How To Manage Salinity In Irrigated Lands

Acronyms; Glossary; Abstract; Introduction; Problems; Chemical processes involved in salinization; Physical processes involved in salinization; Impact of irrigation-induced salinity on plant growth; Remedial management actions; Farmers response to salinity; Discussion; Conclusions.

Chemical processes involved in salinization; physical precesses involved in salinization; impact of irrigation-induced salinity on plant growth; remedial management actions; farmers' response to salinity.

Irrigation has long played a key role in feeding expanding populations and is expected to play a still greater role in the future. However, is it sustainable? Can it remain in existence and function continuously and indefinitely? Some pessimists doubt that it is. This volume presents a more positive approach with carefully conditional optimism. It takes the diffuse, voluminous and disparate facts and combines them in a unified exposition. It merges physico-chemical, agronomic, environmental and economic principles into practical recommendations to help ensure the long-term viability and productivity of irrigated agriculture in arid and semiarid regions.

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.

Approximately half of the irrigated area of Iran falls under different types of salt-affected soils and average yield losses may be as high as 50 percent. Slightly and moderately salt-affected soils are mostly found on the piedmonts at the foot of the Elburz (Alborz) Mountains in the northern part of the country. The soils having severe to extreme salinity are predominantly located in the Central Plateau, the Khuzestan and Southern Coastal Plains and the Caspian Coastal Plain. The process of salinization of the surface water resources is mainly due to natural conditions, and to a lesser extent, to the discharge of drainage water into the river systems. Estimates show that about 6.7 km3 of brackish water flow annually through 12 major rivers. There is no straightforward solution to the complex problems of salt-induced soil and water resources degradation in Iran. The approaches addressing the management of these resources need to be multidimensional and must take into account biophysical and environmental conditions of the target areas as well as livelihood aspects of the associated communities.

The papers assembled here cover topics such as technological advances in soil salinity mapping and monitoring, management and reclamation of salt-affected soils, use of marginal quality water for crop production, salt-tolerance mechanisms in plants, biosaline agriculture and agroforestry, microbiological interventions for marginal soils, opportunities and challenges in using marginal waters, and soil and water management in irrigated agriculture.