CHANGES IN SOIL-PH DUE TO LONG-TERM SOIL STORAGE

Soil pH measured in 0.01 M CaCl2 was found to increase by up to 0.23 of a unit due to long term (7 years) storage of dried surface soil. In comparison, pH measured in water was found to increase by up to 0.55 of a unit after the same time of storage. Soils with the highest ionic strength were found to have the largest pH change. There appeared to be no relationship between soil type and pH change due to storage of soils. We suggest that caution be exercised when re-analysing soils that have been stored for long periods, for water and CaCl2 pH.