Microbial N immobilization is of great importance in acidified mountain spruce forest soils

0392321 - BC 2014 RIV GB eng J - Článek v odborném periodiku
Tahovská, K. - Kaňa, Jiří - Bárta, J. - Oulehle, F. - Richter, A. - Šantrůčková, H.
Microbial N immobilization is of great importance in acidified mountain spruce forest soils.
Soil Biology and Biochemistry. Roč. 59, April (2013), s. 58-71. ISSN 0038-0717
Grant CEP: GA AV ČR(CZ) KJB600960907; GA ČR(CZ) GAP504/12/1218
Institucionální podpora: RVO:60077344
Klíčová slova: N immobilization * microbial biomass * ¹⁵N * N saturation * DOC * nitrate leaching * nitrification * C limitation * fungi/bacteria ratio * forest floor
Kód oboru RIV: CE - Biochemie
Impakt faktor: 4.410, rok: 2013

The study evaluates N transformations in organic soils of acidified near-natural and primeval forests in the Bohemian Forest (watersheds of Plešné and Čertovo Lakes, Czech Republic) and Pop Ivan Massif (Ukraine). The laboratory experiments were performed, in which mixtures of different N sources (N–NH4, N–NO3 and glycine) were added to the soil with only one source 15N-labelled. The composition of the microbial community was analyzed. The microbial N pool was always three to five times higher than the total soluble N pool. All added N forms were rapidly and simultaneously immobilized into the microbial biomass with clear preferences for organic N over inorganic sources. The total N flux to the microbial pool always exceeded N flux into mineral N pools. The pattern of N transformation in the C limited soil was different from the other soils. The microbial pool and N flux into it were smaller compared to the mineral N pools and fluxes. The contribution of N–NO3 to microbial immobilization was negligible, while nitrification was almost equal to N mineralization. Total N flux through soluble N pools was greater than total N flux to insoluble pools (residual and microbial N); this was accompanied by lower microbial N uptake efficiency and shorter residence time of N in microbial pool than in soils with higher C availability. The composition of bacterial community was related to DOC content and C and N in microbial biomass. In soils with higher fungal abundance, more glycine was immobilized regardless of soil C availability, but with higher deamination and subsequent release of N–NH4 back to the soil. The study emphasized the role of microbial N immobilization in preventing N–NO3 loss from N saturated ecosystems as a function of C availability.
Trvalý link: http://hdl.handle.net/11104/0221754