LIVESTOCK POPULATION AND SOIL FERTILITY. Memorandum prepared by Professor A. W. Ashby, Professor F. L. Engledow and Professor J. A. Scott-Warson.

returns to the soil a much larger proportion of the organic residues of fine plants grown, with the consequence that the humus content of the soil can be maintained at a higher level. The practical question is how far we can substitute food-crop production for fodder cropping and live-stock production, over a period of perhaps five years, without seriously impairing the fertility of our soils by depleting their humus reserves. It would seem that the easiest line of approach to this problem is to study the results that have actually been obtained under systems of agriculture rather widely different from the average British system as we know it before the war systems in which food crops have played the major part and livestock the minor one.