Multiscale Investigation of Winter Runoff and Nutrient Loss Processes in Actively

Managed Dairy Agroecosystems

Melanie Stock1

Dr. KG Karthikeyan2

Dr. Francisco Arriaga1 Dr. Laura Ward-Good1 Dr. Peter Vadas3

1. University of Wisconsin-Madison, Dept. of Soil Science, 2. Biological Systems Engineering; 3. USDA-ARS

Research Motivations• Logistical and environmental need Srinivasan et al. (2006)

‒ ~75% of annual runoff on frozen soils Good et al. (2012)‒ Nutrient losses from unincorporated manure‒ Cost-prohibitive long-term storage, emergency situations

• Recent updates to manure regulations• Limited conclusive, mechanistic, or replicated research

‒ Confounding effects from weather, frozen soil complexity‒ Poor model simulations for winter conditions

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Objectives1. Conduct multi-scale, replicated experiments to

investigate biochemical and physical processes controlling snowmelt, infiltration and runoff, and nutrient losses from frozen soil and manure.• Test management techniques producers can realistically

implement

2. Develop model routines for winter manure runoff processes that can be incorporated into process-based, field- and watershed-scale models.

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Multiscale ApproachIf manure is applied to frozen soils, how can management

practices reduce nutrient losses?

LAB FIELD MODEL

SHAW

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Methods: Laboratory Scale1. Test tube: Manure extractions for N and P

‒ 3 manures, 3 temperatures‒ New collaboration with USDA-ARS in St. Paul, MN

2. Snow-Manure Interaction: Type, Rate, Placement‒ 2 dairy manures, 3 rates, 3 placements (represents timing)

3. Snow-Manure-Soil Interaction‒ Rate and placement with soil

4. Soil physical properties

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Methods: Field ScaleTillage and manure timing, in triplicate

– Liquid dairy manure, 7000 gal ac-1

– Continuous corn for silage– Silt loam, south-facing 5.9 % slope

N

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Water-Energy Balance

Precipitation

Frost Depth

Wind

Air TemperatureVapor Pressure Surface

Temperature

Heat Flux

Soil Temperature

Soil Water ContentSoil Potential

Net Radiation

SnowDepth

Precipitation + Manure = Latent Heat + Infiltration + Runoff

Net Radiation+

Sensible Heat+

+Snow Storage

+Ground Heat

=Snow Storage

+Soil Storage

+Soil Water Flux

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Preliminary Results - Lab• No significant effect of temperature or placement in

snowpack on N and P release from manure• Model is working well for winter conditions, consistent

results between scales

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Preliminary Results - Field• Maximum application rate: 4000 gal ac-1 rate • 79 % no tillage plots generated runoff in all 9 events,

14 % tillage plots generated runoff, 2 events• Faster snowmelt with January manure applications

No tillage Tillage

2/1/16

Jan. Manure

No manure

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Summary and Next Steps

• Two upcoming field seasons of winter monitoring• Added year-round monitoring and new collaborations

expand the project toward our goal of a long term trials

Nutrient management is important outside of the growing season, particularly on frozen soils that are susceptible to runoff processes, but historically understudied

• Temperature and manure placement were not significant on N and P release, updates underway in SurPhos• Fall tillage, early manure application reduced runoff loss

Contact Information: Melanie Stock, stock@wisc.edu

Feb. 18, 2016Feb. 19, 2016Feb. 20, 2016Feb. 21, 2016

Thank you