; época de cultivo

Potencial geoturístico das quedas d'água de Indianópolis-MG para o público escolar: unindo ciência e contemplação

The city of Indianópolis is located in the Mineiro Triangle and is recognized by the beauty and diversity of its waterfalls. These attributes have led us to study such city, searching for the identification of the geotouristic potential of its waterfalls for educational activities, as well as select one which shows to be the most suitable for the scholars. The methodology used in the beginning involved bibliographical research about the theme, field work in the area of the waterfalls and, finally, office work, a moment in which data were interpreted and crossed. From the methodology used one has the conclusion that the waterfalls of Indianópolis present a great potential to be used by geotourism, and also the Salto de Furnas (Furnas's leap) has presented the Best place for educational activities, due to, among other factors, the facility to access it, lithoestratigraphic richness, preservation state, etc.O município de Indianópolis está localizado no Triângulo Mineiro e é reconhecido pela beleza e diversidade de suas quedas d'água. Esses atributos nos levaram a estudar tal município, buscando identificar o potencial geoturístico de suas quedas para atividades educativas, bem como selecionar uma que se mostre mais adequada para o público escolar. A metodologia empregada inicialmente envolveu pesquisa bibliográfica sobre a temática em questão, trabalhos de campo na área de ocorrência das quedas e, por fim, trabalhos de gabinete, momento no qual os dados foram interpretados e relacionados. A partir da metodologia empregada conclui-se que as quedas d'água de Indianópolis apresentam grande potencial para serem aproveitadas pelo geoturismo, sendo que o Salto de Furnas apresentou-se como o melhor local para realização de atividades educativas, devido, entre outros, a facilidade de acesso, riqueza litoestratigráfica, grau de preservação etc

Aspectos gerais do clima do arquipélago de Cabo VerdeGeneral aspects of the climate in the Cabo verde archipelago

O clima das ilhas do arquipélago de Cabo Verde sempre impôs muitas restrições ao desenvolvimento da atividade agrícola, devido a um regime pluviométrico com baixos volumes e concentrado numa única estação, chamada estação das águas (agosto - outubro). O presente estudo utiliza as metodologias apresentadas por Thornthwaite e o sistema de classificação de Köppen para avaliar e caracterizar o clima no arquipélago de Cabo Verde. Foram utilizadas séries temporais mensais de precipitação e de temperatura do ar mais longa possível e disponível para as diversas ilhas, que variaram entre 20 e 30 anos de dados. Para as localidades que existem dados de precipitação e não dispunham de dados de temperatura, elas foram estimadas com base no modelo em função das coordenadas geográficas. Os resultados do trabalho permitiram concluir que o período chuvoso de Cabo Verde coincide com o período mais quente do arquipélago. Além disso, o clima do arquipélago varia de semiárido a árido, exceto a ilha do Fogo que apresenta algumas áreas com clima sub úmido. O clima desse arquipélago também pode ser classificado, de forma geral, como seco desértico muito quente com chuva de inverno e irregulares pela classificação de Köppen.Abstract The climate on islands of Cape Verde has always imposed many restrictions on agricultural development due to low rainfall regime mainly concentrated in a single season, called of rainy season (August-October). This study used the methodologies presented by Thornthwaite and the Köppen classification for evaluating and to characterize the climate in the Cape Verde archipelago. It was used time series of both monthly rainfall and air temperature as long as possible as well as available to the various islands on the archipelago, ranging between 20 and 30 years. For locations with rainfall data but no air temperature data, air temperature were estimated based on the model as a function of geographic coordinates. The results indicate that the rainy season in Cape Verde coincides with the hottest period on the archipelago, due to convective effects. Moreover, the climate on the archipelago ranges from arid to semiarid, except in the island of Fogo, which presents some areas with sub humid climate according to the Thornthwaite classification. In general form, the climate on the archipelago can also be classified as hot and dry deserts with irregular winter rainfall according to climate classification of Köppen

Variabilidade da Velocidade do Vento e Influências Oceânicas: Uma Abordagem Para Fins de Geração de Energia Elétrica no Nordeste do Brasil

