Last questions!!

Soil orders:

The lab manual and soil web (http://soilweb.landfood.ubc.ca/classification/) provides a good overview of the characteristics of Soil Orders in the Canadian Classification system (supplementing our class notes). 1st I suggest focusing on the diagnostic horizons / diagnostic characteristics of the Soil Orders.

Columnar structure in the B horizon of Solonetzic soils is indicative of Na salts (as you indicate). Additionally in Luvisolic soils (Bt), the enrichment in clay may result in a blocky structure in the B horizon. What about Chernozems, developed under grasslands, would you expect an influence on soil structure? hint: earthworms. How about vertisols? consider wedge shaped soil peds - how are they formed.

Theoretically any soil order can have an Ap horizon.