504 
seem to show that the addition of nitrogen to the phosphorus and 
potassium treatments causes the higher nitrate content of those soils. 
TABLE 7. 
Nitrates After Two Weeks Incubation and Addition of (NH): SO: 
(Parts per million calculaizd on a Dry Besis) 
| | | / 
Plot | | 
No. Mar. | April May | June | July Aug. | Sept. Oct Nov. Total Ave 
; ; | 
| | | | / 
1 35.60 28.50 41.61 50.51 | 114.50 | 17.50 19.70 | 13.80 | 21.22 | 342.94 38.10 
2 37.40 | 36.10 55.12 | 108.20 | 187.00 50.70 25.07 36.08 41.45 | 577.12 64.12 
3 36.00 37.40 60.51 | 108.00 | 178.00 | 60.45 | 36.09 44.52 47.00 | 607.97 67.55 
4 31.80 37.00 39.21 | 44.51 | 100.00 27.25 | 24.61 16.25 33.90 | 254.53 39.39 
5 | 29.40 32.70 30.22 36.01 97.50 16.11 14.90 ibys 20.02 | 290 11 32.23 
6 | 33.60 31.40 38.90 | 35.82 | 109.00 28.12 21.68 14.17 | 21.40 | 334.09 37.12 
7 | 34.60 28.80 32.81 | 36.23 | 146.00 | 21.91 15.40 16.35 | 26.28 | 358.38 39.82 
8 35.80 35.00 39.23 52.01 | 168.90 | 29.92 | 16.75 15.15 22.18 | 404.94 44.99 
9 | 35.40 27.00 39.12 35.94 | 173.00 41.20 | 20.25 16.00 | 18.00 | 406.21 45.13 
10 35.40 24.10 39.32 41.03 | 147.50 34.50 | 24.21 12.05 20.10 | 378.21 42.02 
ll 32.80 28.10 30.01 42.81 | 103.50 28.39 | 18.61 14.00 | 19.95 | 318.17 35.35 
12 33.10 36.10 38.92 | 35.50 | 100.50 | 37.10 | 27.25 12.02 | 15.95 | 336.44 37.38 
13 34.80 | 20.00 39.00 39.50 | 132.00 | 29.81} 14.80] 14.15 | 18.15 | 337.21 37.47 
Total| 445.70 | 422.50 | 523.98 | 666.07 |1,747.40| 422.96 | 279.32 | 237.79 | 325.60) |e See 560.67 
Ave..| 34.28 2.50 40.30 | 51 23 | 134.41 2.53 | 21.48 18.28 25.04 | 390.05 43.23 
| | 
NITRATES AFTER Two WEEKS INCUBATION PLUS AMMONIUM SULPHATE. 
EXPRESSED IN PARTS PER MILLION PER GRAM OF Dry SoIL Table 7). 
This test was intended to show the efficiency of the different soils in 
changing a soluble nitrogen compound into nitrate nitrogen. Any lack 
of nitrogen was supplied and variations in the amounts of nitrates 
formed in the soils were dependent on their ability to change ammonia 
to nitrate. However, this ability cannot be directly attributed to the 
original soil treatments as their power may have been changed because 
of the influence of the nitrogen added. 
The monthly averages of the nitrates for the plots in this test 
were high for May, June, and July, low for September, October, and 
November and medium for March, April, and August. The manure 
plots Nos. 2 and 3 were high throughout the period with a general aver- 
age of 65.83. The cow manure plot, No. 3, was slightly higher, for the 
period, than the horse manure plot, No. 2. The most noticeable varia- 
tion between these manure plots and the other soils in the study oc- 
curred in October and November when the manure plots were nearly 
twice as high as any other plot. 
Variations among all other plots were small. The range for any 
month was usually less than fifteen parts per million. The range of 
averages for the period was from 32.23 for check plot No. 5 to 45.13 
for check plot No. 9. 
The average for the check plots Nos. 1, 5, 9 and 13, was 38.23 
for the period. The average of the plots Nos. 4, 6, 8, and 11 receiving 
nitrogen in their treatments was 39.21 for the period. The average 
of plots Nos. 10, 12, and 7 receiving phosphorus, potassium, and phos- 
phorus and potassium respectively, was 39.74. Although the average 
for the check plots was slightly lower than for the treated plots the 
