Effects of Wellpad Development and Reclamation on Topsoil Properties: Research at the Pinedale Antic

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Effects of Wellpad Development and Reclamation on
Topsoil Properties Research at the Pinedale
Anticline, Jonah, and Wamsutter Natural Gas Fields

• Jay Norton, Amber Mason, Cally Driessen, Calvin
  Strom, and Jennifer Faulkner
• University of Wyoming Department of Renewable
  Resources and Cooperative Extension Service
• 2009 PAW Oil Gas Reclamation Conference
• November 10, 2009

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Objectives

• Quantify effects of stripping, stockpiling, and
  respreading on soil nitrogen dynamics
• Determine effects of stockpile depth on N
  dynamics
• Determine effects in different soil/climatic
  settings.

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• Stable, labile, and protected SOM pools
• Labile rapidly mineralizes to NH4 and NO3 under
  right temperature and moisture conditions
• Protected is labile material inside soil
  structure
• Disturbance shifts mostly from protected to
  labile (some from stable pool).

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Study sites

• Pinedale Anticline 10-14
• Jonah Field 7-9
• Wamsutter 7-9 saline

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Approach sampling

• 2-meter soil cores in three new stockpiles at
  each site
• Sampled three times in 2009
• Sampled from five depth increments
• Sampled at 0-20 cm along transects after
  respreading
• Adjacent undisturbed site sampled from 0-20 cm
  depth.

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Approach analyses

• Soil moisture content
• Mineral N (nitrate ammonium) by extraction of
  fresh, field moist soil
• Readily decomposable pool Potentially
  mineralizable N by incubation-extraction.

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Results Overall effects
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Depth effects
Undisturbed
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Soil/Climate Effects
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Recap

• Topsoil stripping and stockpiling increases
  labile nitrogen pool by destroying soil
  structure
• Respreading stimulates mineralization
• Disturbance-derived labile N is protected in
  deeper depth of stock pile, but converted with
  spreading
• Soils at all three study sites appear to react
  similarly
• N pools reflect SOM dynamics, but more analyses
  will contribute to better understanding.

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Continued research

• Additional analyses of SOM pools and other soil
  physical and chemical properties
• Continued monitoring of reclaimed sites
• Continued monitoring of remaining stockpiles
• Evaluation of livestock impacts for remediation
  of surface SOM and nutrients.

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QUESTIONS?