Productivity, Potentiality and Soil-site Suitability Evaluation for Rice Crop in the Moridhal Watershed of Dhemaji District of Assam

A study was undertaken to carry out the productivity and suitability evaluation of the soils of the Moridhal watershed in Dhemaji district of Assam. Satellite image interpretation led to the recognition of four different physiographic units in the studied area which included: upper piedmont plain, lower piedmont plain, alluvial plain, and flood plain. One hundred seventy surface soil samples representing different physiographic units were collected and analyzed in the laboratory for various soil parameters. The productivity and suitability of the soils were computed and assessed by following standard procedures. The productivity index of studied soils varied from 12.13 to 62.14 could be ranked as: alluvial plain>flood plain>lower piedmont plain>upper piedmont plain. However, through adoption of proper improvement measures the soils could be improved to land index values of 41.04 to 90.25.The land index value for Sali rice, Ahu rice and Bororice could categorize into permanently unsuitable (N2) to moderately suitable (S2). The studied soils in terms of their suitability for Sali rice, Ahu rice and Boro rice could be arranged in the sequence: flood plain> alluvial plain> lower piedmont plain> upper piedmontplain. The productivity and soil suitability maps as generated under GIS environment will serve as ready reckoner to farmers, planners and administrators in identifying the potential are assuitable for the major crops grown in that area.