Leaching of soils during laboratory incubations does not affect soil organic carbon mineralisation but solubilisation.

PloS one

PubMedID: 28380005

González-Domínguez B, Studer MS, Hagedorn F, Niklaus PA, Abiven S. Leaching of soils during laboratory incubations does not affect soil organic carbon mineralisation but solubilisation. PLoS ONE. 2017;12(4):e0174725.
Laboratory soil incubations provide controlled conditions to investigate carbon and nutrient dynamics; however, they are not free of artefacts. As carbon and nitrogen cycles are tightly linked, we aimed at investigating whether the incubation-induced accumulation of mineral nitrogen (Nmin) biases soil organic carbon (SOC) mineralisation. For this, we selected two soils representative of the C:N ratio values found in European temperate forests, and applied two incubation systems: 'closed' beakers and 'open' microlysimeters. The latter allowed leaching the soil samples during the incubation. By the end of the 121-day experiment, the low C:N soil significantly accumulated more Nmin in beakers (5. 12 g kg-1 OC) than in microlysimeters (3. 00 g kg-1 OC) but there was not a significant difference in SOC mineralisation at any point of the experiment. On the other hand, Nmin did not accumulate in the high C:N soil but, by the end of the experiment, leaching had promoted 33. 9% more SOC solubilisation than beakers. Therefore, we did not find evidence that incubation experiments introduce a bias on SOC mineralisation. This outcome strengthens results from soil incubation studies.