Productivity enhancement of salt-affected environments through crop diversification

Recent trends and future demographic projections suggest that the need to produce more food and fibre will necessitate effective utilization of salt-affected land and saline water resources. Currently at least 20 per cent of the world's irrigated land is salt affected and/or irrigated with waters containing elevated levels of salts. Several major irrigation schemes have suffered from the problems of salinity and sodicity, reducing their agricultural productivity and sustainability. Productivity enhancement of salt-affected land and saline water resources through crop-based management has the potential to transform them from environmental burdens into economic opportunities. Research efforts have led to the identification of a number of field crops, forage grasses and shrubs, aromatic and medicinal species, bio-fuel crops, and fruit tree and agroforestry systems, which are profitable and suit a variety of salt-affected environments. Several of these species have agricultural significance in terms of their local utilization on the farm. Therefore, crop diversification systems based on salt-tolerant plant species are likely to be the key to future agricultural and economic growth in regions where salt-affected soils exist, saline drainage waters are generated, and/or saline aquifers are pumped for irrigation. However, such systems will need to consider three issues: improving the productivity per unit of salt-affected land and saline water resources, protecting the environment and involving farmers in the most suitable and sustainable crop diversifying systems to mitigate any perceived risks. This review covers different aspects of salt-affected land and saline water resources, synthesizes research knowledge on salinity/sodicity tolerances in different plant species, and highlights promising examples of crop diversification and management to improve and maximize benefits from these resources.