ITS NATURE. 29 



this quantity of excrementitious matter at three-fifths 

 of a pound, then the manure produced by a sheep in a 

 day will contain .0429 Ib. nitrogen, and .264 Ib. mineral 

 matter. That is, in a year the quantities of nitrogen 

 and mineral matter in the manure produced by a 

 sheep would be 15.66 Ib. of nitrogen and 96.36 Ib. of 

 mineral matter. 



From its richness in nitrogen, and from its dry condi- 

 tion, sheep-dung is peculiarly liable to ferment. While 

 richer in fertilising substances than horse-manure, it 

 is not so rapid in its fermentation. This is due to the 

 harder and more compact physical character of the 

 solid excreta. The risks of loss of volatile ammonia 

 are, in its case, exceptionally great. The use of artificial 

 " fixers " is therefore to be strongly recommended. 1 



1 See Storer, Agricultural Chemistry, vol. ii. p. 96. 



A question of great importance is as to the amount of farmyard 

 manure produced on a farm in a year, and its value. This is a ques- 

 tion which is extremely difficult to satisfactorily deal with. Various 

 methods of calculating this amount have been resorted to. It may 

 he well to state these pretty fully. Some practical authorities esti- 

 mate the amount by calculating that every ton of straw should pro- 

 duce 4 tons of manure. Another method consists in estimating 

 the amount from the size of the farm. "It is not very wide of the 

 mark to say that the weight of manure produced by consuming with 

 stock in the yards an acre of turnip crop will be 6 tons, and that an 

 acre of green clover similarly fed will give 5-| tons of manure ; an 

 acre of pasture, 5 tons ; an acre of wheat-straw, 4^ tons ; and an 

 acre of barley or oat straw, 4 tons. One hundred acres of good arable 

 land will produce in a year about 5 tons per acre, or 500 tons" (Pro- 

 fessor Scott). Another method is by taking, as the data of calcula- 

 tion, the number of cattle, horses, sheep, &c., producing the manure. 

 Lloyd considers that a fattening animal requires 3 tons of straw in the 



