104 Green Manuring. [May, 



GREEN MANURING. 



H. J. Page, M.B.E., B.Sc, A.I.C., 

 Rothamsted Experimental Station. 



The Scarcity of Animal Manure and its Causes. — One of the 



most serious practical problems with which the farmer is faced 

 at the present time is the shortage of farmyard manure. This 

 manure is almost everywhere more highly esteemed than any 

 other, and it was largely in order to investigate the cause of 

 this well-known superiority that Lawes started at liothamsted 

 in 1843 the famous field experiments which have now been 

 going on there continuously for nearly eighty years. It is 

 interesting to know that even at that time farmers could not 

 usually get enough farmyard manure, and yet how much better 

 off were they than the present-day farmer ! 



Let us pause a moment before considering the reasons under- 

 lying the value of farmyard manure, and look a little more 

 closely at the extent of, and the factors causing, the prose] it 

 shortage. With regard to the extent of the shortage, the 

 rise in the price illustrates this point sufficiently. At the 

 present time a ton of stable manure on rail in London may cost 

 as much as 7s. 6d., and even then it is often of poor quality; 

 in 1912 the cost was 4s. 6d., while in 1905 it was only Is., and 

 usually no difficulty was experienced in finding a supply. What 

 are the causes of this enormous change? The obvious one 

 which immediately suggests itself, is the driving of horse 

 transport from the roads by mechanical transport. Whatever 

 the benefits that the tractor has conferred on the farmer in 

 the fields, its elder brothers, the lorry and the motor 'bus have 

 proved for him by no means an unmixed blessing. The returns 

 of H.M. Commissioners of Customs and Excise show that from 

 1906 to 1920 the number of licensed motor vehicles (excluding 

 motor-cycles) increased by nearly a quarter of a million, 

 whereas licensed horse vehicles decreased by 200,000. When it 

 is borne in mind that the bulk of this fall in horse-drawn 

 vehicles will have occurred in the big stables of commercial 

 firms whence the greater part of the town stable manure is 

 derived, it is not difficult to see why stable manure is now so 

 scarce and dear. 



Nowadays, therefore, the farmer is very much more 

 dependent on his beasts for a supply of dung than formerly, 

 and even this supply is not being wholly maintained. The 

 number of head of cattle in Great Britain in 1921 showed a 



