1. Fear and Leaching in Michigan or, Dude, where’s my nutrients? Emily Farrer, Joshua Haag, Joel Perkovich, Katherine Windfeldt

2. Introduction  Properties of Soil Physical Chemical Biological  Synthesis of Lab and Field Data  The Development of a Northern Oak Ecosystem

3. Physical Properties of Soil  Texture –Sand  H 2 0 Holding Capacity –0.12 cm 3 H 2 O/cm 3 Soil –Lowest of all sites  Bulk Density –1.1 g/cm 3 –2 nd Lowest behind NH

4. Chemical Analyses CEC - Lowest CEC of all sites at 2.2 cmol c /kg (other sites range 3.86-8.71 cmol c /kg) - Thus, smallest nutrient holding capacity of all soils Base Saturation - Lowest BS of all sites at just 13% (other sites range from 97-99%) pH - Most acidic of all sites at 4.21 (Mixed Oak highest pH at 5.97)

5. Soil Biological Properties

6. Ecosystem Biological Properties Ecosystem Biomass Mg/ha% total Aboveground179.079.7 Forest Floor11.55.1 Soil34.015.1 Nitrogen Pools kg/ha% total Aboveground392.724.8 Forest Floor86.25.4 Soil1105.069.8 Low ecosystem biomass and N compared to other forests Aboveground and forest floor second lowest (OH lowest) Soil biomass and N pools lowest

7. Structure / Texture - Well-sorted, sandy PM from former lake bed = larger particle size, weak structure and sandy texture Bulk Density (Db) - Well-sorted (homogenous), loosely packed soil results in second lowest Db `at 1.1 gm/cm 3 (other sites range 1.02-1.34) CEC / Base Saturation - Lowest CEC at 2.2 cmol c /kg 90% sand and 3% clay = weak electronegative charge for CEC - Lowest BS at 13% Role of topography / fire and well-drained sandy PM = nutrient loss Available Water Content - Lowest AWC at 0.12 cm 3 H 2 0/cm 3 soil (other sites range 0.14-0.44) - well-drained sandy PM, lower elevation and southern aspect = H 2 0 loss pH - Most acidic at 4.21, Non-calcareous PM offers no buffer for soil acidification via weathering Northern Oak Physiography

8. Soil: Field and Lab Sandy and acidic throughout Lab data supported Little structure Low OM Moderately shallow, weak profile Well-drained – weathering Low OM, no humus accum. O horizon thin A shallow Low biomass in forest floor and soil E weak Bs weak C sand Profile

9. SOM rules! SOM Water holding capacity Structure Color CEC (& anion EC) Base Saturation pH Microbial biomass Microbial respiration N mineralizationNPP

10. Vegetation History 1880’s white pine logged, big burn Natural fire regime until 1930 when human fire suppression began Composition Overstory –black oak, white oak, red oak, red maple Understory / Ground Cover –white pine, red maple, sassafras, blueberry, wintergreen, Pensylvania sedge

11. Vegetation Low Biomass - 224 Mg/ha Lowest AWC 0.12 cm 3 H 2 O/cm 3 soil Lowest Nutrient Availability –Nitrogen content of 1584 kg/ha –CEC of 2.2 cmol/kg –BS of 0.13 Species Composition – Dry/Acidic Lowest AWC 0.12 cm 3 H 2 O/cm 3 soil Lowest Nutrient Availability Lowest pH of 4.21 Fire regime Perpetuation of system Fire regime/Dry site Oak species

12. The Development of a Northern Oak Ecosystem Young soil Limited weathering Low CEC (and non-calcareous parent material) Well drained (low FC and AWC) -> Loss of nutrients by leaching NutrientsCEC

13. Soil Development and Ecosystem Feedbacks SOM NutrientsCEC Few nutrients -> low biomass Low biomass -> little SOM Little SOM -> Low CEC Loss of nutrients by leaching

14. Soil Development and Ecosystem Feedbacks NutrientsCEC Nutrients Physiographic and topographic characteristics -> prone to fire Loss of nutrients by burning and leaching

15. Summary:  Young, relatively unweathered soil  Susceptible to leaching Loss of nutrients Low productivity and biomass  Low SOM and CEC  Susceptible to fire Loss of nutrients Low productivity and biomass  Low SOM and CEC  Positive feedbacks maintain low biomass