Mechanisms Of Cash Crop Halophytes To Maintain Yields And Reclaim Saline Soils In Arid Areas

Abstract

About 7{%} of the world's total land area is affected by salt, as is a similar percentage of its arable land (Ghassemi et al., 1995; Szabolcs, 1994) when soils in arid regions of the world are irrigated, solutes from the irrigation water can accumulate and eventually reach levels that have an adverse affect on plant growth. Of the current 230 million ha of irrigated land, 45 million ha are salt-affected (19.5 percent) and of the 1,500 million ha under dryland agriculture, 32 million are salt-affected to varying degrees (2.1 percent). There are often not sufficient reservoirs of freshwater available and most of the agronomically used irrigation systems are leading to a permanent increase in the soil-salinity and step by step to growth conditions unacceptable for most of the conventional crops. Significant areas are becoming unusable each year. It is a worldwide problem, but most acute in Australasia (3.1 million hectars), the Near East (1.802 million hectars) and Africa (1.899 million hectars), North and Latin America (3.963 million hectars) and to an increasing degree also in Europe (2.011 million hectares of salt-affected soils; FAO Land and Plant Nutrition Management Service). Although careful water management practices can avoid, or even reclaim damaged land, crop varieties (such as cash crop halophytes) that can maintain yields in saline soils or allow the more effective use of poor quality irrigation water will have an increasing role in agricultural land use in near future.