EXPERIMENTAL WORK WITH RAW ROCK PHOSPHATE, 87 
In 1897 the field was divided into three tracts containing 20 
plots each, and a three-crop rotation of corn, wheat, and clover 
begun, so that each crop was grown every year and each tract received 
every third year the fertilizer treatments outlined below. 
A quantity of manure from the stable, where it had collected under 
Yhe feet of animals kept continually in their stalls, was taken and 
divided into five equal parts, four of which were treated with various 
reenforcing materials at the rate of 40 pounds to the ton of manure. 
The fifth portion was left untreated. Equal or equivalent amounts 
of manure from the open barnyard were similarly treated with the 
same materials. After standing for some time the manure thus 
treated was spread upon clover sod at the rate of 8 tons to the acre, 
and plowed under for corn which was followed by wheat and clover. 
During the first three seasons soy beans were grown and plowed 
under, since clover was. a failure. The arrangement of the plots is 
shown in the following diagram taken from the Ohio station reports; 
and the average yields per acre for 18 crops? and the increases in 
yield due to the various applications are given in Tables LIII 
and LIV. 
Arrangement of plots and plan of fertilizing in experiments with manure; 
plots one-sixteenth acre each. 
11. Nothing. Nothing. 1 
12. Yard manure, gypsum. 7 Yard manure, floats. 2. 
13. Stall manure, gypsum. Stall manure, floats. 3. 
14. Nothing. Nothing. 4, 
15. Yard manure, untreated. Section | Yard manure, acid phosphate. 5. 
16. Stall manure. untreated. ING Stall manure, acid phosphate. 6. 
°17. Nothing. Nothing. ib 
18. Chemical fertilizer. Yard manure, kainit. 8. 
19. Chemical fertilizer. Stall manure, kainit. ) 
20. Nothing. Nothing. 10. 
11. Nothing. Nothing. L. 
12. Yard manure, gypsum. Yard manure, floats. 2. 
13. Stall manure, gypsum. Stall manure, floats. 3. 
14. Nothing. Nothing. 4, 
15. Yard manure, untreated. Section | Yard manure, acid phosphate. 5. 
16. Stall manure, untreated. B. Stall manure, acid phosphate. 6. 
17. Nothing. Nothing. ie 
18. Chemical fertilizer. Yard manure, kainit. 8. 
19. Chemical fertilizer. Stall manure, kainit. 9. 
20. Nothing. Nothing. 10. 
11. Nothing. Nothing. il 
12. Yard manure, gypsum. Yard manure, floats. 2; 
13. Stall manure. gypsum. _| Stall manure, floats. 3. 
14. Nothing. Nothing. 4, 
15. Yard manure, untreated. Section | Yard manure, acid phosphate. 5. 
16. Stall manure, untreated. C. Stall manure, acid phosphate. 6. 
17. Nothing. Nothing. le 
18. Chemical fertilizer. Yard manure, kainit. 8, 
19. Chemical fertilizer. Stall manure, kainit. 9) 
20. Nothing. Nothing. 10. 
1 This applies to all plots, except the commercial fertilizer plots the results of which are 
the averages of 16 years. 
ee 
