Calculation of crop evapotranspiration; Selection of crop coeficient; Calculation of field irrigation requirements.

This publication is intended to provide guidance in determining crop water requirements and their application in planning, design and operation of irrigation projects; Part I.1 presents suggested methods to derive crop water requirements. The use of four well-known methods for determining such requirements is defined to obtain reference crop evapotranspiration (ETo), which denotes the level of evapotranspiration for different set of climatic data. To derive the evapotranspiration for a specific crop, relationships between crop evapotranspiration (ETcrop) and reference crop evapotranspiration (ETo) are given in Part I.2 for different crops, stages of growth, length of growing season and prevailing climatic conditions. The effect of local conditions on crop water requirements is given in Part I.3; this includes local variation in climate, advection, soil water availability and agronomic and irrigation methods and practices. Calculation procedures are presented together with examples. A detailed discussion on selection and calibration of the presented methodologies together with the data sources is given in Appendix II. A computer programme on applying the different methods is given in Appendix III. Part II discusses the application of crop water requirements data in irrigation project planning, design and operation. Part II. 1 deals with deriving the field water balance, which in turn forms the basis for predicting seasonal and peak irrigation supplies for general planning purposes. Attention is given to irrigation efficiency and water requirements for cultural practices and leaching of salts. In Part II. 2 methods are presented to arrived at field and scheme supply schedules with emphasis towards the field water balance and field irrigation management. Criteria are given for operating the canal system using different methods of water delivery, and for subsequent design parameters of the system. Suggestions are made in Part II. 3 on refinement of field and project supply schedules once the project is in operation. The presented guidelines are based on measured data and experience obtained covering a wide range of conditions. Local practical, technical, social and economic considerations will, however, affect the planning criteria selected. Therefore caution and a critical attitude should still be taken when applying the presented methodology.

In the context of improving water productivity, there is a growing interest in deficit irrigation, an irrigation practice whereby water supply is reduced below maximum levels and mild stress is allowed with minimal effects on yield. Under conditions of scarce water supply and drought, deficit irrigation can lead to greater economic gains than maximizing yields per unit of water for a given crop; farmers are more inclined to use water more efficiently, and more water-efficient cash crop selection helps optimize returns. However, this approach requires precise knowledge of crop response to water as drought tolerance varies considerably by species, cultivar and stage of growth. The studies present the latest research concepts and involve various practices for deficit irrigation. Both annual and perennial crops were exposed to different levels of water stress, either during a particular growth phase, throughout the whole growing season or in a combination of growth stages. The overall finding, based on the synthesis of the different contributions, is that deficit or regulated-deficit irrigation can be beneficial where appropriately applied. Substantial savings of water can be achieved with little impact on the quality and quantity of the harvested yield. However, to be successful, an intimate knowledge of crop behavior is required, as crop response to water stress varies considerably.

Richtlijnen voor de werker in het veld om problemen te ondervangen ten aanzien van de waterkwaliteit voor irrigatie-doeleinden. Tenslotte worden praktijkervaringen uit diverse gebieden vermeld

Advanced Machine Learning Techniques includes the theoretical foundations of modern machine learning, as well as advanced methods and frameworks used in modern machine learning. Handbook of HydroInformatics, Volume II: Advanced Machine Learning Techniques presents both the art of designing good learning algorithms, as well as the science of analyzing an algorithm's computational and statistical properties and performance guarantees. The global contributors cover theoretical foundational topics such as computational and statistical convergence rates, minimax estimation, and concentration of measure as well as advanced machine learning methods, such as nonparametric density estimation, nonparametric regression, and Bayesian estimation; additionally, advanced frameworks such as privacy, causality, and stochastic learning algorithms are also included. Lastly, the volume presents Cloud and Cluster Computing, Data Fusion Techniques, Empirical Orthogonal Functions and Teleconnection, Internet of Things, Kernel-Based Modeling, Large Eddy Simulation, Patter Recognition, Uncertainty-Based Resiliency Evaluation, and Volume-Based Inverse Mode. This is an interdisciplinary book, and the audience includes postgraduates and early-career researchers interested in: Computer Science, Mathematical Science, Applied Science, Earth and Geoscience, Geography, Civil Engineering, Engineering, Water Science, Atmospheric Science, Social Science, Environment Science, Natural Resources, Chemical Engineering. - Key insights from 24 contributors in the fields of data management research, climate change and resilience, insufficient data problem, etc. - Offers applied examples and case studies in each chapter, providing the reader with real world scenarios for comparison. - Defines both the designing of good learning algorithms, as well as the science of analyzing an algorithm's computational and statistical properties and performance guarantees.

