Effects of Watershed Acidification on Soil Water and

Stream Water Chemistry

Soil Surface

H2SO4 HNO3

SO42- + H+ H+ + NO3

-

Soil Surface

H2SO4 HNO3

SO42- + H+ H+ + NO3

-

Soil Charge

Soil Surface

H2SO4 HNO3

SO42- + H+ H+ + NO3

-

Mobile Anion Theory

Soil Surface

H2SO4 HNO3

SO42- + H+ H+ + NO3

-

SO42- + cations NO3

- + cationsCation exchange

Ca2+

Mg2

+

K+

2H+

2H+

H+

H+

H+

H+

H+

H+

Ca2+

Mg2

+

K+

H+

H+

H+

H+

H+

Ca2+

Mg2

+

K+

SO42- or

NO3-

SO42- or

NO3-

SO42- or

NO3-

Base cations in solution pair with mobile anions in solution

CaSO4 or Ca(NO3)2

MgSO4 or Mg(NO3)2

K2SO4 or KNO3

leach through soil

Soil Surface

H2SO4 HNO3

SO42- + H+ H+ + NO3

-

SO42- + cations NO3

- + cations

Leachesfrom soil

Leachesfrom soil

Soil Surface

H2SO4 HNO3

SO42- + H+ H+ + NO3

-

Acidifies soil anddissolves soil Al3+

Al3+

Al3+

Al3+

3H+

3H+

3H+

H+

H+

H+

H+

H+

Al3+

Al3+

Al3+

H+

H+

H+

H+

Al Dissolution

and Exchange

H+

H+

H+

H+

H+

Al3+

Al3+

Al3+

H+

H+

H+

H+

SO42- or

NO3-

SO42- or

NO3-

SO42- or

NO3-Al2(SO4)3 or

Al(NO3)3

leach through soil

Soil Surface

H2SO4 HNO3

SO42- + H+ H+ + NO3

-

Acidifies soil anddissolves soil Al3+

SO42- + Al3+

NO3- + Al3+

leached to streams & lakes

Al3+ is toxic to aquaticorganisms

Soluble Al3+

interferes with plant rootfunctions

Al3+ can reduce plant vigorand growth

Mobile/excess anions control base cation and acid cation leaching

Base cation leaching = loss of soil base cations/nutrients/fertility

Acid cation leaching results in acidification of soil water and stream water

Process Summary

Sulfate Deposition across the NESome of the

highest rates in the country

Orographic uplifting and high elevation ridges

Primary sources – Ohio River Valley

Objective: Gather baseline soil chemistry data across the forest for multiple soil types across multiple geologies

• Accomplished through a state wide partnership with NRCS Soil Survey Division, West Virginia University, and USFS

• Over 400 soil pedons characterized in the state

• 2006 Forest Plan requires monitoring of sensitive areas for the purpose of conducting management activities

Wilderness Areas Class 1 Air Monitoring Program Academia

Soil Chemistry Monitoring Program

Acid Deposition Sensitivity MapSoil Forming Factors

PARENT MATERIALGEOLOGY WEATHERING RATES

Based on geochemistry

Compared against 303d impaired stream list for acid rain effects

Soils used to ground truth map in sensitive watersheds

Resource Effects - Acid DepositionWater Chemistry & Watershed Sensitivity on the Monongahela

NF

Non-Management EffectsEffects may include:

Decreasing stream pH, ANC, increasing metal concentrations

Declining fish populations and species

Base cation losses in the soil

Foliar macronutrient imbalances

Shifts in biodiversity in the understory vegetation

Resource EffectsAcid DepositionWATEREffects may include:

Changes in Stream chemistry -decreases in Stream pH and ANC

High Levels of Iron and Aluminum

Nitrogen and Sulfate Leaching from Watershed Soils

Ultimately, losses or Shifts in Stream Biota Populations

Soil Chemistry Monitoring Program Objective: Gather

baseline soil chemistry data

Forest Wide Watershed Assessments NRCS data collection for

soil survey updatesProject Specific

Soil Disturbing activitiesWilderness Areas

Class 1 Air Monitoring Program

AcademiaArchive Soil Samples

Anthony Creek Watershed 2007 Sampling

High ModerateLowAlluvium

Criteria Used to Assess RiskSoil Chemistry

Ca:Al Ratios (SrCl2 Extraction Method; Penn State University Lab)

Base Saturation Effective Cation

Exchange Capacity (ECEC)

Stream Chemistry Foliar IndicatorsAir Quality

Long harvest rotations 100 yearsNo whole tree harvesting; leave tops

and limbsAvoid harvesting in areas with

shallow soilsMinimize soil disturbancePrescribe fire?Chemical additions ?

Mitigations

LimingWhy?Has this been done

before?Cost Efficient?Effects

Pros and Cons

Stream Liming

Cherry River Watershed Lime Dump

Cranberry River Watershed Liming Drum

Station

Pulses of nitrate and sulfate leaching in the months post application

pH does not readily increase in mineral (A, E, and B) horizons

Response held to the O, A, and possibly transition horizons (AE, AB, BA, etc.)

[Al] and [Mn] decrease, [Ca] and [Mg] increase in soils

Effects to the Soil from Liming