Joshi, D., T. Tóth and D. Sári. 2006. Characterization of Spatial Variability of Salinity of Irrigated Plots
for their Improved Management in the Arid Region of Rajasthan, India. Annals of Arid Zone. 45(1): 9-17.

Abstract

Saline and/or high residual sodium carbonate (RSC) groundwater is the major source of irrigation in arid region of India. Despite
fallowing during rainy season or amelioration with gypsum, high salinity prevails in the irrigated soils. There is a large spatial
variability in the amount of accumulated salts. Present study was taken up to characterize the spatial variability in soil salinity at
three sites on farmers' fields where saline/high RSC (EC 3.6 to 8.6 mS/cm, SAR 19 to 62 and RSC 1 to 19 me/l) is being used for
irrigation for more than ten years and some of the parcels have received gypsum for amelioration of salinity and sodicity. Salinity was
measured at 5 m interval with a portable electrical conductivity meter SCT-10 using four electrodes. The data were analyzed for basic
statistical parameters and transformed into natural logarithm to provide a distribution closure to normal. For two sampling directions,
the semi-variogram seemed to depend on irrigation water salinity and soil texture. The largest range (70 m) was found at Narwa where
the salinity of irrigation water was less and soil was loamy sand. At Sathin-1 and Sathin-2 sites low range of 15 m and 11 m,
respectively, was attributed to fine texture and high sodicity of soil.