Mixed Oak Ecosystem:Field and Lab Data

Integration

Deborah HudlestonCatherine Resler

Mary WaltonChris Weber

Review of Field DataMixed Oak

Site 1 (Deborah)

Site 2 (Chris)

Site 3 (Mary)

Site 4 (Cat)

Total BA 51.47 46.56 24.28 49.80

Lab Soil Texture Analysis

Loam Loam Loam Loam

Soil Profile

Site 1 Site 3 Site 2 Site 4

Oi/Oe 1-0 2-0 2-0 1-0

A 0-6 0-5 0-8 0-11

E 6-27 5-13 8-43 11-24

Bt 5-52 13-27 43-63 24-56

B 51-68 27-35 N/A N/A

C 68+ 35+ 63+ 56+

Soil Texture

0%

20%

40%

60%

80%

100%

% Particles Present

1 2 3 4

Sites Sampled

Percent of Sand, Silt, and Clay at 4 sites

Clay

Silt

Sand

Loam textured soil was found at all Mixed Oak sites sampled.

Mixed oak has a greater amount of clay compared to the other three sites sampled.

> amount of rich clay minerals fosters higher NPP.

Available Water Content < Amount of Larger

Particles -> Decrease in Pore Size= Greater AWC

Mixed Oak has a greater amount of clay than sand compared to the other three sites sampled, therefore a higher AWC.

0.44

0.29

0.14 0.12

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

% of AWC

1 2 3 4

Sites sampled

Available Water Content

Bulk Density

Well-structured soils have > amounts of macropores -> a higher water-holding capacity than less developed soils.

Mixed Oak had a larger bulk density than the other three sites sampled.

1.34

1.161.02

1.11

0

0.2

0.4

0.6

0.8

1

1.2

1.4

DB (g/cm3)

1 2 3 4

Sites Sampled

Bulk Density

Chemical PropertiesDeb Chris Mary Cat Mean

pH H2O 5.80 6.12 6.08 5.88 5.97

pH CaCl2 5.53 5.61 5.55 5.40 5.52

OM(%) 4.27 3.47 4.32 3.71 3.94

Total Acidity [cmol(+)/kg] 0.12 0.12 0.06 0.13 0.11

CEC [cmol(+)/kg] 9.88 7.78 8.73 8.44 8.71

Base Saturation (%) 98.70 98.00 99.29 98.50 98.62

MO Chemical Properties pH

Calcium rich parent material Buffer to weathering

Organic Matter Oak/maple leaves; moderate A Horizon Large above ground biomass- rapid

decomposition

CEC/ Base Saturation Large CEC 98% base saturation Lots of nutrients for plants Consistent with soil type

Largest biomass pool of the Mixed Oak ecosystem is aboveground

Largest pool of N in Mixed Oak ecosystem is in the belowground pool

Highest Aboveground

Biomass of all ecosystems studied

Large Discrepancy between aboveground biomass and forest floor biomass - rapid decomposition

Mg

C h

a-1

4 00

3 00

2 00

1 00

0

A boveground C (M g C

ha- 1)

F ores t Floor C (M g C

ha- 1)

Soil C (Mg C ha- 1)

Nutrient Pools

Net N mineralization is highest in the MO ecosystem - high-lignin litter of the oak trees provide a poor quality substrate to microbial decomposers.

Microbes receive little energy from the lignified litter, supporting little microbial growth, and resulting in low microbial N sink, making the N available to plants.

Northern OakNorthern Hardwood

Oak HickoryMixed Oak

Ne

t N

min

era

liz

ati

on

mic

rog

rm N

g-

1 d

-1

6

5

4

3

2

1

0

Nitrogen Mineralization

• Microbial respiration is low – indicating low microbial activity

• Specific respiration is low - each individual decomposes a relatively small amount of C for the N produced

• The ratio of C respired to N mineralized is one of the smallest of the 4 ecosystems - this is a further indication of the poor quality of the oak leaf litter as substrate for decomposers.

Site

BO_WON. HardwOak_HickMixed Oa

Va

lue

300

200

100

0

Microbial biomass mi

crograms C g-1 soil

Microbial respiratio

n micrograms C g- 1 d1418

41

2236

196

44

197

Microbial Biomass and Respiration

High Aboveground

Biomass

Substantial High-Lignin

Litter Production

Poor Quality Substrate for

Microbial Decomposers

High N mineralization

Hig

h P

lant

Ava

ilabl

e N

Biological Property Connections

Summary

Physiography

Climate

Soil Development(Clay = High bulk density and AWC)

High CEC and base saturation = High

nutrients

High N mineralization

High biomass

NUTRIENT RICH SITE

WELL DEVELOPEDSOIL

MO is a Highly Productive System