Nitrate in Groundwater:
Well Testing Results and the Nitrogen
Fertilizer Rule
MVTL Agronomy Update Meeting
February 18, 2016
Larry Gunderson
Pesticide and Fertilizer Management Division
Minnesota Department of Agriculture
Topics Today
• Nitrogen Fertilizer BMP Survey
• Nitrogen Fertilizer Management Plan
• Nitrate in private wells
• Nitrogen Fertilizer Rule
MDA Partners with the National Ag Statistics Service to Document Current Fertilizer Management Practices
Insert
Google: MN NASS Nutrient Management Survey
One Specific Objective of the 2013 Survey was to Examine Fall Nitrogen Application Practices
Did You Fall-Apply Nitrogen Fertilizer for the 2013 Corn Crop?
0
10
20
30
40
50
60
70
80
NW SW and WC SC Combined
Yes No
Per
cen
tag
e o
f R
esp
on
ses
Fall-Applied Anhydrous Ammonia for Next Year's Corn Crop?
(Based on the Last 5 Years of Production)
0
2
4
6
8
10
12
14
16
18
20
NW SW and WC SC Combined
AllSome
Per
cen
tag
e o
f R
esp
on
ses
Did Your Fall-Applied Anhydrous Ammonia Included N-Serve on the 2013 Corn Acres?
0
10
20
30
40
50
60
70
NW SW and WC SC Combined
All My Corn Acres
Some Acres
Per
cen
tag
e o
f R
esp
on
ses
Trends in the Three Major N Sources used in Minnesota (1989-2015)
0%
10%
20%
30%
40%
50%
60%
Relative
Sales
Sales Since 1989
N Solutions
Misc. sources
Anhydrous Ammonia
Urea
(Updated 2-6-2016
Urea
Fall-Applied UREA for Next Year's Corn Crop? (Based on the Last 5 Years of Production)
0
2
4
6
8
10
12
14
16
18
NW SW and WC SC Combined
All Some
Per
cen
tag
e o
f R
esp
on
ses
Critical That Fall Applications Are Applied When Soil Temperatures Are 50F or Less
N BMP Region Average Date of
Urea Application
Average Date of AA Application
Northwest 10/28/13 11/2/13
SW and West Central
11/7/13 11/5/13
South Central 11/2/13 11/4/13
Combined 11/5/13 11/4/13
N Fertilizer Rates on Corn as a Function of Previous Crop (2010 and 2013 Crop)
0
20
40
60
80
100
120
140
160
180
Statewide 2010 2013 NW, WC, andSC Regions
2013 SE and CoarseTextured
Corn-Corn Corn-Soybeans Corn-Alfalfa
Nit
rog
en F
erti
lize
r In
pu
ts L
b/A
Example of How the Results are Presented
NASS Corn Grower N Survey-2010
% of Fields Within UM Recommended N Ranges for Corn Following Corn---Statewide
Details: Analysis included 665 fields. Analysis uses “Nitrogen to corn price ratio”
of 0.05 UM Recs at 0.10: 120-165 (140)
Manured fields not included in this scenario. Additional details on page 57.
NASS Corn Grower N Survey-2010
% of Fields Within UM Recommended N Ranges for Corn Following Soybeans---Statewide
(Results from 2,222 fields)
NASS Corn Grower N Survey-2010
% of Fields Within UM Recommended N Ranges for Corn Following Alfalfa---Statewide
Details: Analysis included 186 fields. “Nitrogen to corn price ratio” 0.05. Manured
fields not included in this scenario. Additional details on page 95.
