Soil changes during stockpiling and after reclamation at three - - PowerPoint PPT Presentation

Soil changes during stockpiling and after reclamation at three Wyoming natural gas production areas

Jay Norton and Calvin Strom University of Wyoming

2017 Joint Conference of the American Society of Mining and Reclamation Mine Drainage Task Force Appalachian Regional Reforestation Initiative Morgantown, West Virginia April 12, 2017

Soil Function in aridisols and aridic alfisols

• A horizon: interface with atmosphere:

– OM accumulation and ELUVIATION; – loss of clays, solutes; – More OM, coarser texture, lower EC & pH than other horizons; – Water infiltration & holding; nutrient cycling (microbes) – Germination/establishment;

• B horizon: zone of accumulation of clays

and solutes: ILLUVIATION

– Less OM, finer texture, higher EC & pH – Water holding in finer texture

Salvage & reclamation procedures One size fits all

A E Bt Cr Btn2 Btn1 Bk sandy loam clay Pre disturbance: ABSTON FINE, SMECTITIC, FRIGID USTIC NATRARGIDS Scraping depth

Clay loam After reclamation: ENTISOL Topsoil Subsoil Clay loam

Loss of A horizon reduces already slim chances for germination & establishment

• Lifeless: little SOM to support

microbial activity and nutrient cycling;

• Finer: inhibits water infiltration

and facilitates evaporation;

• Drier: less OM and fine texture

decrease plant-available water;

• Saline: EC > 4; osmotic potential

and ion toxicity slow germination;

• Sodic: ESP > 15 disperses

aggregates, exacerbating the above.

Pipelines + P&A + Active wells

29,683 Currently Producing Wells On File 121,626 Total Wells On File (DrillingEdge.com)

Great Divide and Green River Basins Objectives: determine short and longer-term effects of natural gas development and reclamation on soil quality across a precipitation gradient. Effects of topsoil depth on organic matter dynamics Aridisols and Entisols formed in saline and sodic marine shales. 11 inches 9 inches 7 inches

PLANT RESIDUE STRUCTURAL SOM METABOLIC SOM ACTIVE SOIL C SLOW SOIL C PASSIVE SOM Slow SOM ACTIVE SOM

Soil Organic Matter Pools

Active, or labile, SOM: Annual turnover Mineral N Mineralizable C& N dissolved organic C & N; Microbial C & N; light fraction C & N. Slow, or protected, SOM: Decades; Same as labile, but protected from mineralization within soil structure. Passive, or stabile, SOM: Centuries to millennia; Humus; Mineral-associated C & N; LOSSES: Harvest, CO2 & N2O emissions, erosion etc.

Pinedale Anticline

Elevation: 2440 meters MATmax: 11°C MATmin: -6.6°C Fine-loamy, mixed, superactive, frigid Calcidic Haplustalfs MAP: 276 mm Annual CV: 26.5%

• 30
• 20
• 10

10 20 30 10 20 30 40 50 60 70 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Temperature (C) Precipitation (mm)

• 30
• 20
• 10

10 20 30 10 20 30 40 50 60 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Temperature (C) Precipitation (mm)

Total Precipitation

• Max. Temperature
• Min. Temperature

Jonah Field

Elevation: 2140 meters MATmax: 11.9°C MATmin: -7.2°C Fine-loamy, mixed, superactive, frigid Calcidic Haplustalfs MAP: 232 mm Ann CV: 27%

Wamsutter/Great Divide Basin

Elevation: 2065 meters MATmax: 13.2°C MATmin: -2.6°C Fine-loamy, mixed, superactive, frigid Typic Haplargids MAP: 180 mm Ann CV: 32%

• 30
• 20
• 10

10 20 30 10 20 30 40 50 60 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Temperature (C) Precipitation (mm)

Three new well pads sampled at each field starting in 2009 (9 points composited)

• 1. Predisturbance;
• 2. Stockpile;
• 3. Respread;
• 4. 1 year later;
• 5. 7 years later.

Soil samples from 0-5, 5-20, and 20-30 cm Stockpiles: Three points sampled to 250 cm

Data Collection

• Vegetation cover
• Physical properties: bulk density, texture
• Chemical properties: pH, EC
• Biological properties (total and labile soil organic matter):

– Total soil organic carbon and nitrogen; – Mineral nitrogen; – Dissolved organic carbon and nitrogen; – Mineralizable organic carbon and nitrogen.

