Atualmente a água é o recurso mais limitante para o desenvolvimento urbano, industrial e principalmente agrícola devido à constante contaminação em função da falta de planejamento e uso inadequado dos recursos hídricos pela humanidade. Assim o presente trabalho teve o objetivo de estudar o impacto ambiental da irrigação nos recursos hídricos da microbacia hidrográfica do ribeirão dos Marins e testar a capacidade do modelo hidrológico MIKE SHE em pequenas áreas irrigadas da microbacia e conseqüentemente detectar problemas relacionados à irrigação e a falta de manejo da água nessas áreas. Avaliou-se a qualidade da água de irrigação utilizada na produção de hortaliças; a qualidade da irrigação praticada pelos produtores, a quantidade de água na microbacia hidrográfica e simulou-se a área irrigada da microbacia. Os parâmetros de qualidade de água analisados foram: sedimentos em suspensão, pH, condutividade elétrica, alcalinidade, turbidez, potássio, cálcio, magnésio, cobre, ferro, manganês, zinco, sódio, fósforo, sulfato, cloreto, nitrogênio amoniacal e nitrato, durante 10 meses. A qualidade da irrigação foi avaliada através do manejo da irrigação via tensiômetros, instalados em duas propriedades agrícolas e em duas profundidades, e avaliação do coeficiente de uniformidade de Christiansen (CUC) foi feito em quatro propriedades agrícolas. A avaliação do impacto ambiental foi feito por meio dos indicadores de qualidade da água e do CUC. Os dados coletados e avaliados permitiram concluir que a agricultura irrigada provoca pouco impacto na microbacia hidrográfica. De acordo com as classificações de Ayers e Westcot e USDA a água pode ser considerada boa para ser utilizada na agricultura. Observou-se que a umidade do solo no período amostrado ficou próxima da saturação. O uso do modelo para a simulação da área irrigada permitiu economia de água quando o manejo da irrigação foi utilizado. / Nowadays the water is the most limiting resource to the urban, industrial and agricultural development due to constant contamination and inadequate water use by the mankind. Then this work aimed to study the environmental impact of irrigation at the Marins stream watershed and to check the ability of the model MIKE SHE in small irrigated area, consequently, to detect problems related with irrigation operations at the small watershed. It were evaluated the water quality used in the horticultural production, the irrigation quality practiced by the farmers, water quantity in the watershed and simulation was done for the irrigated area. The parameters analyzed were physicals and chemicals: suspense sediments, pH, electric conductivity, alkalinity, turbidity, potassium, calcium, magnesium, cupper, iron, manganese, zinc, sodium, phosphorus, sulfate, chlorine, ammonia nitrogen, and nitrate, during 10 months. The irrigation quality was evaluated through the irrigation management by tensiometers installed in two properties and two depths and by the Christiansen uniformity coefficient (CUC) measured in four properties. The environmental impact of irrigation was made by the water quality indicators and the CUC. The results permitted to conclude that irrigated agricultural causes few impact at the Marins stream watershed. The water showed a acceptable quality when compared with the classification proposed by Ayers & Westcot and USDA to irrigation. It was observed that the soil wet was near the saturation. The model allowed to save water when water management was used.

Conhecimentos sobre fisiologia da produção de mudas cítricas sob condições de deficiência hídrica são necessários para fomentar as práticas de irrigação em viveiros telados. O objetivo deste trabalho foi avaliar o efeito de deficiência hídrica induzido por polietileno glicol (PEG) e por interrupção da irrigação sobre o desenvolvimento e variáveis fisiológicas de mudas de laranja Valência (Citrus sinensis L. Osbeck) enxertada sobre limão Cravo (Citrus limonia Osbeck) e citrumelo Swingle (Poncirus trifoliata (L.) Raf x Citrus paradisi Macf). As mudas foram produzidas em sacolas plásticas de 4,5L contendo substrato a base de casca de pinus e submetidas à deficiência hídrica durante três fases fenológicas, e em duas estações do ano (outono-inverno e primavera-verão). O trabalho foi dividido em dois experimentos. No primeiro, avaliaram-se plantas mantidas em capacidade de container e submetidas à interrupção intermitente da irrigação, até o potencial hídrico do substrato atingir -15kPa, e a duas concentrações de PEG, correspondentes ao potencial hídrico no substrato de respectivamente -15 e -25kPa. No segundo experimento, avaliaram-se plantas mantidas em capacidade de container e submetidas a interrupção intermitente da irrigação até o potencial hídrico do substrato atingir respectivamente -15 e -25kPa. Dados coletados incluíram variáveis biométricas, concentrações foliares de nutrientes, de prolina e de clorofila, concentração de carboidratos em raízes, caule e folhas, aproveitamento comercial de mudas, taxa de