The experimental use of correspondence-analysis to assess the relationship between soils and geomorphology in Eastern Zambia
journal contribution
posted on 2023-06-07, 21:40authored byD B Dalal-Clayton, D A Robinson
Correspondence analysis, an eigenvalue technique suitable for application to mainly qualitative data, is used to display relationships between soils and geomorphic units, using data derived from a reconnaissance soil survey in eastern Zambia. The survey involved the direct mapping of Soil Taxonomy subgroups and phases of subgroups within delineated geomorphic units of a national geomorphic. legend. The operation of correspondence analysis is described and correspondence plots presented. Primary Association Groups (PAGs) of soil classes associated with each geomorphic unit are derived from the plots and from accompanying tables of distances (multivariate standard deviations) between soil classes and geomorphic units. The PAGs are shown to be ordered in horseshoe patterns reflecting the catenary sequence of the geomorphic units in the survey area, confirming the 'normal' operation of correspondence analysis on the data. PAG composition is discussed in relation to the geomorphic units, and is evaluated to test the success of pilot detailed soil surveys in predicting soil-geomorphic unit relationships in the overall reconnaissance survey area. On the ba-sis of the analyses undertaken, the geomorphic approach to reconnaissance soil survey is judged a success.