Nitrogen Losses at a Drainage Systems Scale Bruce Montgomery MN Department of Agriculture

Red Top Cooperators UM Dept. of Soil, Water & Climate Blue Earth Agronomics Rob & Janice Meyer-Red Top Farms University of Minnesota Extension UM Dept of Biosystems and Ag Eng. Brown Nicollet Environmental Health And the BNC Water Quality Board

Why do producers error on the high side? “Research is only tested on garden size plots!” Because most research is developed on small plots under ideal conditions, many farmers believe that University recommendations will not work on production scale operations

St. Peter Wellhead Protection Area

Community Water Supplies Impacted by Ag

Key Project Goals: Red Top Farm Demonstration Bridge the gap between UM water quality plot work and farm fields in terms of evaluating nitrogen and pesticide Best Management Practices (BMPs). Characterize long-term water quantity and quality trends on a field scale using subsurface tile drainage systems. Develop a demonstration site that is meaningful on a local and a regional scale.

Red Top is Located in Nicollet County, MN

Red Top Field Layout West Field East Field

Monitoring Equipment at Red Top

Annual Drainage Losses Red Top Farm Annual Drainage Loss (Inches) On average, 7” of drainage or 25% of the annual water budget is transported.

“Storm Events” account for the majority of the annual drainage losses 58% 74% 76% Annual Drainage Loss (Inches)

Monthly Distribution of Sub-surface Drainage 2000 Growing Season-Red Top Typically, April-May- Early June account for approximately 75% of the annual drainage

Nitrogen Fertilizer Application Rates to Corn

1997 and 1999 N Rate Design

St. Peter Nitrogen Fertilizer Rate Validation Project 2000 and 2001 N Fertilizer Rate (Lb/A) on Corn Following Soybeans Bu/Acre

New UM Pub

Midwestern Water Quality Project Symposium March 11, 2003 Country Inn and Suites Mankato 9:00-3:00 Improve water quality in the Minnesota River Basin Midwestern Water Quality Project Minnesota CAP’s Partners MN Corn Growers St. Peter Wellhead Partnership University of Minnesota NAICC

Nitrate-N Changes After Implementation of UM BMPs: Nitrate-N Concentrations (mg/L)

Nitrate-N Changes After Implementation of UM BMPs: Nitrate-N Concentrations (mg/L)

Corn-95 Beans-96 Corn-97 Beans-98 Corn-99 Beans-00 Corn-01 Nitrate-N Concentration Conclusions NO 3 -N mg/Liter Approaching “background levels” (Corn-Sb rotation with no nitrogen fertilizer)

Nitrogen Fertilizer Application Rates to Corn

Nitrate-N Changes –Aggressive N Inputs/Management Changes Nitrate-N Concentrations (mg/L)

2001 and 2002 Nitrate-N Concentrations in Tile Water

Nitrate Concentrations by Growing Seasons and Crop

Nitrate-N Concentrations-Entire Monitoring Cycle at Red Top Farms Nitrate-N Concentrations (mg/L)

Nitrate-N Losses from Corn and Soybeans Average N Losses: 22 lb/A/year

Ortho-Phosphorus Concentrations Flow-Weighted by Growing Seasons

Total Phosphorus Concentrations Flow-Weighted by Growing Seasons

Phosphorus (Total) Losses via Sub-Surface Drainage

Red Top Benefits: Model Calibration

Sands et al, 2003

Pesticides at a Glance at the Red Top Site APPLIED to FIELD Metolachlor (Dual) Acetochlor (Surpass) Nicosulfuron (Accent) Imazethapyr (Pursuit) Dicamba (Banvel) Atrazine Glyphosate (Roundup) Trifluralin (Treflan) DETECTED in TILE WATER Metolachlor (Dual) Acetochlor (Surpass) Nicosulfuron (Accent) Imazathypyr (Pursuit) Dicamba (Banvel) Atrazine

Seven Mile Creek Watershed Characteristics 85% of the watershed is cropland-mostly prime; Very high % tile drained; Documented water quality challenges

Seven Mile Creek High Nitrogen Loading Minor Watershed

Seven Mile Creek Significant Phosphorus Loading Minor Watershed

Red Top and Seven Mile Creek Nitrate-N “Runoff”:

Red Top and Seven Mile Creek Nitrate-N Concentrations:

Field (Red Top) vs Watershed Scale (Seven Mile Creek) Nitrate-N Losses

n Due to the flashy drainage characteristics of these systems, continuous automated monitoring is absolutely critical! n The majority of the drainage and chemical movement occurs in very narrow timeframes. Red Top Farm Demonstration Drainage and Response Times

n Implementation of existing Nitrogen BMPs and University of Minnesota Fertilizer Recommendations resulted in a significant reduction in fertilizer inputs (25-30%), maintained yields and appears to have decreased N losses at this site by 40-50%. n Field scale Nitrogen strip validation work both at Red Top and within the St. Peter Source Water Protection Area continued to demonstrate that the UM Fertilizer Recommendations will optimize yields. Red Top Farm Demonstration Nitrogen Management Conclusions

General Observations based on the First 5 Years at Red Top Expect to see annual N LOSSES between Lb/A under well managed corn-soybean production; Unlikely that the 10 mg/L drinking water standard can be attained under corn-soybean rotations.

Red Top Farm Demonstration Nitrogen Losses in a Nutshell Assuming that nitrate-N levels of mg/L under a corn-soybean rotation are “background levels”, this means the following: 1)For every inch of drainage water, there is 3.2 pounds of N loss; (simply calculated by dividing the concentration by the magic number Of 4.4. In this case 14 mg/L divided by 4.4=3.2) 2) Furthermore, since the average annual drainage is 7”, this means that 22 lb/A is lost each year.

Red Top Farm Demonstration Nitrogen Management Conclusions n The biggest water quality improvements will be realized through the implementation of basic nitrogen management such as correct rate selection and timing of application.

n Monitoring tile drainage systems is a practical methodology for verifying effectiveness of Best Management Practices on a field-scale. n This system is an excellent educational tool for developing the linkage between ag practices and water quality issues. Red Top Farm Demonstration General Conclusions

For more information from MDA Staff…….. Bill VanRyswyk-Surface Water Hydrologist, Mankato Brian Williams-Advisor, Le Sueur Paul Wotzka-Surface Water Hydrologist, Elba (Whitewater State Park) Bruce Montgomery-Unit Supervisor, St. Paul