We may be under-estimating and not optimising the undoubted benefits obtained by 'improving the drainage' of a soil. I propose that the removal of surplus water, and it's dissolved nutrients, is little more than a loss and would be better saved for later in the year when it's sorely needed. I further suspect that what really causes the actual benefit is not the removal of water but the improved aeration this causes. And I speculate we may dramatically improve yields by pumping air into soils and aerating water.