183 



their activity at once. In case of horses and sheep these organisms 

 cause a considerable loss of ammonia in a comparatively short time. It 

 is necessary therefore to adopt prompt measures in order to reduce loss 

 from this source to a minimum. The means which are available for 

 this purpose are the use of absorbents and preservatives, such as straw, 

 peat, sawdust, dirt, gypsum (land plaster), kainit, etc. The litter takes 

 up the liquid manure, thus preserving it to some extent from decompo- 

 sition and also absorbs to a considerable extent the ammonia produced 

 bv fermentation and prevents its escape into the air. 



The relative absorptive power of various materials commonly used 

 as absorbents in stables is shown in the following table : 



Absorptive power of different kinds of litter. 







Ammonia ab- 





Water retained 



sorbed by 100 





by 100 lbs. of 



lbs of dry 





materials after 



matter in dif- 





24 hours. 



ferent ma- 







terials. 





Pounds. 



Pounds. 



Wheat straw ... 



220 



0.170 



Partially decomposed oak leaves ... 



162 





Peat 



600 



1.103 



Sawdust 



435 



0.046 



Spent tan 



450 





Air dried humus soil 



50 



0.660 



Peat moss 



1,300 



0.863 



It thus appears from the table that peat and peat moss are the best 

 absorbents. It has already been shown (p. 178) that they also furnish 

 the largest amounts of fertilising constituents. Peaty soil is also an 

 effective absorbent, and the use of a mixture of peaty earth with straw 

 as lifer as been strongly recommended. An addition of from 35 to 

 40 pounds of loam per head daily has been found advantageous, and 

 where straw is scarce it has been replaced to the extent of one fourth 

 or one third by earth. The amount of litter required for any given 

 animal depends largely upon the character of the food. Watery foods 

 and those containing: a large amount of nitrogen increase the secretion 

 of urine and so increase the amount of litter necessary to absorb the 

 liquid and keep the animal clem. A safe general rule is that the 

 litter should amount to at least one third of the dry matter of the food 

 consumed. The following amounts per day for different animals are 

 recommended : Sheep, three fifths pounds of litter ; cattle 9 pounds ; 

 and horses, 6^ pounds. 



It is not advisable as a rule to vise an excess of litter beyond that 

 required to keep the animal clean and absorb the liquid excrement, 

 since the materials available for bedding are as a rule poor in fertilising 

 constituents, and so extend and dilute the manure unnecessarily. 



A small amount of gypsum (land plaster) sprinkled on the moist 

 dung or urine is a popular and effective means, of fixing the ammonia. 

 It should be remembered, however, that unless the gypsum becomes 

 moist it will have little effect. Kainit used in the same way tends to 

 arrest fermentation, but it must be used with caution or it may injure the 

 feet of the animals standing on it. Both kainit and acid phosphate 

 sprinkled on the manure before it is thrown into the heap are val- 



