The factors of soil formation are discussed in chapter 1 . Climatic and biological factors generally produce broad geographic patterns. These have given rise to a zonal concept and definition of soil distribution.
Parent materials contribute to soil variations within climatic and vegetative zones.
Local topographic patterns add further complexity, affecting both the time of exposure to processes of soil formation and the kinds of processes. The complex interactions among these factors occur in repetitive patterns which lead to the formation of repetitive combinations. These are the basis for defining, identifying, and mapping soils. The repetitive patterns imprinted in soils by the soil- forming factors can be observed at scales ranging from continental to microscopic. The patterns are the basis for soil identification and mapping at vastly different scales.