POSSIBLE INFLUENCE OF DESERT SOIL MICROBIAL CHANGES
F. H. F. Au, V. D. Leavitt, and W. F. Beckert
National Environmental Research Center, Las Vegas*
ABSTRACT
The soil microbial population was determined for soil depth segments
from 0-3 cm, 3-6 cm, and 6-9 cm in a previously uncultivated highdesert area.
Plots in this area were covered by miniature greenhouses
and planted with vegetables.
After harvesting the vegetable crops,
another assessment was made of the microbial population.
The fungal population nearly doubled during the growing season, and
the bacterial population increased by a factor of approximately 12.
The fungal and bacterial live weights per hectare of the investigated
desert soil were calculated and compared with those of agricultural
soils.
Possible consequences of the increase in microbial biomass
are discussed for plutonium availability to plants, and for plutonium
migration in soil.
INTRODUCTION
Soil fertility can be defined as the ability of the soil to supply
nutrients to plants (Bollen, 1959).
This ability depends largely on
the activities of soil microorganisms.
It is well known that soil
microorganisms are responsible for the conversion of atmospheric and
mineral constituents into forms which can be assimilated by plants.
*See footnote, p.
35.
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