Influence of soil properties on the turnover of nitric oxide and nitrous oxide by nitrification and denitrification at constant temperature and moisture
M. Godde et R. Conrad, Influence of soil properties on the turnover of nitric oxide and nitrous oxide by nitrification and denitrification at constant temperature and moisture, BIOL FERT S, 32(2), 2000, pp. 120-128
Soils are a major source of atmospheric NO and N2O. Since the soil properti
es that regulate the production and consumption of NO and N2O are still lar
gely unknown, we studied N trace gas turnover by nitrification and denitrif
ication in 20 soils as a function of various soil variables. Since fertiliz
er treatment, temperature and moisture are already known to affect N trace
gas turnover, we avoided the masking effect of these soil variables by cond
ucting the experiments in non-fertilized soils at constant temperature and
moisture. In all soils nitrification was the dominant process of NO product
ion, and in 50% of the soils nitrification was also the dominant process of
N2O production. Factor analysis extracted three factors which together exp
lained 71% of the variance and identified three different soil groups. Grou
p I contained acidic soils, which showed only low rates of microbial respir
ation and low contents of total and inorganic nitrogen. Group II mainly con
tained acidic forest soils, which showed relatively high respiration rates
and high contents of total N and NH4+ Group III mainly contained neutral ag
ricultural soils with high potential rates of nitrification. The soils of g
roup I produced the lowest amounts of NO and N2O. The results of linear mul
tiple regression conducted separately for each soil group explained between
44-100% of the variance. The soil variables that regulated consumption of
NO, total production of NO and N2O, and production of NO and N2O by either
nitrification or denitrification differed among the different soil groups.
The soil pH, the contents of NH4+ NO2- and NO3-, the texture, and the rates
of microbial respiration and nitrification were among the important variab
les.