South Africa lacks affordable irrigation technologies suited entirely to the needs of small-scale farmers. This is mainly due to the past emphasis on large, commercial farming technologies and the misunderstanding that emerging farmers can utilise scaled down versions of such technologies. It is now believed that increased irrigation amongst smallholders could largely assist with food security and poverty alleviation in South Africa. The object of this project was therefore to evaluate selected appropriate irrigation technologies that are currently being used in other developing countries with the intention of introducing them into South Africa. A literature review on all the irrigation technologies currently being used by small-scale farmers in South Africa was performed. The literature review provided information on the factors affecting the adoption of irrigation technologies. Selected technologies, namely, various low-cost, manual pumps and drip irrigation kits were then imported and evaluated under local conditions. The evaluation process was divided into two sections. Qualitative evaluations were carried out on farms and by farmers themselves and quantitative evaluations were carried out in laboratories and closely monitored field trials. A South African prototype pump was then designed and built following the knowledge gained from testing the imported pumps. The prototype was tested and then refined and rebuilt. The qualitative test results showed a very positive reaction from farmers towards the pumps. The drip irrigation kits were often not used as a result of a lack of understanding by the farmers. The laboratory test phase highlighted the more critical components of the pumps. A recommended introduction strategy was then developed and is presented. This evaluation process and introduction strategy could in future be used as a guideline when developing other suitable technologies for small-scale farmers.I wish to certify that the work reported in this dissertation is my own unaided work except where specific acknowledge is made. In addition I wish to declare that this dissertation has not been submitted for a degree in any other university. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

O Projeto de Irrigação Genil-Cabra (PIGC), Coletividade Santaella, está localizado na província de Córdoba-Espanha. Nesse Distrito avaliou-se a irrigação das campanhas de 2004/2005 e 2005/2006. Como complementações, foram realizadas entrevistas com os agricultores, objetivando determinar os custos de produção da área, a adoção das novas tecnologias, por parte da comunidade, a orientação do Sistema de Assessoramento ao Irrigante SAR , a produtividade e o consumo da água em cada parcela. Após a coleta dos dados, foram determinados indicadores, como a eficiência da irrigação, a produtividade da água e a relação benefício-custo do investimento. Para determinar a eficiência da irrigação, a pesquisa seguiu a metodologia utilizada por Mateos (2007). Como complementação a essa metodologia, foram introduzidas outras ferramentas, como DEM, SIG e entrevistas com os agricultores. No trabalho realizado por Fernandez et al. (2007), essa área estava dividida em 17 parcelas, denominadas recintos. Definiu-se uma nova delimitação da área, por meio de um DEM mais preciso e, após a nova delimitação e a realização da entrevista, identificou-se a necessidade de dividi-la em áreas de cadastro ou parcelas, com informações do produtor e do site oficial de cadastro. Dessa forma, a área passou a ter 33 parcelas, dando maior amplitude à pesquisa. Depois de entrevistar os agricultores e de comparar as informações com as ortofotos obtidas pelo site de cadastro, pôde-se identificar cultivos diferenciados dos citados por Fernandez et al. (2007). Esse fato foi importante para definir a eficiência do uso da água, visto que as áreas globais foram alteradas e, como exemplo, observou-se que o cultivo com oliveira foi menor do que o citado por Fernandez et al. (2007). Na campanha de 2005, tal cultivo ocupou uma extensão de 105,61 ha; já na de 2006, com o cultivo de novas áreas com oliveiras, esse valor passa para 112 ha, que contrastam com os 169,25 ha, calculados anteriormente. A eficiência da irrigação