Nutrient Management Efforts in a Minnesota Watershed

YELLOW MEDICINE RIVER

Nutrient Management Efforts in a
Minnesota Watershed
Yellow Medicine River Clean Water Partnership
Yellow Medicine River Watershed District
Steve Howey, conservation agronomist

Yellow Medicine River Watershed District, SW Minnesota
Minnesota River

Water monitoring sites
1997-2003
Yellow Medicine
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Lyon
Lincoln

Water quality analysis
■ Ortho P - plant available phosphorus
■ Total P - all P in water and solids
■ Total suspended solids - sediment,
etc.
■ Ammonia N
■ Nitrate
■ Total N

Some typical FWMC, mg/L (ppm)
2 year averages (1998-99)
■ Nitrates 2 to 17
■ Ortho P .01 to .14
■ Total P .07 to .40
■ Total Suspended solids 9 to 241

Description of project
■
Nutrient management project that is one part of larger
implementation that also includes CREP, buffers, etc.
■ began in September 2001
■
collaboration with NRCS, MPCA, DNR, SWCD
FOR MORE INFO...
Greater Yellow Medicine River Clean Water Partnership Phase II
Work Plan 2001-2004

Project Goals
■ Reduce nutrient loads significantly.
■ Monitor water quality over time

NITRATES

SITE 1997 1998 1999 2001 2002 AVERAGE
mg/L nitrates
one 1.8 5.2 4.2 4.1 4.2 3.9
two 1.8 4.3 3.4 3.2 3.9 3.3
three 1.8 7.0 4.3 4.2 4.0 4.3
four 3.1 27.9 6.9 6.4 6.7 10.2
five 1.7 3.5 3.6 2.5 3.6 3.0
six 2.5 3.3 3.9 1.9 2.3 2.8
seven 1.4 2.7 2.3 3.3 1.6 2.3
eight 1.5 2.6 1.6 2.0 1.8 1.9

Incentive programs example
■ Registered feedlots were contacted.
■ Incentive offered to do 2 foot nitrate
test.
■ Out of 38 feedlots contacted, 12
committed to project, 7 followed through
to completion.
FOR MORE INFO...
Steve Howey, agronomist. 1-507-872-6720.

Contd.
■ 27 fields were sampled, previous crop
soybean.
■ Average nitrate in top two feet was 48
lb./a.
■ Recommendations were 43 LB/a lower
than standard U of MN.

Evaluating Nitrogen
Management - Two Fields

Conv.
Ed &
Scott
Boehne
Don Bot
107
acres
No-till C / B
till C/B
38
acres

1
4
2
3

Checking nitrogen management
■ Variable rates were applied within the
field in the spring in year 1 (AA) and in
the fall of year 2 (band urea).
■ 4 different areas of field point sampled
in the fall of each year. No- till corn.
■ Cornstalk nitrate test (September) and
soil nitrate tests (Oct - Nov) taken at
point sample locations as well as other
routine tests in each year.

Objectives
■ Try to use all available tools to evaluate
N rate decisions after the fact using site
specific points in a field
■ Identify specific sites within fields that
may need more N management
■ Maybe learn something ?????

1
4
2
3

cornstalk tests
year 1 year 2
ppm
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
1 2 3 4
Drained
depression
point sample

post harvest nitrates in soil
year 1 year 2
lb / a nitrate N in two
feet
150
100
50
0
depression
1 2 3 4
point sample

Characteristics of the soil
2 year
cornstalk
average,
0 to 24 inch sample
Point ppm CEC pH CaCO3 % % OM
1 1885 34.1 7.8 7.8 3.7
2 7139 28.5 7.6 0.5 2.9
3 1789 33.7 8.0 4.6 2.9
4 1728 35.8 7.9 8.1 3.3

Conv.
Ed &
Scott
Boehne
Don Bot
107
acres
No-till C / B
till C/B
38
acres

X = open tile intake in depression
Hybrid A
X
Hybrid B

Field size N treatments
■ 40 lb/a N was applied late in fall with
DAP
■ 60, 80, or 105 lb/a sidedressed in
adjacent strips
■ total N was 100, 120, and 145 lb/a
■ yields weighed with weigh wagon

X = open tile intake in depression
Hybrid A
X
Hybrid B

hybrid A hybrid B overall
means means
lb N /a
100 170.3 / 21.3 157.3 / 16.9 166 / 19.9
120 164.8 / 22.1 151.1 / 16.0 160 / 20.1
145 165.7 / 21.9 148.6 / 15.2 160 / 19.7

Cornstalk tests from each strip
Location in field cornstalk test 2 ft N yield
(ppm) lb/a bu/a
North (well drained hill) 3075 45 158
Middle (drained depression) 477 “low” 19 176
South ( level, SWPD) 5555 54 152

TYPICAL RELATIONSHIP on BOTH FIELDS
rate of N vs nitrate s in 0 to 24"
s oil nitrate N, lb/a
Oct 6
40
30
20
10
0
90 110 130 150
rate of N, lb/a

Summary of N evaluations
■ Positive relationships between rate of N
applied and the residual nitrates in soil
■ Depressional areas appear to be good
candidates for more N management
■ N rates recommended by Univ. of MN
were valid
■ Cornstalk tests not related to soil tests

