226 
Journal of Agricultural Research 
Vol. XI; No. s 
Table XVI.— Soil-moisture content of soils in different portions of a fairy ring , according 
to Molliard , igio 
Zone. 
Zone No. 
Percentage 
of soil 
moisture. 
Dead-grass zone, in mycelium. 
Ill. 
5 
7 
Outer stimulated zone, in mycelium. 
IV (p).. 
IV (s).. 
I. 
Outer stimulated zone, not in mycelium. 
21 
Inside, no mycelium. 
21 
Outside, no mycelium. 
V. 
21 
Bayliss (1911) found soils which contained mycelium difficult to wet, 
and mentioned a case where a rain which moistened the soil to a depth 
of 4 inches did not even penetrate the surface in the mycelium area. 
The conditions of moisture in the rings formed by Agaricus tabularis 
at Akron, Colo., in 1914, 1915, and 1916 are indicated in Tables XVII, 
XVIII, and XX. It will be seen from these tables that the soil in the 
ring is usually very dry in the middle and late summer. During the 
spring the soil in the ring differs but little from that outside or inside 
the ring, provided the previous season was not too dry and a sufficient 
rainfall had occurred during the winter or early spring to wet the whole 
soil mass. 
Table XVII. —Moisture content above or below the wilting coefficient in two Agaricus 
tabularis rings on May 16, 1914, Akron, Colo. 
Ring A. 
Ring B. 
Depth. 
Percentage of moisture. 
Depth. 
Percentage of moisture. 
outside. ; "r a ' 
Outside. 
In bare area, 
zone 3. 
Inches. 
1 to 3. 
3 to 6. 
6 to 12 . 
12 to 18. 
18 to 24. 
+ 17-8 
+ 17-3 
+ 4-4 
-j-10. 8 
+ 9. 1 
+ 18.6 
+ i 3 - 7 
“ 3-2 
“ * 5 
. 0 
Inches. 
i to 3. 
3 to 6. 
6 to 12. 
12 to 18.... 
18 to 24.... 
+23-3 
+ 16. 4 
4-13. 8 
+11. 5 
+ 13. 0 
+ 20. I 
+ 2. 0 
- 3-2 
+ 6.9 
+ 7. 6 
The difference in soil moisture may be due to several different causes. 
In the first place, if the soil is uniformly moist, the stimulated areas in 
the ring (zones 2 and 4, fig. 3) would be the first to become dry as a result 
of the stimulation of growth in these areas, since this increase in growth of 
grasses and other plants dries out the soil rapidly. When once the soil is 
dry, the mass of fungus filaments which permeate every particle of the soil in 
zones 3 and 4 in the case of the rings of the Agaricus tabularis (PI. 14, B) 
will not permit the penetration of water into these soils. In Table XVII 
the moisture content above and below the wilting coefficient is shown 
