8 
Colorado Experiment Station 
point the deep plowing was a decided disadvantage, if we may judge 
from the bacterial counts made on samples of this soil compared 
with those made on samples of soil from the same field which had 
not been plowed so deep. 
The only object which I had in breaking up this land was to 
put it into what I considered good condition. The other and prin¬ 
cipal immediate objects have been mentioned, one of them was ad¬ 
vantageous and the other probably not. The former was the sup¬ 
pression of the barley and oats and the other the diminution of the 
bacterial flora of a beneficient character. While we have reason to 
believe that the occupation of the land by cultivated crops influences 
the bacterial activity in the soil, both by the removal of the products 
formed, and perhaps also by being directly inimical to their develop¬ 
ment, still such activity continues with greater or less intensity. In 
this particular soil we have found nitric nitrogen corresponding to 
160 pounds of sodic nitrate in the surface two inches of the soil and 
342 pounds in the first foot of soil. This was in fallow spots 
occurring in a stand of beets. Perhaps the results obtained with 
land after cropping, compared with land cultivated fallow, may be 
more acceptable. The cropped land had been planted to wheat 
which was harvested in early August. Immediately after harvest 
the stubble was irrigated and disked and allowed to rest till October 
when it was plowed and harrowed. The samples were taken from 
both sections 4 December. A part of the cropped land had received 
a dressing of phosphorus as superphosphate, and another of potas¬ 
sium as muriate. These facts make a very marked difference. The 
section cultivated fallow throughout the season contained nitric 
nitrogen equivalent to 518 pounds of sodic nitrate in the surface 
foot. The cropped land, which had received a dressing of phos¬ 
phorus, contained 257 pounds of sodic nitrate taken to the same 
depth while that which had received the potassium contained 184 
pounds. There is no question but that this is the result of fixation 
and nitrification in this soil and the differences show the effect of 
cropping on the one hand, though modified by the cultivation re¬ 
ceived after the removal of the crop, and cultivation fallow during 
the whole season on the other hand. The results also indicate the 
favorable effect of the application of phosphorus upon the bacterial 
activity of the soil. The application of 518 pounds of sodic nitrate 
per acre to wheat, immediately after sowing, would almost certainly 
lodge it and give small-grained, shrunken wheat, even if all other 
conditions were ideal. The consideration of these facts is impor¬ 
tant in our agriculture. I do not think that this question is as im¬ 
portant to all other sections of this country as it is to us, but I 
believe it to be of very considerable importance to almost all sections 
