480 
Journal of Agricultural Research 
Vol. V, No. ii 
Table I .—Extent of protozoan activity in greenhouse soils 
Lab¬ 
ora¬ 
tory 
No. 
Kind of soil. 
Fertilizer treatment. 
Termpera- 
ture. 
Moisture 
content. 
Presence of 
protozoa.** 
I 
Clay loam. 
20 per cent of compost -j- 
°C. 
20. 8 
Per cent. 
26. 65 
2 
3 
Shale. 
Clay loam. 
minerals. 
20 per cent of compost. 
20 per cent of compost; 20 
20. 9 
21. 0 
34 - 30 
26. 66 
S.C.t A.f 
4 
5 
Sandy. 
Clay loam. 
per cent of sand. 
20 per cent of compost. 
40 per cent of compost. 
21. 0 
24. 0 
26. 84 
36.27 
6 
Shale. 
20 per cent of compost; 30 
22. 7 
25* 17 
7 
Sandy loam.... 
per cent of sand. 
No mixture. 
21. 6 
22. 59 
S.c.t 
8 
Clay loam. 
20 per cent of compost; 20 
21. 1 
27 - 57 
9 
10 
11 
12 
13 
14 
.do. 
Sandy. 
.do. 
Sandy loam. 
Clay loam. 
per cent of sand. 
40 per cent of compost. 
20 per cent of compost. 
40 per cent of compost. 
.do. 
2b per cent of compost. 
20 per cent of compost + 
21. 1 
20. 8 
23. 0 
22. 7 
22. s 
24. 6 
35-75 
26. 59 
35-35 
3 1 - 28 
29. 10 
27. 90 
S.C.t 
S.c.t F.t 
s.c.t 
s.c.t 
15 * 
Shale. 
minerals. 
20 per cent of compost + 10 
21. 0 
3 1 * 75 
16 
Clay loam. 
per cent of sand. 
No mixture. 
19. 0 
20.3 
26. 21 
17 
20 per cent of compost -f- 
31. 07 
18 
Sandy loam.... 
minerals. 
20 per cent of compost. 
24. 0 
25.81 
19 
Clay loam. 
20 per cent of compost; 20 
24. 6 
25.09 
20 
...do. 
per cent of sand. 
No mixture. 
18. 0 
26. 60 
a S.C.=small ciliates; L-C.=large ciliates; F.=flagellates; A.=amebae; f=few; tt=“several; ttt==many. 
FIELD SOILS 
The extent of protozoan activity in field soils was studied in the same 
manner as the greenhouse soils. Samples of 14 field soils of different 
texture and tillage treatment were collected at a depth of 3 inches from 
the surface and brought to the laboratory in flasks. The temperature 
was in all cases noted. These were examined at once, each for half an 
hour, a new sample being placed on the slide every two minutes, as in 
the case of greenhouse soils. The moisture content was likewise deter¬ 
mined. The soils were sampled and examined under normal conditions, 
again two days after a fall of 1.69 inches of rain, and a third time five 
days after 1.69 inches of rainfall. The second sampling was made at 
that period, since it allowed the organisms sufficient time to excyst, if 
possible, when the moisture content of the soil was increased. Like¬ 
wise, the third examination was made five days after the heavy rainfall, 
for if the protozoa excysted and were washed to a lower level in the 
soil, this lapse of time allowed them to return to their normal level in 
the soil. Each soil was subjected to a half-hour’s examination at every 
