Impactos das mudanças climáticas na demanda de irrigação da bananeira na Bacia do Jaguaribe Impact of climate change on irrigation requirement of banana in Jaguaribe river Basin, Ceará, Brazil

As mudanças climáticas têm potencial de alterar os processos do ciclo hidrológico, tais como precipitação, que afeta o escoamento superficial, temperatura e umidade relativa do ar devido à sua estreita relação com evaporação e vazão em corpos hídricos e evapotranspiração das plantas. O objetivo do presente trabalho foi analisar os impactos das mudanças climáticas na necessidade hídrica da cultura da bananeira, considerando-se cenários de mudanças climáticas em escala local, em nível de bacia hidrográfica (rio Jaguaribe, no trecho compreendido entre as barragens do Castanhão e de Itaiçaba). Um conjunto composto de uma baseline (climatologia de base) do modelo de 1961-1990 e de projeções climáticas, foi processado. Os dados foram então extraídos considerando-se as coordenadas geográficas da região em estudo, com resolução de 0,44 x 0,44º, a fim de abranger toda a área. Estimou-se a evapotranspiração de referência (ETo) através de dados da temperatura média mensal e se projetou uma elevação na necessidade hídrica bruta média anual para 2040 com relação às condições iniciais, de 1.989 mm para 2.536 mm e 2.491 mm (27,50 e 25,24%) para os cenários A2 e B2, elaborados pelo Painel Intergovernamental de Mudanças Climáticas, respectivamente.Climate change has a potential to impact hydrologic cycle processes, such as rainfall, which affect run-off, temperature and air humidity that have relationship to evaporation over water bodies and plant evapotranspiration. The purpose of this study was to assess impacts of climate change on irrigation water demand of banana, at the river basin level (Jaguaribe river, between Castanhão and Itaiçaba Dams). A climate data set was generated by a climate model for 1961-90 (baseline) and the future. The output climate data has been generated, considering a georreferenced coordenated system of the study area in a 0.44 x 0.44º resolution, generating spatial distribution output for each variable. The reference evapotranspiration has been estimated using monthly average temperature and projected an increase in mean water requirements for 2040 in relation to initial conditions from 1.989 mm to 2.536 mm and 2.491 mm (27.50 and 25.24%) for A2 and B2 scenarios, developed by Intergovernamental Panel on Climate Change, respectively

Recursos hídricos subterrâneos para fins agropecuários no semiárido brasileiro

[EN] Exploitation of groundwater resources with no proper characterization of water reserves jeopardizes the quantity and quality of water available in the future. A major challenge is finding appropriate methods or coefficients to evaluate the carrying capacity of the aquifer. The objective of this study was to quantitatively and qualitatively characterize water reserves to provide information and management strategies for the rational use of available water resources in an alluvial aquifer in the Brazilian Northeastern semi-arid region. Shallow and medium-depth wells were analyzed. Water tables were monitored in the dry and wet seasons to calculate water reserves. Groundwater samples were collected for the determination of water quality for irrigation purposes. The increase in agricultural activities is jeopardizing the sustainability of the aquifer’s water, as reserves are not sufficient to meet this demand. Groundwater quality is not limiting for agricultural use. Converting surface irrigation into localized methods will potentially increase water productivity and consequently the irrigated area. This study provides data and makes it possible to recommend appropriate strategies for the exploitation of groundwater resources for the maintenance of agricultural activities under semi-arid conditions, and to avoid overexploitation.[PT] A explotação dos recursos hídricos subterrâneos sem a caracterização adequada das reservas hídricas compromete a quantidade e a qualidade da água disponível no futuro. Um grande desafio é encontrar métodos ou coeficientes apropriados para avaliar a capacidade de recarga do aquífero. Objetivou-se caracterizar qualiquantitativamente as reservas hídricas, com vistas a disponibilizar informações e estratégias de gerenciamento para o uso racional dos recursos hídricos disponíveis em um aquífero aluvial no semiárido do Nordeste brasileiro. Foram analisados poços rasos e de média profundidade. Os níveis estáticos dos poços foram monitorados nos períodos secos e chuvosos para calcular as reservas hídricas. Foram coletadas amostras de água para a determinação da qualidade da água para fins de irrigação. A constante ampliação de áreas para atividades agropecuárias está comprometendo a sustentabilidade hídrica do aquífero, uma vez que as reservas não são suficientes para atender a essa demanda. A qualidade das águas subterrâneas não é limitante para uso agropecuário. A conversão da irrigação por superfície em métodos localizados irá proporcionar o aumento da produtividade da água e, consequentemente, a área irrigada. O estudo fornece dados e permite recomendar estratégias apropriadas para a explotação dos recursos hídricos subterrâneos, com vistas à manutenção das atividades agropecuárias em condições semiáridas, de modo a evitar a superexplotação.This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). Acknowledgments are also due to the Agência Estadual de Desenvolvimento do Ceará (ADECE), Secretaria de Desenvolvimento Econômico e Trabalho do Ceará (SEDET), Centro do Instituto de Educação Tecnológica (CENTEC), Fundação de Amparo à Pesquisa Científica e Desenvolvimento Tecnológico do Ceará (FUNCAP), and Chief Scientist Program, Brazil, for the financial support provided for this research and the award of scholarships.Peer reviewe

