Abstract
The calcium carbonate is an essential constituent of dry zone soils. It influences many soil properties. Its global effect on the pH is well known, but the quantitative relationship between the content in calcium carbonate and the pH is disputable. The present work evaluates this relationship in the case of northern Algerian soil. Obtained results show that the soil pH no more evolves since calcium carbonate content is in the order of 2.5%. Beside this threshold, particles of calcium carbonate would have only an steric effect on soil properties.