FERTILIZERS AND AGRICULTURAL LIME 45 



Pulverized Animal Manures 



The analysis of these products includes determination of moisture, organic 

 matter, and acid insoluble ash. The acid insoluble ash is mainly sand although 

 it may contain other materials which are practically valueless as plant food. 



As a rule animal manures are bought and used primarily for their content of 

 ingredients other than nitrogen, phosphoric acid, and potash. Besides containing 

 varying amounts of organic matter and considerable quantities of other major and 

 minor elements, these manures possess other properties which cause them to be 

 regarded as superior to other organic products for some uses. Calculated on the 

 basis of the nitrogen, phosphoric acid, and potash content alone, the unit cost of 

 each of these elements greatly exceeds the corresponding unit cost in other organic 

 fertilizers. Economically, the payment of this higher unit cost is justified wherever 

 it is found that animal manures are best suited for meeting special soil or plant 

 requirements and that their use will lead to optimum results. Otherwise, if it is 

 necessary or desirable to use organic sources of the three major elements m large 

 quantities, consideration should be given to combinations of materials such as 

 ground bone, animal tankage, ground fish, the seed meals, Milorganite, the process 

 tankages, and cotton hull ashes, which will furnish the desired plant food more 

 economically and in the case of nitrogen generally in a more available form. 



Since it is realized that for some users and for some purposes the animal manures 

 apparently possess a real or fancied advantage over the other orgamcs great 

 enough to cause a demand for their sale regardless of the economics involved, the 

 moisture, organic matter, and acid insoluble ash content have been determined 

 and published as a partial indication to the comparative values of the products 

 sold Naturally if either the moisture or the insoluble ash or both are excessively 

 high in any animal manure, the organic matter must necessarily be correspond- 

 ingly low, thus impairing the value of this particular product in comparison with 

 another in which the proportion of these ingredients is reversed. 



In general, the value of an animal manure, unmixed with other materials, vanes 

 somewhat in proportion to its organic matter content. This is not true of manures 

 mixed with large quantities of peat, straw, wool waste, or similar materials which, 

 since the organic matter they contain is very slowly available, have very little 

 value as plant food and are used chiefly as soil conditioners. 



All preceding references to manure in this article refer to the dried, pulverized, 

 and bagged product. It is realized, of course, that ordinary barnyard manure 

 produced on many farms plays an important part in the maintenance and im- 

 provement of soil fertility and is a valuable and economical source of plant food 

 and organic matter. 



