Oct. 39 , 1917 
Fungus Fairy Rings 
219 
in the soils in eastern Colorado, the chances for loss of nitrogen are 
greatly reduced. 
As the mycelium passes on to new soil the old mycelium dies. The 
death of this mycelium is followed by decay produced by bacteria and 
molds which again liberates a supply of nitrogenous material for higher 
plants. The result is an increase in plant growth, the production of 
more roots in the soil, and consequently an increase in the organic 
matter contained in the soil. 
Wollaston (1807) spoke of the exhaustion of the “pabulum” of the 
soil necessary for the growth t>f the fungus, but did not state of what 
this “pabulum” consisted. 
According to Buckman (1870), anything which would kill a patch of 
grass and thus give the fungus something (organic matter) on which to 
live would produce a fairy ring. 
A special study of the carbon content of the soil in fairy rings was 
made by Lawes, Gilbert, and Warington (1883). The percentage of 
carbon (Table V) was found to be uniformly higher outside the ring 
than either in the ring or within the ring. The determinations in and 
inside the ring differ only slightly, the smallest amount of carbon being 
recorded inside the ring. 
Table) V. —Mean percentages of carbon a in the fine dry fairy-ring soils, according to 
Lawes , Gilbert , and Warington (1883) 
Percentage of carbon. 
Description of ring. 
Within the 
ring. 
On the 
ring. 
Outside 
the ring. 
Grove Paddock (May, 1874) . 
Broad balk f Tune. 1877I. 
3. 06 
2. 38 
2. 48 
2. 88 
3. 12 
2.72 
3 - 36 
2. 60 
3. 21 
3 - °4 
3-34 
3 * 29 
3. 12 
3 - 3 i 
3-44 
Broadbalk (September, 1877). 
“Park timber T877I . 
x cu rw v Ltm wvi » au / // *****. 44 * 
Park 1 Anril t 878 ^ t . 
Mean... 
2. 78 
2.99 
3-30 
Carbon "outside** = 100. 
84. 2 
90. 6 
100. 00 
a Carbon determined “by combustion in oxygen." 
The percentage of organic carbon in the soil in the different sections of 
Agaricus tabularis rings at Akron, Colo., is presented in Table VI. It is 
evident from this table that no significant differences are noted in the 
organic carbon content. The organic carbon content, with one exception, 
ranges from 2.15 to 3.79 per cent. Difficulties are encountered in deter¬ 
mining the carbon content where the soil contains only a small amount of 
organic matter. It is evident in this case that the errors due to the inclu¬ 
sion of the roots of plants are so great as to obscure to a great extent the 
effect of the growing mycelium on the organic matter of the soil. 