Ever-increasing population growth has caused a proportional increased demand for water, and existing water sources are depleting day by day. Moreover, with the impact of climate change, the rates of rainfall in many regions have experienced a higher degree of variability. In many cities, government utilities have been struggling to maintain sufficient water for the residents and other users. The Handbook of Irrigation Hydrology and Management examines and analyzes irrigated ecosystems in which water storage, applications, or drainage volumes are artificially controlled in the landscape and the spatial domain of processes varies from micrometers to tens of kilometers, while the temporal domain spans from seconds to centuries. The continuum science of irrigation hydrology includes the surface, subsurface (unsaturated and groundwater systems), atmospheric, and plant subsystems. Further, the book includes coverage of environmental and economic impacts, water quality issues, water harvesting, satellite measurements for irrigation, and more. Features: Offers water-saving strategies to increase the judicious use of scarce water resources Presents strategies to maximize agricultural yield per unit of water used for different regions Compares irrigation methods to offset changing weather patterns and impacts of climate change

Irrigated agriculture produces about 40% of all food and fibre on about 16% of all cropped land. As such, irrigated agriculture is a productive user of resources; both in terms of yield per cropped area and in yield per volume of water consumed. Many irrigation projects, however, use (divert or withdraw) much more water than consumed by the crop. The non-consumed fraction of the water may cause a variety of undesirable effects ranging from water-logging and salinity within the irrigated area to downstram water pollution. This book discusses all components of the water balance of an irrigated area; evapotranspiration (Ch.2), effective precipitation (Ch.3) and capillary rise from the groundwater table (Ch.4). Chapter 5 then combines all components into a water management strategy that balances actual evapotranspiration (and thus crop yield) with the groundwater balance of the irrigated area (for a substainable environment). Chapter 6 presents CRIWAR 3.0, a simulation program that combines all water balance components into a single simulation procedure. The chapter describes the use of the CRIWAR software for developing water requirement tables and other useful information based on the selected water management strategy. This version greatly expands upon the capabilities of previously published programs.

The increasing risk of severe droughts and water shortages emphasizes the need for an integrated approach to drought mitigation. However, effective tools for the implementation of such an approach have not been available till now. This book contributes to an improved preparedness for drought in water supply systems, providing tools useful for a better decision making process in drought management. It presents methods and software features of a Decision Support System (DSS) developed within a European research project and consists of three main parts. The first part deals with the advanced techniques for hydrological drought identification and monitoring; the second analyses the successful use of climate-crop-soil models in defining deficit irrigation strategies; the third provides tools for improving the operation of irrigation supply reservoirs.

This open access book is an outcome of the collaboration between the Soil and Water Management & Crop Nutrition Section, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency (IAEA), Vienna, Austria, and Dr. Shabbir A Shahid, Senior Salinity Management Expert, Freelancer based in United Arab Emirates.The objective of this book is to develop protocols for salinity and sodicity assessment and develop mitigation and adaptation measures to use saline and sodic soils sustainably. The focus is on important issues related to salinity and sodicity and to describe these in an easy and user friendly way. The information has been compiled from the latest published literature and from the authors’ publications specific to the subject matter. The book consists of six chapters. Chapter 1 introduces the terms salinity and sodicity and describes various salinity classification systems commonly used around the world. Chapter 2 reviews global distribution of salinization and socioeconomic aspects related to salinity and crop production. Chapters 3 covers comprehensively salinity and sodicity adaptation and mitigation options including physical, chemical, hydrological and biological methods. Chapter 4 discusses the efforts that have been made to demonstrate the development of soil salinity zones under different irrigation systems. Chapter 5 discusses the quality of irrigation water, boron toxicity and relative tolerance to boron, the effects of chlorides on crops. Chapter 6 introduces the role of nuclear techniques in saline agriculture.