Storage OF Farmyard Manure. 



149 



in the otfier case it was kept firmly compressed. At the end 

 of five months it was found that the loosened substance had 

 lost 31*47 per cent, of dry organic matter, while the com- 

 pressed material had lost only 26-8 per cent., the difference 

 being due, no doubt, to variation in the degree of aeration. 



Pfeiffer also experimented with the following conservation 

 agents in the proportions indicated— Gypsum, 3 per cent. ; 

 double Superphosphate, i per cent. ; and Precipitated Phos- 

 phate, I per cent. — but on the average of the different 

 methods of air-circulation over and through the mass, and of 

 loosened and compressed manure, the loss of organic matter 

 was practically the same with and without the application 

 of these substances. 



Wagner, using 40kg. of horse dung, which was contained 

 in metal cylinders, freely exposed to the air, found that the 

 loss of organic matter was not appreciably influenced in eight 

 months by the application of the ordinary so-called conser- 

 vation agents, the variation being only 2 per cent, ranging 

 as it did between 24 and 26 per cent. After a further period 

 of storage of sixteen months the variation was still only 2 per 

 cent., the limits in this case being 56 and 58 per cent. He also 

 tested the influence of compression on the dung, and found 

 that at the end of two years the manure that had been 

 periodically loosened had lost 46 J per cent, of dry matter, 

 while the loss in the case of that which was less thoroughly 

 aerated was 39 per cent. The same experiment was carried 

 out in a series of cemented pits, each of which received 700kg, 

 (about i4cwt.) of horse manure, and again it was found that 

 at the end of four months ordinary agents (gypsum, soluble 

 phosphate, and kainit) had no effect, the loss of dry matter 

 varying between the limits of 16 and 18 per cent. 



Wagner also carried out a series of experiments with 

 I o — 1 4cwt. of horse manure, which was placed in cemented pits, 

 and kept in the following three conditions : [a) firm and moist, 

 (3) loose and moist, [c] loose and dry. At the end of four months 

 it was found that on the average the " firm manure had lost 

 16 per cent, of dry matter, while that which was kept " loose " 

 had lost 39 per cent. The conservation agents had no effect 

 where the manure was kept firm, but under opposite con- 



