Guidelines For Predicting Crop Water Requirements

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

Equations, tables.

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.

Planning and Evaluation of Irrigation Projects: Methods and Implementation presents the considerations, options and factors necessary for effective implementation of irrigation strategies, going further to provide methods for evaluating the efficiency of systems-in-place for remedial correction as needed. As the first book to take this lifecycle approach to agricultural irrigation, it includes real-world examples not only on natural resource availability concerns, but also on financial impacts and measurements. With 21 chapters divided into two sections, this book is a valuable resource for agricultural and hydrology engineers, conservation scientists and anyone seeking to implement and maintain irrigation systems. Uses real-world examples to present practical insights Incorporates both planning and evaluation for full-scope understanding and application Illustrates both potential benefits and limitations of irrigation solutions Provides potential means to increase crop productivity that can result in improved farm income

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

This important volume, the ninth in the Research Advances in Sustainable Micro Irrigation book series, provides an invaluable addition to the literature and knowledge on the ever-growing need for sustainable irrigation for agricultural crops in many water-scarce parts of the world. The book specifically covers advances in fertigation for water management in general as well as for specific crops, such as peaches, maize, and citrus crops. Specific topics include: • The design of various surface and subsurface water emitters • Using information from weather stations for irrigation purposes • Ultra low drip irrigation technology • The management of weeds in crops using micro irrigation • New technology and advances in fertigation With chapters from researchers and practitioners in agricultural engineering, water research and technology, soil conservation, and other fields, this compendium provides a wealth of useful information that can be put into practice to enhance crop production.

Advances in Irrigation, Volume 4 covers articles on the development and management of irrigation. The book presents articles on the improved method for distributing water in furrows, termed cablegation; the analysis of drip irrigation design based on the criterion of statistical uniformity; and the spatial distribution of water in sprinkling-irrigation systems. The text also includes articles on the critical evaluation of crop yields as influenced by irrigation uniformity; the concept of evapotranspiration from the scale of a field to the scale of an entire region; as well as the drainage of irrigated lands under sequential water application. Articles on the comparison of several models for the purpose of appraising the effect of irrigation on wheat and barley yields and on the economics of kiwifruit production under irrigation in New Zealand are also encompassed. The book concludes with an article about the modification and testing of a model simulating root and shoot growth as related to soil water dynamics. Agriculturists, agricultural engineers, and hydrologists will find the book invaluable.