Delineation and Characterization of Waterlogged and Salt-affected Soils in Gandak Command Area of Bihar for Reclamation and Management

The interpretation of geo-coded IRS-ID LISS-III imageries coupled with ground truth and soil studies indicated waterlogging and the presence of alkali soils as numerous white spots associated with cropped areas in part of Gandak command covering Gopalganj and Siwan districts of Bihar. The alkali soils were noticed in abandoned land, old mango orchard and small patches in arable areas. The presence of calcite and dolomite in soils produced CO₃^2- and HCO₃⁻ ions that accumulated in poorly drained areas. The presence of high sodium ions resulted in high SAR, soil alkalinity and pH. The alkali soils were characterized as very deep with pale brown to light yellowish brown soil matrix and few to common yellowish brown mottles in the sub-surface horizons. These soils can be reclaimed with low (4 t ha⁻¹) doses of amendments like gypsum or pyrites and better management practices.