82 BULLETIN 699, U. S. DEPARTMENT OF AGRICULTURE. 
largest yields, closely followed, however, (and in one case equaled) 
by the basic-slag pots. The raw rock phosphate pots produced an 
appreciable increase in yield over the no-phosphate pots, but far less 
than any of the other treated pots except those receiving sodium 
phosphate. This latter compound, it is said, seemed to have a toxic 
effect. t 
In experiment No. 2, where a soil was employed, the raw-rock pots 
gave little or no increase over the checks, while those treated with 
basic. slag produced in most instances greater yields than the acid 
phosphate pots. 
The data obtained in these pot experiments, however, are of such 
limited value (owing to their short duration, and also to the fact 
that only a single crop was tested) that the writers have hesitated to 
present them, but as far as they go they indicate that liberal appli- 
cations of phosphoric acid in the form of acid phosphate and basic 
slag were superior to twice the quantity in the form of raw rock 
phosphate. 
= 
NEW YORK. 
The first three experiments? conducted by the New York Experi- 
ment Station with raw rock phosphate as a fertilizer were of such 
short duration and the data presented are so limited that they are 
not considered in detail in this bulletin. 
In some pot or greenhouse experiments conducted by the Geneva 
station from 1896 to 1900 sufficient data are given to warrant a repe- 
tition of the figures and a discussion of some of the details. 
The soils in which the plants were grown in the several experi- 
ments were as follows: 
In 1896-97 a natural sandy pine land soil, supposedly poor, was 
used (110 pounds per box). In 1898-99 quartz sand containing from 
99.5 to 99.7 per cent SiO, was employed (46 pounds per box with 12 
pounds of coarse material for drainage). In 1899-1900 for some 
crops the same sand which had been used during the previous year 
after removing roots and organic matter and for some crops an equal 
quantity (46 pounds) of fresh sand. | 
Adequate quantities of readily available nitrogen and potash car- 
riers were added in each case and the same amount of phosphoric 
acid was added to each can or box in the forms given in the table. 
The effect of these phosphates on the yield of several orders of plants 
was studied by running each treatment in duplicate. 
iN. Y. Agr. Expt. Sta., Tth Ann. Rept.. pp. 356-363 (1889); Sth Ann. Rept., pp. 
256-258 (1890) ; Cornell Buls. Nos. 143 (1898) ; 1G6 (1899) ; 182 (1900).; 201 (1902). 
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