Bio-reclamation of secondary salinized soils using halophytes

Abstract

Soil salinity has become one of the major determinants of global crop productivity. Consequently reclamation of such soils is a most urgent requirement for world food production and for sustainable development. Out of an estimated area of 173 million hectares of totally degraded land in India, approximately 7 million hectares are affected by salinity. Besides naturally occurring saline soils, the secondary salinity that developed due to saline water irrigation is posing a great threat to the perspectives of increasing food and fodder production. In arid and semi-arid regions like Rajasthan (India) decreasing water table and increased use of deep wells, following electrification of villages, has resulted in an increased salinity of irrigation water and consequently in increased salinization. Although, in context with the increasing population, the importance of irrigated agriculture cannot be ignored and excessive saline water irrigation may convert productive soil into unproductive and salinized soil. In western Rajasthan, the area that is affected by the use of such problematic water is some 880 km2. The irrigation water being used there is moderate to highly saline/sodic 1], 2]. As such a large percentage of land is going out for production, year by year, due to saline water irrigation it is a major contributory factor to soil degradation in India [3]. Several halophytic plant species have been tried in the past for their possible use in reclamation of salt-affected soils [4, 5, 6, 7, 8]. Besides their positive impact on salt-affected soils, the potential use of some halophytes as forage and as oil seed crops has also been described [9]. However, use of halophytes for soil reclamation is still in an exploratory stage and only a few field studies for bio-reclamation of saline soil using halophytes have been carried out so far [5, 10]. Therefore keeping this fact in mind, the present investigation was undertaken with the objective to study the utilization of halophytes to remove excess salinity added by irrigation.