A Study ot Colorado Wheat 
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formed during the 40 days of our experiment, 15.79 per million, 
is one and a half time the amount applied in some of our experiments, 
Avhich was sufficient to determine the character of the growth of the 
plant and the physical and chemical characteristics of the wheat pro- 
'duced. 
EFFECT OF FALLOWING ON NITROGEN CONTENT 
The bearing of these facts upon the fallowing of our land has 
been pointed out elsewhere, but we will point it out again. We have 
repeatedly given analytical data to illustrate this fact. Perhaps as good 
an illustration of the effect of fallowing upon the amount of nitrogen 
accumulating in the soil as we have, is an experiment made in 1915. 
On 3 August, 1915, we found that land cropped to wheat contained 
nitrogen as nitrates equal to 46.9 pounds of sodic nitrate in the top 
4 feet of soil, whereas the same land from which the wheat had been 
removed as soon as it came up contained nitrogen as nitrates equiv- ‘ 
alent to 285.5 poi-ii'ids per acre taken to the same depth. In this case 
there is 6 times as much nitrogen present as nitrates in the fallow land 
as in the cropped land. 
We are by no means compelled to depend upon our analytical re¬ 
sults to establish this fact, though they constitute more direct proof than 
the crops grown on ground fallowed the preceding year. In order to 
avoid the statement of several analyses I will state that the results, of 
our experiments show that nitrate applied to wheat increases the nitro¬ 
gen and depresses the phosphorus contained in the grain. With this 
explanation the following data will suffice for our present purpose. 
A sample of Red Fife grown on land fallowed the preceding year, 
1912, contained of nitrogen 3.008 percent and of phosphorus 0.414 
percent. The same variety of wheat grown on a check plot which had 
been cropped the preceding year, 1912, contained of nitrogen 2.270 
and of phosphorus 0.453 pei'cent. The difference in the composition 
of these grains grown on plots of land separated by a 16-foot alley 
was due to the nitrogen accumulated in the one plot during its year 
of fallow, whereas the cropped land had been deprived of this ad¬ 
vantage. This is probably the correct explanation for the flintiness 
of our dry-land wheats rather than a scanty supply of water. The 
dry-land practice is to cultivate fallow one year to facilitate the stor¬ 
age and conservation of moisture which at the same time increases 
the supply of nitrates. 
There is another test which we can apply to these dry-land 
wheats which will lead us to the same conclusion. We have seen that 
the addition of nitrogen to the soil in the form of nitrates produces 
flinty berries and that the lack of it produces the condition designated 
