SOILS AND FERTILIZERS 431 



Bedding. Many materials are used for bedding, and these 

 affect the value of the manure. The objects sought in materials 

 used for bedding are as follows: (1) To make the animals a com- 

 fortable bed, and keep them clean; (2) to absorb and retain the 

 urine and watery manure; (3) to dilute and improve the mechani- 

 cal condition of the manure, and make it easier to handle. The ma- 

 terials used for bedding are generally not rich in fertilizing constitu- 

 ents, and to some extent tend to dilute the manure; but as they 

 absorb and hold the valuable liquid parts, which are easily lost, 

 they really improve the quality. Straw is the most universal bed- 

 ding material in use, and it fulfills most of the requirements very 

 satisfactorily. It is abundant on most farms, as it is in a measure a 

 waste or by-product, and has no market. There are many other 

 materials that have better absorbent powers than straw, and are 

 relatively cheaper when bedding must be purchased. 



Dust A bsorbents. In order to help absorb liquid manures, and 

 prevent the loss of volatile ammonia compounds, dust absorbents 

 are used. Good materials for use in this way are land plaster 

 (gypsum), kainit, finely ground phosphate rock and phosphate, 

 fine earth and sand. 



The use of such materials as furnish phosphoric acid and pot- 

 ash are especially valuable, as they enrich the manure in these 

 plant foods. 



It is not advisable to use 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 fertilizing con- 

 stituents, and so extend and dilute the manure unnecessarily. 



Combining Barnyard Manure With Other Materials. It has 

 been the general experience that probably the best way to utilize 

 barnyard manure is in combination with such materials as supple- 

 ment and conserve its fertilizing constituents. It has already been 

 pointed out that certain substances, such as kainit and superphos- 

 phate, which are sometimes employed as preservatives, may also be 

 used to advantage to improve the fertilizing value of the manure, 

 but it is necessary to do more than this if a well-balanced fertilizer 

 is desired, for, as has been shown, barnyard manure considered sim- 

 ply as a supplier of nitrogen, phosphoric acid, and potash is com- 

 paratively poor. The proportions of potash and phosphoric acid 

 especially are low. The potash, however, is in a very available form 

 and does not need to be re-enforced to the same extent as the much 

 less available phosphoric acid. 



Although nitrogen is one of the most abundant constituents in 

 manure, it has been found that in order to get the best results in 

 general it should be re-enforced if prompt action is desired. This is 

 explained by the fact that a large part of the nitrogen of manure is 

 very slowly available. 



The nitrogen of farmyard manure must obviously exist in very 

 different conditions. That due to the urine of animals will be most 

 rapidly available^ that in the finely divided matter in the feces will 



