14 Colorado Experiment Station 
oi the wheat. Uur record is that it does not change the composi¬ 
tion of the wheat produced, and further, that the increase in the 
crop was very moderate indeed. The crops ranged from 17 to dU 
bushels to the acre, so this was not due to the production of a 
great big crop on the unmanured plots that was hard to make 
any bigger. 
The fact is that two experiments made in exactly the same 
manner on two different, perhaps very different pieces of land, 
may give very different results, and this is the explanation for 
the contradictory results in this case; besides, farmyard manure 
may be young or old, of one kind or another. VVe believe that 
the wheat plant can use practically only one form of nitrogen in 
building Its tissues and this form is nitric acid which is present 
in the soil as nitrates. If this be true, then all of the organic 
nitrogen present in the manure must be changed into this form 
before it is of any use to the wheat plant. This change is called 
nitrification, and the ability of soils to bring this about varies 
greatly, and the effects of nitrogen applied to wheat land in the 
form of farmyard manure will vary just as this power of the land 
varies. This is why experiments with farmyard manure on wheat 
on different lands have given such different results. 
With us the practice of cultivating fallow gives excellent 
results for two reasons: First, because the amount of nitrogen in 
the soil actualy increases by amounts as great as are involved in 
the different characters of the crops, and second, by the change 
of this organic nitrogen into a usable form for the wheat. 
EXAMPLES OF RESULTS OF FALLOWING 
When we have no bad weather or other accidents to interfer 
with the development of the wheat, it is perfectly proper to 
compare the gluten in two wheats as the measure of their quality, 
and likewise, as a measure of the nitrogen used by the plant, so 
if we compare the amount of the gluten in two samples of the 
same variety of wheat grown under equally favorable coiid.Uuiis 
of soil and climate, the one having the more liberal supply of 
usable nitrogen will contain the larger amount of gluten. The 
best illustration Hiat I have of this is presented by two samples 
of Red Fife wheat grown on pieces of land separated by a road¬ 
way 16 feet wide. The land on the west side had been cultivated 
fallow, that on the east side had been cropped to oats the preceding 
year. These plots were planted to Red Fife wheat. That grown 
on the fallowed land was flinty and contained 17.14 percent of 
protein, while that grown on the cropped land was affected by 
yellow-berry and carried 12.93 percent protein. I also have a pair 
of samples of Marquis wheat, but they are not so thoroughly 
