THE RELATION OF CERTAIN NUTRITIVE ELEMENTS TO 
THE COMPOSITION OF THE OAT PLANT 
James Geere Dickson 
(Received for publication January 8, 1921) 
The study of the relation of various environmental factors to the com- 
position of plants received its greatest stimulus when Emil Wolff published 
his studies on the analysis of plant ash to determine what constituents were 
to be found therein. Since that time an enormous quantity of literature 
has been contributed to the study, yet the work has never been satisfactorily 
concluded. Climate, availability of nutrients, water supply, and various 
other physico-chemical factors influence the composition of the straw 
greatly and of the grain or reproductive parts to a lesser extent. 
W. Wolff (1864, 1865) and Hellriegel (1869) reported the first extensive 
study on the relation of mineral salts to plant composition. Not, however, 
until the voluminous work of E. Wolff (1871), did the study receive the 
attention of many of the best chemists in Germany. This pioneer study 
stimulated research until the investigations were taken up from several 
rather different yet related lines. 
Von Heinrich (1882), Atterberg (1886, 1887), Dikow (1891), Helmkampf 
(1892), Stahl-Schroder (1904), Jakouchkine (191 5), and Sawine (19 16) 
sought by analysis of the whole plant or of its several parts to determine the 
availability of the mineral nutrients in the soil. On the other hand, Lawes 
and Gilbert (1856, 1884), Pagnoul (1875), and more recently LeClerc and 
Leavitt (19 10), Raymond and Paturel (1910), Hartwell and Wessels (1913 
a, b), Tretiakov (1913), Headden (1916 a, b), Davidson and LeClerc 
(191 7), and Maschhaupt (191 8) have studied the relation of environmental 
factors, chiefly fertility and climate, to the composition of the whole plant 
and of its respective parts. Grifiiths (1884), Takeuchi (1908), Chirikov 
(1914), and Waynick (1918) have extended the investigations still farther 
by studying the effects of the addition of specific substances, in many cases 
in varying amounts, to the composition of the plant. Kossowitsch (1909) 
has taken still another phase of the problem, investigating the composition 
of different plants grown under the same nutritive conditions. 
The work referred to up to this time has been primarily a study of the 
influence of these factors upon the composition of the ash constituents. 
Although it is not within the scope of this paper to discuss the relation of 
environmental factors to the organic composition of the plant, yet the 
study would not be complete without reference to the important literature 
on this phase of the investigation. Thacher (1913, 1917), Grisdale (1913), 
256 
