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Atributos microbiológicos do solo em área de pastagem irrigada com lâminas excedentes de efluente de esgoto tratado; Microbiological soil attributes of a pasture area with surplus irrigation of wastewater effluent

Paula, Alessandra Monteiro de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 15/12/2008 PT
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37.07%
A irrigação de áreas agrícolas com efluentes de esgoto tratado (EET) é interessante e atrativa, quando realizada de forma controlada, pois além de possibilitar a liberação de recursos hídricos de melhor qualidade para outras atividades humanas, serve como uma forma de polimento dos efluentes provenientes do tratamento de esgoto por meio do filtro biológico constituído pelo sistema solo-planta. Entretanto, o reuso agrícola de efluentes é recente no Brasil e são poucos os estudos relacionados aos possíveis impactos dessa prática na qualidade dos solos tropicais. O presente estudo foi elaborado com o objetivo de avaliar o efeito de lâminas excedentes de irrigação de pastagem com capim Tifton, com efluente de esgoto tratado por 18 meses, na atividade microbiana, densidade de grupos funcionais, no potencial metabólico dos microrganismos e na estrutura da comunidade de bactérias oxidantes de amônio do solo. O experimento foi conduzido numa área de pastagem com capim-Bermuda Tifton 85 (Cynodon dactylon Pers. X C. niemfuensis Vanderyst) no município de Lins (SP), ao lado da estação de tratamento de esgoto operada pela Sabesp. Os tratamentos foram definidos a partir da lâmina de irrigação considerada adequada para a demanda hídrica da cultura (controle) e mais três lâminas com excesso de irrigação...

Quality and maximum profit of industrial tomato as affected by distribution uniformity of drip irrigation system

Santos, Francisco Lúcio
Fonte: Irrigation and Drainage Systems Publicador: Irrigation and Drainage Systems
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.84%
Abstract The tomato industry reformed its system of payment by weight of tomato, introducing a corrective system based on percent level of fruit dry matter produced. Such a decision implies significant changes in the management of irrigation systems, with a need to emphasize the technological quality of the marketable product. Three levels of distribution uniformity of the irrigation system are analysed, and related production functions of crop yield and percent of dry matter are presented as well as their use on the optimisation of dry matter, expected revenues and seasonal applied water. Results are critically influenced by the distribution uniformity. They demonstrate the inter-relationship between crop production, percent fruit dry matter and irrigation management, and the importance of considering non-uniformity in the economic analysis of industrial tomato production. Decreases in uniformity lead to a reduction in dry matter production per unit land. Decreases in dry matter are also observed with increasing levels of seasonally applied water, with the optimal level always lower than the required for maximum yield. Such interaction suggests a continuous and inverse relationship between profit and water applied. However, due to the corrective system of payment...

Practical issues in developing a smart surface irrigation system with real-time simulation of furrow advance

Shahidian, Shakib; Serralheiro, Ricardo; Serrano, João Manuel
Fonte: Irrigation and Drainage Publicador: Irrigation and Drainage
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.84%
Automation of surface irrigation can be an economic and ecological way of increasing global food production. In this work a fully automated cablegation system is evaluated that adapts the application time and depth to the actual infiltration rate of the soil in real-time. The system calculates the infiltration equation from advance times in a control furrow and then simulates irrigation in every furrow of the field, establishing the optimum application time for each furrow. The methodology was evaluated in a field organized in contour terraces with furrows of various lengths in order to evaluate practical issues affecting the performance of the system. The results confirm the temporal variability in soil infiltration, and the need for real-time determination of the infiltration equation. The evolution of furrow geometry through the season did not have an important impact on the results of the simulations. The length of the furrow considered for calculating the Kostiakov equation influences the parameters of the equation. Automation with real-time feedback can result in important savings in water and labour and can produce irrigation events with more than 90% application efficiency. Nevertheless, the results also indicate that there are practical limits to what can possibly be achieved with automation and real-time feedback from the field

