70th SWCS International Annual Conference July 26-29, 2015 Greensboro, NC

1. Mark White
Regulatory Stewardship Manager,
Stewardship & Regulatory Policy
Syngenta Crop Protection, LLC,
Greensboro, North Carolina 27419, United States,
Atrazine Stewardship in a Missouri
Watershed

2. 2
Atrazine ecological monitoring
site in Missouri
Claypan Region-
• Comprised of restrictive soil layers
• Prone to surface run-off
MO-02

3. 3
Stewardship Program
● Goal
- Develop a stewardship program that is effective in reducing atrazine
concentrations in watersheds vulnerable to run-off.
● Implementation
- Utilize an approach similar to a TMDL plan to gain voluntary adoption of
cultural and constructed best management practices that are known to be
effective in reducing pesticide run-off.
● Deliverables
- Education and outreach through grower meetings and partnerships
- Implement restricted use pesticide training module for certified applicator
training in the state.
- Develop field vulnerability maps for the watershed.
- Use the Syngenta Farming Practices survey to gauge adoption of practices
over time (2010 through 2013).

4. 4
Implementation & Deliverables
● Stewardship education and outreach
- State level stakeholder meeting annually
- Commodity groups, FB, Ag Retailers Assoc., DNR/EPA, NRCS, Dept. of Ag, Extension, ARS
- Label education
- Grower/retailer watershed meetings annually
- Program updates/year end results feedback
- BMP discussions
- Jointly sponsored meetings with stakeholders
- Corn Growers, Farm Bureau, Extension, Retail
- Restricted Use Pesticide (RUP) training module incorporation into
Certified Applicator Training material
- MU Extension estimates program has reached many thousand applicators
- Field vulnerability maps

5. 5
Atrazine Setbacks
Important: Always read and follow label instructions.
(Label education example)

6. 6
Does your field fall within a watershed with high claypan
soils (MLRA 109,112, 113 or 114)?
Do you intend to plant corn or sorghum
in the next season and use atrazine?
Check watershed map for potential field
vulnerability as a guide for BMP
consideration.
What are your tillage intentions?
Yes
Yes
One or more of the following BMPs are
recommended:
• shallow incorporation after atrazine application
• banded application at planting
• contour or ridge tillage
One or more of the following moderate to highly effective
BMPs are also recommended:
• Do not apply within 1-2 days of rainfall
• Strip cropping (in-field alternating crops)
• Use of precision application equipment
• Plant on the contour
• Use in-field grass contour strips
• Use water retention basins or structures
• Split application
• Riparian buffers (2-3 years to develop)
The following practices are also suggested:
• Apply post-emergence
• Use terraces with grass outlets
• Grass waterways (designed primarily for soil erosion control)
• Use artificial wetlands
• Edge of field grass buffers (2-3 years to develop)
Restricted Use Pesticide decision support tool.
Part of RUP training module.
Tillage
In addition…
Shallow incorporation that retains at
least 30% crop residue cover
recommended.
No-till*
* If using no-till in high claypan soils, soil-applied herbicides cannot be incorporated and pesticide losses to
surface runoff are highest for no-till systems.

7. 7
Field Vulnerability Map
Vulnerability rankings based on:
1. Depth to impervious layer <= 35 cm
2. Slope of field > 1%
Analogous to highly erodible land
(HEL) designation by USDA.
Indicates increased potential for
pesticide and nutrient run-off.
MO-02

8. 8
What BMPs were discussed?
 Label awareness and conformity
 Variable application timing
 Pre-emerge
 Split application
 Total post application
 Sensitive lands setback areas
 Shallow incorporation (see harrow incorporation study)
 Multiple product selection (Halex, Lexar, Lumax)
 Constructed vegetative practices
 Buffers
 Waterways

9. 9
Atrazine Incorporation and Soil Erosion – Balancing
Competing Water Quality Concerns for Claypan and
Restrictive Layer Soils
R. N. Lerch, C. M. Harbourt, R. R. Broz, and T. J. Thevary
ARS Field 1 Missouri

10. 10
Study Results
 Hydrology
- No treatment differences in mean discharge or total runoff volume
- No-till significantly increased normalized runoff volume and decreased time to initiation of runoff
 Erosion
- SS concentration: No-till < Harrow < Minimum-Till
- SS load: No-till = Harrow < Minimum-Till
 Atrazine
- Concentration: Minimum-Till < Harrow < No-Till
- Load: Minimum-Till = Harrow < No-Till
 Supported earlier studies (Capel et al., 2001; Ghidey et al., 2005):
- Effectiveness of incorporation for reducing atrazine transport in runoff
- No-till does not reduce runoff volume and greatly increases atrazine losses on claypan soils
 Roller harrow achieved the needed balance by controlling both erosion and atrazine losses
< Significantly less; = not different

11. 11
Observed BMP Trends in MO-02
● A move away from conventional tillage towards conservation tillage.
- Decrease in multi-pass conventional tillage (field residue < 30% at planting)
- Increase in one pass conservation tillage (field residue > 30% at planting)
- Very limited continuous no-till
● Significant increase in two pass herbicide application.
- Trend away from total pre-emerge program (one pass)
- Planned two pass (atrazine used multiple ways – pre and post)
● Increase in alternative product use.
- Herbicide tolerant genetics (Liberty Link, Glyphosate, Halex vs. Lexar)
● Atrazine rate reduction.
- Use rates declined variably from around 1.5 lb/ac to ~.75 lb/ac in some cases
● Incorporation of atrazine
- Incorporation has not been widely adopted to date

12. 12
MO-02

13. 13
Tillage practice changes for MO-02.
MO-02

14. 14
MO-02

15. 15
Note** all Grain Sorghum acres received a one pass system.
MO-02
% of Fields Using
2 Pass System
Avg. App. Rate
(qts/Ac)
2010 18% 1.00
2011 61% 0.39
2012 40% 0.52
2013 57% 0.50

16. 16
MO-02

17. 17
Corn Field Dispersal and Atrazine Usage
2011 20122010
MO-02
2013

18. 19
Structural BMP survey
● Individual practices identified in each field.
● Surveyed in 2010 with a repeat planned for 2014.
● Changes tracked over time.

19. 21
Structural BMPs
Number of observed practices per field Fields with grassed waterways

20. 22
What were the results?
MO-02 Max 60-Day Atrazine Rolling Averages
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
18.00
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
ppb
Year
Field by field data gathering and individual visits begin.

21. 23
Stewardship Sustainability
Stewardship practices adopted by growers and retailers are sustainable in
that:
• They don’t rely on incentives
• When incentives dry up so do the practices
• They are economically viable
• Expensive practices tend to inhibit adoption
• They are efficacious
• Weed control and crop yield must be equal to or better
• They are easily transferable
• Must be able to easily implement practices across operation

22. 24
Conclusions
● Effective product stewardship depends on:
- Proper stakeholder engagement
- Development of local relationships and trust
- Clarity of purpose and information sharing
● Stewardship at the watershed level takes a commitment of time (years).
● Often, the most effective BMPs were not the most adoptable.
- Incorporation
● Cultural management practices were more readily adopted than
structural management practices.
- Application (rate, timing, method) and tillage
● Success was driven by stakeholder investment in the outcome