assimilação de CO2, condutância estomática, transpiração e eficiência do uso da água. O delineamento adotado foi o de blocos ao acaso, seguindo o esquema fatorial 2 x 3 x 4 (porta-enxerto x fase de crescimento x deficiência hídrica), perfazendo 24 tratamentos e cinco repetições para o primeiro experimento, e esquema fatorial 2 x 3 x 3, com 18 tratamentos e seis repetições no segundo experimento. A parcela experimental foi constituída de seis plantas. Mudas de laranja Valência enxertadas sobre limão Cravo e citrumelo Swingle apresentam crescimento e características fisiológicas distintas, sendo que maior vigor é induzido por aquele porta-enxerto. O emprego de PEG como osmólito em estudos para indução de deficiência hídrica in vivo não é indicado para citros em vasos, já que este material acarreta efeitos fisiológicos distintos daqueles apresentados por plantas submetidas à interrupção da irrigação. Mudas sobre ambos porta-enxertos são afetadas pela interrupção da irrigação entre a retirada do fitilho e a maturação do segundo fluxo de crescimento do enxerto, sendo os prejuízos proporcionais à duração da deficiência hídrica. Os efeitos da seca temporária são mais intensos quando aplicados isoladamente a partir da maturação do primeiro fluxo de crescimento, devido ao maior tamanho das plantas. A interrupção da irrigação até que o potencial hídrico do substrato seja de -15kPa permite produção satisfatória de mudas de laranja Valência sobre limão Cravo e citrumelo Swingle, independentemente do período em que ocorra a deficiência hídrica. A interrupção da irrigação até que o potencial hídrico do substrato atinja -25kPa afeta significativamente a produção das mudas cítricas. O limão Cravo induziu maior aclimatação à copa, apresentando grande capacidade de recuperação do crescimento e do desempenho fisiológico após sucessivos ciclos de suspensão / restauração da irrigação. / Physiological aspects of citrus nursery tree production submitted to water deficit are necessary to support irrigation management in screen houses. This work evaluated water stress induced either by polyethylene glycol (PEG) or irrigation suspending on growth and physiological traits of Valencia sweet orange (Citrus sinensis L. Osbeck) budded on Rangpur lime (Citrus limonia Osbeck) and Swingle citrumelo (Poncirus trifoliata (L.) Raf x Citrus paradisi Macf). Nursery trees were produced in 4.5L containers filled with composted pine bark, and submitted to water stress in three phenological phases in two seasons (autumn-winter and spring-summer). Experimental works were divided in two trials. In the first one, evaluation was carried on plants submitted to container capacity, irrigation suspending when substrate water potential dropped to -15kPa, and two PEG concentrations in water equivalents to substrate water potential of -15 and -25kPa. In the second trial, evaluation was carried on plants submitted to container capacity and irrigation suspending when substrate water potential dropped to -15 and -25kPa. Data collected included biometric variables, leaf concentrations of nutrients, proline and chlorophyll, carbohydrates concentrations in roots, stems and leaves, commercial feasibility of nursery trees, CO2 assimilation rate, stomatal conductance, leaf transpiration and temperature, and water use efficiency. Experimental design was randomized blocks with a 2 x 3 x 4 factorial (rootstock x phenological phase x water stress), performing 24 treatments and five replicates for the first experiment, and a 2 x 3 x 3 factorial with 18 treatments and six replicates for the second experiment. Experimental unit consisted of six nursery plants aligned on concrete benches. Valencia sweet orange budded on Rangpur lime and Swingle citrumelo had different growth and physiological behavior, with the first rootstock inducing higher vigor. PEG should not be used for in vivo water stress studies in containerized citrus, as a result of toxicity and physiological effects distinct from those observed in plants submitted to suspended irrigation. Nursery trees on both materials are affected by suspended irrigation from unwrapping to the maturation of scion second growth flush. Damages to plant development due to water deficit are proportional to stress duration. However, temporary drought is more harmful when partially induced after the scion first growth flush, probably because of higher plant size and container restriction. Substrate water potential of -15kPa can be used as adequate irrigation threshold for Valencia sweet orange nursery production on Rangpur lime and Swingle citrumelo rootstocks regardless of phenological phase. On the other hand, substrate water potential of -25kPa significantly reduces horticultural value of citrus nursery trees. Rangpur lime induces higher morphological and physiological acclimation to the scion due to irrigation suspending, and it also has great plasticity and recovery of growth and physiological performance after successive suspending / restoring irrigation cycles.

