PENNSYLVANIA FIELD EXPERIMENTS 433 



four-year rotation, $13.76 where 8 tons of manure are used in the 

 Ohio three-year rotation (corn, wheat, and clover, see Table 

 396), and 17.29 where 40 cents worth of raw phosphate, or 80 

 cents' worth of acid phosphate, was used in connection with 8 tons 

 of manure in the Ohio rotation. 



From Table 81 it can easily be determined that the absolute 

 value per ton of manure for permanent systems is $1.24 for the 

 smallest amount used, $1.06 for the medium amount, and $1.02 

 for the heaviest application. For the additional 8 tons (12 to 20) 

 the manure was worth 71 cents a ton. 



Based upon comparison with the yields from the untreated land 

 during the last 12 years, the 12 tons of manure for the Pennsyl- 

 vania four-year rotation were worth $2. 14 a ton; while, for the same 

 12 years, the 8 tons of manure, in the Ohio three-year rotation, 

 were worth $1.82 a ton for the yard manure and $2.41 a ton for 

 the stall manure. (See Tables 37, 38, and 39.) 



Director Thorne has emphasized the fact that the Ohio experi- 

 ments at Wooster were started on fields that had for many years 

 been under exhaustive tenant husbandry, and the unfertilized 

 plots at Wooster during the last 12 years are more nearly compar- 

 able with those at State College during the same 12 years than dur- 

 ing the first 12 years. Thus the average annual produce per acre 

 for the same three crops, corn, wheat, and clover, was $10.35 f r 

 the first 12-year period and $7.77 for the second 12-year period, 

 in Pennsylvania; while for the last 12 years the average value 

 in Ohio has been $8.06, these values being based upon the normal 

 unfertilized plots, the No. 8 plots at State College, and the No. i 

 and No. n plots at Wooster (see Table 40) not being included. 

 If the oats are included, the Pennsylvania figures would be $10.47 

 for the first 12 years and $7.61 for the second period. 



In Pennsylvania Bulletin 90 (1909), Director Hunt summa- 

 rizes the results of the first 25 years covered by these experiments. 

 The following tabular statement, containing figures based upon 

 Pennsylvania values, may be of special interest to the student of 

 Eastern conditions. 



The upper part of this table shows the total weights of the seven 

 products harvested, including ear corn, corn stover, oats, oat straw, 

 wheat, wheat straw, and hay; and the lower part shows the total 



