SOILS AND THE PROVISION OF ECOSYSTEM SERVICES

The capacity of soils to sustain ecosystem services such as agricultural and forest productivity varies with land management but also with factors such as geologic parent material, climate, and stage of soil development. For example, soils in glaciated and near-glacial areas of the temperate zone typically have relatively high rates of supply of rock derived nutrients and slow rates of turnover of organic matter and associated nutrients. When such systems are brought into cultivation, supplies of lithophilic elements and biophilic nutrients from organic matter can be supplied for relatively long periods, depending on management. Many old soils of tropical systems, on the other hand, have low rates of rock-derived nutrient supply and rapid turnover of organic matter; traditional sustainable systems here use natural vegetation to accumulate rock derived nutrients, build up organic matter, and then release and exploit nutrients in shifting agriculture. Differences in soil biogeochemistry and fertility call for different approaches to sustainable management. Differences in soil biogeochemistry also influence how ecosystems respond to other anthropogenic changes, such as the addition or mobilization of nutrients by acid deposition.