do ano da campanha de 2005 foi 81,99% e no de 2006, 90%, o mesmo encontrado por Fernandez et al. (2007), o que se justifica pela irrigação deficitária realizada no PIGC. Em relação à produtividade da água (PW), observa-se que os maiores valores foram detectados pela análise por recinto, tanto em 2005 quanto em 2006, justificadas pelo baixo volume de água demandado, observado nos sensores. No cálculo para a PW na parcela, usa-se, como denominador, a evapotranspiração da cultura, enquanto, no cálculo da PW do recinto, usa-se o volume de água que entra na área, ou seja, a água aplicada. Visto que a irrigação foi deficitária, então certamente haverá uma maior produtividade da água no nível do recinto. Os valores obtidos foram 4,06;0,37 m-3 para recintos e parcelas (2005) e 6,60;0,27 m-3 (2006). Esses valores são similares aos encontrados por Garcia-Vila et al. (2008) e Lorite et al. (2004b). Em relação à avaliação socioeconômica, pôde-se concluir que os irrigantes possuem plena consciência do uso correto da irrigação, porém não confiam nos dados do SAR, já que praticamente nenhum deles aceita a recomendação diária ofertada por esse serviço. / The Genil-Cabra irrigation scheme (GCIS), Coletividade Santaella, is located in Andalusia, southern Spain. This irrigation district has a strong run-government performance helping the private sector to do applied researches, whose investments brings good results to the farmers. It was evaluated the irrigation in 2004/2005 season and 2005/2006 season. To complement the work, it was done interviews with the farmers in the studied area to determine: production cost of the area, the technologies adoption, the orientation of farmer helping system (Servicio de Asesoramiento al Regante; SAR), the yield and water consumption in each parcel. After collecting all data it was made a study to determine indicators, such as irrigation efficiency, water productivity and cost/benefit relationship of the investments. To determine irrigation efficiency was followed the methodology used by Mateos (2007) complemented with the SIG and farmer interviews. In work made by Fernandez et al. (2007), this area was divided in 17 parcels called recintos. It was defined a new area delimitation through a land digital model more precise, and after the new delimitation and the interviews, it was realized a necessity to divide them in record areas or parcels, it identified by the farmers and by the record official web. In this way, the area became has to 33 parcels, and it gives bigger range to research. After the farmer interviews and compared the information with the orthophotos obtained from the record web it was identified crops differentiated from Fernandez et al. (2007). This fact was important to define the water use efficiency, due the global areas were altered, for example, it was observed that olive cultivation was smaller than cited by Fernandez et al. (2007). In the 2005 season occupied an area of 105.61 ha, however in the 2006 season it was 112 ha due the increase in olive area, that contrasted with 169.5 ha calculated previously by Fernandez et al. (2007). The irrigation efficiency in the 2005 season was 81.99% and in 2006 was 90%, same values encountered by Fernandez et al. (2007), that is due the deficit irrigation realized in the GCIS. In relation to water productivity (WP), it was observed that the biggest values were detected by recinto analyze, both in 2005 and 2006 season, due to low water volume demanded, observed in the sensors. In the parcel WP calculation, it was used the crop evapotranspiration as denominator; however in the recinto WP calculation it was used the applied water. Since the irrigation was deficiency, then likely will have a bigger WP in the recinto level. The values obtained were 4.06;0.37( m-3) to recintos and parcels (2005) and 6.60;0.27( m-3) to recintos and parcels (2006). These results are similar to encountered by Garcia-Vila et al. (2008) and Lorite et al. (2004b). In the socio-economic evaluation from the area could be concluded that irrigators have a full conscience of irrigation correct use, however they dont trust in the SAR database, since most of them don´t accepted the diary recommendation offer by this service.

