Abstract
Most investigations of edaphic processes are confined to the topsoil even though plant roots explore a much greater volume of soil than the topsoil. However, plant growth is commonly restricted by adverse physical, chemical, or biological properties of subsoils or combinations of such constraints. Testing surface soils does not reveal these limitations, and hence their significance in crop and soil management is often ignored. There is growing body of research on the impact of subsoil constraints on crop production. To synthesize the insights from this body of knowledge for soil scientists, agronomists, and land managers so that due attention is given to the subsoil in soil, crop, and land management, we have commissioned the 15 following chapters dealing with subsoil constraints for crop production.