Yield and water productivity of five chickpea varieties under supplemental irrigation in contrasting years

Silva, L.L.; Duarte, I.M.; Lourenço, E; Simões, N; Chaves, M.M.
Fonte: Irrigation Science, Elsevier Publicador: Irrigation Science, Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.92%
Chickpea (Cicer arietinum L.) is one of the most important pulse crops in the world, cultivated on a wide range of environments. In Mediterranean regions, it is traditionally grown as a spring-sown rainfed crop, very dependent on rainfall. In this situation, supplemental irrigation can improve significantly the crop yield. The objective of this study was to evaluate the improvement on chickpea crop yield and water productivity (WP) of five chickpea varieties with supplemental irrigation, in the Mediterranean conditions, with both dry and wet years. Field tests were carried out over two cropping seasons, in Southern Portugal, using three kabuli-type and two desi-type chickpea varieties and four irrigation treatments, corresponding to 100, 50, 25 % of crop irrigation requirements (IR) and rainfed. The results show that all chickpea varieties responded to supplemental irrigation with the increase in grain and biomass yield. However, the magnitude of individual chickpea response depends on the year and the genotype. In 2009, a dry year, the highest WP values were attained at the 50 % IR treatment, whereas in 2010, a wet year, it was the rainfed treatment that showed the highest WP values.The Elixir variety showed the best grain yields and water productivity.

Assessing economic impacts of deficit irrigation as related to water productivity and water costs

Pereira, L.S.; Rodrigues, G.S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2009 ENG
Relevância na Pesquisa
37.05%
Research Paper:SW-Soil and Water; This study aims at assessing the feasibility of deficit irrigation of maize, wheat and sunflower through an analysis of the economic water productivity (EWP). It focuses on selected sprinkler-irrigated fields in Vigia Irrigation District, Southern Portugal. Various scenarios of water deficits and water availability were considered. Simulations were performed for average, high and very high climatic demand. The potential crop yields were estimated from regional climatic data and local information. Using field collected data on yield values, production costs, water costs, commodity prices and irrigation performance, indicators on EWP were calculated. Results show that a main bottleneck for adopting deficit irrigation is the presently low performance of the irrigation systems used in the considered fields, which leads to high water use and low EWP. Decreasing water use through deficit irrigation also decreases the EWP. Limited water deficits for maize are likely to be viable when the irrigation performance is improved if water prices do not increase much, and the commodity price does not return to former low levels. The sunflower crop, despite lower sensitivity to water deficits than maize...

Assessing economic impacts of deficit irrigation as related to water productivity and water costs

Rodrigues, Gonçalo C.; Pereira, L.S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2009 ENG
Relevância na Pesquisa
37.05%
Research Paper: SW - soil and Water; This study aims at assessing the feasibility of deficit irrigation of maize, wheat and sunflower through an analysis of the economic water productivity (EWP). It focuses on selected sprinkler-irrigated fields in Vigia Irrigation District, Southern Portugal. Various scenarios of water deficits and water availability were considered. Simulations were performed for average, high and very high climatic demand. The potential crop yields were estimated from regional climatic data and local information. Using field collected data on yield values, production costs, water costs, commodity prices and irrigation performance, indicators on EWP were calculated. Results show that a main bottleneck for adopting deficit irrigation is the presently low performance of the irrigation systems used in the considered fields, which leads to high water use and low EWP. Decreasing water use through deficit irrigation also decreases the EWP. Limited water deficits for maize are likely to be viable when the irrigation performance is improved if water prices do not increase much, and the commodity price does not return to former low levels. The sunflower crop, despite lower sensitivity to water deficits than maize...

