8-Drainage of Heavy Soils.

Abstract

Heavy clay soils (Vertisols and associated soils) constitute a major group of soils in India. Because of their clayey nature, these soils are highly moisture retentive and hence possess high potential productivity with proper soil. water and crop management practices. Under irrigated irrigations these soils are very prone to waterlogging and soil salinization on account of their low saturated hydraulic conductivity and impeded internal drainage. Vertisols owe their poor drainability to their high clay content and characteristic swelling—shrinking property. Appropriate preventive measure must be token to ensure sustained productivity of these soils through better management and control of irrigation water on farm and also of the main system. Where the problems already exist, in addition to preventive measures, suitable curative measures also must be adopted. Studies hare shown that the open ditch drains are not very successful in Vertisols for a number of reasons. Vertical drainage is particularly suited to these soils which can also help to achieve water economy through conjunctive use of surface and ground water in the canal command areas. A recent innovation of "chimney" drains has shown considerable promise in e!ffectively draining deep black cotton soils in two projects in Maharashtra. Similar experiments should be conducted elsewhere in the heavy soil areas.