Dec. 15,1925 Mineral Composition of Sunflowers Grown for Silage 1193 
RESULTS PROM SPRING WHEAT 
The plot growing spring wheat, continuously cropped, also shows 
a lower moisture content of the soil to a depth of 3 feet and a lower 
protein content of the grain. Here again the soil containing the 
higher percentage of moisture produced the largest yields and a grain 
of higher protein content. In studying Table I it must be observed 
that in each year the plots containing the highest percentages of 
available nitrogen produced wheat of a higher protein content, one 
exception only being noted. This occurred in 1915 when the alter¬ 
nate fallow and crop plot produced grain having a nitrogen content 
of 2.06 per cent and the continuously cropped plot produced grain 
having a nitrogen content of 2.13 per cent. The results of that year's 
experiment thus show but very little difference in the available 
nitrogen, though the difference is slightly in favor of the alternate 
fallow and crop. An examination of the writer's data indicates that 
in that year the average available nitrogen in the first foot of soil 
was 2.24 parts per million for the continuous cropping and 2.19 for 
the alternate fallow and crop plot. It is possible that the available 
nitrogen in the first foot exerted the greatest influence on protein 
formation, but the difference in the quantity of nitrates in the soil 
was too slight to account for the difference in amount of protein 
formed in the wheat. The fact that the alternate fallow and crop 
flot gave not only a higher average yield but also a higher average 
percentage of nitrogen content in both grain and straw shows at 
east the influence which available nitrogen exerts on the crop and 
its composition. 
MOISTURE AND NITRATES IN SOIL AS RELATED TO YIELDS AND PROTEIN CONTENT 
Winter Wheat 
In order to present more clearly the influence of moisture and 
nitrate nitrogen in the soil upon yield and protein formation of 
wheat, the data have been charted showing the difference in the 
moisture content of the soil at different periods of plant growth and 
also the different amounts of nitrate nitrogen for the same periods 
(figs. 1 and 2). Figure 1 shows a variation of less than 1.5 per cent 
in the moisture content of the soil from the time the winter wheat 
began to grow in the spring until it was ready to harvest. The 
greatest variation occurred at the time of the second sampling, May 
23, and before the winter wheat had made sufficient growth for taking 
moisture from the soil at its maximum rate. After the sampling on 
this date, there is no period in the growth of the wheat when the 
moisture content varies enough to account for any difference in the 
yield or composition of the grain. These differences must then be 
explained by some other cause. Figure 2 indicates that there is a 
wide variation in parts per million of nitrate nitrogen in the soil for 
the same plots continuously and alternately cropped. The continu¬ 
ously cropped plots show a lower percentage of nitrate nitrogen at 
each sampling than do the alternate fallow and crop. The very 
fact that both grain and straw contain a higher percentage of nitro¬ 
gen suggests very strongly that the difference m the quantity of 
nitrate nitrogen present in the soil is also largely responsible for 
the difference in yields. 