Yield Impact of Irrigation Management Transfer : Story from the Philippines

Bandyopadhyay, Sushenjit; Shyamsundar, Priya; Xei, Mei
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
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37.14%
Irrigation management transfer is an important strategy among donors and governments to strengthen farmer control over water and irrigation infrastructure. This study seeks to understand whether irrigation management transfer is meeting the promise of its commitments. The authors use data from a survey of 68 irrigator associations and 1,020 farm households in the Philippines to estimate the impact of irrigation management transfer on irrigation association performance and on rice yields. They also estimate a stochastic frontier production function to assess contributions to technical efficiency. There are three main results. First, the presence of irrigation management transfer is associated with an increase in maintenance activities undertaken by irrigation associations. Second, by increasing local control over water delivery, the presence of irrigation management transfer is associated with a 2-6 percent increase in farm yields. Rice production in irrigation management transfer areas is greater even after controlling for various differences among rice farmers in transfer and non-transfer areas. Third...

Micro and Macro-Level Approaches for Assessing the Value of Irrigation Water

Johansson, Robert C.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Relevância na Pesquisa
37.05%
Many countries are reforming their economies and setting macroeconomic policies that have direct and indirect impact on the performance of the irrigation sector. One reason for the movement toward reform in the water sector across countries is that water resources are increasingly becoming a limiting factor for many human activities. Another reason for increased pressures to address water policy issues is that many countries are in the process of removing barriers to trade, particularly in agricultural commodities. Therefore, knowledge of the value of water when crafting domestic and macroeconomic policies is important to compare the variable impacts of reform across sectors of the economy and populations within the country. Researchers have used many methods for assessing the value of irrigation water. This survey reviews a broad literature to ascertain how two basic questions have been addressed by research over the past few decades. First, what is the value of water across different sectors and levels? Second, how will this value change under different macroeconomic and domestic policies? This survey details a number of methods for approaching these two questions. The literature has been organized according to a progression from theoretical underpinnings to empirical approaches to how the value of irrigation services are relevant to the link between globalization and poverty.

Participation in the Irrigation Sector

Meinzen-Dick, Ruth; Reidinger, Richard; Manzardo, Andrew
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
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37.08%
The irrigation sector provides a rich source of experiences and lessons in user participation. Participation by farmers in system design and management helps to ensure the sustainability of the system, reduce the public expenditure burden, and improve efficiency, equity and standards of service. Mobilizing support at all levels and establishing the participatory process, however, involves costs; it also demands knowledge of the incentives facing each group of stakeholders, and of the essential elements in building effective users organizations.

Review of World Bank Engagement in the Irrigation and Drainage Sector in Azerbaijan

World Bank
Fonte: Washington, DC Publicador: Washington, DC
EN_US
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37.09%
The sector review includes seven chapters and one annex. This first chapter is an overview of agriculture, irrigation and the purpose and content of this report. The second chapter provides a review of the Bank s own strategy and priorities for irrigation and drainage within its portfolio of investments, from the time of its 2004 Strategy until the present. It also includes a short summary of key lessons learned in this sector. The third chapter provides a brief situation analysis for irrigation and drainage in Azerbaijan, including a description of key parameters and changes; a description of rising challenges, needs and opportunities; and an overview of the Government s State Program (SP) for Sustainable Development of Amelioration and water management for 2008-2015. The fourth chapter describes the issues of investment and financing of irrigation and drainage priorities for infrastructure development, rehabilitation and modernization, and management. This includes investment priorities for the Government as well as needs for cost recovery by water users for the cost of irrigation and drainage system operations and maintenance. The fifth chapter describes the institutional framework and how it has emerged since independence. It also identifies outstanding issues for further institutional development...

Irrigation scheduling strategies for cotton to cope with water scarcity in the Fergana Valley, Central Asia

