JOURNAL OF AGMffllTiAL BEAM 
Vol. XI Washington, D. C., November 19, 1917 No. 8 
REACTIONS OF THE PHOSPHORUS OF THE THICK¬ 
ENED ROOT OF THE FLAT TURNIP 1 
By Burt L. Hartwell, Directory Agronomist, and Chemist; F. S. Hammett, form¬ 
erly Assistant Chemist; and P. H. Wessels, Associate Chemist, Agricultural Experi¬ 
ment Station of the Rhode Island State College 
INTRODUCTION 
In earlier publications of the Rhode Island Agricultural Experiment 
Station (4, 7) 3 it was shown that the percentage of total phosphorus 
in flat-turnip roots (Brassica rapa L.) grown in different soils generally 
varied in the same direction as the variation in the amount of phos¬ 
phorus which was available to the plant. The work herein recorded repre¬ 
sents a study of the reactions, to various reagents and treatments, of 
different portions of the phosphorus in turnip roots, mainly for the 
purpose of ascertaining whether the variation in the percentage of 
phosphorus in roots from different soils is limited to certain of the groups 
of phosphorus compounds or is distributed proportionately among 
them all. This information was expected to throw light upon the ques¬ 
tion as to whether a determination of the total amount of phosphorus, 
or the amount in some particular group of phosphorus compounds, 
would be most useful in attempting to ascertain whether or not there 
existed sufficient phosphorus at the disposal of the plant. 
ANALYSIS OF DRIED TURNIPS 
To secure preliminary indications, the following work was done in 
1907 with samples of turnips from different localities where there were 
found by soil tests to be wide differences in the amount of available 
phosphorus. 
Dried turnips which had been ground to particles less than 1 mm. in 
diameter were first extracted with ether in a Soxhlet apparatus. As 
scarcely more than traces of phosphorus proved to be soluble in this 
solvent, the ether was removed, and the extraction continued with 95 
per cent alcohol. These two extracts were united and evaporated and 
1 Contribution No. 235 from the Rhode Island Agricultural Experiment Station. 
2 Reference is made by number to “ Literature cited,” p. 370. 
Journal of Agricultural Research, 
Washington, D. C. • 
ko 
( 359 ) 
Vol. XI, No. 8 . 
Nov. 19, 1917 
Key No. R.I.—I 
