EXPERIMENTAL WORK WITH RAW ROCK PHOSPHATE. 67 
said to be well worn. In order to exhaust the field still further of 
its natural fertility, corn, Hungarian hay, and legumes were grown 
in 1888 and 1889 without the application of any fertilizer whatever, 
but no attempt was made to determine whether or not the field was 
uniform. 
y In the spring of 1890 the plots (1% acre each) were laid out and 
each one furnished annually with what were thought to be optimum 
quantities of potash and nitrogen. The following applications of 
phosphates were made to the various plots annually for four years: 
Plot No.1: Basic (phosphatic) slag_____--_ (19.04 per cent P20;) =127 pounds 
eG Ae UA ee ee ee (21.88 per cent P2O;) =128 pounds 
38: Ground Florida rock phosphate__ (21.72 per cent P:0;) =129 pounds 
4: Ground South Carolina phosphate_ (27.57 per cent P20;) =131 pounds 
5: 1Dissolved. -bone black. (15.82 per cent P20;) = 78 pounds 
In 1894 the phosphate applications were discontinued in order to 
study their residual effects but the potash and nitrogen applications 
were increased 50 per cent. A check or no phosphate plot was intro- 
duced in 1895, and the experiment continued until 1902 (12 years). 
In Table XX XVII the yields of the various crops during the en- 
tire period of the experiment are given. Apparently no details of 
the corn crop of 1898, and the oat crop of 1899, have been published, 
and the yields of the check plot during 1895 wa 1896 could not be 
found in the records. 
TABLE XXXVII.—Yields per acre of various crops during twelve years of ez- 
periment (1890-1901). 
ean 1890 1891 1892 1893 1894 1895 
Ain tS | SS eS SSS SS SS 
Fertilizer. tion per : ease 
acre. | Potatoes.) Wheat. | Gana. Corn. | Barley. Rye. 
Pounds. | Pounds. | Pounds. | Pounds. | Pounds. | Pounds. | Pounds. 
IBASIGISIAL tees aceaedssenia~see- 762 9, 600 2, 280 24, 420 9, 960 2, 910 4,170 
MONA SUAN Oa soc ocecee se aace 768 8, 490 2, 040 26,460 | 8, 286 2, 430 3,780 
Ground Florida rock. .......... 774 9, 000 1, 290 16, 500 8, 082 1,740 2, 298 
Ground South Carolina rock.... 786 10, 980 2, 280 18, 660 8, 814 2,760 4,554 
Dissolved bone black........... _ 468 12,720 2, 430 17,520 7, 932 2,340 3. 750 
No phosphatess.=..-se s<. -<2 5s ge Slaps ae chee. Sac | eee ee Not giv en 
| 
1896 1897 1898 1899 1900 1901 
Annual! ) 
s4: lica- et oe Se > ta as Sa Ea 
Fertilizer PP 
% tion per So : 
y beans} Turnips Cab- Oats 
aCe (beans). | (roots). Corn. Oats. bage.? | (grain). 
Pounds. | Pounds. | Pounds. Pounds. | Bushels. 
RASICISIAP Sc aeecle tenes os tc ois oe 762 1,524 11, 220 (3) (3) 1, 980 100 
Monat oan Oe=c6 see o08 scenic coe 768 1,398 21, 930 (3) (3) 1, 500 84 
Ground Florida rock. .......... 774 tote 4,920 (3) (3) 60 67 
Ground South Carolina rock.... 786 1512 11, 790 (3) (3) 3, 300 95 
Dissolved bone black........... 468 1, 482 9,714 (3) (3) 1, 560 79 
INOSPHOSPHALE Mas scass Se aces cas |SsoeSaseee Not given 4,980 (3) (8) 48 87 
- 1 Phosphates applied during the first four years only. 
2 The weights given represent cabbages which erened over 24 pounds, 
3 No detailed yields given, 