Pereira, L.S.; Paredes, P.; Cholpankulov, E.D.; Inchenkova, O.P.; Teodoro, P.R.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2009 ENG
Relevância na Pesquisa
37.05%
The Central Asian countries face high water scarcity due to aridity and desertification but excess water is often applied to the main irrigated crops. This over-irrigation contributes to aggravate water scarcity problems. Improved water saving irrigation is therefore required, mainly through appropriate irrigation scheduling. To provide for it, after being previously calibrated and validated for cotton in the Fergana region, the irrigation scheduling simulation model ISAREG was explored to simulate improved irrigation scheduling alternatives. Results show that using the present irrigation scheduling a large part of the applied water, averaging 20%, percolates out of the root zone. Several irrigation strategies were analyzed, including full irrigation and various levels of deficit irrigation. The analysis focused a threeyear period when experiments for calibration and validation of the model were carried out, and a longer period of 33 years that provided for an analysis considering the probabilities of the demand for irrigation water. The first concerned a wet period while the second includes a variety of climatic demand conditions that provided for analyzing alternative schedules for average, high and very high climatic demand. Results have shown the importance of the groundwater contribution...

Changes in properties of vineyard red brown earths under long - term drip irrigation, combined with varying water qualities and gypsum application rates

Clark, Louise Jayne
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 736965 bytes; 3776926 bytes; 1087958 bytes; 2127339 bytes; 181381 bytes; application/pdf; application/pdf; application/pdf; application/pdf; application/pdf
Publicado em //2004 EN
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37.11%
Irrigation water of poor quality can have deleterious effects on soils. However, the effect of drip irrigation on seasonal and long term (e.g. over 50 years) changes in soil chemical properties is poorly understood, complicated by the two-dimensional water flow patterns beneath drippers. Field and laboratory experiments were conducted, along with computer modelling, to evaluate morphological and physio-chemical changes in a typical Barossa Valley Red Brown Earth (Palexeralf, Chromosol or Lixisol) when drip irrigated under various changing management practices. This work focused on the following two management changes : (i) switching from long-term irrigation with a saline source to less saline water and (ii) gypsum (CaSO₄) application. A literature review (Chapter 1) focuses on the distribution, features, properties and management of Red Brown Earths in the premium viticultural regions of the Barossa Valley and McLaren Vale, South Australia. The effects of irrigation method and water quality on the rate and extent of soil deterioration are emphasised. The review also discusses the irrigation of grapes (Vitis vinifera) and summarises previous research into the effect of sodicity and salinity on grape and wine characteristics. This chapter shows the importance of Red Brown Earths to Australian viticulture...

The Possibility of a Rice Green Revolution in Large-scale Irrigation Schemes in Sub-Saharan Africa

Nakano, Yuko; Bamba, Ibrahim; Diagne, Aliou; Otsuka, Keijiro; Kajisa, Kei
Fonte: Banco Mundial Publicador: Banco Mundial
Tipo: Publications & Research :: Policy Research Working Paper
ENGLISH
Relevância na Pesquisa
37.07%
This paper investigates the potential of and constraints to a rice Green Revolution in Sub-Saharan Africa's large-scale irrigation schemes, using data from Uganda, Mozambique, Burkina Faso, Mali, Niger, and Senegal. The authors find that adequate irrigation, chemical fertilizer, and labor inputs are the key to high productivity. Chemical fertilizer is expensive in Uganda and Mozambique and is barely used. This is aggravated when water access is limited because of the complementarities between fertilizer and irrigation. Meanwhile, in the schemes located in four countries in West Africa's Sahel region, where water access is generally good and institutional support for chemical fertilizer exists, rice farmers achieve attractive yields. Some countries' wage rate is high and thus mechanization could be one solution for this constraint. Improvement of credit access also facilitates the purchase of expensive fertilizer or the employment of hired labor.

Methodology for Ranking Irrigation Infrastructure Investment Projects

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Economic & Sector Work :: Policy Note; Economic & Sector Work
ENGLISH; EN_US
Relevância na Pesquisa
37.1%
The Government of Uzbekistan is aware that the irrigation and drainage infrastructure constructed under the Former Soviet Union - serving some 4.3 million hectare of cultivable land for agriculture as well as many villages for drinking water - is in urgent need of repair and/or rehabilitation. Also, given multiple competing demands of investment project proposals (as many as 180) on the nation's limited, annual investment budget earmarked for this purpose, it realized the need for a national strategy aimed at modernizing the water sector including a medium-term investment plan. It has thus asked the World Bank to undertake, over a two-year period beginning in mid-2007, a study that is designed to provide solutions to the twin problems of how to approach the rehabilitation of the irrigation and drainage sub-sector and which of the many competing projects to prioritize. To overcome this problem as well as the general lack of readily available, comparable data of proposals, the technical working group used the Investment project data sheet to gather relevant information from sub-basin authorities throughout the country with the instruction to fill in the required information. Initial progress with data collection proved extremely slow and cumbersome as the habit of looking at projects in an integrated manner...