PHOSPHORUS

SOIL TESTING LOCATIONS
Red- high, VH
Yellow -
medium
Green -low

P soil tests in the YMRW, 2001-2003 197 fields
35
30
OVERALL AVERAGE = 15 ppm
average = 28 ppm
25
% of samples
20
15
10
5
0
very low low medium high very high
Soil test category

WATER QUALITY / LAND USE / P SOIL TESTS
Yellow Medicine River Watershed
11/03
growing season
3 yr avg 4 yr avg avg avg %
mg/ L mg/ L soil approx % river % hay % animal
river ortho P Total P test acres acres slope cult. grass forest units/
acres chnl SITE includes FWMC FWMC (ppm) test tested feet/mi land land acre
300609 main 2 all ex. 4-->2 0.06 0.26 16 6240 2.1 16.2 91 7 4 0.22 0.36 15 2000 5.1 3.4 93 2 5 0.05 0.20 13 1840 2.3 22.6 84 8 6 0.18 0.33 14 1480 4.2 36.9 81 14 7 0.07 0.20 11 1480 3.4 23.3 80 13 8 0.06 0.30 10 1440 3.3 21.6 77 14

TYPICAL RESULTS - a relationship between soil
test P and landscape position.
P soil tests, 0 to 3 inch, down a 6 to 12% slope
35 ppm
40 ppm
42 ppm
100 feet

PHOSPHORUS MOVEMENT IN THE FIELD
100
80
60
40
20
0
Soil test, expressed as a
% of intake sample
P K
Nutrient
Field average
Around tile intakes

WHERE ARE THE HIGH PHOSPHORUS FIELDS ??
Soil tests from sampling in YMRWD,
fall 2001
soil test as % of
manure history
field
100
50
0
N P K Zn
Nutrient

MN P index experiences
■ If BMPs for P are followed, current P
index values would be “very low” or
“low” for our watershed.
■ Screening tool was developed to
suggest what to do based on soil test,
% slope, and texture.
■ Possible applications to site specific
work.

Some examples of calculated P
index values in the watershed
Field Soil test NRCS P index
(ppm) RUSLE
(tons/acre)
1 50 3.4 0.82
2 8 1.3 0.26
3 29 1.3 0.32
4 16 2.5 0.45
5 20 2.5 0.47

“GRID” sampling and P index - what is
the potential ?
Drainage Ditch
Farm site
1
6
8
12
intake
2
5
3 4
9
11
7 10
This field is within 1 mile
of a large dairy operation,
and has an average P soil
test of 19 ppm. More
manure applications are
scheduled for the future.
½ MILE

soil closest manure STP SDR soil P Path 1 Path 2 Path 3 P index
test RUSLE distance factor total risk risk risk Value
1 7 0.9 1100 0.75 0.2 0.25 0.9669 0.1 0.0 0.1 0.3
2 14 2 600 0.75 0.2 0.28 1.0138 0.3 0.1 0.1 0.5
3 13 1.1 100 0.75 0.2 0.4 1.0071 0.2 0.1 0.1 0.3
4 23 0.9 600 0.75 0.2 0.28 1.0741 0.1 0.1 0.1 0.4
5 15 2 500 0.75 0.2 0.28 1.0205 0.3 0.1 0.1 0.5
6 24 2 500 0.75 0.2 0.28 1.0808 0.3 0.1 0.1 0.6
7 19 0.9 500 0.75 0.2 0.28 1.0473 0.1 0.1 0.1 0.3
8 16 0.9 10 0.75 0.2 0.5 1.0272 0.1 0.1 0.1 0.3
9 16 0.9 10 0.75 0.2 0.5 1.0272 0.1 0.1 0.1 0.3
10 19 0.9 700 0.75 0.2 0.26 1.0473 0.1 0.1 0.1 0.3
11 26 4.1 400 0.75 0.2 0.3 1.0942 0.7 0.1 0.1 0.9
12 32 4.1 450 0.75 0.2 0.3 1.1344 0.7 0.2 0.1 1.0

MN P index experiences
■ IF phosphorus BMPs are followed, current P
index values would be interpretated “very
low” or “low” for our watershed.
■ Screening tool was developed to suggest
what to do based on soil test, % slope, and
texture.
■ Possible applications to site specific work.

Average % Slope of Field or application area**
Other
less than 2 %
2 to 6 % greater than 6% Sandy Flooding
P soil (nearly level) (gently sloping) (hilly or steep) soils or Ponding
test 0-6"
Nutrient Source
Fertilizer Manure* Fertilizer Manure* Fertilizer Manure* All All
Low A G A G A G K K
Medium B G B G B G K K
High C G C G E I K K
Very High D H D I F J K K
stop applying P2O5
if over 80 ppm
stop applying P2O5
if over 40 ppm
stop applying P2O5
if over 20 ppm
All L L L L L L L L

Future work in the Yellow
Medicine River Watershed
■ Phosphorus BMPs, erosion control,
and state manure rules will be
stressed.
■ Soil and manure testing.
■ Field testing of MN P index.
■ Water quality will be monitored.