IMAGE TRANSFORMS AS A TOOL FOR THE STUDY OF SOIL-SALINITY AND ALKALINITY DYNAMICS

Principal components analysis (PCA), ratioing, image differencing and intensity-hue-saturation (IHS) transformation have been widely used in monitoring various natural resources and environmental hazards. In ou r study, the temporal behaviour of salt-affected soils in the Indo-Gan getic alluvial plains of Uttar Pradesh has been studied using Landsat MSS data for 1975 and 1992. Apart from routine digital classification of temporal MSS data using Guassian maximum likelihood algorithm, PCA, image differencing, and ratioing were also evaluated for their potent ial in bringing out temporal changes in salt-affected soils, if any. T he results indicate that the third principle component, image differen cing, and ratioing of the first two MSS bands for two periods have bro ught out substantial information associated with the temporal behaviou r of salt-affected soils.