32 MANURES. 



vegetable substances. It consists of the excrements of the ani- 

 mals kept and fed upon the farm, together with the straw or 

 other materials used as litter, and generally of the refuse and 

 oflfal produced about the homestead. 



This mixed mass is collected during the process of feeding, 

 when it undergoes a certain degree of fermentation. When 

 trodden down by the feet of the animals kept in the yards, the 

 effect is to exclude the external air, and to prevent the fer- 

 mentative process from that rapidity which would take place 

 were the mass not compressed. The principal animal sub- 

 stances which are mixed with the lignous [woody] fibre of the 

 litter, and which cause it to undergo decomposition, are the 

 dung and urine of the animals. 



The properties of this dung, to a certain extent, depends 

 upon the kind of animals and the nature of their food. The 

 dung of horses is easily fermented, and is more readily decom- 

 posable, in proportion to the succulent and nutritive qualities 

 of the food consumed. The dung of oxen or horned cattle 

 also soon ferments when it is collected into a heap, and is only 

 moistened by its own humidity; but this process is slower 

 than in the dung of horses, because it is not so much exposed 

 to the same internal heat, in consequence of which its evapo- 

 ration is less; and being voided in a very moist state, it does 

 not require to be wetted. 



Sheep dung decomposes quickly when it is moist and com- 

 pactly heaped together; but when dry and dispersed, its de- 

 composition is slow and imperfect. Its effect upon the soil is 

 soon dissipated, and is generally exhausted after a second crop. 

 It is rendered more particularly valuable upon soils which 

 contain insoluble mould, from the ammonia [volatile alkali] 

 which is disengaged from the excrements, and more especially 

 from the urine of sheep. 



When animals are fed on straw and the dried stems and 

 leaves of plants, the dung is less rich and decomposable than 

 when they are fed on roots and other nourishing food; and 

 the same thing holds with respect to the dung of the hog and 

 other animals. The dung of the different feeding animals is 

 mixed in greater or less proportion with their litter; and the 

 greater the proportion of the animal to the vegetable matter, 

 the more readily will the latter ferment and decompose. 



The urine of animals is in itself a very rich manure, and 

 contains, in certain states of combination, all the elements 

 which enter into the composition of plants. It is necessarily 

 mixed with, and partly absorbed by, the litter and other sub- 

 stances in the yards, and it hastens in a material degree the 

 fermentation of these substances. The urine, however, is apt 