Thesis (Ph.D. (Agricultural Economics)) -- University of Limpopo, 2015 / Various types of management practices/institutional arrangements of the irrigation schemes exist in the world. According to the principles delineated in literatures, these irrigation schemes are categorized in terms of their management practices. The study was designed to compare the level of technical efficiency of farmers at different management practices of the irrigation schemes (i.e. integrated, specialised and multipurpose water management practices of the irrigation schemes) in Limpopo Province. Data were collected using a structured questionnaire which was administered on 200 farmers at different irrigation schemes. Stochastic frontier production function of Cobb-Douglas type was employed to analyse the data and thereby ascertain the level of technical efficiency and its determinants. The results indicated the mean technical efficiency of 0.74, 0.72 and 0.76 for the integrated, specialised and multipurpose water management practices of the irrigation schemes respectively which implied that, there is a greater scope to increase maize, tomato, onion and spinach production with the current technology and resources available at the irrigation schemes. The most important contributors in maize, tomato, onion and spinach production efficiencies were seed, fertilizer, capital and land. Thus an appropriate amount of seed, fertilizer, capital and land could increase the productivity of maize, tomato, onion and spinach. The results further revealed that education level of farmers, age of the farmers and land size were negatively significant toward the technical inefficiency of farmers at different irrigation schemes, which imply that an increase in any of the three variables will reduce the inefficiency and enhance the efficiency. While the family size of the farmer was positively significant, which implies that the bigger the family size, the higher the inefficiency farmers would become for the production of maize, tomato, onion and spinach. Gender and income level of the farmers at different irrigation schemes were revealed to be insignificant toward the inefficiency. The institutional arrangements or the management practice of the irrigation schemes showed slight differences in affecting the efficiency of farmers at different irrigation schemes. Policies designed to educate famers at different irrigation schemes through proper agricultural extension services could have a great impact in increasing the level of efficiency and hence maize, tomato, onion and spinach productivities. The Department of Agriculture should allocate more funds to strengthening the extension directorate and expanding the delivery of extension services to farmers at different irrigation schemes. Irrigation schemes were established in order to insure food security, alleviate poverty, job creation, among others. Therefore, it is of paramount importance for the government of South Africa in collaboration with the private sector to revitalise the irrigation schemes in Limpopo Province irrespective of the institutional arrangements. It is of vital concern for the policy makers to focus on the benefits of economies of scale in agricultural farming system. Therefore, land size should be increased for the farmers in integrated water management practice of the irrigation schemes to an optimum level in order for them to improve the level of technical efficiency.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project. / Preface by G. E. P. Smith

ARAÚJO, Antonio Flávio Batista de. Demanda de água em sistemas de produção agrícola e seus impactos: ambientais e financeiros. 2009. 84 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola, Programa de Pós em Engenharia Agrícola, Fortaleza-CE, 2009. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-14T14:22:29Z No. of bitstreams: 1 2009_dis_afbaraujo.pdf: 1570832 bytes, checksum: f92fc3f878d426c9e847801d10327717 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-14T14:23:00Z (GMT) No. of bitstreams: 1 2009_dis_afbaraujo.pdf: 1570832 bytes, checksum: f92fc3f878d426c9e847801d10327717 (MD5) / Made available in DSpace on 2016-06-14T14:23:00Z (GMT). No. of bitstreams: 1 2009_dis_afbaraujo.pdf: 1570832 bytes, checksum: f92fc3f878d426c9e847801d10327717 (MD5) Previous issue date: 2009 / This work aims to investigate the agricultural production systems used by small farmers in rainfed and irrigated areas and also to identify the water productivity. The explored irrigated agricultural field was the Curupati irrigated perimeter, located in Jaguaribara, Ceará, Brazil. The rainfed system (tillage) was implanted in the Chapada do Apodi region, sited in Tabuleiro do Norte, Ceará, Brazil. The quantification of the water required to supply the irrigated crops was quantified through the flow rate of drippers. Also, the moisture of the soil profile was evaluated until the depth of 120 cm. The total of applied water in the irrigated field was 2,663,296.20 m3. The studied crop was papaya, although the guava crop was also explored. In the rainfed crop using tillage, the field was a 137 ha with the sorghum culture. The supplying water was quantified by rain gate implemented and monitored throughout the rainy season of 2008. The total rainfall during the cycle of the culture was 940 mm. The productivity for the cultivation of papaya ranged from 80 ton ha -1 to 106 ton ha -1 during the it’s productivity period. It was identified that for every 1 kg of papaya produced, 1,042 m3 of water was consumed, expressing a 0.95 kg m3 yield. In the rainfed area, the productivity of sorghum ranged from 438 kg ha-1 to 2,143 kg ha-1. Due to the fact that the