Energy requirements in pressure irrigation systems

Modernization of irrigation schemes, generally understood as transformation of surface irrigation systems into pressure –sprinkler and trickle- irrigation systems, aims at, among others, improving irrigation efficiency and reduction of operation and maintenance efforts made by the irrigators. However, pressure irrigation systems, in contrast, carry a serious energy cost. Energy requirements depend on decisions taken on management strategies during the operation phase, which are conditioned by previous decisions taken on the design project of the different elements which compose the irrigation system. Most of the countries where irrigation activity is significant bear in mind that modernization irrigation must play a key role in the agricultural infrastructure policies. The objective of this study is to characterize and estimate the mean and variation of the energy consumed by common types of irrigation systems and their management possibilities. The work includes all processes involved from the diversion of water into irrigation specific infrastructure to water discharge by the emitters installed on the crop fields. Simulation taking into account all elements comprising the irrigation system has been used to estimate the energy requirements of typical irrigation systems of several crop production systems. It has been applied to extensive and intensive crop systems, such us extensive winter crops, summer crops and olive trees, fruit trees and vineyards and intensive horticulture in greenhouses. The simulation of various types of irrigation systems and management strategies, in the framework imposed by particular cropping systems, would help to develop criteria for improving the energy balance in relation to the irrigation water supply productivity.

Managing drought economic effects through insurance schemes based on local water availability.

In many arid or semi-arid Mediterranean regions, agriculture is dependent on irrigation. When hydrological drought phenomena occur, farmers suffer from water shortages, incurring important economic losses. Yet, there is not agricultural insurance available for lack of irrigation water. This work attempts to evaluate hydrological drought risk and its economic impact on crop production in order to provide the basis for the design of drought insurance for irrigated arable crops. With this objective a model that relates water availability with expected yields is developed. Crop water requirements are calculated from evapotranspiration, effective rainfall and soil water balance. FAO?s methodology and AquaCrop software have been used to establish the relationship between water allocations and crop yields. The analysis is applied to the irrigation zone ?Riegos de Bardenas?, which is located in the Ebro river basin, northeast Spain, to the main arable crops in the area. Results show the fair premiums of different hydrological drought insurance products. Whole-farm insurance or irrigation district insurance should be preferable to crop specific insurance due to the drought management strategies used by farmers.

Testing of crop Models for Accurate Predictions of Evapotranspiration and crop Water Use

All crop models, whether site-specific or global-gridded and regardless of crop, simulate daily crop transpiration and soil evaporation during the crop life cycle, resulting in seasonal crop water use. Modelers use several methods for predicting daily potential evapotranspiration (ET), including FAO-56, Penman-Monteith, Priestley-Taylor, Hargreaves, full energy balance, and transpiration water efficiency. They use extinction equations to partition energy to soil evaporation or transpiration, depending on leaf area index. Most models simulate soil water balance and soil-root water supply for transpiration, and limit transpiration if water uptake is insufficient, and thereafter reduce dry matter production. Comparisons among multiple crop and global gridded models in the Agricultural Model Intercomparison and Improvement Project (AgMIP) show surprisingly large differences in simulated ET and crop water use for the same climatic conditions. Model intercomparisons alone are not enough to know which approaches are correct. There is an urgent need to test these models against field-observed data on ET and crop water use. It is important to test various ET modules/equations in a model platform where other aspects such as soil water balance and rooting are held constant, to avoid compensation caused by other parts of models. The CSM-CROPGRO model in DSSAT already has ET equations for Priestley-Taylor, Penman-FAO-24, Penman-Monteith-FAO-56, and an hourly energy balance approach. In this work, we added transpiration-efficiency modules to DSSAT and AgMaize models and tested the various ET equations against available data on ET, soil water balance, and season-long crop water use of soybean, fababean, maize, and other crops where runoff and deep percolation were known or zero. The different ET modules created considerable differences in predicted ET, growth, and yield.

Exploring strategic farming choices to respond to mitigation and adaptation to climate change