Institutional Reform for Irrigation and Drainage : Proceedings of a World Bank Workshop

Gonzalez, Fernando J.; Salman, Salman M.A.
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Tipo: Publications & Research :: Publication; Publications & Research :: Publication
ENGLISH; EN_US
Relevância na Pesquisa
37.07%
The report consists of an introduction, and three separate, but inter-related parts. The introduction provides an overview of the workshop discussions, arguing that the irrigation sector is blamed for many environmental problems, suggesting to set the right incentives, and regulations, including stakeholders involvement, and partnerships to overcome sector obstacles. The first part looks at the institutional diversity in irrigation, and drainage sectors, reviewing institutional changes within components of the Bank's portfolio of irrigation, and drainage projects. It addresses the extent to which the Bank's major policy documents of the 1990s have shaped the portfolio, and suggests recommendations to promote institutional changes, and the introduction of alternative solutions, such as private sector involvement, to increase competition, service contracts, and intergovernmental agreements. The second part reviews the irrigation regulatory framework, arguing that participation of Water Users Associations (WUAs) in the management of irrigation systems...

Africa : Irrigation investment Needs in Sub-Saharan Africa

You, Liang Zhi
Fonte: Washington, DC, World Bank Publicador: Washington, DC, World Bank
Tipo: Economic & Sector Work :: Other Infrastructure Study; Economic & Sector Work
ENGLISH; EN_US
Relevância na Pesquisa
37.12%
In Sub-Saharan Africa, rainfall is highly variable and, in many places, plainly in sufficient. Although irrigation has the potential to boost agricultural yields by at least 50 percent, food production in the region is almost entirely rain-fed. The irrigated area, extending over 6 million hectares, makes up just 5 percent of the total cultivated area, compared to 37 percent in Asia and 14 percent in Latin America. Two-thirds of that area is in three countries: Madagascar, South Africa, and Sudan. The 2005 Commission for Africa report, for example, called for a doubling of the region's irrigated area by 2015. To achieve expansion on that scale, however, we must deepen our understanding of the locations that could benefit most-and of the technologies best suited to those locations. One purpose of this study of irrigation in 24 countries, undertaken as part of the Africa infrastructure country diagnostic, is to identify agricultural areas, where irrigation investments promise to yield significant returns. A related purpose is to estimate the amount and scope of investment needed to secure those returns. Water for irrigation can be collected in two ways: through large...

An Impact Evaluation of India's Second and Third Andhra Pradesh Irrigation Projects : A Case of Poverty Reduction with Low Economic Returns

Independent Evaluation Group
Fonte: Washington, DC : World Bank Publicador: Washington, DC : World Bank
Tipo: Publications & Research :: Publication; Publications & Research :: Publication
ENGLISH; EN_US
Relevância na Pesquisa
37.14%
Irrigation has made a major contribution to poverty reduction in the past decades, enabling higher yields and better nutrition. Despite these achievements, large-scale irrigation schemes have usually yielded low returns and attracted negative publicity because of their adverse environmental and social impacts. As a result, the Bank has largely switched its support for irrigation away from new construction toward rehabilitation and policy reform. This evaluation supports the need for reform but shows that there are substantial benefits from further investment in infrastructure. This study analyzes these issues through an impact evaluation of one of the last "old generation" of projects in which the Bank directly supported creation of a new irrigation scheme: India's Second and Third Andhra Pradesh Irrigation Projects (AP II and AP III). Together these projects created a new command area, the Srisailem Right Branch Canal (SRBC), and rehabilitated an existing one that had been constructed with Bank assistance...