total rainfall depth in 2008 was 27.4% higher than the annual average of the region, it was not possible to evaluate the water productivity in the tillage system, since the total rainfall depth was 280% higher than the required by the culture. / O presente trabalho teve por finalidade investigar os sistemas de produção agrícola adotados pelos pequenos produtores em áreas de sequeiro e irrigada onde se identificasse a produtividade da água, bem como suas perdas. O campo agrícola explorado com o sistema de agricultura irrigada corresponde ao perímetro irrigado Curupati, localizada no Município de Jaguaribara enquanto que o sistema de sequeiro (plantio direto) foi implantado na região da Chapada do Apodi na porção inserida no Município de Tabuleiro do Norte. A quantificação da demanda de água na agricultura irrigada foi realizada computando-se os números de horas de funcionamento da unidade de bombeamento que abastece o lote, determinando-se a vazão dos gotejadores que compunham o sistema e avaliando-se o perfil de umidade do solo até a profundidade de 120 cm. O total de água aplicada no campo irrigado foi de 2.663.296,20 m3. A cultura irrigada considerada nessa pesquisa foi o mamão, embora os irrigantes também explorem a cultura da goiaba. Na área com plantio de sequeiro (plantio direto), o campo agrícola correspondia a 137 ha com a cultura do sorgo. A demanda de água foi quantificada através de pluviômetros implantados e monitorados por todo o período chuvoso do ano de 2008. O total precipitado durante o ciclo da cultura foi de 940 mm. A produtividade para a cultura do mamão variou de 80 ton ha-1 a 106 ton ha-1 durante o ciclo da cultura. Foi identificado que para cada 1 kg de mamão produzido foram consumidos 1,042 m3 de água expressando uma produtividade 0,95 kg m3 Na área de sequeiro a produtividade do sorgo variou de 438 kg ha-1 a 2.143 kg ha-1. Em decorrência do total precipitado para o ano de 2008 ter sido superior em 27,54%, da média anual da região, não se pode de fato avaliar a produtividade da água em sistema de plantio direto, uma vez que o total precipitado foi superior em 280% ao requerido pela cultura.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O presente trabalho teve por finalidade investigar os sistemas de produÃÃo agrÃcola adotados pelos pequenos produtores em Ãreas de sequeiro e irrigada onde se identificasse a produtividade da Ãgua, bem como suas perdas. O campo agrÃcola explorado com o sistema de agricultura irrigada corresponde ao perÃmetro irrigado Curupati, localizada no MunicÃpio de Jaguaribara enquanto que o sistema de sequeiro (plantio direto) foi implantado na regiÃo da Chapada do Apodi na porÃÃo inserida no MunicÃpio de Tabuleiro do Norte. A quantificaÃÃo da demanda de Ãgua na agricultura irrigada foi realizada computando-se os nÃmeros de horas de funcionamento da unidade de bombeamento que abastece o lote, determinando-se a vazÃo dos gotejadores que compunham o sistema e avaliando-se o perfil de umidade do solo atà a profundidade de 120 cm. O total de Ãgua aplicada no campo irrigado foi de 2.663.296,20 m3. A cultura irrigada considerada nessa pesquisa foi o mamÃo, embora os irrigantes tambÃm explorem a cultura da goiaba. Na Ãrea com plantio de sequeiro (plantio direto), o campo agrÃcola correspondia a 137 ha com a cultura do sorgo. A demanda de Ãgua foi quantificada atravÃs de pluviÃmetros implantados e monitorados por todo o perÃodo chuvoso do ano de 2008. O total precipitado durante o ciclo da cultura foi de 940 mm. A produtividade para a cultura do mamÃo variou de 80 ton ha-1 a 106 ton ha-1 durante o ciclo da cultura. Foi identificado que para cada 1 kg de mamÃo produzido foram consumidos 1,042 m3 de Ãgua expressando uma produtividade 0,95 kg m3 Na Ãrea de sequeiro a produtividade do sorgo variou de 438 kg ha-1 a 2.143 kg ha-1. Em decorrÃncia do total precipitado para o ano de 2008 ter sido superior em 27,54%, da mÃdia anual da regiÃo, nÃo se pode de fato avaliar a produtividade da Ãgua em sistema de plantio direto, uma vez que o total precipitado foi superior em 280% ao requerido pela cultura. / This work aims to investigate the agricultural production systems used by small farmers in rainfed and irrigated areas and also to identify the water productivity. The explored irrigated agricultural field was the Curupati irrigated perimeter, located in Jaguaribara, CearÃ, Brazil. The rainfed system (tillage) was implanted in the Chapada do Apodi region, sited in Tabuleiro do Norte, CearÃ, Brazil. The quantification of the water required to supply the irrigated crops was quantified through the flow rate of drippers. Also, the moisture of the soil profile was evaluated until the depth of 120 cm. The total of applied water in the irrigated field was 2,663,296.20 m3. The studied crop was papaya, although the guava crop was also explored. In the rainfed crop using tillage, the field was a 137 ha with the sorghum culture. The supplying water was quantified by rain gate implemented and monitored throughout the rainy season of 2008. The total rainfall during the cycle of the culture was 940 mm. The productivity for the cultivation of papaya ranged from 80 ton ha -1 to 106 ton ha -1 during the itâs productivity period. It was identified that for every 1 kg of papaya produced, 1,042 m3 of water was consumed, expressing a 0.95 kg m3 yield. In the rainfed area, the productivity of sorghum ranged from 438 kg ha-1 to 2,143 kg ha-1. Due to the fact that the total rainfall depth in 2008 was 27.4% higher than the annual average of the region, it was not possible to evaluate the water productivity in the tillage system, since the total rainfall depth was 280% higher than the required by the culture.

