MAPPING AND CHARACTERIZATION OF SALT AFFECTED SOILS FOR RECLAMATION AND MANAGEMENT: A CASE STUDY FROM THE TRANSGANGETIC PLAIN OF INDIA

Abstract

Soil salinity/alkalinity and poor quality groundwater are major constraints causing reduced productivity in the arid and semiarid region of the Trans- Gangetic plain of Central Haryana covering Kaithal district. Visual interpretation of Resourcesat LISS-III data for March, May and October (2009) seasons revealed the presence of salt affected soils spatially distributed as barren patches and intermixed with cropped areas in the irrigated zones. The white to yellowish white tones with high reflectance from salt crusts on barren soil surface prompted the detection of strongly sodic/saline soils. The mixed signatures (yellowish white and red mottling) of salt stress and patchy crop stand indicated the presence of slightly to moderate salt affected soils, which is authenticated by ground truth study. In absence of natural drainage, the waterlogging for stagnated water bodies in irrigated areas was easily identified by the higher energy absorption showing dark blue/black to gray shades in March and November data. Salt affected soils showing low permeability, infiltration and hydraulic conductivity, also showed similar signatures amidst the cropped areas. The prolonged use of poor quality groundwater favored salt build-up in irrigated areas and showed mixed spectral signatures (grayish red to reddish white tones) in the satellite imageries. The sodic (alkali soil dominated by sodium and carbonate salts) and saline (neutral salts dominated by chloride and sulfate) soils are common in the study area. Sodic soils were distributed in northern and central parts of Kaithal district covering Pundri (2.1%), Kaithal (3%), Guhla (1.1%) and Siwan (1.1%) blocks while saline soils were distributed in southern part covering Kalayat (2.6%) and Rajaund (1.3%) blocks. The fine texture (clay to clay loam) sub-surface soils in Ghaggar plain impaired natural drainage thus favored waterlogging and sodicity development. The precipitated calcium carbonates concretions (calcareous layer) are common in strongly sodic soils that impair salt and nutrient movements and root penetration. An area of 26301 ha (11.3%) is salt affected in Kaithal district, of which sodic and saline soils covered 17570 ha (7.3%) and 9388 ha (4%), respectively. The groundwater quality was sodic in north of Kaithal district (Guhla block), at places, showing high Residual Sodium Corbonate (RSC) (12.7 me L–1), saline in the east at Kalayat block (Sodium Adsorption Ratio (SAR) 33.6) and sodic (pH 9.2) in central part of Kaithal block, and also showed high RSC (6.5 me L–1) in selected samples. Based on the soil physico-chemical characteristics and the quality of groundwater, suitable reclamation and management options were also suggested.