EXPERIMENTAL WOEK WITH RAW ROCK PHOSPHATE. 



103 



A study of Table LXII will show that in 1894, the first year of the 

 experiment, the plots receiving applications of raw rock phosphate 

 gave no increase in the yield of corn, even when the probable differ- 

 ence in the natural fertility of the raw rock plots and the check plots 

 is taken into consideration. The soluble phosphate plots (both limed 

 and unlimed) on the other hand gave substantial increases in yield 

 over the check plots. The following year (1895) the yields of oats 

 on the raw rock phosphate plots exceeded that of the no phosphate 

 plots by a considerable margin, and during the next three years of 

 the first period, the yield of hay on the raw rock phosphate plots 

 (both limed and unlimed) surpassed the yield, not only of the check 

 plots, but of the soluble phosphate plots as well, indicating that the 

 ground raw rock was becoming increasingly effective. 



Owing to the change in the plan of the experiment the plots were 

 again left in grass in 1899. It was intended to equalize the phoS' 

 phoric acid applications on all the plots (except the checks) this 

 year, but owing to a mistake the additions of phosphoric acid in other 

 forms was not brought up to that already applied in the form of 

 raw rock until 1902, 



No separate figures are given for the grass crop of 1899, but in 

 1900 the land was plowed, treated with adequate quantities of mu- 

 riate of potash and nitrate of soda, and planted to corn. The fol- 

 lowing year (1901) miscellaneous crops were grown in each series in 

 rows extending across the plots. 



In 1902, the fourth year of the second period, the plots were 

 planted in soy beans. The results of this second period of the 

 experiment including the years 1900, 1901, and 1902 are given in 

 Table LXIII. 



Table LXIII. — Yields of crops obtained during second period of experiment 



(1899-1902). 



Treatment. 



1900: 



Corn, yield per 



acre. 



1901: 



Miscellaneous 



crops.i 



1902: 



Soy beans, yield 



per acre. 





Limed. 



Unlimed. 



Limed. 



Unlimed. 



Limed. 



Unlimed. 



Dissolved bone black 



Bushels. 

 71.1 

 75.6 

 78.5 

 84.0 

 79.4 

 82.3 

 76.4 

 82.6 

 75.1 

 78.3 



Bushels. 

 54.7 

 63. 2 

 70.9 

 69.8 

 65.6 

 67.8 

 54.3 

 54.1 

 48.1 

 50.9 



Per cent. 

 304 

 327 

 250 

 329 

 336 

 243 

 93 

 257 

 100 

 279 



Per cent. 

 409 

 366 

 395 

 440 

 444 

 382 

 177 

 226 

 100 

 143 



Bushels. 

 27.5 

 29.3 

 27.7 

 29.3 

 29.8 

 26.5 

 17.2 

 24.6 

 16.7 

 25.3 



Bushels. 

 23.3 



Dissolved bone 



26.8 



Acid phosphate 



25.3 



Fine ground bone 



27.5 



Basic slag meal 



27.3 



Floats 



23.6 



Redondite (raw) 



16.0 



Redondite (roasted) 



19.1 



No phosphates 



14.2 



Double superphosphate 



19.7 







1 Relative yields of miscellaneous crops, taking no phosphate plot as 100. 



For the second year of the second period of the experiment when 

 the plots were in corn, the raw rock phosphate plot (limed) exceeded 



