The goal of irrigation is to supply sufficient water for crop growth to all areas within a field. Therefore, the uniformity of application of irrigation water is of great importance. The objectives of this study were to quantify the performance of irrigation systems under field conditions using standard evaluation techniques and to investigate the use of spatial statistics to characterise the spatial variability of application. The main objective was to develop techniques to estimate gross irrigation water requirement that incorporates the uniformity of application. Different practitioners have given different definitions to the criteria used to evaluate the performance of an irrigation system. A literature review was conducted to determine the current definitions used and the factors that affect these performance criteria. The theory and application of spatial statistics was investigated in order to charaterise spatial distribution of irrigation water. The spatial distribution of irrigation water under centre pivots was determined using field measurements. A number of centre pivot, sprinkler, floppy, drip and micro-irrigation systems were evaluated using standard techniques. The results from the evaluation of spatial data show that this approach is useful to determine a map of the distribution of applied irrigation water. Due to the smoothing characteristic of the spatial statistical method employed, the maps have a uniformity that is greater than in reality. The results from the standard evaluation techniques show that quick and representative results for the performance of an irrigation system can be obtained. The distribution uniformity has an affect on the efficiency of a system and should therefore be included in the calculation of the gross irrigation water requirement. The methods for these calculations are discussed. Further research needs to be conducted to determine actual distribution uniformities and application efficiencies for irrigation systems under various field conditions. This will provide useful standards to include in the calculation of gross irrigation water requirements. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

The implementation of the National Water Act (1998) requires significant changes in the institutional arrangements for water management and, to cater for human and environmental needs, as well as addressing historical inequities, water allocations to irrigated agriculture are likely to be affected. As a result, farmers are facing increasing pressure to use water more effectively, to justify existing water requirements and to budget and plan with growing uncertainty regarding water availability. Therefore, a tool to manage and assess catchment water supply and demand interactions and the associated impacts on the profitability of irrigated sugarcane would be of great value. Although there have been several independent model developments in the fields of water management and sugarcane growth, none provide the required management information in an integrated manner. However, these models provide the foundation for the development of the required modelling tool. An irrigation model for sugarcane, ACRUCane, was developed and incorporated into the ACRU2000 modelling system. The water budget simulated by ACRUCane is linked to a surrounding catchment, the hydrology of which is simulated by the ACRU model. In doing so, a tool has been developed that has the capacity to: • model the soil water balance at a field scale for irrigated areas and at a catchment scale for non-irrigated areas, • link an accurate estimation of crop water requirement for an irrigated area with the availability ofwater at a catchment scale, • explicitly account for the impact of the performance of different irrigation systems on the hydrology and, ultimately, on the sugarcane yield of an irrigated area, • assess the impact of different supply constraints on sugarcane yield, and • estimate both sugarcane and sucrose yield. Extensive verification of the model has been undertaken using data from an irrigation trial at La Mercy, South Africa and two separate trials conducted in the Lowveld of Zimbabwe, with the primary objective of the verification studies being to assess the model's ability to account for different scheduling strategies on sugarcane and sucrose yield. The results obtained show that the model accurately captured the relative differences in yield associated with different irrigation treatments and can thus be used evaluate the impact of different scheduling strategies. A case study was conducted where the feasibility of several hypothetical irrigation scenarios were compared. Different scenarios were created by varying application uniformity, scheduling strategies and system type. This case study illustrated how ACRUCane can be used to provide reliable decision support information to irrigators. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2005.

The purpose of this thesis is to design a computer model which compares three sprinkler irrigation systems---portable pipe with volume gun, traveller with volume gun and towable/non-towable centre pivot---for potato production. The model user is required to enter a set of basic data: crop and field conditions, irrigation technical parameters and basic economic data, following which the model establishes the preliminary irrigation system and a comparative investment analysis. The model was applied and tested on a potato farm situated in Notre-Dame-de-la-Paix (southwestern Quebec). Based on a 14-year climatic analysis, supplemental irrigation for a normal rainfall growing period (368 mm) was estimated at 250 mm. The application of the model indicates that for a normal rainfall period with an assumed yield increase of 25% over non-irrigated production, all three systems provide net profits (increases of 11% to 50%). However, when determining the Internal Rate of Return (IRR) on a 10-year period, the maximum rate attained by the more profitable systems---portable pipe and non-towable centre pivot (both with an electric pump)---was 14%, a rate inferior to the IRR for non-irrigated production (17%). The Net Present Value (NPV) analysis for the two most profitable irrigation systems provided a slightly higher NPV value for irrigated than for non-irrigated production ($10,942---irrigated vs $10,522---non-irrigated production). The payback period for those two irrigation systems was 7 years. Greater gains of irrigated over non-irrigated yields would be expected for a dry period because of low and unpredictable yields in non-irrigated conditions. A farmer planning to invest in an irrigation system must carefully investigate all technical and socio-economic aspects. The model presented gives the farmer a useful tool with which to do this.

