442 INVESTIGATION BY CULTURE EXPERIMENTS 



TABLE 82. OHIO EXPERIMENTS: FIVE-YEAR ROTATION 

 Average Records per Acre for Three Rotations, 1894 to 1908 



1 The standard forms of plant food are 50 Ib. of dried blood (25 Ib. on 

 plots 17 and 24, and 20' Ib. on plot 26) and the balance of the nitrogen in sodium 

 nitrate (70 Ib. N in 440 Ib. of nitrate), acid phosphate (20 Ib. P in 320 Ib. of 

 phosphate), and potassium chlorid (108 Ib. K in 260 Ib. of potassium chlorid, 

 "muriate" of potash). Where some other material is used for any element, as 

 linseed-oil meal for nitrogen, less acid phosphate and potassium chlorid are applied, 

 so as to correct for the phosphorus and potassium carried in the oil meal. 



The possible influence of abnormal years upon the average of a 

 few years is well illustrated in the wheat yields of these experi- 



