1907. | Nitrification in Acid Soils. 205 
‘was introduced into the culture solution. For the last two series the sample 
o 
' . 
’ 
> SS 
o> a 
of soil was extracted with an auger 2 inches in diameter having a slot in 
the side; at the selected depth in the slot a clean surface of soil was exposed 
and a small sample, approximately 0°5 gramme, was picked out with a sterile 
spatula and introduced into the culture flask, the operation being carried out 
in the field. 
Number of Times reacting after Four Weeks’ Incubation. 
Unlimed portion. Limed portion. 
Depth. — ~ oo ares re 
cm, : No nitrate , o nitrate 
Nitrate. ee Ce rary Nitrate. NE BFE. 
Plot 3.—Unmanured. 
10—15 7 Uf ih 0 
30 2 3 1 0 
45 0) 1 
75 0 1 
105 0 1 
135 0 1 
Plot 4-2.—Ammonium Salts and Superphosphate only. 
10—15 2 vi 1 2 
20—30 5 1 1 1 
45 I 0 0) 1). 
75 0 1 0 E 
105 0 1 0 1 
135 0 if 0 Vi 
Plot 9.—400 Ib. Ammonium Salts and Complete Minerals. 
10—15 0 11 3 A. 
20—30 2 3 2 Z 
50 it 0 iE 0. 
70—76 ” 2 0 0 1 
105 0 1 0) 1 
135 0 ul 0 ai 
Plot 11-1.—600 Ib. Ammonium Salts and Complete Minerals. 
15 0 2 0 2 
30 0 2 0 2; 
45 1 0 0 1 
75 0 i 1 0 
105 0 it 0) I 
135 0 1 0 1 
Plot 14.—550 lb. Sodium Nitrate and Complete Minerals. 
15 
30 
45 
75 
105 
135 
SOM wee 
RKrEOSOOO 
C. The Nitrification of the Soils in Bulk. 
Large samples,of the soil down to six depths of 9 inches were taken in 
October, 1906, and one portion of each was at once dried at a temperature of 
R2 
