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

Atrazine ecological monitoring

site in Missouri

Claypan Region-

• Comprised of restrictive soil layers

• Prone to surface run-off

MO-02

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).

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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

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Atrazine Setbacks

Important: Always read and follow label instructions.

(Label education example)

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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.

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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

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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

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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

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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

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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 MO-02

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Tillage practice changes for MO-02.

MO-02

14 MO-02

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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 MO-02

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Corn Field Dispersal and Atrazine Usage

2011

2012

2010

MO-02

2013

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Structural BMP survey

● Individual practices identified in each field.

● Surveyed in 2010 with a repeat planned for 2014.

● Changes tracked over time.

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Structural BMPs

Number of observed practices per field Fields with grassed waterways

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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

pp

b

Year

Field by field data gathering and individual visits begin.

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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

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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