A method for establishing the modal profile that typifies the central concept and for defining range in characteristics of soil series using quantitative morphological data of soil profiles is presented. Fifteen soil profiles grouped under M.M. Kunta (Mmk) series established in an operational research project for watershed development in Andhra Pradesh has been used to illustrate the methodology. The method uses the simple mathematical computations which can be done easily in the field for establishing the modal profile and for determining the range in characteristics of soil series. The method can be automated if a computer is made available to the soil surveyor in the field. The method has been used with necessary modifications in respect of key attributes in detailed, reconnaissance and soil resource mapping projects in different landscapes and found to be better as compared to the subjective method that many soil surveyors use in establishing the modal profile and for defining range in characteristics of soil series. The methodology is an open system that can accommodate such modifications which are situation dependent.
Modal profile, range in characteristics, soil series, soil map unit, taxonomic unit
