Characterization of cation exchange capacity (CEC) for agricultural land-use areas

Abstract

Spatial assessment of soil properties needs conversion of point data to an area-oriented model. Methods are required that create a reproducible map. The development of a map is shown by the example of cation exchange capacity. Twenty sorption types are formed and derived from the vertical sequence of values for substrate types and are aggregated to six main types. A qualitative assessment of the main CEC sorption types is carried out with comparative ranking. The association of different substrate types on an areal soil pattern requires the identification of sorption association types. These are shown by the areal share of the main sorption types for the substrate types involved in each case. For interpreting the site parameters from the MMK (Mittelmaßstäbige Landwirtschaftliche Standortkartierung), the procedure is presented in detail. An example of the results is shown with CEC maps. Tables complement the visualization for different areas, defined by administrative or natural landscape boundaries. The application of this method for relative evaluation of CEC is demonstrated using KA5-rules. The CEC characterization of agricultural areas can be reproduced on the basis of the mapping units of soil maps with different scales (BÜK 200). The areal-specific labeling of CEC constitutes soil-related decision guideline.

Keywords:

• cation exchange capacity (CEC)
• soil property map
• site comparison method (SICOM)

Acknowledgements

The authors would like to thank the anonymous reviewers and the associate editors, and also Bradley Miller and Tony Tismer for their check of English and comments on this paper.

Notes

1. In KA5, this is ‘The substrate … the material of which is the solid substance of the land …’ (KA5). Substrate are characterized by the substrate composition (texture class, carbonate and carbon content, parent material), and substrate origin (KA5 2005). The criteria of substrate go along with the designation of the vertical sequence in the various hierarchical levels substrate systematic units – expressed as a class of substrates, substrate type and substrate subtype. The concept of area association type (formulation of substrate association types and other site parameters) has not yet been adopted in the KA5-directives.

2. Legendeneinheit.