602 SOILS: PROPERTIES AND MANAGEMENT 



alent in manure producing capacity to about 100,000,000 

 cattle, each weighing 1000 pounds. Assuming that 

 each animal will produce manure to the value of $21 

 a year and that the cattle are yarded for four months, 

 the total value of excrement produced during the yarding 

 period would be, in round numbers, $700,000,000. If 

 only one-third of the value of the manure is lost by mis- 

 handling, an annual waste of $233,000,000 would occur. 

 This is a very conservative estimate regarding the losses 

 of farm manure throughout the United States. The an- 

 nual sale of commercial fertilizers in this country, prob- 

 ably amounting to over $100,000,000, is entirely inade- 

 quate to replace this loss. 



506. Handling of manures. l The ultimate considera- 

 tion in a study of farm manures comprises the best 

 methods of economic handling, both as to labor and as to 

 the saving of the constituents carried by the product. The 

 greater the amount of plant-food that can be saved in 

 the manure and returned to the land, the less will be the 

 necessity of commercial sources of these elements. Many 

 methods present themselves as being more or less effica- 

 cious, but none are absolutely perfect, as losses by fer- 

 mentation are bound to occur even though leaching is 

 entirely prevented. Methods of handling are usually 

 chosen because of their adaptability to particular cir- 

 cumstances, rather than because of the exact amount 

 of valuable constituents that they will conserve. 



1 Good discussions of handling farm manure are as follows : 

 Hart, E. B. Getting the Most Profit from Farm Manure. 

 Wisconsin Agr. Exp. Sta., Bui. 221. 1912. Beal, W. H. Barn- 

 yard Manure. U. S. D. A., Farmers' Bui. 192. 1904. Roberts, 

 I. P. The Fertility of the Land, Chapter IX, pp. 188-213. 

 New York. 1904. 



