Influence of Roadside Establishment Practices on Sediment and Nutrient Loss

Kyle R. Briscoe G. Munshaw, J.J. Varco, B.R. Stewart

Plant and Soil SciencesMississippi State University

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

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

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

Runoff Field Site• Plot area disked and tilled• Weather station - rainfall, wind speed, air

temp., relative humidity, photosynthetically active radiation

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

Half Rates

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

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)

Vegetative Cover Evaluation

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

Vegetative Coverage

Natural Rainfall - DRP

Simulation 1 – DRP

Simulation 2 – DRP

Simulation 3 – DRP

Simulated Rainfall – Total DRP

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

Influence of Roadside Establishment Practices on Sediment and Nutrient Loss

Dr. Jac VarcoProfessor

Plant and Soil SciencesMississippi State University

jvarco@pss.msstate.edu

Kyle BriscoeGraduate Research Assistant

Plant and Soil SciencesMississippi State University

kb371@msstate.edu