Exchangeable Ions, pH, and Cation Exchange Capacity

Abstract A lmost all nutrients taken up by plants and microbes are taken up in their ionic form from the soil solution, and knowledge of the size and composition of the soil solution, together with knowledge of nutrient turnover rates, can provide valuable insight into soil nutrient availability and into other biogeochemical processes such as rates of weathering and leaching losses. While nutrient pool size per se can be a poor indicator of availability, changes in pool sizes can indicate changes in ecosystem processes that bear closer examination. Moreover, in all soils the potential for significant hydrologic loss of mobile nutrients is directly related to the size of the exchangeable nutrient pool and the proportion in solution at any given time.