CLIMATE CHANGE IMPACTS ON WATER DEMAND OF MELON PLANTS IN JAGUARIBE-APODI REGION, BRAZIL

<div><p>ABSTRACT The aim of this study was to evaluate the impacts of climate change on irrigation water demand of melon plants grown in Jaguaribe-Apodi Irrigation District (DIJA), which is located between the states of Ceará and Rio Grande do Norte, in Northeastern Brazil. Future scenarios were developed using the Eta-CPTEC/HadCM3 climate change projections, after being submitted to downscaling method. We used a set of climate data from the same model for the period of 1961 through 1990, and further projections after bias correction. Local geographic coordinates were interpolated using GIS techniques. Reference evapotranspiration (ETo) was estimated from the monthly minimum and maximum mean temperatures, using a limited data method. The rainfall, temperature, ETo, and water demand future projections were mapped for the area of investigation to analyze spatial variability. ETA model simulations for climatic change showed growth in irrigation water demands due to evapotranspiration increase (from 28.4% to 33.4%), even though rainfall increases (between 61.9% and 89.9%). The increase in the average gross water demand is varied from 37.5% to 78.2% within the period of 2031 to 2060, respective to the common planting season.</p></div

Drought Diagnosis : What the Medical Sciences Can Teach Us

Drought management is currently informed by a variety of approaches, mostly responding to drought crisis when it happens. Toward more effective and integrated drought management, we introduce a conceptual drought diagnosis framework inspired by diagnostic concepts from the field of medicine. This framework comprises five steps: 1. Initial diagnostic assessment; 2. Diagnostic testing; 3. Consultation; 4. Communication of the diagnosis; and 5. Treatment and prognosis. To illustrate the need for the proposed approach, four case studies of recently drought-affected regions were selected: the city of Cape Town, the state of California, the Northeast region of Brazil, and the Horn of Africa. Contrasting elements for these cases include the geographic extent and political boundaries, climate, socio-economics, and the relevance of different water resources (e.g., rainfall, reservoirs, and aquifers). For each case, we identified documented practices and policies and reflected on them in terms of drought misdiagnosis or incomplete diagnosis that have aggravated socio-economic and environmental drought impacts. A common example is the preference for technical solutions (e.g., installing infrastructure to augment water supply), rather than measures that reduce vulnerability. Analysis of these four drought case studies confirmed the anticipated need for a comprehensive approach to drought diagnosis for more successful treatment and prevention of drought. Using an analogy with medical science can be helpful toward comprehensively diagnosing droughts for a variety of contexts and assessing the effectiveness of proposed interventions. This framework can help drought managers to be more proactive in enabling drought-affected regions to become more drought resilient in the future

Hydrophilic polymer changes the water demand in the implementation of a dwarf cashew orchard.

Abstract: Important losses of dwarf cashew seedlings during the establishment of orchards in the Brazilian semiarid are related to the relatively short rainy season. This study aimed to evaluate biochar and hydrophilic polymer as soil amendments to increase water retention and reduce plant death in the first year. An experiment was conducted at the Curu Station, Paraipaba, CE, Brazil, using the clone BRS 226. The experimental design consisted of randomized blocks, with amounts of 0.5, 1.0, 2.0, and 4.0 kg of cashew wood biochar and 20, 40, 60, 80 g of hydrophilic polymer applied per pit, as well as a control treatment (no soil amendment). Seedlings were submitted to an irrigation regime to avoid water stress (5 L water seedling-1 when the tensiometer installed at a depth of 0.15 m reached 60 kPa). The variables of plant development number of leaves, plant height, stem diameter, and canopy diameter were evaluated up to 374 days after transplanting to the field. The analysis of variance showed no treatment effect on plant development. However, minimum water consumption was observed when 29.56 g of hydrophilic polymer was applied per pit, providing 100.0% seedling survival