Jonah, 2011 Jonah, 2016

Anticline, 2011 Anticline, 2016

2009 2010 2011 2012 2013 2014 2015 2016

Sep-Nov

2009 2010 2011 2012 2013 2014 2015 2016

Sep-Nov

20 40 60 80 100 120 140 160 2009 2010 2011 2012 2013 2014 2015 2016

Sep-Nov

Study Period Precipitation

50 100 150 200 250 300 350 400 450 2009 2010 2011 2012 2013 2014 2015 2016 Precipitation (mm)

Pinedale

2009 2010 2011 2012 2013 2014 2015 2016

Jonah

2009 2010 2011 2012 2013 2014 2015 2016

Wamsutter

50 100 150 200 250 100 200 300 400 500 Depth (cm) CO2-C mineralized (mg kg-1) May June August 50 100 150 200 250 100 200 300 400 500 Depth (cm) CO2-C mineralized (mg kg-1) 50 100 150 200 250 200 400 600 800 Depth (cm) CO2-C mineralized (mg kg-1)

Mineralizable C in stockpiles, 2009

Pinedale Jonah Wamsutter

5 10 15 20 25 30 35 10 20 30 Clay Content (%)

Wamsutter

5 10 15 20 25 30 35 10 20 30 Clay Content (%)

Jonah

Reclaimed Undisturbed 5 10 15 20 25 30 35 10 20 30 Depth (cm) Clay Content (%)

Anticline

5 10 15 20 25 30 35 10 20 30 Clay Content (%)

Wamsutter

5 10 15 20 25 30 35 10 20 30 Clay Content (%)

Jonah

Undisturbed 5 10 15 20 25 30 35 10 20 30 Depth (cm) Clay Content (%)

Anticline

Reclaimed: Soil texture

5 10 15 20 25 30 35 10 20 30 Clay Content (%)

Wamsutter

5 10 15 20 25 30 35 10 20 30 Clay Content (%)

Jonah

Reclaimed Undisturbed 5 10 15 20 25 30 35 10 20 30 Depth (cm) Clay Content (%)

Anticline

Reclaimed: Soil texture

50 100 150 200 250 300 5 10 15 20 25 30

Predisturbance Stockpiled Reclaimed Reclaimed 1 yr

PMC (mg kg-1) PMN and Mineral N (mg kg-1)

Mineral N PMN PMC

Jonah

0-30 cm weighted averages

Disturbance Effects

• 1. Undisturbed: high labile SOM concentrations, low

mineral N concentrations (low net mineralization);

• 2. Pulse of labile and mineral nutrients after

disturbance truncated in cold storage in stockpile;

• 3. Pulse of mineralization at expense of PMC and N;
• 4. Loss of mineral N, labile OM begins to rebound.

100 200 300 400 500 600 10 20 30 40 50 60

Predisturbance Stockpiled Reclaimed Reclaimed 1 yr

PMC (mg kg-1) PMN and Mineral N (mg kg-1)

Anticline

50 100 150 200 250 300 5 10 15 20 25 30

Predisturbance Stockpiled Reclaimed Reclaimed 1 yr

PMC (mg kg-1) PMN and Mineral N (mg kg-1)

Mineral N PMN PMC

Jonah

50 100 150 200 250 300 350 400 450 500 5 10 15 20 25 30 35 40 45 50

Predisturbance Stockpiled Reclaimed Reclaimed 1 yr

PMC (mg kg-1) PMN and Mineral N (mg kg-1)

Wamsutter

Disturbance Effects 0-30 cm weighted averages

Anticline: complicated by stockpile being moved at least twice.

Loss of labile C and N

5 10 15 20 25 30 35 Mineral Nitrogen (mg kg-1)

All Well Fields

10 20 30 40 50 100 200 300 400 500 PMC and N (mg kg-1)

Anticline

5 10 15 20 25 50 100 150 200 250

PMC and N (mg kg-1)

Jonah

5 10 15 20 25 30 35 40 45 50 50 100 150 200 250

PMC and N (mg kg-1)

Wamsutter

TOC TN % change Anticline 72 88 Jonah

• 45
• 197

Wamsutter 3.7

• 1.7

Change: predisturbance to seven years after reclamation.

Recovery of SOM

0.05 0.1 0.15 0.2 0.25 0.0 0.5 1.0 1.5 2.0 2.5 Soil Organic Carbon (%)

Anticline

0.1 0.2 0.3 0.4 0.5 0.0 0.5 1.0 1.5 2.0 2.5 Soil Organic Carbon (%)

Jonah

0.05 0.1 0.15 0.2 0.25 0.0 0.5 1.0 1.5 2.0 2.5 Soil Organic Carbon (%)

Wamsutter

Conclusions

• Stockpiles in semiarid region may not be affected by depth, at least in the

short-term;

• What about age?
• Compared with degraded reference sites, reclaimed sites seem to recover
• r exceed original SOM levels within seven years;
• Possibly due to increased herbaceous vegetation
• Potentially mineralizable carbon recovers more slowly;
• Possibly due to loss of soil structure, which protects labile SOM from mineralization,

and continued accelerated mineralization, lack of woody species…

• Interest in reclamation research is as variable as annual rainfall.

Thanks to

• Calvin Strom
• Cally Driessen
• Amber Mason
• Jennifer Faulkner
• Leann Naughton
• Luke Driessen
• Kristi Bear
• Todd Loubsky
• K.C. Harvey, Inc.
• Gary Austen, BP America
• Pete Guernsey, QEP Resources
• Ralph Swift, Encana Exploration
• UW School of Energy Resources
• Wyoming Reclamation &

Restoration Center