Effect of biochar addition on C mineralisation and soil organic matter priming in two subsoil horizons
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The impact of biochar on subsoil organic carbon mineralisation has never been assessed despite its susceptibility to downward transport after soil amendment. In this study, we analysed the potential mineralisation of biochar and plant material as well as their effect on native soil organic matter (SOM) decomposition in subsoil horizons.
Materials and methods
We used 13C-labelled biochar and plant material to allow disentangling substrate mineralisation and priming effects. The substrates were added to two mountain subsoils under different land use and incubated for 1 year under optimum conditions. We analysed for physical parameters and C mineralisation in the two soils. Moreover, microbial communities were assessed by phospholipid fatty acid (PLFA) analyses.
Results and discussion
Our results indicated contrasting potential C mineralisation of subsoils under different land use probably related to sampling depth, contribution of stabilised organic matter compounds, carbon content as well as quality. In general, very low proportions of biochar were mineralised in the two soils as compared to plant material. The mineralisation of each of the added substrates (biochar and plant material) was slightly, but significantly different in the two soils. Native C mineralisation was much higher after plant material addition than after biochar addition. Subsoil type influenced the kind and magnitude of priming effects for both added substrates.
Biochar mineralisation and its priming effects in subsoil are small as compared to uncharred plant litter. We suggest that substrate mineralization and priming effects induced on subsoil organic matter are dependent on the composition of the added substrate, as well as soil parameters rather than microbial community characteristics.
Keywords13C-labelled biochar Mineralisation Priming Subsoil
Our research was funded by the European Community under the framework of the EuroChar project (FP7-ENV-478 2010ID-265179). We thank the Observatoire Homme-Milieux Pyrenees Haut-Vicdessos CNRS-INEE for access to the sampling sites and the Poznan radiocarbon laboratory for the 14C activity analyses.
- Blume E, Bischoff M, Reichert JM, Moorman T, Konopka A, and Turco RF (2002) Surface and subsurface microbial biomass, community structure and metabolic activity as a function of soil depth and season. Appl Soil Ecol 20:171–181Google Scholar
- Budge K, Leifeld J, Hiltbrunner E, Fuhrer J (2011) Alpine grassland soils contain large proportion of labile carbon but indicate long turnover times. Biogeosci 8:1911–1923Google Scholar
- Fang Y, Singh B, Singh BP, Krull E, (2014) Biochar carbon stability in four contrasting soils. Eur Soil Sci 65:60–71Google Scholar
- Frostegard A, Baath E, Tunlid A (1993) Shifts in the structure of soil microbial communities in limed forest as revealed by phospholipid fatty-acid analysis. Soil Biol Biochem 25:723–730Google Scholar
- Nocentini C, Guenet B, Di Mattia E, Certini G, Bardoux G, Rumpel C (2010) Charcoal mineralisation potential of microbial inocula from burned and unburned forest soil with and without substrate addition. Soil Biol Biochem 42:1472–1478Google Scholar
- Rumpel C (2011) Carbon storage and organic matter dynamics in grassland soils. In: Lemaire G, Hodgson J, Chabbi A (eds) Grassland Productivity and Ecosystem Services. CAB International, pp 65–72Google Scholar
- Singh BP, Cowie AL, Smernik RJ (2012) Biochar Carbon Stability in a Clayey Soil As a Function of Feedstock and Pyrolysis Temperature. Environ Sci Technol 46:11770–11778Google Scholar
- Stone MM, Plante AF, (2014) Changes in phosphatase kinetics with soil depth across a variable tropical landscape. Soil Biology and Biochemistry 71:61–67Google Scholar
- Stuiver M, Polach HA (1977) Discussion: reporting of 14C data. Radiocarbon 19:355–363Google Scholar
- Vance ED, Brookes PC, Jenkinson DS (1987) An extraction method for measuring soil microbial biomass-C. Soil Biol Biochem 19:703–707.Google Scholar