The development of agricultural technologies and a better appreciation of the existing but under-utilized knowledge of resource management will be crucial in meeting the ecological needs and in achieving the anticipated food demands of the growing population in the future. The greatest challenge for the coming decades lies in the fact that the production environments are unstable and degrading. Land degradation is proceeding so fast that unless policies and approaches change, many countries will not be able to achieve sustainable agriculture in the foreseeable future. Soil salinization has been identified as a major process of land degradation. The greatest technical causes of decreasing production on many irrigated projects, particularly in arid and semi-arid areas, or failure of large areas in rainfed agriculture, are waterlogging, salinization and sodication. It was estimated from various available data that the world is losing at least three hectares of arable land every minute because of soil salinity.

Images: Saline soil,  Sodic Soil,  Profile in Sodic Soil

Based on the FAO/Unesco Soil Map of the World, the total area of saline soils is 397 million ha and that of sodic soils is 434 million ha, which are not necessarily arable but cover all salt-affected lands at global level. Of the current 230 million ha of irrigated land, 45 million ha are salt-affected soils (19.5 percent) and of the almost 1,500 million ha of dryland agriculture, 32 million are salt-affected soils (2.1 percent) to varying degrees by human-induced processes (Oldeman et al. 1991).

Management of salt-affected soils requires a combination of agronomic practices depending on a careful definition of the requirements based on a detailed, comprehensive prior investigation of soil characteristics, water quality, and local conditions including climate, crops, economic, social, political and cultural environment and existing farming systems. There is usually no single way to control salinity, particularly in irrigated agriculture. However, several practices can be combined into an integrated system that functions satisfactorily (Mashali 1995).

Although many countries are using salt-affected soils because of their proximity to water resources and the absence of other environmental constraints, there is a clear need for a sound scientific basis to optimize their use, determine their potential, productivity and suitability for growing different crops, and identify appropriate integrated management practices. Because of this and the increasing awareness of continuing soil salinization and sodication, FAO's Regular Programme is supporting national institutes in countries having problems of salt-affected soils to strengthen their experimental programmes on adapted soil management practices. Since 1990, collaborative projects have been identified to develop management practices for sustainable use of salt-affected soils: experiments and demonstrations on pilot farms have been conducted in 22 countries in different regions - (i) Africa (Ghana, Kenya, Nigeria and Tanzania); (ii) Asia and Pacific (Bangladesh, China, Indonesia, Pakistan, Philippines, Thailand and Viet Nam); (iii) Europe (Hungary, Romania and Turkey); (iv) Latin America and Caribbean (Argentina, Brazil, Cuba and Mexico); (v) Near East (Egypt, Iran, Syria and Tunisia).

To avoid the fragmentation of technical research and development efforts in developing countries and to stimulate coordination of work between different international and national organizations in the management of salt-affected soils, a cooperative project was signed in November 1994 between FAO and UNEP, in association with the Subcommission on Salt-affected Soils of IUSS.

The project was to establish a Network on Integrated Soil Management for Sustainable Use of Salt-affected Soils. The 22 countries involved in the mentioned FAO collaborative projects are "Members" in the Network, in addition to other "Associated Members" running their country national programmes on Management of Salt-affected Soils (Australia, Canada, Colombia, India, Italy, Spain, Sudan and Uzbekistan).