SYSTEMS OF FARMING ON DAIRY FARMS 235 



The cost of hauling is usually about 50 cents so that these 

 figures would make the manure cost the crops $1.50 to $2 

 per 1on. For some new regions these figures may be high, 

 but i n the eastern half of the United States manure is always 

 wort i at least $1 per ton at the barn. Where truck crops or 

 other very intensive crops are raised, it may be worth much 

 mor< . 



211. The Value of Manure Depends on the Rate of Appli- 

 cation. The Pennsylvania Experiment Station has con- 

 duct od an extensive series of fertilizer and manure experi- 

 meni s since 1882. A four-year rotation of corn, oats, wheat, 

 hay s followed. On one plot 6 tons of manure is applied 

 on the corn and on the wheat. On another plot 10 tons is 

 used The check plots receive no treatment. The total 

 value -s of the crops per acre for 32 years were as follows : l 



No treatment $474 



Hx tons manure every other year (96 tons) ... 714 

 Ten tons manure every other year (160 tons) . . 747 



When a total of 96 tons of manure was applied, the value of 

 the increased crops amounted to $2.50 per ton of manure. 

 An additional application of 64 more tons gave increased 

 crops worth 51 cents for each additional ton. For the 

 entire period of 32 years this extra manure would have 

 been worth nearly five times as much per ton if applied 

 at the lesser rate. If one kept 30 animal units and ob- 

 tained 6 tons of manure from each one, or 180 tons per 

 year, he would have 5760 tons of manure in 32 years. If 

 this manure were applied at the lesser rate, the total value 

 of the increased crops would be $14,400. If applied at the 

 heavier rate, the same manure would have brought increased 



1 Pennsylvania Agricultural Experiment Station, Bulletin 90. Later data 

 furnished by F. D. Gardner. 