Las alteraciones del sistema climático debido al aumento de concentraciones de gases de efecto invernadero (GEI) en la atmósfera, tendrán implicaciones importantes para la agricultura, el medio ambiente y la sociedad. La agricultura es una fuente importante de emisiones de gases de efecto invernadero (globalmente contribuye al 12% del total de GEI), y al mismo tiempo puede ser parte de la solución para mitigar las emisiones y adaptarse al cambio climático. Las acciones frente al desafío del cambio climático deben priorizar estrategias de adaptación y mitigación en la agricultura dentro de la agenda para el desarrollo de políticas. La agricultura es por tanto crucial para la conservación y el uso sostenible de los recursos naturales, que ya están sometidos a impactos del cambio climático, al mismo tiempo que debe suministrar alimentos para una población creciente. Por tanto, es necesaria una coordinación entre las actuales estrategias de política climática y agrícola. El concepto de agricultura climáticamente inteligente ha surgido para integrar todos estos servicios de la producción agraria. Al evaluar opciones para reducir las amenazas del cambio climático para la agricultura y el medio ambiente, surgen dos preguntas de investigación: • ¿Qué información es necesaria para definir prácticas agrarias inteligentes? • ¿Qué factores influyen en la implementación de las prácticas agrarias inteligentes? Esta Tesis trata de proporcionar información relevante sobre estas cuestiones generales con el fin de apoyar el desarrollo de la política climática. Se centra en sistemas agrícolas Mediterráneos. Esta Tesis integra diferentes métodos y herramientas para evaluar las alternativas de gestión agrícola y políticas con potencial para responder a las necesidades de mitigación y adaptación al cambio climático. La investigación incluye enfoques cuantitativos y cualitativos e integra variables agronómicas, de clima y socioeconómicas a escala local y regional. La investigación aporta una recopilación de datos sobre evidencia experimental existente, y un estudio integrado sobre el comportamiento de los agricultores y las posibles alternativas de cambio (por ejemplo, la tecnología, la gestión agrícola y la política climática). Los casos de estudio de esta Tesis - el humedal de Doñana (S España) y la región de Aragón (NE España) - permiten ilustrar dos sistemas Mediterráneos representativos, donde el uso intensivo de la agricultura y las condiciones semiáridas son ya una preocupación. Por este motivo, la adopción de estrategias de mitigación y adaptación puede desempeñar un papel muy importante a la hora de encontrar un equilibrio entre la equidad, la seguridad económica y el medio ambiente en los escenarios de cambio climático. La metodología multidisciplinar de esta tesis incluye una amplia gama de enfoques y métodos para la recopilación y el análisis de datos. La toma de datos se apoya en la revisión bibliográfica de evidencia experimental, bases de datos públicas nacionales e internacionales y datos primarios recopilados mediante entrevistas semi-estructuradas con los grupos de interés (administraciones públicas, responsables políticos, asesores agrícolas, científicos y agricultores) y encuestas con agricultores. Los métodos de análisis incluyen: meta-análisis, modelos de gestión de recursos hídricos (modelo WAAPA), análisis multicriterio para la toma de decisiones, métodos estadísticos (modelos de regresión logística y de Poisson) y herramientas para el desarrollo de políticas basadas en la ciencia. El meta-análisis identifica los umbrales críticos de temperatura que repercuten en el crecimiento y el desarrollo de los tres cultivos principales para la seguridad alimentaria (arroz, maíz y trigo). El modelo WAAPA evalúa el efecto del cambio climático en la gestión del agua para la agricultura de acuerdo a diferentes alternativas políticas y escenarios climáticos. El análisis multicriterio evalúa la viabilidad de las prácticas agrícolas de mitigación en dos escenarios climáticos de acuerdo a la percepción de diferentes expertos. Los métodos estadísticos analizan los determinantes y las barreras para la adopción de prácticas agrícolas de mitigación. Las herramientas para el desarrollo de políticas basadas en la ciencia muestran el potencial y el coste para reducir GEI mediante las prácticas agrícolas. En general, los resultados de esta Tesis proporcionan información sobre la adaptación y la mitigación del cambio climático a nivel de explotación para desarrollar una política climática más integrada y ayudar a los agricultores en la toma de decisiones. Los resultados muestran las temperaturas umbral y la respuesta del arroz, el maíz y el trigo a temperaturas extremas, siendo estos valores de gran utilidad para futuros estudios de impacto y adaptación. Los resultados obtenidos también aportan una serie de estrategias flexibles para la adaptación y la mitigación a escala local, proporcionando