The importance of irrigation in the world's agriculture is rapidly increasing. Although it is practised on a large scale mainly in arid and semi-arid zones, supplementary irrigation is becoming popular in semi-humid regions as well. The record of irrigation speaks for itself in terms of increased crop production. However, the question remains as to how permanent the achievement may be. Judging from history, it seems that irrigation eventually failed in many regions because the knowledge and technology available to society at the time were incapable of coping with the problems created. Undoubtedly soil salinity is the most prevalent and widespread problem limiting crop productivity in irrigated agriculture. It has, therefore, attracted the attention of the scientific community since the advent of modern agronomic research. Through the past six to seven decades a considerable body of information has been accumulated, which has promoted the understanding of the principles involved and helped to develop the technology for coping with the problems. Our present knowledge, if judiciously applied, is adequate for coping with many of the salinity problems resulting from mismanagement of irrigation and drainage. But for this knowledge to be used, it has to be generally known and understood and be re-examined from time to time.

Inhalt

1 Introduction.- 1.1 Impact of Salinity on the Development of Soil Science.- References to Chapter 1.- I Soil Salinity under Irrigation - Processes.- 2 Basic Chemistry of Salinity.- 2.1 Salt-Affected Soils: Thermodynamic Aspects of the Soil Solution.- 2.2 Colloid Properties of Clay Minerals in Saline and Sodic Solution.- References to Chapter 2.- 3 Chemical Reaction and Control of Soil Physical Properties.- 3.1 The Effect of Electrolyte Concentration on the Hydraulic Properties of Sodic Soils..- 3.2 Soil Structure in Saline and Sodic Soils.- 3.3 Potassium, Magnesium and Boron in Soils under Saline and Sodic Conditions.- References to Chapter 3.- 4 Movement and Accumulation of Salts in Soils.- 4.1 Salt and Water Movement in the Soil Profile.- 4.2 Field Scale Water and Solute Transport Through Unsaturated Soils.- References to Chapter 4.- 5 Diagnostic Criteria and Methodology.- 5.1 Principles and Methods of Monitoring Soil Salinity.- 5.2 Reassessment of Water Quality Criteria for Irrigation.- References to Chapter 5.- II Soil Salinity under Irrigation - Management.- 6 Irrigation Management and Field Salt Balance.- 6.1 Leaching for Salinity Control.- 6.2 Drainage Design for Salinity Control.- 6.3 Spatial Variability Considerations in Salinity Management.- References to Chapter 6.- 7 Reclamation of Sodic Soils.- 7.1 Amendments for Reclaiming Sodic Soils.- 7.2 Simulation Modeling for Reclamation of Sodic Soils.- References to Chapter 7.- 8 Management Aspect for Crop Production.- 8.1 Analysis of Crop Salt Tolerance Data.- 8.2 Prediction of Crop Yield and Water Consumption under Saline Conditions.- 8.3 Plant Response to Salinity: Experimental Methodology and Application to the Field.- 8.4 Management of Irrigation with Brackish Water.- 8.5 Plant Nutrition under Saline Conditions.- References to Chapter 8.