296 Proceedings of Indiana Academy of Science 
apparently unaffected by moisture, temperature or soil treatment. 
Some factors as yet uninvestigated probably account for the fluctuation. 
The small number of molds in soil compared with bacteria may not 
necessarily mean that they are less important and certainly will not 
prove that they are unimportant. 
Greaves and Carter (12) found in their study of twenty-two soils 
that each one gave a maximum ammonification when its water content 
was sixty per cent of its water holding capacity. Nitrification was at 
its maximum at fifty or sixty per cent and varied with specific soils. 
Whiting and Schoonover (13) conclude that soil treatment is a very 
important factor in nitrate production. 
HISTORY OF THE PLOTS. 
The field where this experiment was carried on is a part of the 
Purdue Experimental plots and is located on a brown silt loam under- 
laid with gravel at a depth of about two feet. It has been classified by 
the United States Department of Soils as a Sioux Silt Loam. 
The field consists of thirteen one-sixteenth-acre plots. The first, fifth, 
ninth, and thirteenth plots are untreated or check plots and the other 
nine received the treatments shown in Table 1. The crop rotation of 
the field consists of corn, oats, wheat, clover and timothy. In 1920, the 
year this experiment was conducted, the field was in oats followed by 
fall sown wheat. 
This field was laid out in 1889 and the different treatments were 
begun in 1890. A different system of treatment was used at first and 
it was not until 1918 that the present treatment was started, the field 
having received no treatment during 1917. The object of the change 
of treatment, which involved only the amount and method of applica- 
tion, was to secure more efficient use of the nitrogen applied. 
TABLE 1 
Series [V East—Field 6—Purdue Farm 
Fertilizer Treatment in Pounds Per Acre 
Plot No.) Corn Oats Wheat Clover Timothy Treatment 
1 None None None None None Check 
2 12,000 6,000 6,000 None 6, 000 Horse Manure 
3 12,000 6,000 6,000 None 6,000 Cattle Manure 
4 N 30 N 15 N 15 None N 15 NG Phe 
P 30 1 Ed ha) PP 5 Seta a eae Pane 
K 30 Mee 15 Kodo nae K 15 
5 None None None None None Check 
6 N 30 N 15 N 15 None N 15 N. P. — 
> Beso P 15 P 15 . P 15 
7 P 30 P15. |) Pp as None P 15 
K 30 K 15 K 15 ‘ rer K 15 —P. K. 
8 N 30 N 15 N 15 None N 15 N—K 
K 30 K 15 K 15 ea K 15 
9 None None None None None Check 
10 P 30 P15 Palo None P15 —P— 
11 N 30 N 15 N 15 None N 15 N — 
12 K 30 K 15 K 15 None K 15 —K 
13 None None None None None Check 
Rotation Corn, Oats, Wheat, Clover and Timothy— 
P=lbs. P.O; per acre. 
K=Ilbs. K.,O per acre. 
N=lbs. N per acre. 