a su vez una mejor comprensión sobre las barreras y los incentivos para su adopción. La capacidad de mejorar la disponibilidad de agua y el potencial y el coste de reducción de GEI se han estimado para estas estrategias en los casos de estudio. Estos resultados podrían ayudar en el desarrollo de planes locales de adaptación y políticas regionales de mitigación, especialmente en las regiones Mediterráneas. ABSTRACT Alterations in the climatic system due to increased atmospheric concentrations of greenhouse gas emissions (GHG) are expected to have important implications for agriculture, the environment and society. Agriculture is an important source of GHG emissions (12 % of global anthropogenic GHG), but it is also part of the solution to mitigate emissions and to adapt to climate change. Responses to face the challenge of climate change should place agricultural adaptation and mitigation strategies at the heart of the climate change agenda. Agriculture is crucial for the conservation and sustainable use of natural resources, which already stand under pressure due to climate change impacts, increased population, pollution and fragmented and uncoordinated climate policy strategies. The concept of climate smart agriculture has emerged to encompass all these issues as a whole. When assessing choices aimed at reducing threats to agriculture and the environment under climate change, two research questions arise: • What information defines smart farming choices? • What drives the implementation of smart farming choices? This Thesis aims to provide information on these broad questions in order to support climate policy development focusing in some Mediterranean agricultural systems. This Thesis integrates methods and tools to evaluate potential farming and policy choices to respond to mitigation and adaptation to climate change. The assessment involves both quantitative and qualitative approaches and integrates agronomic, climate and socioeconomic variables at local and regional scale. The assessment includes the collection of data on previous experimental evidence, and the integration of farmer behaviour and policy choices (e.g., technology, agricultural management and climate policy). The case study areas -- the Doñana coastal wetland (S Spain) and the Aragón region (NE Spain) – illustrate two representative Mediterranean regions where the intensive use of agriculture and the semi-arid conditions are already a concern. Thus the adoption of mitigation and adaptation measures can play a significant role for reaching a balance among equity, economic security and the environment under climate change scenarios. The multidisciplinary methodology of this Thesis includes a wide range of approaches for collecting and analysing data. The data collection process include revision of existing experimental evidence, public databases and the contribution of primary data gathering by semi-structured interviews with relevant stakeholders (i.e., public administrations, policy makers, agricultural advisors, scientist and farmers among others) and surveys given to farmers. The analytical methods include meta-analysis, water availability models (WAAPA model), decision making analysis (MCA, multi-criteria analysis), statistical approaches (Logistic and Poisson regression models) and science-base policy tools (MACC, marginal abatement cost curves and SOC abatement wedges). The meta-analysis identifies the critical temperature thresholds which impact on the growth and development of three major crops (i.e., rice, maize and wheat). The WAAPA model assesses the effect of climate change for agricultural water management under different policy choices and climate scenarios. The multi-criteria analysis evaluates the feasibility of mitigation farming practices under two climate scenarios according to the expert views. The statistical approaches analyses the drivers and the barriers for the adoption of mitigation farming practices. The science-base policy tools illustrate the mitigation potential and cost effectiveness of the farming practices. Overall, the results of this Thesis provide information to adapt to, and mitigate of, climate change at farm level to support the development of a comprehensive climate policy and to assist farmers. The findings show the key temperature thresholds and response to extreme temperature effects for rice, maize and wheat, so such responses can be included into crop impact and adaptation models. A portfolio of flexible adaptation and mitigation choices at local scale are identified. The results also provide a better understanding of the stakeholders oppose or support to adopt the choices which could be used to incorporate in local adaptation plans and mitigation regional policy. The findings include estimations for the farming and policy choices on the capacity to improve water supply reliability, abatement potential and cost-effective in Mediterranean regions.