Informações sobre o potencial eólico de uma região são relevantes para o gerenciamento e monitoramento em parques eólicos para fins de geração de energia elétrica. Neste trabalho foram utilizados dados da velocidade do vento a 10 m de altura da superfície, oriundos do European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim, para avaliar a sua variabilidade sazonal e interanual na Região Nordeste do Brasil. Os resultados obtidos indicam que a primavera é a estação do ano com maior intensidade do vento, enquanto que o outono é a de menor intensidade. Em anos de atuação de El Niño o vento é mais intenso que o valor médio (ultrapassando 45% no outono e até 25% na primavera), enquanto que em anos de La Niña esse ficou abaixo da média nas áreas com maior potencial eólico médio (40% no outono e de até 30% na primavera). Os episódios de Gradiente/Dipolo de Temperatura da Superfície do Mar (TSM) do Oceano Atlântico positivo acarretam ventos mais intensos que o normal (até 35% na parte norte da região), contrário aos anos de eventos de Gradiente/Dipolo negativo onde os ventos ficam com intensidade abaixo da média (até 40% no outono)

IDENTIFICAÇÃO E CLASSIFICAÇÃO ESPAÇO-TEMPORAL DE EVENTOS CRÍTICOS CHUVOSOS OU SECOS OCORRIDOS EM PERNAMBUCO

The objective of this study was to analyze the dry and wet events historically occurred in the Pernambuco state and diagnose their intensities and durations. The identification and classification of areas susceptible to critical events has become a frequent need in the current context of climate change, which has caused disasters in the world. The diagnosis based on meteorological, agricultural and hydrological impacts can be measured with the application of the methodology of the Standardized Precipitation Index (SPI) for different time scales. The SPI was able to identify critical events in the state of Pernambuco and highlight the main through their intensities and durations. Scales were analyzed from quarterly to biennial which indicated the beginning, trend, duration and intensity of events. The results identified years with rainfall events in the moderate and severe categories, but also dry events in moderate to extreme categories. It was observed that the values of correlations between SPI scales are better as they approach in time. The cluster analysis of the SPIs showed well-defined areas, up to four groups, at all scales of time, this indicates that these groups have similar behavior during critical events.O objetivo deste estudo foi analisar os eventos secos e chuvosos historicamente ocorridos no estado de Pernambuco e diagnosticar suas intensidades e durações. A identificação e classificação de áreas susceptível a ocorrência de eventos críticos tornou-se uma necessidade frequente no contexto atual das mudanças climáticas, que vem provocando catástrofes no mundo. O diagnóstico com base nos impactos meteorológicos, agrícola e hidrológico pode ser aferido com a aplicação da metodologia do Índice de Precipitação Padronizado (em inglês SPI) para diferentes escalas temporais. O SPI foi capaz de identificar os eventos críticos ocorridos no estado de Pernambuco e destacar os principais através de suas intensidades e durações. Foram analisadas escalas desde trimestrais até bienais o que indicou o início, tendência, duração e intensidade dos eventos. Nos resultados se identificou anos com eventos chuvosos nas categorias moderada e severa, mas também eventos secos nas categorias de moderada a extrema. Observou-se que os valores das correlações entre as escalas do SPI são melhores à medida que se aproximam no tempo. A análise de agrupamento do SPI mostrou áreas bem definidas, até quatro grupos, em todas as escalas de tempo, isto indica que esses grupos têm comportamentos similares durante a ocorrência de eventos críticos

