Jan 13, 1923 
Effect of Inorganic Nitrogen on Wheat 
65 
available nitrogen at the time of heading was distinctly physical, which 
may be the reason why no such correlation was found. It would seem, 
therefore, that there is no direct correlation between the protein content 
and the weight per 1,000 kernels and the weight per bushel of wheat. 
PROTEIN CONTENT 8 
The results reported in Table V show that the application of nitrogen 
at the second stage gave the highest nitrogen contents. Although series 
A proved to be somewhat irregular, of the nine nitrogen canriers used 
six were consistent with the general tendency. Series B was wholly 
consistent. The irregularities, as well as the fact that increased nitrogen 
contents were obtained from the first and third application, can be 
explained in the same way as the irregularities with reference to yellow- 
berry. The increased nitrogen content, which resulted from the first 
stage application, was due to the fact that not all the nitrogen was used 
up during the first stage. The increased nitrogen content resulting from 
the third stage application can be explained by the lack of uniformity in 
transition from one stage to another, already discussed. The same 
causes are responsible for the fact that the increases in nitrogen obtained 
from second stage applications are not as sharp as they were in the 
bureau’s previous experiment. 9 While the first application showed an 
increase in nitrogen, due to the fact that not all the applied nitrogen had 
been utilized during the first stage, the nitrogen content from the plots 
which received their nitrogen at the second stage did not reach its proper 
height, for the reason that part of the nitrogen of this application was 
utilized in making vegetative growth as was shown by the increased 
yields from these plots. 
The nitrogen content of the straw (Table VI) shows the same tenden¬ 
cies as that of the grain. 
PHOSPHORIC-ACID CONTENT 
Headden 10 found that the application of sodium nitrate to wheat 
plots caused a depression in the phosphoric-acid content of the grain. 
In the bureau’s previous experiment, 11 where sodium nitrate had been 
applied on a number of plots at the three stages of growth, no correla¬ 
tion between the application of nitrogen and the phosphoric-acid content 
was disclosed. In the present experiment, however, a correlation is 
observed between the application of nitrogen and the phosphoric-acid 
content, both in the grain and in the straw. As seen from Table V, the 
phosphoric-acid content in the grain from the plots which received their 
nitrogen in the first and second stages is consistently lower than that in 
the grain from the plots which received it at the third stage and the 
controls which, in this case, may include all the plots which received 
chemicals other than nitrogen carriers. The only exceptions are the 
8 It is understood that the term “protein’.’ represents values obtained by multiplying the nitrogen con¬ 
tent, determined in the regular way, by certain factors. These factors vary with the substance analyzed. 
In this paper the factors used were 5.7 for the grain and 6.25 for the straw. It has been the general practice 
in agricultural literature to express the nitrogen values in terms of protein. This practice has been estab¬ 
lished because of the fact that the main bulk of the nitrogen in mature plant substance is protein m charac¬ 
ter and because of the accepted food value associated with proteins. 
9 Davidson, J., and LeClErc, J. A. op. cit. , 
18 Headden, W. F. a study op Colorado wheat, part in. Colo. Agr. bxp. bta. Bui. 219, 131 p. 
1916. 
11 Davidson, J., and LeClerc, ,T. A. op. cit. 
