SREL Reprint #0339




Structure and Function of Hardwood Litter and Soil Subsystem after Chronic Gamma Irradiation.

Gerald T. Cowley, J. W. Martin and David C. Coleman



The microfungal populations in six experimental and two control plots were studied before and after irradiation for 113 days with a 9200-Ci 137Cs source.  Experimental plots received cumulative dosages ranging from 5 million to 4 thousand rads.  The number of detectable propagules was reduced sharply in the three plots receiving the highest dosages.  Recovery was slow, since reduced populations in the soil were still in evidence 13 months after termination of irradiation.

Species composition of soil and litter populations was also seriously altered.  Before irradiation, populations in all plots were predictably similar.  However, immediately after irradiation, an abnormally high percentage of both soil and litter species isolated from the most heavily irradiated sites was darkly pigmented, and populations displayed little similarity to those in control and lightly irradiated sites.  Some lightly pigmented or nonpigmented species soon became reestablished.  However, similarities between heavily irradiated plots and nonirradiated plots remained low and had not returned to preirradiation levels in the soil by 13 months after irradiation.  Apparent recovery of litter populations was more rapid than for soil populations in regard to both number of detectable propagules and species composition.


SREL Reprint #0339

Cowley, G.T., J.W. Martin, and D.C. Coleman. 1971. Structure and function of hardwood litter and soil subsystems after chronic gamma irradiation. II. Microfungi. p. 1229-1236. In Third National Symposium on Radioecology, edited by D.J. Nelson. ORNL CONF 710501 P2. Oak Ridge, TN.

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