Baldwin and Associate’s Genetic Approach:

Marbut’s morphogenetic soil classification system was revised and elaborated by Baldwin, Kellogg and

Thorp (1938).

The important characteristics of the system were:

(i) A return to the zonality concept of Russian school.

(ii) The pedocal and pedalfer concept was not given emphasis.

(iii) More emphasis was given on soil as a three-dimensional body and its characteristics.

A new category like soil family was introduced between great soil group and soil Series but neither the Family nor the higher category was defined in relation to soil properties. Serious problems were found when some soil series did not fit in any of the existing great soil groups; whereas others could be placed equally well in two great soil groups.

Realising this problem, the soil classification of Baldwin et al. (1938) was notified by Thorp and Smith (1949)