WIND ERODIBILITY OF BIOSOLIDS AMENDED SOILS: A STATUS REPORT

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WIND ERODIBILITY OF BIOSOLIDS AMENDED SOILS A
STATUS REPORT
John Tatarko USDA-ARS Wind Erosion Research
Unit Manhattan, Kansas Nikki Stefonick Metro
Wastewater Reclamation District Denver, Colorado
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• A consortium of 57 local governments in the
  Denver metro area.
• Treat more than 165 million gallons of wastewater
  a day.

• 52,000 acres of agricultural land 65 miles
  east of Denver, Colorado.

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• 1 to 3 dry tons/acre depending on background
  nutrients, crop, and yield goal

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• Objectives
• Determine fraction of biosolids in wind eroded
  material compared to that of the adjacent
  biosolids amended land.
• Determine wind erodibility of cultivated soils as
  influenced by applied biosolids.

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• Objective 1
• Wind erosion catchers are located on two sites
  from December through May.
• Biosolid applications
• 3 and 5 (2005-2006)
• 4 and 5 (2006-2007)
• Catcher and adjacent source soils are collected
  to determine organic matter and available heavy
  metal content.

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Figure 1. Layout of field BSNE sediment sampler
clusters in relation to source soil sample
locations.
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Figure 2. Sediment flux (kg m-2) by height for
measured data and fitted equation for 4
January, 2006 storm at site DC343.
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• Objective 2
• Five sites at Metrogrow Farms established in
  December, 2005 on wheat-fallow rotations.
• Biosolids applications
• 0, 1, 2, 3, and 5
• Wind erodibility measurements
• (3 replicates, sampled quarterly)
• aggregate stability
• soil surface roughness
• aggregate size distribution

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Table 2. Physical and chemical characteristics
of wind erodibility study sites.
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Table 3. Biosolids applications and organic
matter at wind erodibility study sites.
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Figure 3. Oriented roughness (mm) on sample date
at each site with varying number of biosolids
applications.
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Figure 4. Random roughness (mm) on sample date
at each site with varying number of biosolids
applications.
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Figure 5. Erodible fraction (lt0.84 mm) of
aggregates on sample date at each site with
varying number of biosolids applications.
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Figure 6. Geometric mean diameter (mm) of
aggregates on sample date at each site with
varying number of biosolids applications.
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Conclusions
Disclaimer This study is ongoing and
statistical analysis is not complete. Only
general trends can be observed from the data
collected thus far.
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Conclusions

• Oriented Roughness
• tends to decrease with time (i.e., precipitation)
• higher and more recent applications had highest
  roughness and retained it longer
• no applications had the lowest roughness

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Conclusions

• Random Roughness
• low roughness compared to oriented
• higher and more recent applications had highest
  and retained it longer
• no applications tended to degrade the fastest

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Conclusions

• Aggregate Size Distribution
• tend towards smaller size over time
• higher and more recent applications had larger
  aggregates
• no applications tended to smaller sized
  aggregates

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Summary

• erodibility tends to increase with time after
  planting (i.e., with precipitation)
• biosolids effects are temporary
• less erodibility for most recent applications
• no applications tended to highest erodibility

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