2019 SWCS International Annual Conference July 28-31, 2019 Pittsburgh, Pennsylvania

1. DECISION SUPPORT TOOLS FOR COVER CROPS:
CREDITING WATER AND NITROGEN CONSERVATION
CHRIS REBERG-HORTON, STEVEN MIRSKY,
AND MANY, MANY MORE
July 29, 2019 – Pittsburg, PA

2. 2
COVER CROPS
Hairy Vetch
Cereal Rye
OatsRed Clover
Winter Wheat
Forage Radish
Nitrogen
Fixation
Nutrient
Scavenging/
Retention
Insect Pests
Erosion
Control
Nutrient Use
Efficiency
Conserve
Water
Crop
Productivity
Weed
Suppression
Organic
Matter
Habitat for
Beneficial
Organisms
Cover
Crops

3. ON-FARM NETWORK
• On-farm trials
• Cover crop adopters
• 6 states
• 2017-present
• 75+ site-years
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4. OBJECTIVES
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Objectives:
1) to demonstrate the short-term benefits of cover crops on soil
water and N conservation, and
2) to deploy decision support tools for growers to increase
cover crop adoption in the mid-Atlantic and Southeast US.
Many farmers believe cover crops are a net detriment to water storage
and that grass cover crops increase N fertilizer requirements due to N
immobilization.
Low Cover Crop Adoption

5. Cover Crop TreatmentNo Cover Crop Treatment
EXPERIMENTAL DESIGN
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• 2 adjacent treatments.
• Cover crop management is chosen by the grower.
• Cover crop residues remain on the surface.
• Next cash crop can be corn, cotton, or soybeans.

6. NITROGEN CONSERVATION
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Annual nitrate mass loss in tile drainage for corn-soybean
rotation near Ames, IA, with and without cover crop.
Presence of the cover crop significantly reduced nitrate loss.
Modeling effort is conducted to quantify the amount nitrogen
released by the cover crop based on cover crop biomass
composition, rainfall, temperature, and relative humidity.

7. WATER CREDIT
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• Increased infiltration rates were observed in
the cover crop treatments.
• Differences between treatments was higher
for more intense storms.
• Further data analysis is ongoing.

8. GROWER DASHBOARD
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For real-time data access and co-learning.
Enter grower’s last name
Grower’s sites
Map site locations
Sampled fresh
cover crop biomass
Dry cover crop biomass
Cover crop biomass
at grower’s sites in
comparison to all
the other sites
Cover crop Nitrogen content
and availability for cash crop
Volumetric soil water content by depth and treatment

9. DECISION SUPPORT TOOLS
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10. IMPACT OF THE PROJECT
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Scientific Community
 Better understanding of the short-term effects of
cover crops on soil water dynamics and soil fertility.
Field Educators
 Development of an outreach program that identifies and
overcomes misconceptions about the cost and value of cover crops.
CC and CT Adopters
 Growers have data to advocate with neighbors.
 Development of advanced risk management tools to
help growers improve their management strategies.
Middle Adopters
 We leverage our findings to increase CC and CT
adoption across the US.
General Public
 Development a website to make our research
program and findings accessible online.

11. FUTURE WORK
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• On-farm network will be deployed to 23 states in 2020.
• New metrics will be conducted to:
- Evaluate the short-term effect of cover crops on weed and pest management.
- Identify the social, economic, and intrinsic barriers to cover crop adoption
• RGB and NIR cameras will be deployed to measure the effect of cover crops on cash
crop water stress during the hot summer months.

12. FUTURE WORK
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13. FUNDING SOURCES AND ACKNOWLEDGMENTS
NRCS CONSERVATION INNOVATION GRANTS
USDA – NIFA WATER FOR AGRICULTURE
NRCS SOIL HEALTH DIVISION
NRCS FIELD STAFF IN MULTIPLE STATES
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14. Questions?
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