Orientadores: Edson Eiji Matsura, Regina Célia de Matos Pires / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-25T22:38:01Z (GMT). No. of bitstreams: 1 Santos_LeonardoNazarioSilvados_D.pdf: 9014714 bytes, checksum: 443fd6aa43099fa45fe1a9d094fc9afb (MD5) Previous issue date: 2014 / Resumo: A agricultura irrigada é a atividade caracterizada pelo alto consumo de água. Nesse contexto, a utilização de efluente de esgoto tratado (EET) como fonte de água para a irrigação pode ser uma alternativa para substituição de água doce, mas que requer estudos específicos para adoção e uso de forma sustentável. Assim, objetivou-se avaliar os efeitos da aplicação de EET via gotejamento subsuperficial sobre as propriedades físicas do solo (Latossolo Vermelho distroférrico), distribuição da umidade no perfil do solo, desenvolvimento do sistema radicular, a produção de colmos e a qualidade tecnológica do caldo da cana-de-açúcar (Saccharum officinarum L.). O experimento foi instalado em Campinas-SP, Brasil, adotando-se delineamento em blocos casualizados em esquema fatorial 2x2x2+1, com cinco repetições. Os fatores estudados foram: duas profundidades de instalação do tubo gotejador (0,2 e 0,4 m); duas qualidades de água (efluente de esgoto tratado ¿ EET, e água de reservatório superficial ¿ ARS); complementação nutricional via fertirrigação (com complementação nutricional ¿ CN, e sem complementação nutricional ¿ SN); e a testemunha sem irrigação. Para avaliação da umidade no perfil do solo foi utilizada a técnica da TDR (Time Domain Reflectometry); para a avaliação radicular foi utilizado o sistema minirhizotron; para determinar os atributos físicos do solo foram utilizadas amostras deformadas e indeformadas; e a produtividade estimada por biometria. O uso de efluente de esgoto tratado como fonte hídrica na irrigação demonstrou ser opção sustentável do ponto de vista agronômico, proporcionando incrementos na produtividade e melhoria na qualidade tecnológica da cana-de-açúcar em relação ao tratamento sem irrigação. A instalação do tubo gotejador a 0,2 m de profundidade disponibilizou água na região de maior desenvolvimento radicular e reduziu as perdas de água por evaporação e por percolação profunda. Os fatores testados não alteraram significativamente os parâmetros sódico-salinos, as propriedades físicas do solo e o comprimento radicular da cana-de-açúcar / Abstract: Irrigated agriculture is characterized by higher water consumption. In this context, the use of treated sewage effluent (TSE) as a water resource for irrigation can be an alternative in replacing freshwater, however it requires specific studies for adoption and as well as for sustainable use. Therefore, this study aimed to evaluate the TSE subsurface drip irrigation effect on a dystrophic Red Latossolo (Oxisol) physical properties, the effect on the moisture distribution in the soil profile, on the root system development, as well as on the yielding and quality of produced sugarcane (Saccharum officinarum L.). The experiment was carried out in Campinas-SP, Brazil, adopting a randomized block design in a 2x2x2+1 factorial, with five replications. Studied factors included: two depths of the dripline (0.2 to 0.4 m); two water qualities (treated sewage effluent ¿ TSE, and surface reservoir water ¿ SRW); nutritional supplementation by fertigation (with nutritional supplementation ¿ NS, and without nutritional supplementation - WNS); and no irrigation (NI). To evaluate the moisture in the soil profile it was used the technique named TDR (Time Domain Reflectometry); to evaluate root development was used the system known as minirhizotron; to determine soil physical properties it was employed disturbed and undisturbed samples; and productivity estimated by biometrics. The use of treated sewage effluent as a water resource for irrigation proved to be a sustainable option through the agronomic point of view, providing productivity increases and improvement of technological quality of sugarcane compared to treatment without irrigation. The installation of the dripline to 0.2 m depth provided of water in the region highest root development and reduced water losses by evaporation and deep percolation. The tested factors did not significantly alter the sodic-saline parameters, the physical properties of soil and root length of sugarcane / Doutorado / Agua e Solo / Doutor em Engenharia Agrícola

Made available in DSpace on 2014-08-20T14:33:14Z (GMT). No. of bitstreams: 1 Dissertacao_Rosimeri_da_ Silva_Fraga.pdf: 4545345 bytes, checksum: e5c23e2318d32e9e5d64d050317e9f1f (MD5) Previous issue date: 2011-08-18 / The strawberry cultivation has been among the main features in family production systems in Turuçu-RS (Brazil), being produced and sold both fresh as well as in the processed form, allowing to the farmers employment generation, income and social inclusion. The strawberry production system, in general, is characterized by the use of soil cover with black color plastic, the use of low tunnels and drip irrigation systems with the fertilizer application through irrigation water (fertigation). The importance and benefits of irrigation for strawberry production have been found by farmers, as it has allowed the improvement of fresh fruits quality. However, as strawberry fields were mostly located far from major water sources, many farmers need to build dams to impound water efficiently, to assure the success of the irrigation for crops, and also to ensure the quality and quantity of water for these activities. Based on this, this study aimed to evaluate: i. spatial and temporal behavior of physical and hydraulic properties of soils in the 0-200 mm layer (available water capacity and water storage) related to