Laterite, its Petrology and Relation to Plant Growth

As basalts are believed to be the chief basic rocks which alter into laterite, their origin is briefly described. The several theories about the origin and development of laterite have been stated and their merits considered. The writer's own views about the origin of laterite have been set forth. He believes that the residual soil stratum over the highest volcanic flows was metamorphosed by the ultimate lava flows that must have occurred at different times in different places, and the scoriae together with the baked and friable upper layer was denuded in the long march of time.The processes of weathering and leaching further altered the stratified subsoil into the petrological mass which is called the laterite. The writer is of the opinion that the true laterite is not perhaps forming at the present day, as what is found at the surface is but the subsoil laterite formation exposed on account of continuous erosion. He also believes that the red soil layers overlying the true laterite, instead of being a transition stage of the rock, is only the soil resulting from the process of weathering of the underlying laterite coupled with leaching out of the bases.The capacity of laterite to maintain the moisture contents as also the slivicultural treatment that may be best suited to such soil with a view to maintain the soil quality have also been considered.