Influence of Roadside Establishment Practices on Sediment and Nutrient Loss

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Influence of Roadside Establishment Practices on
Sediment and Nutrient Loss

• Kyle R. Briscoe
• G. Munshaw, J.J. Varco, B.R. Stewart
• Plant and Soil Sciences
• Mississippi State University

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Research Motivation

• Mississippi Nonpoint Source Management Plan lists
  sediment as a potential surface water pollutant,
  nutrients are not mentioned (MDEQ, 2000)
• Mississippi Department of Transportation
  specifications
• 13-13-13 fertilizer applied during seeding at
  1123 kg ha-1
• N and P can contribute to eutrophication of
  surface water

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Objectives

• Determine the influence of nitrogen (N) and
  phosphorus (P) sources and rates, and fertilizer
  application timing on sediment and nutrient
  losses during runoff
• Evaluate species establishment under various
  fertility programs

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MDOT Specifications

• MS Department of Transportation (MDOT)
• Soil tests
• Lime applied as needed
• Fertilizer 13-13-13 applied at 1123 kg
  fertilizer ha-1
• Seed Mixture
• Bahiagrass 28 kg seed ha-1
• Tall fescue 28 kg seed ha-1
• Sericea lespedeza 28 kg seed ha-1
• Common bermudagrass 23 kg seed ha-1
• Crimson clover 23 kg seed ha-1 (fall planting
  only)
• Hay or wheat straw applied at 4490 kg ha-1

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Runoff Field Site

• Plot area disked and tilled
• Weather station - rainfall, wind speed, air
  temp., relative humidity, photosynthetically
  active radiation

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Runoff Experimental Design

• Randomized complete block, 4 replicates
• Stainless steel frames (0.75 x 2 m) and plastic
  collection containers were used to collect runoff
  from simulated and natural rainfall

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Half Rates
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Simulated Rainfall

• Simulated rain events conducted 14, 28, and 56
  days after seeding
• Simulated rainfall intensity 66 mm hr-1
• Total runoff volume determined on a weight basis
• Runoff samples collected every 5 minutes after
  runoff began and continued for 30 minutes

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Nutrient Loss Evaluation

• Runoff water analyzed for total sediment (TS),
  dissolved reactive P (DRP), total P (TP), NH4-N,
  NO3-N, and total N (TN)

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Vegetative Cover Evaluation

• Weekly percent cover data collected visually and
  by digital image analysis

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Vegetative Coverage
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Natural Rainfall - DRP
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Simulation 1 DRP
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Simulation 2 DRP
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Simulation 3 DRP
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Simulated Rainfall Total DRP
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Conclusions

• Establishing vegetation on roadsides can be
  difficult due to infertile disturbed soils
• MDOT fertilizer specifications could potentially
  lead to nutrient loss
• No significant differences in vegetative coverage
  were observed between fertilizer sources or rates
• Phosphorous source may have an influence on DRP
  lost during runoff events
• Significantly more DRP was lost from plots
  treated with a mixture of poultry litter and TSP
• A second project is evaluating the influence of
  various mulches on sediment and nutrient losses

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Influence of Roadside Establishment Practices on
Sediment and Nutrient Loss

• Dr. Jac Varco
• Professor
• Plant and Soil Sciences
• Mississippi State University
• jvarco_at_pss.msstate.edu

Kyle Briscoe Graduate Research Assistant Plant
and Soil Sciences Mississippi State
University kb371_at_msstate.edu