A method for identifying soil catenas and determining map unit composition used in a reconnaissance soil survey in Tanzania

Abstract

A method of reconnaissance soil survey is described in which land units are delineated by photo interpretation and soils are investigated along traverses. The start points of traverses are randomly located along the existing road network within each land unit. Each traverse is oriented to cross an interfluve and is systematically sampled at intervals defined by the distance from the crest line to the margins of the valley floor on either side. Proportions of different soil types within each land unit can be calculated, with standard deviations if required, and typical soil catenas recorded. The method proved difficult to use in areas without clearly defined interfluves and where the geology and landform are complex. The authors conclude that, despite limitations, the method is rapid and is especially suited to terrain where soil distribution can be characterised by catenas. The method can be implemented by a number of survey parties to provide quantitative estimates of the proportions of soils within mapping units; this is of great benefit to land use planners.