Phytoremediation of Coastal Saline Vertisols of Gujarat Through Biosaline Agriculture

Sustainability of an ecosystem rests on the scientific management based on a sound database. Managing the coastal agricultural ecosystem is more complex when it is affected by natural phenomena like seawater ingress and the introduction of large-scale human interventions. Such a situation is prevailing in the coastal districts of Gujarat state, India, where salinity of the agricultural lands is constantly on the increasing trend. The problems of environmental degradation in Gujarat are as diverse and complex as the ecological fabric of the state. About 6.73 million hectares (mha) of land is salt-affected in India, of which 2.22 mha is present in Gujarat State. Of this, about 60% area is affected by coastal salinity problems with highly saline groundwater. Three approaches, changes in natural resource management, changes in technology used, and development of salttolerant varieties of the crops can be used to overcome the constraints of salinity of soil and groundwater. The use of salt-tolerant varieties and economic halophytes through saline agriculture is an effective, economic, and eco-friendly approach in the management of salt-affected vertisols. Soil salinity either before sowing or that occurs during the growing period is detrimental to crop growth and productivity. Unlike salt-loving plants, the halophytes, saltsensitive ones, and the glycophytes, which comprise the crop plants, are greatly affected by salinity of soil and irrigation waters. Thus, identifying salt-tolerant crop plants/varieties and their cultivation on coastal saline vertisols holds promise for maximizing the production. Research efforts made resulted in identifying and evolving agrotechnologies, viz. (1) cultivation of Salvadora persica on highly saline vertisols (for nonedible seed oil); (2) cultivation of Salicornia brachiata (edible oil and herbal salt); (3) forage production using halophytic grasses (fodder); (4) cultivation of seed spice, Anethum graveolens, on moderately saline vertisols (spice and pharmaceutical derivatives), (5) salt-tolerant herbaceum/desi cotton (Gossypium herbaceum) (commercial) and wheat accessions (food) on costal saline vertisols, (6) farming system model for maximizing on-farm production, and (7) saline water use in conjunctive mode in different arable crops (wheat, dill, safflower, mustard) and some fruit species. While cultivation of Salvadora resulted in reduction in soil salinity over the years, desi cotton was found ideal and profitable crop to the farmers in saline and rainfed coastal areas. Desi cotton accession, G. Cot 23, gave yield in the range of 1.6-1.9 t ha under the average salinity of 7.6 dS m. In saline vertisols of southern, central, and Saurashtra areas of Gujarat (EC range 5.9-7.2 dS m), salt-tolerant wheat varieties KRL 210 and KRL 19 gave yield in the range of 36-39.5q ha. The details of technologies, economics of their cultivation, and their role in remediation of salinity along with future prospects are discussed in the chapter.