Estudio para un Modelo de Gestión de un Acuífero Costero, mediante Metodologías Participativas y Análisis Geoestadístico en el marco del Desarrollo Local. Manglaralto, Ecuador

El presente estudio se fundamenta en la investigación-acción-participativa (IAP), para buscar alternativas que tiendan al desarrollo local de un territorio. Se centra en la cuenca hidrográfica del rio Manglaralto-Santa Elena-Ecuador, aplicando un sistema metodológico participativo que considera las características peculiares del territorio, que se analizan geoespacialmente reconociendo la influencia de la dinámica de sus cambios y observando los móviles que la propiciaban. A través de mecanismos participativos, se conectan los aspectos técnicos para el conocimiento y el aprovechamiento racional del acuífero costero, con los valores de los habitantes del territorio, para mejorar su abastecimiento de agua y crear nuevas condiciones y oportunidades en el camino del desarrollo local, vislumbrando la sostenibilidad. Cabe indicar que el ente administrativo y propulsor es la Junta de Agua Potable Regional Manglaralto (JAPRM). La hipótesis del estudio considera, que los métodos participativos generan en la comunidad una respuesta basada en su identidad y sus deseos de mejorar, que propiciará una gestión del acuífero costero que conlleve al desarrollo local. Otra hipótesis complementaria estipula que las estrategias del gobierno respecto al turismo propicia un crecimiento en la demanda del agua del acuífero. En Manglaralto-Ecuador, una parroquia de 30.000 habitantes aproximadamente, donde la JAPRM, administra y suministra agua a 23.586 habitantes que cuenta en su organización, llevada por 6 representantes de las comunidades rurales que la conforman, empezaron hace 7 años a buscar una forma de lograr un cambio, de tener agua para el desarrollo de la comunidad. Buscaron ayuda por diferentes medios, políticos, económicas, sociales y encontraron como base fundamental a la cooperación con el Organismo Internacional de Energía Atómica (OIEA) y la Escuela Superior Politécnica del Litoral (ESPOL) para entrelazar aspectos técnicos, ambientales, sociales y culturales. La gestión del acuífero costero, desde la perspectiva del IAP repercute en el desarrollo de Manglaralto. También se realiza un análisis geoespacial-geoestadístico, para vislumbrar aspectos de cambios en el territorio ligados al crecimiento turístico, que afectan a la demanda del recurso agua proveniente del acuífero costero bajo la administración de la JAPRM. La tesis presenta el modelo integral y propio de la comunidad de Manglaralto, que refleja una evolución que alcanzó un apogeo en 2011 y parte del 2012, con 9 pozos de agua que daban servicio los 365 días del año, 24 horas al día ininterrumpidamente. Las condiciones externas (promociones turísticas de la ruta del Spondylus) han repercutido en nuevas problemáticas (crecimiento elevado de la demanda del agua). El acuífero costero se convierte en el emblema y móvil de solución, gracias a la gestión integral y a la interacción IAP que se amolda a la evolución de las condiciones, buscando soluciones para la comunidad y su entorno. El modelo integral del territorio con la participación de sus pobladores, considera el aspecto turístico, como un agente que propicia la mayor demanda del agua. Situación a la que hay que dar respuesta mediante la observación-reflexión en el ciclo del IAP para generar nuevas directrices estratégicas y gestionar el desarrollo local. ABSTRACT The present study is based on the participatory action research (PAR) methodology in order to look for alternatives which tend to the local development of a territory. It focuses on the Manglaralto hydrographic river basin located in Santa Elena-Ecuador through the application of the participatory methodology which considers the peculiar characteristics of the territory. These are geospatially analyzed recognizing the influence of its dynamic of changes and observing the causes that originated them. Through the use of participatory mechanisms, technical aspects are connected for stimulating knowledge and rational use of the coastal aquifer with the values of inhabitants of the territory to improve the water supply and create new conditions of sustainability. It is important to point out that the administrative organism and promoter is the Manglaralto Regional Fresh Water Board (JAPRM). In Manglaralto-Ecuador, a parish of approximately 30,000 inhabitants, the MRFWB manages and supplies water to 23.586 inhabitants. This organization is composed by 6 representatives of rural communities. It started 7 years ago looking for a way to achieve a change, from obtaining water to developing the community. They seeked for help in different fields such as: political, economic and social and they found International Atomic Energy Agency (IAEA) and Escuela Superior Politécnica del Litoral (ESPOL) as a fundamental basis for cooperation to bond technical, environmental, social and cultural aspects. Management of coastal aquifer, from the PAR perspective affects the development of Manglaralto. Also, a geospatial and geostatistical analysis is carried out to distinguish change aspects in territories related to touristy growth which affects the demand of water obtained from the coastal aquifer under the management of the MRFWB. The thesis presents a comprehensive model that belongs to the Manglaralto community and reveals an evolution that reached a peak in 2011 and part of 2012, with 9 water wells that operated the 365 days of the year 24 hours a day without interruption. The external conditions (touristic packages of Spondylus route) have created new problems (higher demand of water). The coastal aquifer is a symbol and solution, thanks to the comprehensive management and PAR interaction which fits the evolution of conditions, looking for solutions for the community and its surroundings. The comprehensive model of territory with the participation of inhabitants considers the touristic aspect as an agent which brings about a higher demand of water. This situation requests a response through the observation-reflection in the PAR cycle to generate new strategic guidelines and promote the local development.

Optimization of water procurement decisions in an irrigation district: the role of option contracts

Water supply instability is one of the main risks faced by irrigation districts and farmers. Water procurement decision optimisation is essential in order to increase supply reliability and reduce costs. Water markets, such as spot purchases or water supply option contracts, can make this decision process more flexible. We analyse the potential interest in an option contract for an irrigation district that has access to several water sources. We apply a stochastic recursive mathematical programming model to simulate the water procurement decisions of an irrigation district?s board operating in a context of water supply uncertainty in south-eastern Spain. We analyse what role different option contracts could play in securing its water supply. Results suggest that the irrigation district would be willing to accept the proposed option contract in most cases subject to realistic values of the option contract financial terms. Of nine different water sources, desalination and the option contract are the main substitutes, where the use of either depends on the contract parameters. The contract premium and optioned volume are the variables that have a greater impact on the irrigation district?s decisions. Key words: Segura Basin, stochastic recursive programming, water markets, water supply option contract, water supply risk.