CHAPTER XVII 

 FARM MANURES 



The use of animal manure to enrich the soil antedates 

 written history, and it is still the most commonly and widely 

 used fertilizer. It is produced on nearly every farm. Mar- 

 ket-gardeners, who usually keep few animals, buy large quan- 

 tities of horse manure from cities. Its use constitutes a 

 way of returning to the land a part of the plant nutrients 

 taken up by crops, as well as replacing some of the or- 

 ganic matter destroyed by cultivation. Farm manure con- 

 tains nitrogen, phosphoric acid, potash, lime and the other 

 ingredients removed from soils, and hence is a direct ferti- 

 lizer. In addition to these it contains a large quantity 

 of organic matter, which by its influence on tilth, moisture 

 and absorptive properties is a valuable soil amendment, and 

 finally it favors, in a number of ways, a vigorous bacterial 

 activity that does much to bring plant nutrients into an 

 available condition. 



278. Solid and liquid manure. — Farm manure is made 

 up of the solid excreta of animals, the urine, which is usually 

 largely absorbed by the solid ingredients, and the litter 

 used for bedding the animal. As these constituents differ 

 greatly, not only in composition but also in physical proper- 

 ties, their proportions must appreciably affect the agri- 

 cultural value of the manure. Litter usually does not have 

 as high a fertilizer value as do the solid and liquid excreta. 

 Of the excreta the larger part is solid and the smaller is 

 urine. The ratios may be found in Table 45. The propor- 



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