Distribution of Zeolitic Soils in India

Calcium-rich zeolites control naturally occurring chemical degradation in the black soils (Vertisols and their intergrades). With the help of modern tools such as remote sensing, geographic information system, soil database, geological information, topography and other related datasets, an attempt was made to update the distribution of zeolitic soils in India. To ascertain the presence of Ca-rich zeolites in soils, mineralogical information was generated using X-ray diffraction techniques for the selected soils from the Indo-Gangetic Plains and the black soil region (BSR). The zeolitic soils are mostly confined in the pediments (sloping regions of the upland) of the Deccan plateau in BSR, although a few are also found along the valley floor. The IGP, on the other hand, hosts the zeolitic black soils along the drainage channels in the valley floor where the basaltic alluvium deposited the smectite and clay-rich sediments. The study indicates Ca-rich zeolitic soils in India to occupy an area of ~2.8 m ha, of which BSR and IGP constitute ~92% and ~8% respectively. The zeolites are mostly concentrated in the drier tracts of the country and help in maintaining soil health against natural soil degradation. While the occurrence of Ca-rich black soils in BSR was known, those in the IGP are new findings. With the help of the available information, we have generated state-of-art information approximation map on the distribution of Ca-rich zeolites in Indian soils.