Microscale spatial distribution and soil organic matter persistence in top and subsoil

The spatial distribution of organic substrates and microscale soil heterogeneity significantly influence matter (OM) persistence as constraints on OM accessibility to microorganisms. However, it is unclear how changes in driven by factors such depth affect the relative importance substrate persistence. This work evaluated decomposition 13C 15N labeled water-extractable inputs over 50 days either hotspot (i.e., pelleted 1–2 mm-size pieces) or distributed added < 0.07 μm suspended water) forms topsoil (0–0.2 m) subsoil (0.8–0.9 samples an Andisol. We observed greater C with OM, indicated a 17% reduction cumulative mineralization 10% higher conversion mineral-associated OM. A lower availability potentially reduced due dispersion throughout soil. NanoSIMS (nanoscale secondary ion mass spectrometry) analysis identified organo-mineral associations cross-sectioned aggregate interiors subsoil. On other hand, topsoil, we did not observe significant differences suggesting that large amounts particulate already present outweighed distribution. Here, demonstrated under laboratory conditions fresh input alone affected seems play role topsoils rich divergence between top likely mineralogy composition.