HEN MANURE 605 



is introduced into the soil large quantities of humus bodies 

 whereby the physical state of the soil is profoundly modified and 

 its adaptability to the growth of crops, as a rule, increased. The 

 addition of active nitrifying ferments to stall manures is also ad- 

 vantageous, since they often contain active denitrifying organisms 

 derived from straw and similar sources whose activity is checked 

 by the proper treatment to secure progressive nitrification. Stall 

 manures, however, may in many cases prove to be injurious to 

 a crop, as for instance, when they are applied in a poorly decom- 

 posed state and in a season deficient in moisture. 



It is essential, therefore, that the bedding of animals be in a 

 finely divided state, whereby not only are the absorptive powers 

 of the organic matter increased, but also the conditions for their 

 speedy decay favored. To avoid the loss of ammonia arising 

 from decomposing urine, it is advisable to compost the stall 

 manure with gypsum or to sprinkle it from time to time with 

 oil of vitriol. 



In the analysis the moisture may be estimated by drying to 

 constant weight at 100 or at a lower temperature in a vacuum. 

 The potash and phosphoric acid are determined as usual, with 

 previous careful incineration, and the nitrogen secured by the 

 moist combustion process. 



The organic matter of farmyard manure in many cases exerts 

 a very beneficial effect on the texture of the soil, and in addi- 

 tion serves as a source of humus, which still further improves 

 fertility. For these reasons the actual returns from the applica- 

 tion of such manures- are often much greater than would be 

 expected from the total quantity of plant food which they con- 

 tain. 



There is no other virtue in stall manure than is found in its 

 content of plant food and its effects on soil texture. 



512. Hen Manure. This fertilizing substance is a mixture 

 of the excrement of the fowl yard with feathers, dust, and other 

 debris. Measured by the standard applied to commercial fer- 

 tilizers, hen manure has a low value. As in the case of other 

 farm manures, however, it produces effects quite out of propor- 

 tion to the amount of ordinary plant foods which it contains. 



