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Fear and Leaching in Michigan
or,
Dude, where’s my nutrients?
Fear and Leaching in Michigan
or,
Dude, where’s my nutrients?
Emily Farrer, Joshua Haag, Joel Perkovich , Katherine Windfeldt
IntroductionIntroduction
Properties of SoilPhysicalChemicalBiological
Synthesis of Lab and Field Data The Development of a Northern Oak Ecosystem
Physical Properties of SoilPhysical Properties of Soil Texture
– Sand
H20 Holding Capacity– 0.12 cm3 H2O/cm3 Soil– Lowest of all sites
Bulk Density– 1.1 g/cm3 – 2nd Lowest behind NH
Chemical AnalysesChemical Analyses
CEC - Lowest CEC of all sites at 2.2 cmolc/kg (other sites range 3.86-8.71 cmolc/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)
Soil Biological PropertiesSoil Biological PropertiesProperty Value Relative amount
Soil organic matter 3.06% lowest
Microbial biomass 5.3 g/m2 lowest (w/ OH)
Microbial respiration 12.9 ug/g/d lowest
Specific respiration 304 mg/g/d intermediate(OH higher)
Net mineralization 0.098 g/m2/d lowest
Nitrification 0.002 g/m2/d lowest
C resp./N min. 14.3 ugC/ugN intermediate (MO lower)
Ecosystem Biological PropertiesEcosystem Biological Properties
Ecosystem Biomass
Mg/ha % total
Aboveground
179.0 79.7
Forest Floor 11.5 5.1
Soil 34.0 15.1
Nitrogen Pools
kg/ha % total
Aboveground
392.7 24.8
Forest Floor 86.2 5.4
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
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/cm3 (other sites range 1.02-1.34)
CEC / Base Saturation - Lowest CEC at 2.2 cmolc/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 cm3 H20/cm3 soil (other sites range 0.14-0.44)- well-drained sandy PM, lower elevation and southern aspect = H20 loss
pH - Most acidic at 4.21, Non-calcareous PM offers no buffer for soil acidification via weathering
Northern Oak PhysiographyNorthern Oak Physiography
Soil: Field and LabSoil: Field and Lab
Sandy and acidic throughoutLab data supported
Little structureLow OM
Moderately shallow, weak profileWell-drained – weatheringLow OM, no humus accum.
O horizon thinA shallow
Low biomass in forest floor and soil
E weak Bs weak C sand
Profile
SOM rules!SOM rules!
SOMWater holding capacity
Structure
Color
CEC (& anion EC)
Base SaturationpH
Microbial biomassMicrobial respiration N mineralization NPP
VegetationVegetationHistory
1880’s white pine logged, big burnNatural fire regime until 1930 when human fire suppression began
CompositionOverstory– black oak, white oak, red oak, red maple
Understory / Ground Cover– white pine, red maple, sassafras, blueberry, wintergreen,
Pensylvania sedge
VegetationVegetationLow Biomass - 224 Mg/ha
Lowest AWC 0.12 cm3 H2O/cm3 soilLowest Nutrient Availability
– Nitrogen content of 1584 kg/ha– CEC of 2.2 cmol/kg– BS of 0.13
Species Composition – Dry/AcidicLowest AWC 0.12 cm3 H2O/cm3 soilLowest Nutrient Availability Lowest pH of 4.21Fire regime
Perpetuation of systemFire regime/Dry siteOak species
The Development of a Northern Oak Ecosystem
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
Nutrients CEC
Soil Development and Ecosystem Feedbacks
Soil Development and Ecosystem Feedbacks
SOM
Nutrients CEC
•Few nutrients -> low biomass•Low biomass -> little SOM•Little SOM -> Low CEC•Loss of nutrients by leaching
Soil Development and Ecosystem Feedbacks
Soil Development and Ecosystem Feedbacks
Nutrients CEC
Nutrients
•Physiographic and topographic characteristics -> prone to fire
•Loss of nutrients by burning and leaching