FOUR DECADES OF HYDROLOGICAL PROCESS SIMULATION OF THE ITACAIÚNAS RIVER WATERSHED, SOUTHEAST AMAZON

The impacts of anthropogenic degradation are becoming increasingly more evident in the Amazon and are jeopardizing its environmental systems and water resources, particularly in low monitored watersheds. Thus, the use of hydrological models is necessary to gain an understanding of these impacts on Amazonian river systems. The aim of this study was to analyze the simulation of some hydrological processes in the Itacaiúnas River watershed and its relation with human-induced impacts in the Southeast region of the Pará state using the Soil and Water Assessment Tool (SWAT) model. SWAT modeling requires several databases, such as relief, land use and land occupation, soil type, and climatic and hydrological variables. These data are input parameters for the SWAT model. The results showed that the hydrological variables in the Amazon tend to follow the seasonal precipitation cycle, with the highest values occurring between January and June and lowest between July and November. It was evident that base and lateral flows are responsible for maintaining perennial river flow during the dry season. Regarding anthropogenic actions in the watershed, precipitation, evapotranspiration, and sediment transportation are clearly affected by environmental degradation, as well as by the replacement of forest by grassland and mining activities. The results may assist in public policy including mitigation and adaptation of environmental systems in the region. In addition, they can improve the management of natural resources in the Itacaiúnas River watershed

Modelo integrado das pegadas hídrica, ecológica e de carbono para o monitoramento da pressão humana sobre o planetaAn integrated approach based on water, ecological and carbon footprint for tracking human pressure on the planet

Modelos de pegadas de carbono ecológicos e de água estão sendo cada vez mais usado para monitorar uso pessoal e doméstico dos recursos naturais. As pegadas humanas são uma séria ameaça global e cada nação está olhando para as opções possíveis para reduzi-las pois suas conseqüências são alarmantes. Este trabalho propõe uma pegada integrada como ferramenta para avaliar os impactos ambientais diretos e indiretos da atividade humana. Com base nas definições das pegadas de carbono, hídrica e ecológica, um modelo empírico foi construído para a avaliação dos impactos ambientais da produção e consumo. Neste trabalho, foi definido, pela primeira vez, o termo “pegada ambiental” como um conjunto de indicadores para acompanhar a pressão humana sobre o planeta sob ângulos diferentes, constituindo-se, assim, o Índice de Sustentabilidade Ambiental Multidimensional (ISAM). Esse índice foi construído na premissa de que nenhum indicador, por si só, é capaz de monitorar de forma abrangente o impacto humano sobre o meio ambiente; os indicadores precisam ser usados e interpretados em conjunto. Semelhanças e diferenças entre os três indicadores são, então, destaque para mostrar como esses indicadores se sobrepõem, interagem e se complementam. A revisão conclui que a “pegada ambiental” é adequada para avaliar sustentabilidade.Abstract Carbon, ecological and water footprints models are increasingly being used for monitoring personal and domestic use of natural resources. These human footprints are a serious global threat and every nation is looking at the possible options to reduce it since its consequences are alarming. This work proposes an integrated footprint as a tool for assessing the direct and indirect environmental impacts from human activity. Based on the definition of carbon, water and ecological footprints, an empirical model was built for the assessment of the environmental impacts of production and consumption. In this work the term “environmental footprint” was first defined as a set of indicators to track human pressure on the planet from different angles, constituting, therefore, the Environmental Sustainability Index Multidimensional (ISAM). This index is built on the premise that no indicator by itself is able to comprehensively monitor human impact on the environment, but indicators must be used and interpreted together. Similarities and differences among the three indicators are then highlighted to show how these indicators overlap, interact, and complement each other. The review concludes that “footprint environmental” is appropriate to assess sustainability

DOWNWARD LONGWAVE RADIATION ESTIMATES FOR CLEAR AND ALL-SKY CONDITIONS IN CENTRAL AMAZONIA

The downward longwave radiation (L↓), really is difficult of the net radiation the measured values component. Therefore, different parameterizations have been proposed to estimate it. Thus, in this study we evaluated the performance of various parameterizations for the L↓ flows estimated and their interaction with other variables measured as well as the air temperature and water vapour pressure interactions with L↓. In this study evaluates the performance of the downward longwave radiation parameters for clear and cloudy sky days applied in Central Amazonia region. The datasets used in this study was measured from micrometeorological tower controlled by Large Scale Biosphere Atmosphere experiment in Amazonia (LBA) from Manaus city, Amazonas. It was also found that precipitation and water vapour pressure exert enough on L↓ flows influence, especially in the wet season. The models for clear-sky conditions proposed, using their original coefficients trend to underestimate the L↓ flows measured. Best results for clear-sky were obtained with Idso & Jackson (1969), Brutsaert (1975) and Prata (1996)