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Gewählte Publikation:

Friedel, JK; Gabel, D.
(2001): Microbial biomass and microbial C : N ratio in bulk soil and buried bags for evaluating in situ net N mineralization in agricultural soils
J PLANT NUTR SOIL SCI. 2001; 164(6): 673-679.

The in situ net nitrogen mineralization (N-net) was estimated in five agricultural soils under different durations of organic farming by incubating soil samples in buried bags. Simultaneously, soil microbial C and N was determined in buried bags and in bulk soil under winter wheat and after harvest. The aim was to check for variations in soil microbial biomass contents and microbial C:N ratios during the incubation period, and their importance for N-net rates: Microbial C and N contents were highest in soils that had been organically farmed for 41 years, whereas N-net rates were highest in a short-term organically managed soil that had been under grassland use until 36 years ago. The mean coefficient of variation in the bulk soil for microbial C estimates ranged from 5 to 12 %. Microbial N contents were similar inside buried bags and in the bulk soil at the end of the incubation periods. Under winter wheat during the incubation period until harvest, microbial C contents and microbial C:N ratios (in 10-27 cm depth only) decreased more strongly inside buried bags than in the bulk soil. Following harvest of winter wheat and ploughing, microbial biomass increased while in situ N-aet decreased, presumably due to N immobilization. The N-net rates were not correlated with microbial N contents or changes in microbial N contents inside buried bags. At the end of the vegetation period of winter wheat, N-net rates were negatively correlated with microbial C:N ratios. Because these ratios concurrently decreased more inside buried bags than in the bulk soil, the Nnet estimates of the buried bag method may differ from the N-aet rates in the bulk soil at that time.
Autor*innen der BOKU Wien:
Friedel Jürgen Kurt

Find related publications in this database (Keywords)
organic farming
nitrogen mineralization
buried bag method
microbial C and N availability
soil microbial biomass

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