IDENTIFICATION OF SALINITY AFFECTED BLACK SOIL AREAS AND THEIR ASSESSMENT IN SEMI-ARID REGION

ABSTRACT: Soil salinization is one of the problems that affect the crop production from arid and semi-arid regions. Anthropogenic activities such as excess irrigation, mono-cropping pattern of water intensive cash crops and chemical fertilizers lead to the development of soil salinity. Black soil in Peninsular India is not known for salinity potential. However, 10 to 20 years of irrigated cultivation has resulted in the soil degradation. The salinity in black soils is observed in discontinuous patches having salt encrustation observable only after harvest or in fallow lands. During the crop growth, stunted growth is observed. The highly saline soils are kept fallow due to uneconomical rectification measures and salt tolerant species of shrub (Prosopis Juliflora) grow wildly over that area. Salt tolerant sugarcane species are grown in moderately saline agriculture land. For proper management of salinity, the extent of saline soils needs to be demarcated. The objective of this study is identification of saline areas and the assessment of methods with reference to ground conditions. Vegetation indices such as Normalized Difference Salinity Index (NDSI), Brightness Index (BI), and Soil Adjusted Vegetation Index (SAVI) were estimated using the Satellite data collected during the crop growth period. Various combination of reflectance of bands along with reflectance of individual bands were correlated with field observed soil salinity. Response from salinity indices is observed to be different for various land use and land cover classes. Best performing indices were used to derive multiple regression model, which in turn was used to predict soil salinity. The differentiation of bar