MDA is lead agency for Nitrogen Fertilizers
Legislatively MDA must:
• Develop voluntary Best Management Practices (BMPs) to “prevent or minimize the source…to the extent practicable”;
• Promote BMPs via education and demonstration projects;
• Evaluate BMP adoption and effectiveness;
• Consider regulation if BMPs are proven ineffective
Nitrogen Fertilizer Management Plan
Nitrogen Fertilizer Management
Plan (NFMP)
• Many wells exceed the health standard for nitrate in areas where groundwater is vulnerable to contamination
• The NFMP is the state’s blueprint for minimizing groundwater impacts from the use of nitrogen fertilizer
• Has voluntary and regulatory components
• Revised in March 2015
Nitrate Leaching from Fertilizer
• A very challenging problem
• Losses may vary significantly between years due to
weather
• May be long lag times (years) between changes in
practices and changes in groundwater quality
• Enormous variability between and within aquifers
There is no simple solution
Nitrate Leaching from Fertilizer
• Nitrogen loss will occur under row crop production even
without additional fertilizer inputs;
• “Background” nitrogen losses of 5-20 Lb/A per year can
occur under some of Minnesota’s most productive soils
when producing annual row crops;
• Through careful N management, N losses can be
reduced by 10-20% without significantly reducing yields
The Revised NFMP
1. An emphasis on prevention;
2. Extensive testing of private wells by township;
3. A new phased approach to assessing and prioritizing areas with nitrate contamination;
4. An emphasis on involving local producers and communities in problem solving through local advisory groups; and,
5. Promoting alternative management tools (AMTs) – changing land management in targeted areas.
Primary Goal of the Revised NFMP
“…is to involve the agricultural community in problem solving at the local level. We all need to work together to respond to and address localized concerns about unsafe levels of nitrate in groundwater.“ Commissioner of Agriculture, Dave Fredrickson
Phased Approach
• A four level approach based on percent of wells exceeding the nitrate drinking water standard
• Two levels are voluntary, two are regulatory
• Starts with one of the voluntary levels
• Becomes regulatory only if BMPs are not voluntarily adopted
Nitrate Reduction Strategies
• Adoption of the nitrogen fertilizer
Best Management Practices
(BMPs)
• Increased low nitrogen vegetative
cover (perennial crops, forages
and cover crops) or taking land
out of production in targeted high
risk areas
Township Well Testing Program
• In townships with vulnerable groundwater and significant
row crops
• Partnership effort with local government
• Includes all private wells (up to 70,000 wells)
• Voluntary
• No cost to owner – funded by the Clean Water Fund
• If nitrate is detected follow-up sampling is conducted for
pesticides
Township
Testing
Approximately 250 to
300 townships with row
crop agriculture and
vulnerable groundwater,
or history of high nitrate
will be tested
Two Step Process
Step 1 – Initial test
• Work with local partner (SWCDs or County)
• All well owners are offered a free nitrate test kit
• Homeowner collects sample and mails it in
Step 2 – If nitrate is detected:
• Collect follow-up nitrate and pesticide samples
• Samples collected by trained staff
Preliminary Results
For 2013-2014
• Approximately 7342 wells were sampled
• 13% (982) of those wells were >= HRL
Does not include hand dug wells or wells with unclear locations
Results are preliminary and subject to change
Percent of Wells
above the Standard
(10 mg/L Nitrate-N)
Number of
Townships
Less than 5% 14
5%-9.9% 17
10% or more 29
Total 60
Results for
Central Minnesota
Results for
SE Minnesota
Testing
Schedule
• Sampling will occur over
several years
• The first round of
sampling should be
completed by 2019
Prevention Level One
Level Two
Level Three
Level Four
Nitrate Levels
BMP Adoption
Regulatory Status
Acceptable or Undetermined Not Acceptable
Increasing
Voluntary Regulatory
Revised NFMP: Clear Definition of Prevention & Mitigation Levels for Localized Responses
Thresholds for NFMP Mitigation Levels for Private
Wells Level One
Level Two
Level Three
Level Four
Private Wells
5% or More Above 10
mg/L
OR
10% or More Above 7 mg/L
10% or More Above 10 mg/L
15% or More
Above 10 mg/L
• First considers nitrate levels • Next considers rate of BMP adoption
Voluntary Regulatory
Nitrogen Fertilizer Rule
• Part One— Restrict application of nitrogen fertilizer in
the fall and to frozen soils in areas vulnerable to
groundwater contamination
• Part Two—Place the process for moving to regulations,
as outlined in the NFMP into rule
Nitrogen Fertilizer Rule – Part One
Applies to areas with vulnerable groundwater These may include: • Coarse textured soils • Shallow fractured bedrock (karst) • Elevated nitrate in local wells • Defined as vulnerable by the DNR
based on groundwater infiltration rates
Nitrogen Fertilizer Rule – Part Two
The NFMP process for moving to regulations will be placed
into rule
• Generally based on township(s) or source water
protection area
• Selected from a list of options based on local and
regional conditions
• Input from local advisory committee
• Only regulate if BMPs are not adopted
• Applied on a site specific basis via Commissioner’s
Order
Regulatory Options: • Appropriate Regional
BMPs
• Record keeping
• Attend training
• Collect well water samples
• Credit N from previous crop and manure
• Soil Testing
• Nitrification inhibitor
• Irrigation Management
Part Two Rule Process
Commissioner’s Order
Example Commissioner’s Order:
• Record keeping • Credit nitrogen from all
sources • Soil testing • Select BMPs
Local Advisory Team
Thank you!
