ABSTRACT
The improvements in English farming to which reference has been made, were based on recognition of the facts that plants require food like human beings, but not upon any exact knowledge of the constitution neither of this food nor of the mechanism by which it was obtained. The order of the rotation was the result of experience, and so also was the use of farmyard manure to restore the impoverished soil to its former condition, or to increase the yield of the crop on fertile soils. Deterioration goes on in new countries in all cases until wheat is displaced by rotation of crops. The exhaustion of the soil is not produced directly by the wheat crop, but by the method of cultivation altering the microscopic flora of the soil and destroying the natural balance of food supply and food demand.
