302 SYSTEMS OF MANURING CROPS [chap. 



for a given outlay in manure, are really unpractical ; so 

 variable is the basis — the condition of the land — upon 

 which the return depends, and so much does the power 

 of realising products like roots change from farm to 

 farm. The style of farming, and with it the amount of 

 fertilisers that can be profitably employed, will always 

 be dictated by such local conditions as the markets 

 available, the supply of labour, and the rent of the land. 

 On the one hand we have the systems prevailing in the 

 middle west of America and other more newly settled 

 countries where the farmer is living upon the capital 

 originally stored up in the virgin soil. He grows, for 

 example, maize and wheat alternately, using no fertiliser 

 and restoring nothing to the soil, often burning the 

 straw and not even taking the trouble to cart out 

 the manure accumulated beneath any cattle he may 

 feed. Year after year 50 to 100 lb. of nitrogen per acre 

 are being removed and the soil is getting steadily 

 poorer, yet it has proved to be more profitable to move 

 to fresh land than to spend money in restoring the lost 

 fertility. On the other hand, in many parts of Great 

 Britain we may see a strictly conservative system at 

 work. The land possesses a certain condition and will 

 yield fair average crops, only part of which are sold — 

 the wheat and barley — the rest are converted into meat 

 and dung, by which means the greater part of the plant 

 food drawn from the soil is returned. There is, however, 

 a certain removal in the corn and meat and a certain 

 amount of waste in dung-making, but this is repaired 

 by the growth of clover, etc., and by the purchase of a 

 comparatively limited amount of fertilisers or feeding 

 stuffs, so that the condition of the land is maintained 

 but not at a very high level. Again, at the other end 

 of the scale we have the intensive farmer who uses 

 his land as a sort of manufacturing medium to convert 



