312 SOILS AND MANURES 



is in the proportion of nitrogen in the latter. The animals 

 fed on mangolds produced more than six times as much 

 urine as those fed on lucerne hay, and more than twice 

 as much total excrement. The total quantity of nitrogen 

 voided by the latter was nearly 50 per cent, greater, 

 but the quantity of phosphoric acid was slightly less, 

 and of potash considerably less than by the former. The 

 differences observed bear a close relation to the composi- 

 tion of the food and serve to illustrate its influence on the 

 character of the manure. It may be observed, however, 

 that a diet consisting wholly of roots is not a normal or 

 generally appropriate one for cows. 



THE LITTER. 



The character of the litter employed affects the quality 

 of the manure produced, according to its composition, i.e., 

 the amount of fertilising ingredients it contains and con- 

 tributes to the bulk, its power of absorbing the liquid 

 excrement and its influence on the fermentation. 



Straw. The litter generally consists of straw, which 

 is perhaps more suitable for the comfort and cleanliness 

 of the animals than any other substance. Also it is 

 produced on the farm, is not of much use for any other 

 purpose, and its manurial value is greatly enhanced by 

 being practically composted with the animal excreta. 

 Ordinary cereal straws contain from 0*4 to 0*7 per cent, 

 of nitrogen, 0'2 to 0'25 per cent, of phosphoric acid and 

 from 1 to 1'5 per cent, of potash. The proportions 

 of these ingredients are, however, very variable, and 

 greater differences are often observed between two 

 samples of one kind than between those of different 

 kinds. Wheat straw is generally preferred to any of the 

 others. Barley straw is disliked because of its dusty 

 character. Oat straw is rather richer than any of 



