Summary An investigation was made of the time taken by a ley to change the physical state of an old arable soil ro that of an old grassland soil so that, for example, its physical condition on ploughing is the same as that of old grassland on ploughing. The process was found to be slow, taking possibly 50 years or more on some clay soils. On coarse sandy soils the process may be considerably faster, e.g. 5–10 years.

An investigation was made of the time taken by a ley to change the physical state of an old arable soil ro that of an old grassland soil so that, for example, its physical condition on ploughing is the same as that of old grassland on ploughing. The process was found to be slow, taking possibly 50 years or more on some clay soils. On coarse sandy soils the process may be considerably faster, e.g. 5-10 years. I Old pasture and old grassland have been used synonymously.