Anaerobic conditions are formed within natural soil aggregates of 0.4-
1 cm diameter in chernozem. These conditions suffice to maintain the p
rocess of denitrification even in a normal oxygen atmosphere (oxygen c
oncentration 20%). Emission of nitrous oxide from aggregates increases
with their diameter. More cells of bacteria and actinomyces mycelium
and more intense accumulation of nitrous oxide by bacteria cultures an
d actinomyces-bacteria associations are found in the centers of aggreg
ates as compared with their periphery.