Published online by Cambridge University Press: 27 March 2009
1. A large number of observations on different soils in incubation, pot and field experiments have been made to determine the effect of the growing plant upon seasonal changes in soil acidity.
2. In every case it has been shown that the acidity of the uncropped soil increases to a maximum during the growing season and that the change may amount to more than one pH unit.
3. The plant reduces the change in acidity to a marked extent and at the height of growth there is a considerable difference between the acidity of the cropped and uncropped soil.