Larry Gunderson
For more information:
http://www.mda.state.mn.us/nfmp
Reference Slides
300,000
400,000
500,000
600,000
700,000
800,000
900,000
To
ns o
f A
ctu
al N
Sales Since 1990
Data Source: MDA, TVA, and AAPFCO
Commercial Nitrogen Fertilizer Sales Trends in Minnesota: 1990-2015
Decade Averages 1990-1999: 653,817 2000-2009: 648,274 2010-
2015:762,573 (Updated 2-6-2016)
300,000
400,000
500,000
600,000
700,000
800,000
900,000
To
ns o
f A
ctu
al N
Sales Since 1990
14% Increase Compared to Last 25 Years
Data Source: MDA, TVA, and AAPFCO
Commercial Nitrogen Fertilizer Sales Trends in Minnesota: 1990-2015
Decade Averages 1990-1999: 653,817 2000-2009: 648,274 2010-
2015:762,573 (Updated 2-6-2016)
Data Source: MDA, TVA, and AAPFCO
Commercial Nitrogen Fertilizer Sales Trends in Minnesota: 1965-2015
Ten Year Averages 1990-1999: 653,817 2000-2009: 648,274 2010-2015:
762,573
100,000200,000300,000400,000500,000600,000700,000800,000900,000
Tons o
f A
ctu
al N
Sales Since 1965
(Updated 2-6-2016)
Data Source: National Ag Statistics-MN Dept of Ag
Trends in Planted Corn (Grain) Acres in MN from 1986-2015
5,000,000
5,500,000
6,000,000
6,500,000
7,000,000
7,500,000
8,000,000
8,500,000
9,000,000
Acre
s P
lan
ted
to
Co
rn (
for
gra
in)
(Updated 2-6-2016)
Statewide Estimates of N Fertilizer Rates on Across All Grain Corn Acres (1992 to 2015)
(N BALANCE TECHNIQUE, MDA Unpublished Data, Montgomery)
(Updated 2-6-2016)
106
116
127 130
124
139
127 129
132
111
121
126
158
120
117 113
122
112
132 134
143
138
143
138
100
110
120
130
140
150
160
170
Es
t. N
Rate
on
Co
rn G
rain
“Nitrogen Use Efficiency” for Minnesota Corn Production 1992 to 2015
0.3
0.6
0.8
1.1
1.3
1.6
Rati
o o
f B
ush
els
Pro
du
ced
per
Lb
N
Fert
iliz
er
Inp
ut
Statewide "NUE" on Corn Using the N Balance Method
(Updated 2-6-2016)
Relationship Between Production and N Fertilizer Inputs on MN Corn
(1992-2015)
0
200
400
600
800
1,000
1,200
1,400
1,600
1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016
Corn Acres (X10000)
Est. Tons of N Fertilizer on Corn (X1,000)
Bu. Produced (Millions)
Bushels Produced
N Fertilizer Inputs
(estimated for corn)
Planted Acres
(Updated 2-6-2016)
Trends in the Three Major N Sources used in Minnesota (1989-2015)
0%
10%
20%
30%
40%
50%
60%
Relative
Sales
Sales Since 1989
N Solutions
Misc. sources
Anhydrous Ammonia
Urea
(Updated 2-6-2016
Urea
Minnesota Drinking Water
• 8 community water supply systems treat for nitrate 50,000 people Up from 6 systems in 2008
• 105 non-community system’s had water sources with
nitrate at or above the maximum contaminant level (MCL) of 10 milligrams per liter (mg/L).
