EXPERIMENTAL WOEK 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. 



In the spring of 1890 the plots (% 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 P2O5) =127 pounds 



2: Mona guano (21.88 per cent P2O6) =128 pounds 



3: Ground Florida rock phosphate— (21.72 per cent P2O6) =129 pounds 

 4 : Ground South Carolina phosphate- (27.57 per cent P2O5) =131 pounds 

 5: Dissolved bone black (15.82 per cent P205)= 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 XXXVII 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 and 1896 could not be 

 found in the records. 



Table XXXVII. 



-Yields per acre of various crops during twelve years of ex- 

 periment (1890-1901). 



Fertilizer. 



Basic slag 



Mona guano 



G round Florida rock 



Ground South Carolina rock. 



Dissolved bone black 



No phosphate 



Annual! 

 applica- 

 tion per 

 acre. 



PouruJs. 

 762 

 768 

 774 

 786 

 468 



Potatoes. 



Pounds. 



9,600 



8,490 



9,000 



10,980 



12, 720 



Wheat. 



Pounds. 

 2,280 

 2,040 

 1,290 

 2,280 

 2,430 



1892 



Serra- 

 della. 



Pounds. 

 24, 420 

 20, 460 

 16, 500 

 18, 660 

 17,520 



Com. 



Pounds. 

 9,060 

 8,286 

 8,082 

 8,814 

 7,932 



1894 



Barley. 



Pounds. 

 2,f>10 

 2,430 

 1,740 

 2,760 

 2,340 



Rye. 



Pounds. 

 4,170 

 3,780 

 2.298 

 4; 554 

 3,750 

 Not given 



Fertilizer, 



Annuali 

 applica- 

 tion per 

 acre. 



Soy beans 

 (beans). 



Turnips 

 (roots). 



1898 



Com. 



Oats. 



Cab- 

 bage.2 



1901 



Oats 

 (grain). 



Basic slag 



Mona guano , 



Groimd Florida rock 



Ground South Carolina rock 



Dissolved bone black 



No phosphate 



Pounds. 



762 

 768 

 774 

 786 



Pounds. 

 1,524 

 1,398 

 1,572 

 1,512 

 1,482 

 Not given 



Pounds. 

 11,220 

 21,930 

 4,920 

 11,790 

 9,714 

 4,9S0 



(») 



(') 

 (') 

 (') 

 (') 

 (') 



(5) 



(') 



Pounds. 

 1,980 

 1,500 

 60 

 3,300 

 1,560 



Bushels. 

 100 

 84 

 67 

 95 

 79 

 87 



1 Phosphates applied during the first four years only. 



2 The weights given represent cabbages which weighed over 2^ pounds. 

 » No detailed yields given. 



