474 STATE i.V WHICH FARM-YARD MANURE CAN BE 



In this case, then, the carbon, nitrogen, and saline matter were con- 

 tained in the proportion of — 



Carbon. Nitrogen. Saline matter. 



28 1 5 in the food, 



and of 10^ 1 5 in the dung ; 



The analysis of the dung itself proving that in passing through the 

 body of an animal, the food — 



a diminishes very considerably in weight ; 



h losing a large but variable proportion of its carbon, 



c but parting with scarcely any of its nitrogen and saline matter — 

 and therefore 



d that the fertilizing virtues of the dung above that of the food of 

 animals — weight for weight — depends mainly upon the larger pro- 

 portion of these two constituents (the nitrogen and the saline matter) 

 which the dung contains. 



I have only further to remind you upon this subject that the state 

 of combination also in which the nitrogen exists in the excretions has 

 a material influence in rendering their action more immediate and 

 sensible than that of unchanged vegetable matter. It passes off for 

 the most part in the form of urea, which is resolved into ammonia and 

 its compounds more rapidly than the albumen of the dried or even of 

 the recent plant, and is thus enabled sooner to exert an appreciable 

 influence upon the growing crop. 



§ 17. Of farm-yard manure, and of the state in which it ought 

 to he applied to the land. 



The manure of the farm-yard consists, for the most part, of cow- 

 dung and straw mixed and trodden together, in order that the latter 

 may be brought into a state of decomposition. In the improved hus- 

 bandry, where green crops are extensively grown and many cattle 

 are kept, the horse-dung forms only a small proportion of the whole 

 manure of the farm-yard. 



On an average, the quantity of recent manure obtained in the farm- 

 yard amounts to a little more than twice the weight of the dry food of 

 the cattle and of the straw spread in the farm-yard or in the stables 

 (p. 469). That is to say, for every 10 cwt. of dry fodder and bedding, 

 20 to 23 cwt. of fresh dung nit, y be calculated upon. But if green 

 clover or turnips (every 100 lbs. of which contain from 70 to 90 lbs. 

 of water) be given to the cattle, an allowance must be made for the 

 water they contain — the quantity of mixed manure to be expected 

 being from 2 to 2 J times the weight of the dry food and fodder only. 



But the recent manure loses weight by lying in the farm-yard. The 

 moisture evaporates and volatile matters escape by fermentation. By 

 the time that the straw is half rotten this loss amounts to one fourth of 

 the whole weight, while the bulk is diminished one-half If allowed to 

 lie still longer the loss increases, till at length it may approach lo one- 

 half of the whole, leaving a weight of dung little greater than that of 

 the food and straw which have been consumed. The weight of com- 

 mon mixed farm-yard dung, therefore, obtained from 10 cwt. of dry food 

 and straw, at different periods, may be thus stated approximately — 