irrigation management adopted in 12 crops of strawberry, ii. geotechnical and safety characteristics of two small earth dams used to store water for irrigation of strawberries and other crops, and iii. the existence of correlation between eight water quality parameters with: different types of water sources used for strawberry irrigation; with the micro-regions where they are located; and with the preceding precipitation, referring to 14 rural properties in Turuçu RS (Brazil). Box-plot charts were built to study the spatial and temporal behavior of the available water capacity and of the soil water storage based on the data collected by Bamberg (2010) and on data resulting from the installation of tensiometers at 200 mm depth in the 12 fields. The following activities were conducted in two rural small dams: studies of the embankment geometry, execution of geotechnical tests, assessment of security conditions and the estimative of the project design flood and design of the spillway. Multivariate statistical tools and Pearson correlation analysis were applied to data collected from 2007 to 2008 to identify the existence of correlation between eight water quality parameters (alkalinity, electrical conductivity, biochemical oxygen demand, dissolved oxygen, suspended solids, dissolved solids, total solids and turbidity) with the different types of water sources used for the strawberry irrigation, with the micro-regions where they are located and with the preceding precipitation, referring to 14 rural properties Turuçu-RS. We found that: i. there was not a similar pattern of spatial and temporal behavior for the values of available water capacity and water storage in the soil for the evaluated months, ii. the soil erosion on the upstream slope observed in the embankments is a major problem, since the sediments produced may impair the quality of irrigation water and there is a undersizing of the spillways considering the maximum discharge on the drainage area, and iii. There was strong correlation just between turbidity of the water used in irrigation and the preceding precipitation in some fields. / O cultivo do morangueiro tem sido destaque em sistemas familiares de produção em Turuçu-RS, sendo produzido e comercializado in natura e de forma processada, propiciando aos produtores geração de emprego, renda e inclusão social. O sistema de produção de morango, de forma geral, é caracterizado pela utilização de cobertura do solo com plástico de coloração preta, pela utilização de túneis baixos e pelo sistema de irrigação por gotejamento com aplicação de fertilizantes via água de irrigação (fertirrigação). A importância e os benefícios do uso da técnica de irrigação na cultura do morango vêm sendo constatados pelos agricultores, já que tem influenciado na melhoria da qualidade do produto in natura . Entretanto, em virtude das lavouras de morango localizarem-se na sua maior parte distantes de grandes mananciais, muitos agricultores necessitam construir barramentos para represar a água de forma eficiente, garantir o êxito da irrigação das lavouras, e também para assegurar a quantidade e a qualidade de água para estas atividades. Baseado nisto, este trabalho teve como objetivos avaliar: i. o comportamento espacial e temporal, na camada de 0-200 mm, de parâmetros físico-hídricos do solo (capacidade de água disponível e armazenamento de água) relacionados ao manejo de irrigação adotado em 12 lavouras de morango; ii. as características geotécnicas e de segurança de duas pequenas barragens de terra que armazenam água para a irrigação de morango e outras culturas; e iii. a existência de correlação entre oito parâmetros de qualidade da água com os diferentes tipos de mananciais usados como fonte de captação na irrigação do morango, com as micro-regiões em que se localizam e com a precipitação antecedente, referentes a 14 propriedades rurais de Turuçu-RS. Gráficos em caixa foram construídos para representar o comportamento espacial e temporal da capacidade de água disponível, do armazenamento de água no solo a partir dos dados coletados nas lavouras e de dados de tensiômetros instalados na profundidade de 200 mm em cada uma das 12 lavouras no ano de 2007. Foram realizadas as seguintes atividades em duas pequenas barragens de terra agrícolas: estudos de geometria do aterro, execução de ensaios geotécnicos, avaliação das condições de segurança e o cálculo da vazão de projeto bem como de dimensionamento de vertedouro. Ferramentas da estatística multivariada e utilização da correlação de Pearson foram aplicadas aos dados de análises da água coletados nos anos de 2007 e 2008 para identificar a existência de correlação entre oito parâmetros de qualidade da água (alcalinidade, condutividade elétrica, demanda bioquímica de oxigênio, oxigênio dissolvido, sólidos suspensos, sólidos dissolvidos, sólidos totais e turbidez) com os diferentes tipos de mananciais usados como fonte de captação na irrigação do morango, com as micro-regiões em que se localizam e com a precipitação antecedente, referentes a 14 propriedades rurais de Turuçu-RS. Conclui-se que: i. não houve um padrão de comportamento espacial e temporal dos valores de capacidade de água disponível e de armazenamento de água no solo para os meses de setembro e dezembro de 2007 avaliados; ii. o processo erosivo no talude a montante observado nos maciços de terra constitui um problema, pois os sedimentos assoreados podem prejudicar a qualidade da água de irrigação e existe subdimensionamento dos vertedouros quanto a vazão máxima referente à área de drenagem; e iii. houve correlação forte somente entre o parâmetro turbidez de qualidade de água usada na irrigação e a precipitação antecedente em algumas propriedades.

