30 FERMENTATION OF FARMYARD MANURE. 



Fermentation of farmyard manure. Having now 

 considered the nature of the different manures pro- 

 duced by the four common farm animals separately, 

 it is of importance to consider the exact nature of the 

 fermentation, decomposition, or putrefaction which 

 takes place in the manure-heap. 



It is now more than thirty years since Pasteur 

 showed that the fermentation which ensued on keep- 

 ing a sample of urine was due to the action of a 

 minute organism, for the propagation of which a cer- 

 tain amount of warmth, air, and moisture, as well as 



year, and makes about 12 tons of manure. A farmer, therefore, should 

 make 8 tons of manure for every acre of that part of his land which, 

 in the four-course rotation, is put down to turnips. 



The last method consists in taking as the data the amount of food 

 consumed and litter used in the production of the manure. Of these 

 methods Heiden considers the last as alone satisfactory and trust- 

 worthy. Applying this method to the horse, he shows, from experi- 

 ments, that a little over 47 per cent of the dry matter of its food has 

 been proved to be voided in the solid and liquid excreta. Taking 

 the average percentage of water in the excreta as about 77.5, the 

 percentage of dry matter in the excreta will be 22.5. That is, every 

 pound of dry matter in the food eaten by the horse yields a little over 

 2 Ib. of excrementitious matter. To this of course must be added 

 the amount of straw used as litter, which, may be taken at 6.5 Ib. 



From these data we may calculate the amount of manure produced 

 in a year by a horse, making certain assumptions as to the amount of 

 work performed. This Heiden does by assuming that a horse works 

 260 days, of twelve hours each, in the course of a year, or 130 whole 

 days, spending 235 days in the stall. Calculating from the above 

 data, he estimates that a well-fed working horse will produce about 

 50 Ib. of manure in a day, or 6.5 tons in a year. Of course this 

 does not necessarily represent all the manure actually produced by the 

 horse, but how much of the remaining portion of the manure actually 

 finds its way to the farm it is impossible to say. According to the 



