The seasonal behavior observed was related to the influence of other forcing factors and to the different state (density and activity) of the microbial biomass pool during the year.
We posit that the persistence of these intact N-containing biomolecules represents a growing contribution from the microbial biomass pool, but also from non-specific interactions among biomolecules in the Oe and Oa horizons and from biomolecule-mineral interactions in mineral soils.
Since N limits tree growth in forest ecosystems, and because soil microbial biomass plays a key role in N mineralization, data suggest that harvest practices that minimize removal of litter and slash will favor soil N retention, maintain the size of the soil microbial biomass pool, and maximize the potential productivity of future rotations.
where N, O, and B are pool sizes (mg C g−1 soil) of new C, old C, and microbial biomass; VN and VO are maximum substrate C (new or old C) assimilation rates (per day); KN and KO are Michaelis Menten constants (mg C g−1 soil); μB is turnover rate of microbial biomass (per day); ε is microbial growth efficiency (unitless); fN and fB are the initial fraction of the new and microbial biomass pools.
where N, O, and B are pool sizes (mg C g−1 soil) of new C, old C, and microbial biomass; μN, μO, and μB are turnover rates (per day) of new C, old C, and microbial biomass; KB is a coefficient for C consumption by microbes (mg C g−1 soil); ε is microbial growth efficiency (unitless); fN and fB are the initial fraction of the new and microbial biomass pools.
The size of the microbial biomass C pool appeared resilient to the exclusion of geese as there was no effect of the treatment (P > 0.6) and there were no significant variation in microbial biomass over time (P > 0.1) (Fig. 2c).
Our findings emphasize the important contribution of microbial biomass to labile SOC pools while revealing that soil neutral sugar profiles do not respond to climatic zone drivers as expected.
Mineral N (NH+4N and NO−3N) and microbial biomass carbon (MB-C) pools and mineral N supply rate (net nitrification and net soil N mineralization rates) were measured in both microhabitats for consecutive 12 months representing wet, post wet and dry seasons.
In order to test these hypotheses we measured CO2 and CH4 fluxes, standing biomass and litter C pools, microbial biomass and DOC and soil C concentrations in established (4 and 9 years old) grazing exclosures and their adjacent controls.
To test this hypothesis, we conducted a long-term experiment examining how different farming practices affect soil C and N pools and microbial biomass and activities in a fine-sandy loam (FAO: Acrisol) in the southern Appalachian mountains of North Carolina, USA.
The first order decay rates currently used in the model are 0.84 w-1 for decomposable plant material (i.e. 84% of the material will degrade in one week at 25°C at optimum moisture conditions), 0.07 w-1, 0.95 d-1, 0.055 w-1 and 0.0009 w-1 for resistant plant material, unprotected and protected microbial biomass and stable organic matter pools respectively.
