EXPERIMENTAL WORK 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 LXITI. 
TaspLE LXIII.—Yields of crops obtained during second period of experiment 
(1899-1902). i 
1900: 1901: 1902: 
Corn, yield per Miscellaneous Soy beans, yield 
acre. crops.! per acre. 
Treatment. 
Limed. | Unlimed.| Limed. | Unlimed.} Limed. | Unlimed. 
Bushels. | Bushels. | Per cent. | Per cent.| Bushels. | Bushels. 
Dissolved bone black......-.-..--..------ 71.1 54.7 304 27. 23. 
MISSOlVved DONC s.2s.0 see hoe e ccc cbctccs 75.6 63. 2 327 366 29.3 26.8 
MCI ROSPHALO wat sce Oo ase seine ne eae se 78.5 70.9 250 395 Pe Uh 25.3 
MinevgerouNGd DONG. 22 25s 02s snc. ss. 5 eel. s 84.0 69.8 329 440 29.3 27.5 
asicvslagameale tee eee eee ee 79. 4 65.6 336 444 29.8 27.3 
Sas poem cite CGT in a 82.3 67.8 243 382 26.5 23.6 
UBC ONGIGO CLAW.) ogee eee ec eeh acs sccse 76.4 54.3 93 177 17.2 16.0 
Redondite (roasted)... --. 52.2. .2 eee 82.6 54.1 257 226 24.6 19.1 
INoiphosphatess ecco cecicccewccee cscs e=- U5 1! 48.1 100 100 16.7 14.2 
Double superphosphate...............---- 78.3 50.9 279 143 25.3 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 
