Soil Slope Exposure Affects Physico-Chemical and Microbiological Properties in Soil Aggregate Size Fractions

Slope exposure is known to affect soil biogeochemical processes in mountainous forest ecosystems, but little attention has yet been paid its influence at a aggregate scale. Therefore, we evaluated the effects of slope (north- vs south-facing slope) on physico-chemical and microbiological properties bulk dry-sieved water-stable size fractions both organic (OF) mineral (AE) horizons an Italian alpine forest. The changes carbon (OC) nitrogen (ON) were assessed together with battery thirteen enzyme activities involved main nutrient cycles. In addition, biological including microbial biomass (estimated as double-stranded DNA content), activity (assessed ratio between extra-(exDNA) intracellular (iDNA) total pool) determined. OF horizon north-facing was enriched recalcitrant insoluble OC ON characterized by lower activity, indicated higher exDNA/iDNA respect slope. On contrary, exDNA iDNA contents, biomass, well most activities, reached levels southern AE horizon. These exposure-effects soil- fraction-specific. Overall, values chemical parameters found fraction. Our findings indicate that (and thus topography), horizon, distinctly dynamics mountain ecosystems.