The extent of salt affected soils in the country is around 6.73 mha while use of poor quality ground water ranges from 32-84% in different semi-arid and arid states of India. Responses of crops to salinity/ sodicity stresses have been utilized to assess success of different chemical amendments /reclamation packages as well as to know tolerances of newly developed crop varieties for salinity/ sodicity. Multi-disciplinary research on reclamation and management of sodic and saline soils and salt tolerant crop varieties at ICAR-CSSRI since 1969 and at Centres of AICRP on Salt Affected Soils & Use of Saline Water in Agriculture since 1972 has paid rich dividend till today. This AICRP developed national guidelines for use of saline/ alkali water under different agro-climatic regions considering soil type, rainfall and salt tolerance of crops, in addition to the major ion chemistry of water.
Also map of groundwater quality for irrigation purpose was developed. Besides, the experiments on efficacy of different amendments for reclamation of sodic soils, subsurface drainage for waterlogged saline soils, mapping of salt affected soils and groundwater, and screening of crop varieties for soil salinity/ sodicity tolerances were undertaken successfully. During XII plan, mapping and delineation of salt affected soils and ground waters in different affected states of the country was successfully continued. Several technologies were developed which are notably chemical amendments and organic manures for reclamation of black sodic soils, cost effective agronomical/irrigation management interventions to use saline/sodic waters in alluvial soils, resource conservation technologies in sodic soils in Gangetic plains, subsurface drainage with controlled option for waterlogged saline Vertisols in southern peninsular India, groundwater recharge in poor quality areas, use of drip/ sprinkler for vegetables in coastal region as well as for field crops in arid region, use of protected structures for growing vegetables with poor quality waters, land shaping and integrated farming system models in coastal lands. These technologies were successfully demonstrated through field trials and operational research programmes by various centres. Despite of sincere efforts, large extent of salt affected soils in country varying from inland salinity/ sodicity to coastal salinity or coastal salinity-acidity in different agro-climatic regions need to be treated with appropriate reclamation packages to achieve potential yield levels. There are reports that groundwater availability and quality are declining and issues of specific ion toxicity are arising. Availability of gypsum and its quality for continuing sodic soil reclamation, repeat application of amendments in sodic groundwater areas, higher cost of subsurface drainage system in waterlogged saline soils, sea water intrusion through creeks and groundwater in coastal areas, dry land salinity/ sodicity in groundwater irrigated areas are impeding factors in pushing reclamation activities in forward direction. During 2017-20, focus of AICRP centres will be for searching out cheap alternative options to existing amendments including organic/ green manuring and distillery spent wash. Different drainage methods such as surface, subsurface and bio-drainage in alluvial soils as well as subsurface and mole drainage in heavy soils are to be used to their potential capacities. Crop diversification options and new crop varieties tolerant to salinity/ sodicity are required to be tested for making best use of available resources. It is important to note that global warming and climate change are making farming activities on salt affected soils more vulnerable than earlier. To address this alarming situation due to global warming and climate change, centres of AICRP will give emphasis to work on Integrated Farming System (IFS) approach supported with resource conservation technologies for making farming on such soils sustainable and climate resilient. It appears to plausible that current challenges associated with reclamation of saline/ sodic soils, ground water depletion and quality deterioration particularly by fluoride and nitrate, dry land salinity, wastewater use, mapping of salt affected soils and poor quality waters, uses of poor quality ground waters, environmental degradation and climatic change can be addressed with collective wisdom within this AICRP setup.
(M J Kaledhonkar)