Irrig Sci (1985) 5:1-2 Irrigation

: cience © Springer-Verlag 1985

Editorial

Soil Salinity under Irrigation - Processes and Management

Many of the areas of the world in which the demand for food and fiber by rapidly expanding populations exceeds supply are in arid and semi-arid regions. In such regions, saline and sodic water are more and more frequently being considered for use in irrigation - either because high quality waters are already fully utilized or because of the need to dispose of saline drainage water. It has been estimated that a third of the irrigated land in the world is affected by salinity and sodicity problems.

All soils contain a certain amount of soluble salts, indeed they are essential for crop production. It is only when soluble salt accumulation in the soil reaches a level harmful to the growth of particular plants that they are termed saline. The processes by which soluble salts enter the soil solution and cause salinity include: the application of waters containing salts and/or fertilizers, weathering of primary and secondary minerals in soil, ion hydrolysis, and organic matter decay. The im- portance of each source depends on the type of soil and the agricultural manage- ment.

The composition and concentration of the soluble salts in soil solution may influence plant growth in three ways, by osmotic effects, by specific toxicity effects, and by changing the physicomechanical properties of soils. Considerable effort has been directed toward the study of the effect of osmotic pressure in solution on plant growth, but less information is available regarding the effect of specific ions and changing soil properties on plant growth.

Three major approaches to the management of saline water in irrigated agriculture exist: of greatest importance is its use after dilution with high quality water, second is the use with crop plants which naturally possess tolerance and third, the breeding and selection of salinity tolerance in crops which are currently intolerant of salinity.

Whereas the first approach is most likely to provide an immediate solution to the problem, the last two approaches hold much promise for the more distant future. Based on the immediately relevant first approach, an international conference on "Soil Salinity Under Irrigation - Processes and Management" was organized by the Israel Society of Soil Science under the auspices of the International Soil Science

2 Editorial

Society. This conference, held at Bet Dagan on March 25th-April 4th, 1984, was hosted by the Institute of Soils and Water, the Agricultural Research Organization, ARO, Israel and was attended by scientists from 16 countries who presented 68 papers. In addition to the formal communications, abundant informal contacts between those attending, were responsible, in large part, for the success of the conference.

This special issue of Irrigation Science contains a reviewed selection of the research communications given at the conference. The general state-of-the-art, review papers have been published elsewhere 1. It is hoped that the selection of papers presented in this issue will give some indication of the progress that has been made in research currently underway in many countries of the world aimed at solving the problems associated with the use of saline water and soils in irrigated agriculture and indicate the problems still to be solved.

R. Keren, Editor Special Issue

1 Shainberg I, Shalhevet J (1984) Soil Salinity Under Irrigation - Processes and Manage- ment. Springer-Verlag, Heidelberg, Berlin, New York, Tokyo