This paper analyzes the management problem of the conjunctive use of surface and ground water in an irrigation system on both sides of the Lower Yellow River. For this purpose, a stochastic dynamic programming model is developed. In the model, the statistical characteristics of seasonal rainfall within 2 years are considered; groundwater level control is also emphasized in order to prevent soil salinity and waterlogging. Through computer calculations, optimal operation policies are obtained for efficient conjunctive use of surface and groundwater. These policies take into account the interactions between pumping groundwater by farmers, canal diversions by irrigation system managers, and the physical response of the stream- aquifer system, and minimize the total operation costs. In this paper, we take an irrigation district, the People's Victory Canal System, as an example to illustrate the development and solution of the model. At the same time, the effects of system parameters, including surface irrigation efficiency and rainfall recharge coefficient, on the optimal policies or total operation costs, are discussed. The analytical results in this example indicate that the variation in optimal operation costs caused by the proportion of rainfall infiltrated is small, but the effect of surface irrigation efficiency on the costs is significant. Hence, the surface irrigation efficiency must be increased as much as possible. Then, efficient conjunctive use of surface and groundwater can be attained with the optimal policies.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / The Tulare Lake basin at the base of the Sierra Nevada Mountains is the basis for water supply for several cities and a highly productive agricultural area. Little attention has been given to groundwater quality during the past one hundred years. A careful study of the salt balance produced a set of guidelines for future groundwater managers to follow. The major emphasis for future water consumption should be the efficient use of irrigation. This would produce a positive impact on groundwater quality, energy savings, and less imported water would be needed. Groundwater management in the future must consider water quality as well as quantity. Appropriate monitoring programs are urgently needed to provide data on trends in groundwater quality.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-07-02T14:34:40Z No. of bitstreams: 1 LINDIBERG FARIAS DUARTE DA SILVA - DISSERTAÇÃO PPGEA 2006..pdf: 10915027 bytes, checksum: b7387260843429ed741c76bb28e94e87 (MD5) / Made available in DSpace on 2018-07-02T14:34:40Z (GMT). No. of bitstreams: 1 LINDIBERG FARIAS DUARTE DA SILVA - DISSERTAÇÃO PPGEA 2006..pdf: 10915027 bytes, checksum: b7387260843429ed741c76bb28e94e87 (MD5) Previous issue date: 2006-08 / Capes / Apesar das tecnologias já existentes dos sistemas de irrigação, as práticas de manejo de água e solos nas áreas irrigadas, através de critérios adequados, se revestem de importância cada vez maior, face à intensificação do uso dos recursos hídricos. Na exploração agrícola nos grandes pólos irrigados, nas empresas privadas ou até mesmo na agricultura familiar, o controle dos recursos naturais, como um todo, é uma questão de sustentabilidade das comunidades. O objetivo da presente pesquisa é verificar a viabilidade técnica e económica da agricultura familiar irrigada no Perímetro Irrigado município de Sumé, PB. O trabalho foi conduzido em uma área que, do ponto de vista administrativo, pertence à área de atuação da 3a Diretoria Regional (DR) do Departamento Nacional de Obras Contra as Secas-DNOCS, cuja área total é de 700 hectares distribuídos em 51 lotes dos quais, 47 estão em atividade sendo atualmente, sendo 42 com criações de animais de pequeno porte e apenas 5 cultivados com hortaliças, principalmente o tomate e o pimentão. As avaliações técnica e econômica foram realizadas com as culturas de pimentão e tomate rasteiro, em uma área irrigada de aproximadamente 02 ha, dividida em duas subáreas irrigadas por gotejamento, nos meses de fevereiro a julho de 2005 e de outubro a janeiro de 2005/2006. Em visita à área onde estava localizado o sistema de irrigação, levantaram-se os seguintes dados, equipamentos instalados, comprimento e diâmetro das tubulações (nominal e interno), cota