Composite Units For The Mapping Of Complex Soil Associations

Abstract

It often happens that two or more soil types, whose profiles and conditions of formation differ fundamentally, are found in association together, their boundaries forming a pattern which is repeated, with variations, over a considerable extent of country. It is, of course, possible, given the resources of an organised survey, to map such a piece of country in detail; but unless a large-scale map is the object in view, there still remains the problem of generalising the information thus laboriously obtained, for convenient and air representation on a smaller scale. In the undeveloped countries of the tropics the method of detailed survey is rarely practicable, and the description of such an area must depend on the investigation of sample localities and the discovery of a key that will explain matters for the whole area. The problem is then, not the mapping of soil types individually, but the schematic rendering of an association or physiographic complex of soils, defined in general terms in relation to a set of conditions.