Geo-Information Systems in Study of Spatial Variability of Spotted Salinity in Arid Irrigated Indus Plains

Muhammad Nawaz Syal

Geodata, Pakistan

Salinity is the single most widespread land resource problem of the Indus Plains. A type salinity which occur within the agriculturally important lands in the form of scattered small patches, called 'spotted salinity', and for which canal water and other inputs are continuously without any production, makes up the crux of the problem. The soils representing spotted salinity could not be optimally recorded by past ground imaging sensors and hence escaped the due attention of the soil investigators. In addition, the principal agencies responsible for land resource data acquisition failed to appreciate this form of salinity in respect of its genesis and causes of such spatial distribution. This study employs resources of geo-information technology such as data integration and analysis to study spatial variability of soils with spotted salinity. It was found that seperation of these soils is not possible at any rational scale. Spatial variability was, however, best represented by semi-variograms constructed automatically by calculating autocorrelation and semivariance of soils in the ILWIS environment.