do terreno e vazão do emissor. Com os dados levantados pode-se determinar: vazão, velocidade da água, perda de carga acumulada e pressão. Através da análise dos dados de vazão coletados em campo, avaliou-se o sistema de gotejamento, em função do parâmetro de desempenho: uniformidade e eficiência de aplicação de água. Apesar da elevada variação de vazão nas linhas laterais, não comprometeu o manejo, sendo os coeficientes de uniformidade de distribuição de água dos emissores considerados bons, mas os valores de eficiência de aplicação da irrigação estão abaixo do mínimo recomendado (80%) caracterizando má qualidade para o sistema de irrigação localizada. Os resultados indicam que a prática da irrigação é realizada com ausência de critérios técnicos, causando perdas ou excessos na aplicação de água necessitando, dessa forma, da utilização de técnicas de manejo que visem melhorar a eficiência de aplicação de água. Apesar dos benefícios proporcionados aos produtores que cultivam hortaliças irrigadas no perímetro irrigado de Sumé, como doação de kits de irrigação e tarifas reduzidas de energia elétrica (tarifa verde) os mesmos não dão a devida importância ao manejo da irrigação. Apesar de todos os problemas levantados, ainda é economicamente viável o cultivo irrigado de tomate e pimentão no Perímetro Irrigado de Sumé, desde que o preço do produto esteja em um patamar satisfatório; desta forma, é salutar que o produtor realize, previamente, uma análise de mercado. / In spite of the technologies existents in irrigation systems, the handling practices with water on irrigated áreas, through right criterions, gets more and more importance, due to the intensification of water reserves explorer. On the agricultural explorer on biggest irrigated polés, in prívate enterprise including the familiar agriculture is a case of surviveness the careful with the natural water reserves. The objective of this search is to verify the technical and economical viability of the familiar agriculture on the Irrigated Perimeter of Sumé - PB. The job was conducted in an area that in the administrative point of view is pertinent at the action area of the 3rd Regional Directing (RD) of Departamento Nacional de Obras Contra as Secas - DNOCS. Witch haves an area of 700 ha, distributed in 51 potions and 47 of these potions are in activity, been 42 destined to creation of animais of little postage and just 5 destined at the vegetables culture principally tomatoes and pimentos. The economical and technical appraisement were made with the cultures of pimentos and creep tomatoes, in an irrigated area with 2ha, divided in two sub áreas irrigated by system of drops, in the months of February until July of2005 and since October until January - 2005/2006. About the area were localized the system of drops, we had collected the following information: equipments installed, length and diameter of tubes (nominal and boarding), coat of plot and drains of the emission. With the information we can conclude. empty of each bit, speed of water for bit, lose of load on the bit and cumulated pressure in each bit. Through the analysis of information about the drains for bits we had concluded the system of drops referent to the following parameters: uniformity and efficient application of water. Ali though the high variation on the lateral lines, this has not influenced the handling, and, because that the distribution water coefficient was considered good. On the other hand the values of application of irrigation are less than the aimed (80%) characterizing a bad quality for the localized irrigation system. The results indicate that the practices are realized with no technical criterions, doing loses or exceptions in water application, with the necessity of techniques of handling for get better the water application. Although the benefices given to vegetable producers, irrigated on the perimeter irrigated of Sumé, like donations of irrigation kits and reduced tariffs of electrical energy (green tariff) these people don't care about the irrigation handling. Even though ali of problems mentioned, the irrigation is economically viable to cultivate tomatoes and pimentos on the Irrigated Perimeter of Sumé, off course, unless the price not to be satisfactory, for that the better is to make a marketing search.