(Minnesota Drinking Water Annual Report 2014, MDH)
Regulatory
NFMP Phased Approach to Regulation
Regulatory
Status Voluntary Voluntary Voluntary Regulatory Regulatory
Criteria Prevention
Level Level One Level Two Level Three Level Four
1
<5%
5% ≥ 10 mg/L
10% ≥ 10 mg/L 10% ≥ 10 mg/L 15% ≥ 10 mg/L Nitrate
Concentration or
10% ≥ 7 mg/L
2
Unknown Unknown Acceptable Not acceptable Not acceptable BMP
Use/Adoption
Alternative Management Tools (AMTs)
Changing the cropping
system:
• Crop rotation
• Cover crops
• Use of perennials (alfalfa)
• Land swapping
• CRP/hunting preserve
• Lower N use varieties
• Taking land out of
production
Hand Dug Well
Step Two Sampling
A. Document well information • Well type, depth and construction
B. Inventory other possible nitrate
sources close to the well • Construction problems
• Septic sources
• Animal sources
• Other sources
Exceptions to Part One Restrictions
Proposed exceptions include:
• To establish cover crops, perennials or small grains
• For pasture fertilization
• Monoammonium phosphate (MAP)
• Diammonium phosphate (DAP)
• MDA approved land application of soil from spills or
facility cleanups
Fall Nitrogen Fertilizer Application
What?
Proposed rules will restrict fall application and application to frozen ground of nitrogen fertilizer when it is listed under “Not Recommended” in the U of M BMPs for nitrogen fertilizer:
• Coarse Textured (Sandy) Soils: Fall application of nitrogen regardless of source
• Southwestern and West-Central Minnesota: Fall application of UAN (28-0-0) or any fertilizer containing nitrate-nitrogen
• Southeastern: Fall application of ammonia, urea and UAN with or without a nitrogen inhibitor.
• South Central: Fall application of urea and ammonia without N-Serve. Fall application of UAN.
• Northwestern: Fall application of liquid nitrogen (UAN (28-0-0)) or any fertilizer containing nitrate-nitrogen.
The rule will include exceptions where appropriate.
Problematic Areas of Minnesota?
• Significant portion of Dakota County; • Localized areas of the outwash plains; • Critical recharge areas in Southwest
MN used for Rural Water Systems; • Southeast Karst; • Small number (but critically important)
of Community Water Suppliers
St. Peter was one of the pioneer wellhead projects in Minnesota starting in the early 1990’s
0
2
4
6
8
10
12
14
16
Nit
rate
-N (
mg
/l)
Year
Well # 6 (Jordan)
Well # 9 (Jordan)
Jefferson (South WaterPlant)
St. Julien (North WaterPlant)
Monthly Nitrate-Nitrogen Levels
City of St. Peter Drinking Water Wells
Safe Drinking Water Standard
1994 1998 2002 2006 2010
Legislation provided guidance for a variety of NFMP activities including…..
• Development of voluntary Best Management Practices (BMPs);
• Promotion of BMPs via education and demonstration projects;
• Evaluation of BMP adoption and effectiveness; and
• A process for going to regulations if BMP implementation steps are proven ineffective
Perham Golf Course Demonstration Project
Perham Golf Course Nitrate-N Levels Below the Fairways
Lake Side Country Course at Perham Demonstration Project
0
2
4
6
8
10
7/21 8/
38/
18 9/7
11/1
4
5/24
/200
16/
207/
248/
239/
25
4/29
/200
26/
11 7/5
8/25
9/20
5/20
/200
36/
187/
31
Sampling Dates
Pa
rts
Pe
r M
illio
n 2000 2001 2002 2003
0
10
20
30
40
50
60
5/11
/200
0
6/1/
2000
6/26
/200
0
7/21
/200
0
8/11
/200
0
9/8/
2000
10/1
8/20
00
5/15
/200
1
6/20
/200
1
8/9/
2001
9/26
/200
1
5/9/
2001
6/19
/200
2
8/6/
2002
9/20
/200
2
Sample Dates
Nit
rate
-N (
mg
/L)
Nitrogen-PPM
Golf All
(Approximately)
Golf 323 Samples
Irrigated Ag 1200 Samples
Nitrate-N Concentrations under Traditional Irrigated Cropping Rotation vs. Golf Course Perham Wellhead Protection Area
Due to the dense fibrous root system, coupled with following recommended rates, turfgrass contributions are generally low to very low
