228 
Journal of Agricultural Research 
Vol. XI, No. 5 
the effect of the stimulated growth of vegetation on the reduction of soil 
moisture. The soil in the ring is first to be dried below the wilting point. 
Table XIX. — Soil-moisture content above or below the wilting coefficient in Agaricus 
tabularis rings in igi6, Akron , Colo. 
Sample No. and location. 
Ring 8, 
June 12. 
Ring 6, 
June 21. 
Ring 7, 
June 26, 
Ring B, 
June 2S. 
Average. 
1, outside (see fig. 13 ). . 
— O. 2 
+0.3 
+ 3 - 2 
+4- 8 
+ 2. O 
2 , youngest mycelium. 
+ * 5 
-2. 3 
-4. I 
-1.8 
- 1.9 
3, mycelium densest driest. 
-1. 7 
. 0 
-2. 5 
- 2.3 
- .6 
4, below No. 3. 
— 1. 1 
-1. 5 
-I. 7 
- .6 
— 1. 2 
5, old dying mycelium . 
- .6 
—2. 2 
-I. 4 
-2. 5 
-r. 7 
6, inside . 
-2. 5 
- .8 
-4. I 
-2.8 
—2. 6 
Table XX.-—. Moisture content above or below the wilting coefficient in a Calvatia cyathi - 
formis ring in IQ15, Akron , Colo. 
June 26. 
July 13 . 
Ring No. 
Depth 
of soil. 
Outside, 
zone 5. 
In stimu¬ 
lated 
area 2. 
Inside, 
zone i. 
Outside, 
zone 5. 
In stimu¬ 
lated 
area 2. 
Inside, 
zone 1 . 
Ring s. 
Feet. 
I 
+ 2. 2 
“ 1-3 
+°. 5 
-0.8 
— 2. 6 
— 1. 2 
Do. 
2 
+6. 4 
+ 1. O 
+ 5 - 5 
+ 3-3 
-2.9 
+ -7 
Do. 
3 
+6.8 
+ 1. 7 
+ 3 - 5 
+ 4 * 1 
-2.8 
+2. 7 
For the purpose of studying the penetration of water both into the 
mycelium infected soil and into the natural sod outside, a strip about 9 
meters long was selected on the edge of a ring of Agaricus tabularis 
where the zones were well defined. Holes were made 6 inches deep with 
a soil tube. They were made in rows 1 meter apart, consisting of three 
holes each. One row was outside in the natural sod (fig. 3, zone 5), the 
next row at the border between the withered (fig. 3, zone 4) and bare 
areas (fig. 3, zone 3), and the third row in the bare area. Two-liter flasks 
of water were then inverted into the holes to determine the rate of pene¬ 
tration (PI. 23,A). The results are given in Table XXI. 
In both records the number of cubic centimeters of water that pene¬ 
trated into the soils was much greater in the natural sod outside the ring 
and least at the border line between the withered and bare areas where 
the mycelium was most dense. The individual records vary consider¬ 
ably. This is probably largely due to the varying density of the mycelium 
in the soil and to differences in the dryness of the soil. In the first meas¬ 
urements the penetration in the outside was three times as rapid outside 
as in the withered zone and twice as rapid as in the bare zone. The dif¬ 
ference is a little less marked in the second experiment due partly to the 
fact that part of the soil had already been moistened by the first irri¬ 
gation. After heavy rain the water stands on the soil over these rings 
