Open AccessInfluence of soil pH on the nitrate‐reducing microbial populations and their potential to reduce nitrate to NO and N 2 O
Author(s) -
Nägele Wolfgang,
Conrad Ralf
Publication year - 1990
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1990.tb04051.x
Subject(s) - nitrate , denitrifying bacteria , nitrite , chemistry , population , soil ph , environmental chemistry , soil water , denitrification , bacteria , nitrogen , ecology , biology , organic chemistry , genetics , demography , sociology
Slurries of an acid forest soil (pH 4.0) and two slightly alkaline agricultural soils (pH 7.6–7.8) were adjusted to pH values between 3.8 and 7.8 and tested for the nitrate‐reducing potential; the perceptual production of nitrite. NO, N 2 O and NH 4 + ; and the most probable number (MPN) counts of nitrate‐reducing bacteria. As a general trend, pH had a 2‐fold effect, i.e. nitrate‐reducing potentials decreased with pH, whereas the proportions of NO, N 2 O and NH 4 + production increased. Experiments with chloramphenicol indicated that this behaviour was due to adaptation of the resident bacterial activity rather than to population changes. The relatively high rates of NH 4 + production indicated the presence of nitrate‐ammonifying in addition to denitrifying bacteria. The population size of the nitrate‐reducing bacteria was similar when MPN culture media with acid or neutral pH were used, but increased by 3 orders of magnitude when slurries of the acid soil were preincubated at neutral pH. The potential of the resident populations for nitrate reduction and growth populations for nitrate reduction and growth apparently was limited but not completely precluded by low soil pH. The acid forest soil did not contain a population that was specifically adapted to the low pH in situ.