La gestion efficace de l'eau dans les régions arides et semi-arides est un problème majeur, principalement dans les zones irriguées. La conception d'outils fournissant des estimations régionales des composantes du bilan hydrique peut aider à la gestion durable de la ressource en eau dans ces régions. La télédétection multi-capteurs a démontré un très fort potentiel pour le suivi des ressources hydriques agricoles à différentes échelles. Cette thèse vise à développer des techniques et des méthodes efficaces pour estimer les variables hydrologiques (évapotranspiration et les volumes d'irrigation) afin d'évaluer, dans l'espace (résolutions "métrique" et "kilométrique"), les besoins en eau des cultures du couvert végétal de la plaine de Kairouan (Tunisie centrale) ainsi que les volumes d'irrigation extraits de son aquifère surexploité. L'approche adoptée combine l'expérimentation, la modélisation et l'utilisation de données de télédétection multi-capteurs / multi-résolutions. Les deux types d'outils utilisés sont le modèle de bilan hydrique SAMIR et le modèle de bilan d'énergie SPARSE. Les variables estimées par SAMIR et SPARSE sont évaluées à l'aide des mesures terrain (mesures d'un scintillomètre XLAS) et des enquêtes de terrain (volumes d'irrigation observés). Les volumes d'irrigation saisonniers estimés par SAMIR sont acceptables, même si les résultats à des échelles de temps plus fines (mensuelles) doivent être améliorés. Ainsi, les paramètres de SAMIR, en particulier les paramètres non calibrés, sont revisités afin d'améliorer les performances de simulation de l'ET et des volumes d'irrigation. Les estimations des flux de chaleur sensible et latente par SPARSE sont en étroit accord avec celles obtenues à partir du XLAS. Cependant, l'extrapolation de l'évapotranspiration instantanée au pas de temps journalier est moins évidente. / In arid and semi-arid regions, efficient agricultural water management is a major issue, mainly in irrigated areas. The design of tools that provide an estimate of water balance components at the regional scale may help sustainable management of limited water resources in the water scarce regions. Remotely sensed Earth observation has become a major research field for agricultural water resources management. The main objective of this thesis is to develop and test efficient techniques and methods to estimate hydrological variables (Evapotranspiration (ET) and irrigation volumes) in order to assess, at "metric" and "kilometric" resolution , the crop water requirements and the extracted irrigation volumes in the Kairouan plain (central Tunisia). The adopted approach combines field experimentation, modeling and the use of multi-sensor / multi-resolution remote sensing data. Two modeling tools are used: the soil water balance model SAMIR and the energy balance model, SPARSE. SAMIR and SPARSE estimates are assessed using field measurements (Scintillometer XLAS measurements) and field surveys (observed irrigation volumes). The seasonal irrigation volumes estimated by the SAMIR model are acceptable, even though results at finer timescales (monthly and below) needed to be improved. Hence, the SAMIR model parameters, especially the uncalibrated ones are revisited in order to improve the results. SPARSE estimates of sensible and latent heat ?uxes are in close agreement with those obtained from the XLAS. However, the extrapolation from instantaneous to daily ET is less obvious.

A greenhouse pot study was conducted on three soils with varying clay contents to establish K critical value at -3 and -1/3 bar soil moisture levels. Four K fertilizer treatments (0, 0.07, 0.14, and 0.3 g/pot) replicated three times were arranged in a complete randomized block design. The Cate-Nelson graphical procedure revealed that K critical values for corn and soybeans were not equal at the two designated moisture levels. The corresponding percentage yield however was higher at -1/3 bars for corn and at -3 bars for soybean. Statistical regression analysis showed that there was a minor response in plant tissue K to changes in soil test K at both soil moisture levels. The ANOVA at 0.05 significance level showed the observed data were consistent with the null hypothesis that there was no significant difference between plant percentage yield and the increasing K fertilizer application rates at the two moisture levels.