[Abstract]: The performance of surface irrigation is a function of the field design, infiltration characteristic of the soil, and the irrigation management practice. However, the complexity of the interactions makes it difficult for irrigators to identify optimaldesign or management practices. The infiltration characteristic of the soil is the most crucial of all the factors affecting the performance of surface irrigation and both spatial and temporal variations in the infiltration characteristic are a major physicalconstraint to achieving higher irrigation application efficiencies. Real-time optimisation and control has the potential to overcome these spatial and temporalvariations and return highly significant improvements in performance. Calculation of the infiltration parameters from irrigation advance data is now the preferred method.If the process is to be included in a real time control system it must be done accurately, reliably and rapidly, and with a minimum of field data. Substantial workhas been directed towards developing methods to estimate the infiltration characteristics of soil from irrigation advance data. However, none of the existing methods are entirely suitable for use in real time control. The greatest limitation is that they are data intensive and or unreliable and provide soil infiltration propertiesafter an irrigation event.A simple real-time control system for furrow irrigation is proposed that: predicts the infiltration characteristics of the soil in real-time using data measured during anirrigation event, simulates the irrigation, and determines the optimum time to cut-off for that irrigation. The basis of the system is a new method for the Real-timeEstimation of the Infiltration Parameters (REIP) under furrow irrigation, developed during this research study, and that uses a model infiltration curve, and a scalingprocess to predict the infiltration characteristics for each furrow and each irrigation event. The underlying hypothesis for the method is that the shape of the infiltration characteristic for a particular field or soil is relatively constant (across the field andwith time), despite variations in the magnitude of the infiltration rate or amount. A typical furrow in the field is selected for evaluation (known as the model furrow)and its infiltration parameters (a, k, fo) in the Kostiakov–Lewis equation are determined by a model such as INFILT or IPARM using inflow, advance and runoffdata. Subsequently the infiltration parameters for this model furrow can be scaled to give the cumulative infiltration curves for the whole field. In this process a scaling factor (F) is formulated from rearrangement of the volume balance equation and is calculated for each furrow/event using the model infiltration parameters and the single advance point. The performance of each furrow can then be simulated and optimised using an appropriate simulation model to determine the preferred time tocut-off.Using this new method, infiltration parameters were calculated for two different fields T & C. The SIRMOD simulation model was then used to simulate irrigationperformance (application efficiency, requirement efficiency and uniformity) under different model strategies. These strategies were framed to assess the feasibility of and demonstrate the gains from the real-time control strategy. The infiltration evaluation results revealed that the infiltration curves produced by the proposed method were of similar shape and hence gave a distribution of cumulative depths of infiltration for the whole field that was statistically equivalent to that given using the complete set of advance data for each furrow. The advance trajectories produced bythe proposed method also matched favourably to the measured advances.The simulation results showed firstly that the scaled infiltration gave predictions of the irrigation performance similar to the actual performance. They also indicated that by adopting the simple real time control system, irrigation application efficiencies forthe two fields could be improved from 76% for field T and 39% for field C (under usual farm management) to 83% and 70% for the fields T & C, respectively. Savingsof 1239 m3 in the total volume of water applied per irrigation over the area of 7.1 ha of both fields were indicated, which can be used beneficially to grow more crop. The proposed real-time control system is shown to be feasible. It requires few data for itsoperation and provides the infiltration characteristics for each furrow without significant loss of accuracy. The irrigation performance is improved greatly from thatachieved under current farmer management and a substantial reduction in the volume of water applied per irrigation is achievable.

The decision to commence the Ord River Irrigation Scheme in the East Kimberley region of Western Australia had extensive political repercussions in national and state politics . The thesis is introduced with an analysis of the decision in relation to the literature of decision making theory, in particul are the two most actively supported decision making theories the rational and the incremental approaches. The thesis demonstrates that the Ord River Scheme accords with the empirical patterns of incremental decision making, The processes of decision making on the Ord River Scheme involved a seemingly endless sequence o f small, incremental and unco-ordinated adjustments on the part of both the Commonwealth and the Western Australian governments. The initial chapters trace the early exploration of the Kimberley region, the state encouraged experiments in tropical agriculture in the 1920's and the early plans for settlement in, and development of the area. Later chapters analyse the main decisions made by both the Commonwealth and Western Australian governments relating to the development of the region - decisions concerning the establishment of Kimberley Research Station, the construction of the Ord River Diversion Dam and early farming developments. The thesis then examines the attempt by both the Commonwealth and Western Australian governments to inject some rationality into the decision making process on the Ord, in the form of cost benefit analysis , the Commonwealth government's agreement of 1967 t o finance the construction of the Main Ord Dam and finally, the Western Australian government's decision in 1974 to abandon cotton growing.

