Mineral soil horizons, particularly the upper mineral layer, become enriched with combustion products, i.e. pyrogenic carbon and nitrogen of free and occluded fractions.
A lower proportion of lignin-degrading taxa associated with mineral layer soil (5/16) had previously reported activity compared to those associated with the organic layer (8/12), suggesting the former may be more difficult to culture or were less frequently targeted for study.
As biological properties of such mineral layers vary with slight changes in composition, a good physical characterization is necessary in order to study their biological activity.
Layer specialization was also found for nitrogen fixers, as five nifH families, four from Alphaproteobacteria and one from Cyanobacteria were consistently associated with the organic layer and family 320, the most abundant nifH family from a Bradyrizobiaceae member was consistently associated with the mineral layer.
Microcosms contained either organic (top 2 5 cm) or mineral layer soil (5 20 cm) and were amended with either 13C-labeled hemicellulose, cellulose or lignin (Fig. 1a).
The soils of Japan are customarily divided from northeast to southwest into a weak podzolic (soils with a thin organic mineral layer over a gray leached layer) zone, a brown earth zone, and a red earth zone.
They tested out a variety of solutions, with the goal of finding one that removed the mineral layer without harming the silk.
When comparing mineral and organic soil layers, pH levels were higher in the organic layers in the PP, IDF, and BS ecozones, similar between layers in the LP ecozone, and higher in the mineral layer in the JP ecozone.
In the mineral layer, these correlations involved carbon or nitrogen content.
Our results demonstrate that we could coat β-TCP granules with mineral layers possessing different dissolution properties.
