3 °° 
Journal of Agricultural Research 
Vol. IX, No. 9 
Moll (40) even goes so far as to claim from his work that the season of 
the year is the principal factor in determining the biochemical transforma¬ 
tion in a soil, and Heinze (24) found that the number of organisms in a 
soil was highest in the summer months and lowest in the fall and spring. 
As already pointed out, the highest nitrifying power of a soil is not 
necessarily correlated with the highest nitrate content. The latter is 
highest in spring or early summer, while Vogel (62) found the former 
to be highest in October and November, after which there was a falling 
off until April, when it rose again, but not so high as in autumn. This 
corresponds fairly with the findings of Green (23) for the ammonifying 
powers of the soil. These findings, however, are contrary to those of 
Wojtkiewicz (66), who found the maximum number of organisms to 
occur in soil during the spring and the minimum in the winter. He also 
notes a correlation between the bacteria present and the amount of 
nitrates in the soil. 
Inasmuch as we have taken no samples while the soil was frozen, no 
attempt has been made to review the literature dealing with this very 
interesting phase of the subject. 
EXPERIMENTAL WORK 
NATURE OF THE EXPERIMENTAL FIELD 
The investigations were conducted on the Greenville farm, belonging to 1 
the Utah Experiment Station, which is located 2 miles north of the 
college farm. The soil of the farm is of a sedimentary nature, being 
derived from the weathering of the mountain range near by, which con¬ 
sists largely of limestone, quartzite, and dolomite. At the time of Lake 
Bonneville (19) the mountain streams poured their waters, loaded 
with the weatherings of these rocks, in the various stages of subdivision 
(gravel, sand, and silt) into the still waters of the lake. When the 
swiftly running water of the stream met the quiet water of the lake, the 
stream began to deposit its load. The gravel and coarser material 
being deposited first, gave rise to the well-defined deltas found at the 
mouths of all the larger streams. One of the best defined deltas is 
that on which the old college farm is located. The fine material, con¬ 
sisting mainly of fine sand, silt, and clay, was carried out farther into the 
lake, where it was gradually deposited. It is of this sedimentary material 
that the Greenville farm is composed. 
At the beginning of the investigation a soil survey was made of the 
farm in the following manner: Samples of soil were taken in foot sec¬ 
tions from each plot, the corresponding foot sections of these samples were 
thoroughly mixed and taken to the chemical laboratory, where they were 
subjected to chemical and physical analyses. 
Table II gives the chemical composition of the soil to the depth of 8 
feet. The method of analysis followed was that advocated by the 
Association of Official Agricultural Chemists (65). 
