940 
Journal of Agricultural Research 
Vol. XXIV, No. II 
Richardson {i8) and Brewer (j) concurred that climate exerted the 
greatest influence. According to Wiley (jp, p. 244; 40) a cool climate 
and short periods of growth are favorable for high protein, while a warm 
climate and long periods of growth are favorable for low protein content. 
Jensen (6) expressed the opinion that a “continental climate” was 
favorable to the formation of a small grain of high nitrogen content. 
Schindler (19) concluded that a warm, moist climate prolonged the 
kernel development, resulting in a high starch and low protein wheat. 
Melikov (ij) gave heavy rainfall as the cause for low nitrogen content in 
wheat. LeClerc (9) deduced that the differences in composition for 
any one locality from season to season was due to varying weather con¬ 
ditions. The differences in composition of wheat analyzed by him for 
different localities were pronounced. Williams {41) stated that varia¬ 
tion in protein was independent of variety and of soil treatment. He 
ascribed it to seasonal influences. When the wheat was small or shrunken 
the protein content was high and vice versa. Thatcher, in a study cor¬ 
relating the protein content of wheat with the rainfall in various districts 
from which samples were taken, observed that the protein content 
varied inversely with the total rainfall (55). According to Deherain (5), 
slow ripening was favorable to a heavy yield of wheat with average 
gluten content, while hot summer conditions were favorable to rapid 
ripening and high gluten content. 
LeClerc {gyp. 202), in making a comparative study of the composition of 
wheat grown under arid and humid conditions, concluded from his 
experiments that the nitrogen content is higher in the wheat grown on 
the arid and semiarid land fiian it is found in wheat grown on humid and 
irrigated land. In other words— 
an excessive amount of rainfall or irrigation is always accompanied by a crop contain¬ 
ing a very low percentage of protein. 
IRRIGATION WATER 
Investigations pertaining to the influence of water on composition of 
grain have been carried on over a comparatively long period. The 
irrigation investigations in charge of the Utah Agricultural Experiment 
Station are especially valuable, and show how the nitrogen content 
of the grain is increased through the judicious use of water. The report 
of a progressive study of the nitrogen content of grain by Widstoe (57) 
in 1921 shows that large applications of water may increase slightly the 
percentage of protein in wheat.. The percentage of nitrogen in spring 
wheat decreases with the increased use of water, ranging from 15.26 per 
cent protein for 20 inches to 26.7 per cent protein for 4.63 inches. With 
applications of water ranging from 8.89 inches to 40 inches, the variation 
in nitrogen content is found to be irregular, but the 40-inch application 
of water shows higher protein than is found in the wheat receiving either 
21 or 30 inches of water. 
The time of applying the water appears to be very important, since 
Widstoe and Stewart {38) find that the protein content of wheat de¬ 
creased from 18.05 15-98 with the increased use of water 
after the middle of July. When water is applied before the first of 
July, the protein content of the wheat is increased. Stewart and Greaves 
{28) concur with LeClerc (9, p. 202) that wheat grown on arid non- 
irrigated land contains more protein than is found in wheat grown on 
adjoining irrigated land. Prianischnikov (17) finds that high per- 
