The Appalachian Region of the USA is characterized by steep, complex terrain and high average annual precipitation (> 1.1 m yr -1). Most of the region is geologically old and soils are highly leached resulting in low pH and nutrient deficiencies for most agricultural production systems. The indigenous vegetation is dominated by species diverse forests. Within the soil a web of tree roots and fungi are very efficient at capturing nutrients from decaying vegetation and on many sites most of the nutrients in the system are contained in the vegetation itself.
Due to the hilly topography, agricultural acreage requiring tillage is restricted to a small percent of the total with forage-based animal production systems dominating. With the conversion of forest to pasture, additions of lime and fertilizer are required on a regular basis to maintain a high level of productivity. The microbiological populations in soils that evolve after conversion to pasture are more strongly dominated by bacteria and are much more nutrient-leaky than the forest soils they replace.