PhDRDV / Institute for Rural Development / Throughout the world, irrigation is appreciated because of its immense contribution to agricultural production, food and nutrition security, combating poverty and enhancing development, especially in rural areas. The worsening effects of climate change on rainfall patterns as well as food and nutrition insecurity in sub-Saharan Africa are elevating the importance of irrigation schemes in smallholder farming. However, studies conducted in sub-Saharan Africa indicate that the performance of irrigation schemes remains suboptimal. In addition, the studies are highly skewed towards technical and physical dimensions of the schemes and ignore social aspects such as gender. Consideration of gender imperatives would help define and structure who uses water, when and how. This situation necessitated carrying out the PhD thesis research, aiming to explore and explain inherent gender dynamics in water use and management. The ultimate aim was to propose intervention strategies anchored on differential gender power dynamics embedded in irrigation water use in smallholder irrigation schemes. Specific objectives adopted for the study of the Nyanyadzi irrigation scheme in Manicaland Province of Zimbabwe were to: 1) assess the gendered nature of irrigation water use; 2) determine the gendered nature and extent of participation of male and female members of the irrigation scheme in water management; 3) identify the gendered challenges and constraints to irrigation water use; and 4) propose strategies for improved access and management of water. An exploratory sequentially integrated mixed method research design was used in the two phased PhD studies. Seventy three farmers (26 men and 47 women) were the respondents in the first phase in which qualitative data were collected. The gender analysis matrix and activity profile were used to gather and document the perceptions of men and women farmers relating to use of irrigation water. One hundred and nine conveniently sampled respondents (47 men and 62 women) were the source of data in the second phase of the study, which was quantitative and confirmatory in nature. A questionnaire, requiring responses on a Likert-type scale ranging from 1 (strongly disagree) to 5 (strongly agree) was used to collect data. Qualitative data collected during the exploratory phase were analysed using the Cresswell (2013) Thematic Content Analysis technique. Pair-wise ranking was conducted to determine the major constraints to access, use and management of irrigation water. The Predictive Analytics Software Statistics 18 for Windows (PASW Inc: Chicago, IL, USA) was used to analyse quantitative data. Gender, age, marital status, location of irrigation plot, plot ownership and level of education were the independent variables used. Dependent variables included nature of water use, participation in water management and constraints to water use. Cross-tabulation was carried out and the iii Pearson’s Chi-square test for association used to establish if relationships existed between variables. Statistical significance was considered at P < 0.05. The Cramer’s V post-hoc test was performed to measure the strength of association of the perceptions which the Chi-square test had determined to be significantly different. The uses of canal water were found to be varied and gendered. More women than men used canal water for reproductive purposes such as laundry and bathing. Highly significant positive associations (P < 0.01) were observed among gender, age, marital status, ownership of irrigation plot and level of education with use of irrigation water for laundry, bathing, livestock watering and other communal uses. However, location of plot was not associated with different types of water uses (P > 0.05). With respect to farmers’ participation in meetings, contributing in meetings, repair of canals, provision of labour in canal maintenance, hiring labour for canal maintenance and contributing cash for canal repairs and maintenance, highly significant positive associations (P < 0.01) were observed with gender, age, marital status, level of education, and ownership and location of irrigation plot. Level of education of the farmer was observed to be not associated with his/her attendance of meetings (P > 0.05). Plot location was negatively associated with participation, provision of labour for maintenance, contribution of cash and hiring labour for canal repairs (P > 0.05). Exorbitant payments for using water were regarded as the major constraint to performance of the smallholder irrigation scheme. Highly significant positive associations (P < 0.01) were observed between gender and plot location, and all the constraints to water use that the farmers identified. The constraints ranged from unequal water distribution between and within men and women, and upstream and downstream farmers; unfriendly water delivery times; conflicts and corrupt practices in water distribution; and discrimination with respect to schedules of delivering water. Overall, gender imbalance in the use and management of irrigation water existed. This was evident in the disparities in uses and users of canal water that followed gender and social lines. Men dominated decision making in water management, especially in meetings. In contrast, women dominated in implementation stages mainly in relation to provision of labour for cleaning and maintaining water canals. Considering all the results obtained in the current study, it can be concluded that a combination of socio-economic and socio-cultural factors caused the water problems that the Nyanyadzi irrigation scheme experienced. The need for introducing gender-sensitive interventions in use and management of irrigation water was evident. Thus, gender needs, roles and responsibilities should be reconceptualised so as to align them with the socio-cultural context of the Nyanyadzi community. In addition to this, the fact that both men and women iv are not homogeneous interest groups should be factored into irrigation water management. Lastly, it is crucial to incorporate various social hierarchies that interact with gender to influence irrigation water use and management. How this can be done deserves further scientific investigation. / NRF

