UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 600 Ys 
Contribution from the Bureau of Soils ‘yy a WS y 
MILTON WHITNEY, Chief y 
Washington, D. C. PROFESSIONAL PAPER December 10, 1917 
THE RELATION OF SOME OF THE RARER ELE- 
MENTS IN SOILS AND PLANTS. 
By W. O. Ropsinson, L. A. STEINKOENIG, and C. F. Miirr, Scientists in 
Chemical Investigations. 
CONTENTS. 
Page. Page. 
MEEOMMCtION SS 2s )es |S ee eS 1: | Amalyticaleresults22 722s te es eee 8 
Selection and preparation of the Appen Gix 22266 Sohn regis ede et 17 
Sets we ee Se ae 4 Analytical methods____________ 17 
Description of the samples_-_____~_ 5 
INTRODUCTION. 
In an earlier publication’ there were given the results of the 
examination of a number of important American soil types for the 
presence of certain of the rarer elements for which reliable methods 
of analysis had been developed and which it seemed likely might 
occur in soils. 
When this work was completed, it seemed desirable to know 
whether the rare elements found in soils occurred in plants grown on 
these soils. If a certain element, though present in minute amounts 
only, is absorbed by a particular species of plant in relatively large 
quantities and occurs in other plants in traces only, it would seem 
reasonable to assume that the element in question has some physio- 
logical function. In such cases the element must be in the soil in 
sufficient quantity or added in the form of fertilizer. There is but 
little in the literature of plant physiology pertaining to the physio- 
logical action of the rarer elements in plant tissues. Frequently 
when culture experiments have been carried on the elements tested 
have been found toxic. 
Some of the rarer elements very much resemble the commoner 
ones in chemical reaction. Notable examples are the resemblarices 
of vanadium and phosphorus and of rubidium and potassium. 
1 Bul. 122, U. S. Dept. of Agriculture (1914). 
11192°—17—Bull. 600——1 