Thesis (M.S. - Soils, Water and Engineering)--University of Arizona, 1984. / Includes bibliographical references (leaves 63-68).

Thesis--Auburn University, 2008. / Abstract. Includes bibliographical references (p. 53-56).

Made available in DSpace on 2014-06-11T19:26:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-06-22Bitstream added on 2014-06-13T18:55:09Z : No. of bitstreams: 1 peres_mr_me_botfca.pdf: 447911 bytes, checksum: 06235bd11b664da7bc2fbecfde5fcbb1 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / O aumento da população mundial, aliado à atividade humana e ao fenômeno da urbanização, torna necessário uma disposição eficiente e ambientalmente segura das águas residuárias (esgotos). Deve-se ressaltar que os resíduos orgânicos presentes nestas águas são fontes riquíssimas de matéria orgânica e nutrientes minerais, elementos necessários à produção das culturas. O uso de esgotos tratados, principalmente de origem doméstica na irrigação de culturas, tem sido praticado em muitos países há muitos séculos. Nos países em desenvolvimento ou em processo de industrialização acelerada existe atualmente uma grande necessidade do desenvolvimento de métodos para atender à crescente demanda de água, particularmente para irrigação, e de proteger os mananciais existentes contra a poluição. Conforme esta demanda cresce, o tratamento e uso de águas residuárias vai se tornando mais importante. Em quase todos os países do Oriente Médio grandes projetos de reuso foram e continuam a ser implantados para atender a irrigação e reservar os limitados mananciais existentes para o abastecimento de água potável. Há um enorme potencial de reuso de águas residuárias na agricultura, entretanto, este uso requer estudos que orientem sua aplicação. É fundamental que se inicie o desenvolvimento de padrões e códigos de uso, visando uma atividade sustentada, ecologicamente compatível e isenta de riscos à saúde pública dos grupos de risco envolvidos. Esta dissertação teve como objetivo avaliar o uso do esgoto doméstico tratado na irrigação de melão. Foram testadas duas formas de aplicação da água de irrigação: esgoto doméstico tratado e uma fonte de água limpa, com três sistemas de irrigação (gotejamento superficial, gotejamento enterrado e sulco). Foram avaliados o desempenho agronômico e o grau de contaminação do produto agrícola... / The increase of the world population, ally to the human activity and the phenomenon of the urbanization, turns necessary an efficient disposition of wastewater (sewers). It should be emphasized that the present organic residues in wastewaters are rich sources of organic matter and nutrients minerals, necessary elements to the production of the crops. The use of treated sewers, mainly of domestic origin in the irrigation of crops, it has been practiced in many countries from many centuries. In the developing countries exists a great need of the development of methods to assist to crescent demand of water, particularly for irrigation, and of protecting the existent springs against the pollution. As this demand grows, the treatment and use of wastewater goes if turning more important. In almost all of the countries of Middle East projects have been implanted to assist the irrigation and to reserve the limited existent springs for the drinkable water supply. There is an enormous potential of wastewater use in the agriculture, however, this use requests studies to guide its application. It is fundamental that it begins the development of patterns and use codes, seeking a sustained activity, ecologically compatible and it exempts from risks to the public health of the risk groups involved. This dissertation had as objective evaluate the use of domestic wastewater in the melon irrigation. Two water qualities were evaluated: domestic wastewater and a source of clean water, with three irrigation systems (surface drip, subsurface drip and furrow). They were appraised the agronomic acting and the degree of contamination of the agricultural product, for each combination of quality of the water and adopted overhead irrigation. The results showed us that the irrigation systems didn't differ considering the melon yield. The use of wastewater didn't bring benefits for the increase of the productivity... (Complete abstract click electronic access below)