Thesis (M. Tech) - Central University of Technology, Free State, 2008 / Food and water are two basic human needs. International projections indicate that water shortages will be prevalent among poorer countries where resources are limited and population growth is rapid, such as the Middle East, parts of Asia and Africa. Provisional estimates are that South Africa will run out of surplus usable water by 2025, or soon thereafter. Urban and peri-urban areas will therefore require new infrastructure and inter-basin transfers to provide safe water and adequate sanitation. Due to the high cost of these developments, such water is seen as being used for industrial and public needs only and not for irrigation. Currently, the agricultural water users consume the majority of the water used by humans. Taking cognisance of the before mentioned it is a reality that in the future the irrigation sector will have to sacrifice some of its water for public and industrial usage. This suggests growing conflict between the different water users and the agricultural water users. An attempt by the Department of Water Affairs and Forestry (DWAF) to address this conflict has been the implementation of pilot studies to determine the steps Water User Associations (WUAs) could take to ensure more effective water use in the future by the agricultural sector. These steps include an increase in irrigation efficiency according to the benchmarks of crop irrigation requirements and more efficient dam and canal management. The Water Administration System (WAS) has been developed to fulfill this exact requirement as it ensures optimal delivery of irrigation water on demand. The program is designed as a management tool for irrigation schemes, WUAs and water management offices to manage their accounts, and also to manage water supply to clients more efficiently through canal networks, pipelines and rivers. The WAS program consists of four modules that are integrated into a single program. Three modules of the WAS program have already been implemented at the Vaalharts irrigation scheme. This scheme has been transformed from a government controlled scheme to a privately owned scheme, and is now known as the Vaalharts Water User’s Association (VHWUA). The main purpose of this study was to implement the fourth module of the WAS program at the VHWUA as only full functionality of the complete program will ensure effective water use at the scheme. The fourth module calculates the volume of water to be released for all the canals (main canal and all its branches), allowing for lag times, water losses and accruals in order to minimise waste and thus save water. The methodology followed in this study was to first of all develop an understanding of the distribution cycle and the current calculation procedure of the VHWUA. The fourth module was then applied on a typical feeder canal and used to calculate the release volumes in order to compare these results with the current values. The next step was then to verify all data abstracted from the database used by the WAS program to calculate the release volumes. The database consists of information like cross-sectional properties, positioning of the sluices, canal slope, as well as canal capacities. The verification of data was done by field work, by studying existing engineering design drawings, through meetings and consultations with all parties involved in the VHWUA as well as by mathematical calculations. Cross-checking and verification, if necessary, of all above mentioned data were done. After the verification process, the database was updated and another cycle of calculations were run to do the final calibrations. Accurate calibrations were done to the seepage and the lag time coefficient. Some final adjustments were also made to the canal geometry in the database. This was an important part of the study as only a trusted and verified database will deliver correct results, irrespective of the software program used. After calibration of the database, the fourth module was again applied, but this time water losses were included in the calculations and the results revealed trustworthy and accurate real-time release volumes. The study therefore succeeded in the implementation of the fourth module on a typical feeder canal at the VHWUA. The study was concluded by the compilation of a checklist, which the VHWUA can use to implement the module on the whole scheme. This would enable the VHWUA to implement and apply the complete WAS program, which offers all the benefits and answers in every need of any water management office. Sustainable water resource utilisation can only be achieved through proper management. Applying this most effective management program will ensure a cost effective and optimised process at the VHWUA.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-06-15T20:28:16Z No. of bitstreams: 1 RIUZUANI MICHELLE BEZERRA PEDROSA LOPES - DISSERTAÇÃO PPGEA 2008..pdf: 44618002 bytes, checksum: 10bd1e265640cd193f330756b03247d2 (MD5) / Made available in DSpace on 2018-06-15T20:28:16Z (GMT). No. of bitstreams: 1 RIUZUANI MICHELLE BEZERRA PEDROSA LOPES - DISSERTAÇÃO PPGEA 2008..pdf: 44618002 bytes, checksum: 10bd1e265640cd193f330756b03247d2 (MD5) Previous issue date: 2008-02 / Busca-se, com a realização deste trabalho, a avaliação dos custos de água e energia elétrica para frutíferas irrigadas no Estado da Paraíba. Com este propósito se obtiveram, de início, as demandas de água e energia elétrica para as culturas do mamão, coco e banana, através do sistema de irrigação por aspersão e microaspersão. João Pessoa, Capital da Paraíba, localizada no baixo Rio Paraíba, é o município de menor consumo de água, necessitando de apenas de 37,71, 40,6 e 44,7% das demandas de água e energia elétrica do município de Desterro para as culturas do mamão, coco e banana, respectivamente. O município de Desterro, localizada na subbacia do Taperoá, apresentou a maior evapotranspiração anual e diária, combinada com as menores precipitações anuais, enquanto o município de João Pessoa, localizado no Baixo Rio Paraíba, teve a menor média de evapotranspiração, combinado com boas médias de precipitação provável a nível de 75% de probabilidade de ocorrer; desta forma, Desterro necessita