Die Landwirtschaft ist heute der wichtigste Treiber der globalen Degradation von Ökosystemen. Es existiert jedoch wenig konkretes Wissen, wie Ökosysteme zu schützen sind und gleichzeitig die Nahrungsproduktion für die wachsende Weltbevölkerung gesichert werden kann. In dieser Dissertation untersuche ich Optimierungsmöglichkeiten im landwirtschaftlichen Wassermanagement. Ich quantifiziere praxisorientierte Verbesserungen der Regenwassernutzung und Optimierungen von Bewässerungssystemen, unter Einhaltung der „environmental flow requirements“ (EFRs). Um diese komplexen Interaktionen zu untersuchen, entwickle ich ein agro-hydrologisches Modell auf Basis detaillierter, mechanistischer Prozessabbildung weiter. Erstens, 39% der derzeitigen Wasserentnahmen für Bewässerung sind nicht nachhaltig und somit auf Kosten der Ökosysteme. Zweitens, solche lokalen Wasserentnahmegrenzen legen nahe, dass die globale Grenze für den menschlichen Wasserverbrauch deutlich niedriger liegt, als bisher angenommen (2800 vs 4000 km3yr-1). Drittens, die Implementierung von EFRs würde die landwirtschaftliche Produktion erheblich beeinträchtigen, mit >20% in stark bewässerten Gebieten. Verbesserte Nutzung des Niederschlagswassers und die Optimierung von Bewässerungssystemen, können die weltweite Nahrungsmittelproduktion allerdings um rund 40% nachhaltig steigern - ausreichend, um die Nahrungsmittellücke der wachsenden Weltbevölkerung bis 2050 zu halbieren. Zusammenfassend stellt diese Arbeit die erste umfassende und systematische Einschätzung globaler Potentiale der nachhaltigen Intensivierung der Landwirtschaft aus der Wasserperspektive dar. Die in dieser Arbeit vorgebrachten innovativen und quantitativen Erkenntnisse legen nahe, dass das Potential der diskutierten Interventionen höhere politische Aufmerksamkeit erfahren sollte. Meine Ergebnisse können eine konkretere Diskussion zur Umsetzung der Sustainable Development Goals untermauern. / Agriculture is today''s most important driver of ecosystem degradation across scales. However, there is little evidence on how to attain the historic twin-challenge of maintaining environmental integrity while producing enough food for a growing world population. In this thesis, I assess opportunities in agricultural water management to reconcile future food needs with environmental limits to water use. I explore solution-oriented ways to improve rainfed and irrigation systems alike, while safeguarding environmental flows (EFRs). To study complex interactions quantitatively, I advanced a state-of-the-art global modeling framework based on detailed, mechanistic process representation. First, a systematic upscaling of EFRs to global coverage indicates that 39% of current freshwater withdrawals for irrigation are unsustainable and occur at the cost of ecosystems. Second, accounting for EFRs indicates that the planetary boundary for freshwater use might be notably lower (2800 vs. 4000 km3yr-1) than expected. Third, maintaining EFRs would significantly affect food production, cutting >20% of total kcal production across intensely irrigated areas. Fourth, improving irrigation systems in combination with optimizing the use of precipitation water, provides effective and accessible measures to compensate for adverse impacts from protecting EFRs and climate change. Such integrated interventions could sustainably intensify global food production (+40% kcal) to the degree sufficient to halve the global food gap by 2050. In conclusion, this thesis provides the first comprehensive and systematic assessment of hitherto largely unquantified water opportunities in sustainable intensification of agriculture. While requiring corroboration by finer-scale research, the innovative quantitative foundation provided in this thesis suggests that farm water management merits a rise in political attention, and it can inform a more comprehensive discussion of related SDG target interactions.