A Study or Codorado Wheat 
7 
best results by shallow plowing. The result of this in our case was 
that the land, to any depth greater than an average of six inches, 
was as firm as it had ever been with a slight plow sole at about six 
inches. My aim was to plow this land to the greatest feasible depth 
and subsoil it to a depth of eighteen inches in the fall of 1912, allow 
it to mellow and settle during the ensuing winter and plant it in the 
spring.' I was not able to get this done, so I was compelled to plow 
and subsoil in the spring. As the season was quite wet, this made 
my planting late. Of the three sections of land on which I am mak¬ 
ing my experiments, I turned two of them to a depth of twelve 
inches and subsoiled four inches deeper, sixteen inches in all. The 
other section was turned to a depth of nine inches but was not sub¬ 
soiled. All the advantages of fall plowing were lost, but I saw no 
disadvantages in the mechanical condition of the seed bed arising 
from the spring working of the soil. I did not do this spring plow¬ 
ing because I wished to, but because I had to begin some time to 
get the land in the condition that I desired. 
This plowing turned up some six inches of subsoil and put it 
on top. Ordinarily this would be very disadvantageous, but in our 
case the subsoil is capable of making just as kind a soil as the sur¬ 
face portions, as there is no very great difference between the soil 
and subsoil from a chemical standpoint, but from a biological stand¬ 
point there is a very great difference in favor of the surface soil. 
So far as this feature was concerned, my deep turning of the soil 
was decidedly disadvantageous, but in another respect it was very 
much to my advantage. This land had been planted to oats and 
barley the preceding season; both crops had grown luxuriantly, 
lodged badly, were harvested late and there was a very heavy loss 
of grain. Even with my deep plowing there were many spots where 
the oats and barley crowded out the wheat. Had it not been for 
the deep plowing the oats and barley would have been very much 
worse. This land is a somewhat clayey loam 1 with visible deposi¬ 
tion of calcium carbonate and sulfate below the depth to which it 
previously had been plowed. On irrigating, it takes water readily, 
and on drying cracks badly. This last factor cannot fail to be of 
considerable importance, for these cracks often gape open as much 
as one-half or even three-quarters of an inch and extend into the 
ground for several inches. Many of them are as much as four inches 
deep. I cannot state that I saw any decidedly injurious effects from 
this cracking, but the segments of soil formed or separated from 
one another by these cracks dry out rapidly. 
We made no study of the bacteriology of the soil but we know 
that the surface soil that we turned under possessed a decided abil¬ 
ity to fix nitrogen and convert it into nitrates. From this stand- 
