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Farmyard Manure : Its Making and Use. [Aug., 



FARMYARD MANURE: ITS MAKING 

 AND USE.* 



Not many years ago it used to be the custom for cortairi repre- 

 sentatives of agricultural science to extol the virtues of artificial 

 manures, while farmers, on the other hand, stoutly maintained 

 the superiority of farmyard manure. In recent years the position 

 has changed. It is now the scientific worker who emphasises 

 the importance of farmyard manure and the need for making 

 and storing it properly. Farmyard manure and artificial ferti- 

 lisers do not compete Vv'ith one another ; they serve quite different 

 purposes in the soil. No farmer can do without artificials, no 

 matter how much farmyard manure he may have at his disposal, 

 and, conversely, no arable farmer, except in a few special 

 districts, would like to do v\dthout farmyard manure, even if he 

 could have unlimited supplies of artificials at '\'ory low prices. 

 The best results are always obtained on arable land by proper 

 combinations of farmyard and artificial manures, although on 

 grazing land farmyard manure ma}^ not act well. 



So far as is at present known, the effects produced by farmyard 

 manure in the soil are three : — 



1. To supply nitrogen and potash to the plant. 



2. To improve the physical condition of the soil, and thus 

 increase its capacity for going into a good tilth and for liolding 

 water. The effect of this is to steady the yield. 



3. To assist some of the micro-organisms of tho toil; among 

 other effects, to benefit the clover crop. 



Only in the first of these is there any competition v\ ith artificial 

 fertilisers, ;ind even here the competition is restricted, because 

 artificials usually exert their full action on the crop to which 

 the}" are applied, while farmyard manure does not. 



The Constituents of rarmyard Manure.— 1.—^/^^' Excretions.— 

 The animal excretions constitute an important part of the fertil- 

 ising material of farmyard manure. The urine is bv far the most 

 important — it is the chief source of the immediately beneficial 

 part of the dung. The amount and value of the urine depend 

 on the food and on the anim^al; urine contains the fertilising 

 constituents of all the digested food which has neither been 

 retained in the animal nor secreted in the milk. 



Its composition can be calculated, and this is done in deter- 

 mining the manurial value of foods, but the calculation never 



* Reprint (abrid^sed) of a paper read by Dr. E. J. Russell, F.R.S.. Director of 

 Rotbamsted Exi)erimental Station, at a meeting of the Farmers' Club, 31st May, 1920. 



