A Study of Colorado Wheat 
33 
bushel” synonymously. The weights per bushel given for the season 
of 1879 range from 2.7 to 5.4 pounds below the average for wheat 
grown under the same conditions of manuring for the preceding 27 
years. That this is whatf is understood by quality in this case, seems 
apparent from the manner in which they refer to it. They say: 
“The defect in weight per bushel of the dressed com was great under all 
the conditions cited.” 
“Lastly, great as was the deficiency in the produce of com, and in the 
weight per bushel of dressed com, under all the conditions, the proportional 
deficiency of straw was much less.” 
After discussing the conditions under which the crop of 1878-79 
was grown they add: “Thus, the! plant, which luxuriates in a compara¬ 
tively dry soil and climate passed its whole existence under exactly op¬ 
posite conditions; and the result was only what was to be expected.” 
“It has of course long been known that an excess of wet is injurious 
to the wheat crop, but it is only comparatively recently that one at least 
of the material causes of the adverse influence has been made out; namely, 
the great loss of nitrogen carried off by drainage in the form of nitrates.” 
These authors clearly hold that the weather conditions, especially 
the mean temperature and rainfall, exercise a big influence upon the 
yield and quality of wheat, meaning by quality, primarily, weight per 
bushel. They further assign as one cause of this, the removal of nitra¬ 
tes by the leaching action of excessive rainfall. The same authors re¬ 
turn to this subject in a subsequent article ‘‘On the Continuous Growth 
of Wheat, etc., from 1864 to 1883”.* 
“We find the two crops running a parallel course, showing great differ¬ 
ences in their yield as the seasons are favorable or unfavorable. The Roth- 
amsted soil, like a great many cultivated soils, contains a large amount of 
mineral food of plants: it also contains organic nitrogen, that is to say, 
nitrogen in combination with carbon, the residue of previous vegetation. 
This organic nitrogen does not appear to be available as food for the wheat 
plant, but every year a certain amount of it is converted into nitric acid, 
which combines with the lime in the soil. In this state it is very soluble in 
water, is readily washed out of the soil by heavy rain, and, further, is a 
most important and essential food of the wheat plant.” 
“The amount of nitric acid formed each year will vary, the formation 
being the most rapid in the hottest weather, provided the soil is sufficiently 
moist. The amount of nitric acid which the wheat crop can take up will 
also vary, and in a cold and wet winter much will be washed beyond the 
reach of the roots of the plants.” 
* Rothamsted Memoirs. Vol. VI., 3 rd Article, p. 44 . This originally appeared 
in the Jour. Roy. Ag. Soc. Eng. Vol. XX, s. s. Part, II. 