de uma reposição maior de água para as plantas, o que acarreta também maior custo com água e energia elétrica. A demanda de água e energia elétrica aumenta na medida em que os municípios se afastam do litoral paraibano, devido às características hidroclimáticas dos locais do estudo. A região do Baixo Rio Paraíba, obteve as menores médias de demanda e a sub-bacia do Taperoá, obteve as maiores médias de demanda de água e energia elétrica, assim os maiores custos de água e energia elétrica ocorreram na sub-bacia do Taperoá e os menores custos no Baixo Rio Paraíba. Para a agricultura irrigada, a cobrança de água a ser implementada pelo comité da bacia do Rio Paraíba pode servir de incentivo, desde que sejam cobradas tarifas diferentes, isto é, implementar uma tarifa menor para os sistemas de irrigação mais eficientes, acarretando assim, maior economia no consumo de água e, consequentemente menor impacto na bacia, além de uma produção maior por hectare, com o mesmo volume de água captado. Palavras-chaves: Simulação, irrigação, frutíferas. / iis work deals with the evaluation of the costs of power and water for irrigated the planning áreas in Paraíba State. First, the demands of water were obtained and power electricity for cultures of papaya, coconut and banana using the irrigation system based on aspersion e microaspersion. João Pessoa, capital of Paraíba State, located in the lower Paraíba River, is the city which has the lowest water consumption and it requires only 37.71, 40.6 and 44.7% the demands of power and water of Desterro city for cultures of papaya, coconut and banana, respectively. The city of Desterro, located at the basin of Taperoá River, has presented the highest leveis for annual and daily evapotranspiration combined with the lowest rain rates. On the other hand, Jõao Pessoa, presented in the lower Paraíba River, presented the lowest leveis for average evapotranspiration and good rain rates of 75% of occurrence probability. Thus, the city of DesteiTO needs a higher reposition of water for the plants which leads a higher costs of water and electrical power. For cities located in the Paraíba State, the demand of water and electrical power increases when the distance between the cities and the offshore increases as a consequence of the precipitation and weather carachateristics of the cities used in this study. The region of the lower Paraíba River achieved the lowest average leveis for demand of water and electrical power while the sub-basin of the Taperoá River achieved the highest average leveis. Thus, the highest costs of water and electrical power occurred in sub-basin of the Taperoá River and lowest ones occurred in the lower Paraíba River. For irrigated agriculture, the taxes for the use of water should be implemented by the committe of the River Paraíba and they can be serving as a motivation for the efficient use of the water. In this case, lower taxes can be applied for efficient irrigation systems. So, a lower consumption of water should be achieved and the higher productivity by hectare can be obtained for the same volume of water. Keywords: Irrigation, simulation, planning

MESHWR / Department of Hydrology and Water Resources / Irrigation uses the largest amount of water, estimating to 60 % of the total consumption in South Africa. For this reason, the efficient and reasonable use of water by irrigators is of paramount importance. Thus, this study was carried out to assess the suitability of Wetting Front Detectors (WFDs) in improving water management. The study involved an on-farm survey; field installations; testing of WFD technology on selected plots within the scheme; identification of the crops grown; documentation of the current water supply and documentation of the challenges faced by farmers in relation to irrigation. These were carried out to identify the ideal situations in the scheme. Irrigation scheduling helps farmers to know when to irrigate and amount of water required supplying for crop need. The study presented WFD, as a means of improving irrigation efficiency. The WFD is a simple tool that helps farmers to identify what is occurring around the root zone. Four plots with a representative farmer in each of the plot were identified in four Blocks (Block 1 farmer 1, Block 1 farmer 2; Block 2 farmer 1; Block 3 farmer 1 and Block 4 farmer 1). On-farm experiment of the WFD was carried out. However, with Block 4 farmer 1, insufficient data was collected due to absence of LongStop equipment. This also involved field installation, observation and measurements of the LongStops (LSs) and FullStops (FSs) WFDs at placement depth of 30 cm, 45 cm and 60 cm. The efficiency of an irrigation system depends on different performance indicators including Irrigation Efficiency (IE), Conveyance Efficiency (CE), Application Efficiency (AE), Storage Efficiency (SE), Distribution Uniformity (DU) and Coefficient uniformity (CU). In this study, attention was focused only on DU; CU and SE, as represented by water moisture availability. All the DU for all plots in blocks were below the standard DU of furrow, which is 65%. Farmer 2, in Block 1, had a higher DU and CU, which were 60% and 68%, respectively- considered closer to the standard DU value. For the other farmers, their DU and CU prior to irrigation were very low, which indicated that there was uneven distribution of water in these plots. The poor DU in Block 1 farmer 1, indicated by the uneven infiltrated water, resulted in excessive watering. Analysing the WFD showed that farmers were performed well in all the Blocks, except for farmer 1 in Block 1. Average soil moisture content result indicated high water loss through deep percolation. The highest volumes of water recorded before and after irrigation were 131 ml and 159 ml, respectively, for LS90 placed at a depth of 90 cm in Block 2 farmer 1. High volumes of water were collected in Block 1 farmer 2, Block 2 farmer 1 and Block 3 farmer 1 before and after irrigation. The result showed that, the more placement depth down the soil profile, the more accumulation of water in the LSs. Therefore, it was recommended that farmers continue to use the WFD as a tool for irrigation efficiency. However, there is need for improvement and capacity building in using the tool.