Biodiversity of Indian Saline Habitats and Management Utilization of High Salinity Tolerant Plants with Industrial Application for Rehabilitation of Saline Areas

摘要

In India about 8.6 million ha of land is suffering from degradation due to salinity and alkalinity problems. These lands occur under different environmental conditions and have different morphological, physical, chemical and biological properties. Secondary salinization is rapidly increasing in irrigated areas. These saline soils are universally low in fertility and difficult for conventional agricultural use. Sub-surface drainage is the most effective tool to wash out salts in saline soils, but this method is costly and can not be adopted in the entire area. However, such lands can effectively be utilized for salt-tolerant biological systems. A survey conducted by traversing inland and coastal saline areas in India has indicated the occurrence of about 1116 vascular plant species distributed under 528 genera and 131 families. Out of these 37 species are exclusive mangroves and about 7 dozen species are associate mangroves distributed in 4533 sq km mangal formation zone. This vast diversity of flora in addition to providing food for different fauna also provides livelihood for the people inhabiting these areas. In recent years, however, worldwide attention is being given to accommodating salt tolerant species of industrial importance for highly saline degraded areas, including coastal marshes. Some oil yielding species such as Salicornia bigelovii, Salvadora persica, S. oleoides, Terminalia catappa, Calophyllum inophyllum and Pandanus spp. are important and can be grown in highly saline areas irrigating with sea water or water of high salinity. The Palmyra palm (Borassus flabellifer) common in coastal areas is a source of alcoholic beverages, vinegar, toddy, jaggery and confectionery syrup. The Alexandrian Laurel (Calophyllum inophyllum) is essentially littoral and is a good source of seed oil used for soap making and skin infections. Cynometra ramiflora yields medicinal oil used for leprosy. Nypafrutican is a mangrove palm found in mangrove swamps of Andaman & Nicobar Islands and valued for its sweet sap which may be used for making jaggery, alcohol and vinegar while the leaves are used for thatching. Kair (Capparis decidua) is found on sand dunes and saline arid regions. Its fruits are medicinal and valued for commercial pickles. Neem (Azadirachta indica) is well known for its medicinal value and thrives well on Vertisols and calcareous saline soils irrigating with saline water up to 12 dS m~(-1). Jojoba (Simmondsia chinensis) is considered a gold mine for desert and yields seed oil like the oil of the sperm-whale. It thrives well on sandy soil and may be irrigated with saline water of 12 dS m~(-1). Oil yielding Matricaria chamomilla, Vetiveria zizanioides and Cymbopogon martinii; flower yielding species of Chrysanthemum which are also valued for insecticidal properties; and medicinal Plantago ovata, Catharanthus roseus, Adhatoda vasica and Jatropha curcas have been grown successfully on calcareous soil irrigating with saline water of 12 dS m~(-1). These are also of industrial application. There are many other salt tolerant fruit, forage and fuelwood species, which have been tried and found suitable for highly saline situations. The scope of many of these species for industrial application in saline and sodic habitats, along with their management and utilization, are discussed in this paper.