Pricing Irrigation Water : A Literature Survey

Johansson, Robert C.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
37.06%
As water scarcity and population pressures increase, more countries are adopting water pricing mechanisms, as their primary means of regulating the consumption of irrigation water. The way to allocate water efficiently is to "get the prices right", but how to accomplish this is open to debate. Water pricing methods are sensitive to the social, physical, institutional, and political setting. To assess the costs and benefits of a particular irrigation project, the pricing method must be tailored to local circumstances. The author's survey of the resource economics literature on irrigation services and pricing, will be useful for developing comprehensive guidelines for water policy practitioners. He synthesizes accumulated knowledge about the implementation, and performance of various water pricing methods used over the past two decades: volumetric pricing (marginal cost pricing), output and input pricing, per area pricing, tiered pricing, two part tariffs, and water markets. As water scarcity and population pressures increase...

From on-farm solid-set sprinkler irrigation design to collective irrigation network design in windy areas

Zapata Ruiz, Nery; Playán Jubillar, Enrique; Martínez-Cob, Antonio; Sánchez Marcos, Ignacio; Faci González, José María; Lecina Brau, Sergio
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 348954 bytes; application/pdf
ENG
Relevância na Pesquisa
37.06%
The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774; In this paper, a contribution to the design of collective pressurized irrigation networks in solid-set sprinkler irrigated windy areas is presented. The methodology is based on guaranteeing minimum on-farm performance, using a historical hourly wind speed database and a ballistic solid-set irrigation simulation model. The proposed method was applied to the Montesnegros Irrigation District (central Ebro basin, Spain). The district irrigates an area of 3,493 ha using an on-demand schedule. The average wind speed in the area is 2,8 m s-1. An analysis of district water records showed that farmers often reduce water demand when the wind speed is high, but their irrigation decision making is limited by the capacity of the irrigation network and by the unpredictable character of local winds. Simulations were performed for eleven irrigation seasons, two triangular sprinkler spacings (18x18 and 18x15 m), and two sprinkler models. The percentage of monthly suitable time for irrigation was determined for four management strategies. The first one was based on a wind speed threshold (3 m s-1), while the other three were based on three levels (standard...

Analysis of an irrigation district in northeastern Spain: I. Characterisation and water use assessment

Dechmi, Farida; Playán Jubillar, Enrique; Faci González, José María; Tejero-Juste, Miguel
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 1004435 bytes; application/pdf
ENG
Relevância na Pesquisa
37.07%
The definitive version is available at http://www.sciencedirect.com/science/journal/03783774; In this work, the Loma de Quinto irrigation district, located in Zaragoza (Spain) was characterised, and water use was assessed. The study was performed to contribute to the Diagnostic Analysis phase of an incipient Management Improvement Process in this sprinkler-irrigated district. The objectives of this first paper of the series include: 1) characterizing the irrigation systems, soil types and crops; 2) evaluating irrigation performance through the relationship between on-farm water use and net irrigation requirements; and 3) identifying factors affecting on-farm water use. In order to accomplish these objectives, statistical analyses of field data, district records on water use and farmers’ interviews were performed. Technical deficiencies were detected in solid-sets, centre-pivots and linear-moves. A Seasonal Irrigation Performance Index (SIPI), defined as the percentage of net irrigation requirements to seasonal water billing, was determined at each plot and for each of the three study years. The average interannual SIPI amounted to 127 %, indicating that crops in the district were consistently water stressed. An analysis of the SIPI for the main crops in the district revealed that water stress was more intense in drought resistant and/or heavily subsidized crops (SIPI for sunflower was 142 %). The average irrigation interval (12.3 days) and irrigation depth (44 mm) were too high for some of the soils in the district. Farmers adjusted the irrigation interval to meet the seasonal change in irrigation requirements. The irrigation depth was reduced in windy days. In two of the three study years...