Orientador: José Renato Zanini / Banca: Reges Eduardo Franco Teodoro / Banca: Antônio Carlos Barreto / Banca: Carlos Ruggiero / Banca: José Eduardo Pitelli Turco / Resumo: Com este trabalho o objetivo foi avaliar o desempenho do abacaxizeiro cultivar Smooth Cayenne submetido a níveis e frequências de reposição de água no solo, sobre a produtividade, qualidade do fruto e eficiência do uso da água. O trabalho foi realizado no Instituto Federal de Educação, Ciência e Tecnologia do Triângulo Mineiro (IFTM), Campus Uberaba, no período de outubro de 2009 a dezembro de 2010. O experimento foi conduzido no delineamento em blocos casualizados, esquema fatorial 4 x 2, constituído por quatro níveis de reposição de água no solo (50%, 75%, 100% e 125% da evapotranspiração da cultura (ETc)) e duas frequências de irrigação (1 dia = F1 e 3 dias = F2) e quatro repetições. A ETo foi estimada a partir da evaporação diária da água do tanque "Classe A". As lâminas de irrigação foram aplicadas por meio de um sistema de irrigação por gotejamento, com gotejadores espaçados a cada 30 cm e vazão de 3,75 L h-1. A parcela experimental foi constituída de duas linhas duplas, com 4 m de comprimento, 2,80 m de largura, densidade de 52 plantas por parcela, sendo consideradas 20 plantas para avaliação. No plantio foi usado o espaçamento em linhas duplas de 0,90 x 0,50 x 0,30 m. A produtividade dos frutos, diâmetro médio do caule, peso médio dos frutos com coroa, diâmetro médio do pedúnculo, número de mudas tipo filhote, filhote rebentão, ácido ascórbico, rendimento de suco e resistência média dos frutos sem casca não foram influenciados pelas lâminas de reposição da ETc e frequência de irrigação. Número médio de folhas, mudas tipo rebentão, sólidos solúveis totais, acidez total titulável, relação de SST/ATT, resistência média dos frutos com casca, potencial hidrogeniônico de suco e diâmetro médio dos frutos foram influenciado pelas lâminas de reposição... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: With this research the objective was to evaluate the performance of the cultivar Smooth Cayenne pineapple subject to levels and frequencies of water reposition on soil by dripping, about productivity and quality of the fruit and water use efficiency. The research was performed at Federal Institute of Triângulo Mineiro (IFTM), Uberaba Campus, Brazil, from October 2009 to December 2010. The experiment was carried out on randomized block design, factorial 4x2, consisting of four levels of water reposition on soil (50%, 75%, 100% and 125%), of the crop evapotranspiration (ETc) and two irrigation frequencies (1 day = F1 and 2 days = F2), with four repetitions. The ETc was estimated from the daily water evaporation on the "Class A" reservoir. The depths were applied through a dripping irrigation system, with drip emitters spaced every 30 cm, flow of 3,75 L h-1. The experimental plot was constituted of double rows, with 4 m of length, 2,80 m wide and density of 3,3 plants per meter, with 52 plants per plot. At planting, it was used spacing double lines measuring 0,90 x 0,50 x 0,30 m. The results showed that the increase on the ETc reposition and on the irrigation frequency did not produce a decrease in fruit productivity, average stem diameter, average fruits weight with crown, stalk diameter, number of slips, suckers, ascorbic acid, hydrogen potential of juice, juice yield and average unshelled fruit hardness. Bigger ETc reposition depths cause the increase on the average leafs number, the reduction of sucker slips, the increase of soluble solids (TSS), decreased acidity (TTA), increased the ratio of TSS/TTA, hardness rating of unpeeled fruits and decreased average of fruit diameter. Depths of 50% reposition... (Complete abstract click electronic access below) / Doutor

M.Ing. (Civil Engineering) / In South Africa water is considered to be a scarce resource, whichshould be used effectively. By using scheduling, the Agricultural sector can help to alleviate the burden on this resource. The determination of reference evapotranspiration (ETo) or potential evapotranspiration (PET), form an integral part of any scheduling model. Four methods for the determination of ETo was investigated, and their advantages and disadvantages singled out. The combination method was found to be the best method, because it make use of a mechanistic approach, and also take into account all the factors influencing evaporation. The SWB program's Priestley-Taylor and the FAO combination methods for the determination of PET was compared. Wheather data for Lions River, Pretoria, Rietrivier and Stellenbosch was used in the comparison. The correlation between the methods was good, especially after the initial difference was reduced, by multiplying the Priestley-Taylor method with a constant. The SWB program was used to simulate wheat growth. Data for the growth simulation of cultivar SST86, was supplied by the Institute for Soil, Climate and Water. The comparison between measured and simulated data are relatively good and could be further refmed. Data for use in growth models are at present being accumulated for peanuts, tobacco and maize.