Saline Soils of the Indo-Gangetic Alluvial Plain (North Bihar): Their Characteristics and Genesis

Saline soils are widespread amidst the narrow strip of calcareous alluvial soils in the Indo-Gangetic alluvial plain covering parts of the Champaran, Muzaffarpur, Darbhanga and Saharsa districts in Bihar state. The soils owe their origin mainly to the limestone rocks forming part of the middle and inner Himalayas and have been deposited by the fluviatile action of the tributaries of the Ganges. Developed under moist subhumid climate, these occupy soilscape positions within the upland plain where the geochemical process of salt accumulation continues. The dominant salts occurring are chlorides and sulphates of sodium, mangesium and calcium and are deposited by the continental geochemical cycles. Main problem is of salinity but bicarbonates and carbonates of sodium occurring in sizeable quantities result in ESP values as high as 40 and pH (paste) values exceeding 9. With the low clay content and fine calcareous nature the sodic conditions however fail to manifest poor soil physical conditions.