Radrick Forest: A Mixed Oak Ecosystem Well Developed Soil Productive Ecosystem Radrick Forest: A Mixed Oak Ecosystem

Outline Re-introduction to Radrick Forest Soil characteristics: Physical Chemical Biological Synthesis: How do the factors above combine to influence soil formation and ecosystem development?

Glacial History of Michigan

Soil Formation Why does Radrick have well developed soil? Climate Soil type Mixed Oak Loam Oak-Hickory Sandy Loam N. Hardwoods Loamy Sand Black Oak/White Oak Sand Why does Radrick have well developed soil? Climate Glacial History Parent Material

Chemical properties of the mixed oak ecosystem pH (DI water) pH (CaCl2) CEC (cmolc/kg) % Base Saturation Mixed Oak 6.14 5.71 8.57 0.99 Oak Hickory 4.98 4.19 10.78 Northern Hardwoods 4.50 3.11 4.03 0.93 Black Oak/White Oak 3.50 2.63 1.90 0.13

Comparison graph for pH and CEC

Why do we see these differences? Parent material may explain the north/south data But, OH and MO share the same parent material, so we look to weathering and %organic matter These play into soil texture; MO is the most clayey of the sites. The MO profile is highly developed and has a strong buffering capacity.

But total microbial activity is not much different; Radrick Forest Microbial Carbon Utilization Compared to Other Ecosystems Mixed Oak has relatively high levels of microbial biomass compared to other ecosystems; But total microbial activity is not much different;

Composition of microbial community? Discussion of Microbial Activity in Radrick Forest: What factors explain why MO has high microbial biomass, but low activity? Composition of microbial community? -A higher proportion of actinomycetes would tend to result in lower respiration, but unlikely to account for the higher biomass. -A high proportion of bacteria would account for a higher biomass, but not for the low activity. -A higher presence of fungi would account for the higher biomass, and possibly into lower respiration, if C is incorporated in building biomass rather than respired. Other Potential Factors: Presence of organic matter? Radrick forest has a moderate level of soil organic matter. Soil physical characteristics? The more clayey texture of the MO system would tend to reduce gaseous diffusion, causing locally increased CO2 levels, thus slowing respiration rates even with a high microbial biomass. Soil chemical characteristics? The overall pH is moderate, and not particularly conducive to fungi. But poor diffusion could create microzones with high CO2 concentrations, and low pH. It may explain It may explain It may explain It may explain

Radrick Forest Mineralization and Nitrification Compared to Other Ecosystems Mixed Oak has a high rate of N Mineralization compared to other ecosystems; Efficiency of MO

Radrick forest has: highest above ground biomass highest litter production intermediate soil organic matter

*High decomposition rate Why does Radrick forest not have the highest soil organic matter? *High decomposition rate Near neutral PH, Sufficient soil moisture Good aeration and Relatively warm climate High litter quality * Relatively lower allocation to root and n nutrient-rich ecosystem

Why is the soil OM in Radrick forest such a big pool of N? 1. Clayey soil with high CEC  large amount of inorganic N is bound 2. Contain some species with nutrient-rich tissue  higher litter quality. (N concentration in forest floor = 1.35%) (even higher than NH??) 3. High microbial biomass can be part of the pool Species Relative Dominance (%) Leave N concentration(%) Branch N Blake Oak (Quercus velutina) 8.5 1.19 0.39 Red Maple (Acer rubrum) 13.1 2.29 0.59 Sassafras (Sassafras albidum) 15.0 Bitternut Hickory (Carya cordiformis) 25.2 1.31 0.45 Red Oak (Quercus rubra) 33.4 1.23 0.42 Shagbark Hickory (Carya ovata) 1.2 Black Cherry (Prunus serotina) 3.6 2.11 0.48

Radrick Forest has highest aboveground biomass, faster nutrient uptake Effect of high nitrification: Negatively charged nitrate ions are not adsorbed by the negatively charged colloids, so it leaches out of the ecosystem easily.

Nutrient tightly bound within the ecosystem Climate: Relatively warm and humid Low fire frequency Nutrient tightly bound within the ecosystem High Above ground biomass High quality of both above- and below- ground litter Fast uptake High rate of decomposition and mineralization Soil: *Fine texture *Calcareous parent material *High water availability *High PH *High CEC Large soil microbial community Low leaching

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