Technology to Manage Nitrogen
Fertilization
Women In Ag Educator Conference
OKC, OK
April 1-2, 2008
Agriculture Producers have a choice!
Live in the past or move forward with
technology?
A Soil Test only works if a
test is taken
11 % every year
17 % every 2 yr
32% every 3 yr
37 % never
Laboratory Soil Testing
-Oil dipstick for P & K
-2 lbs./ac. Actual N =
1 bu./ac. Wheat Yield
Cereal (corn, wheat, rice) NUE
averages 33% world wide
Questionable Profit Margins
Environmental Sensitivity of Wheat
and Corn Production Systems
Excess nitrogen flowing down the
Mississippi each year is estimated to
be worth $750,000,000 (Science,
Malakoff, 1998)
NUE in cereal production must be
improved
Fertilizer N requirement (total yield/N rate) for
maximum wheat yield (trial 502).
N Requirement (lb/bu)
4.0
y = 1.33E-02x + 1.49E+00
Ave = 1.7; C.V. = 39
3.5
3.0 2.7
2.7
2.5
2.1
2.0
3.4
2.6
2.6
1.8
1.7
2.2
1.9
1.9 1.8
1.9
2.2 2.2
2.1
1.9 1.8 1.9
1.6
1.5
1.2
1.3
1.3
1.2
1.3
1.2
0.8 0.9
0.8
1.0
0.6
0.4
0.5
0.0
0.0
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
Year
The NITROGEN
CYCLE LEAKS….
What can be done?
Lahoma Wheat Field May 18, 2006
RAMP’s & N-Rich Strips being
established Oct. 30, 2007
Marking RAMP’s and N-Rich Strips
Measuring off 40’ x 600’ SBNRC Harvest Demo
Bicycle flags mark a 40’ x 600’ area to be harvested
40’
600’
600’
40’
Two RAMP’s and an N-Rich Strip seen from pickup
N-Rich Strip bordered by two RAMP’s
RAMP with 0 lbs./ac. on this end
N-Rich Strip on January 20, 2008
Producer Sensing RAMP’s and Strips 2-2-08
SBNRC rates applied to harvest demos 2-7-08
Normalized Difference
Vegetative Index - NDVI
• Calculated from the red
and near-infrared bands
GreenSeekerTM Sensor
Light Detection and
Filtering
Detection of
Reflected
NIR and RED
+Sun
Direction
NIR and RED
Modulated
Illumination
Target
Normalized Difference
Vegetative Index - NDVI
• Calculated from the red
and near-infrared bands
• Equivalent to a plant
physical examination
Normalized Difference
Vegetative Index - NDVI
• Calculated from the red
and near-infrared bands
• Equivalent to a plant
physical examination
• Correlated with:
– Plant biomass
– Crop yield
– Plant nitrogen
– Plant chlorophyll
– Water stress
– Plant diseases
– Insect damage
INSEY
=
NDVI at F5
Days from planting to sensing, GDD>0
1308.0
7.0
110
43 Locations, 1998-2006
YP0 = 0.409e258.2 INSEY
6.0
Grain yield, Mg/ha
Bushels/acre
90
R2=0.50
YP0 + 1Std Dev = 0.590 e258.2 INSEY
5.0
Winter
Wheat
70
4.0
50
3.0
302.0
1.0
10
0.0
0
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
0.01
INSEY
Units: biomass, kg/ha/day, where GDD>0
In Season Estimated Yield
PKNP 1998
PKSN 1998
TPSN 1998
PKNP 1999
222 1999
301 1999
EFAA 1999
801 1999
502 1999
PKNP 2000
222 2000
301 2000
EFAA 2000
801 2000
502 2000
HNAA 2000
PKNP 2001
222 2001
301 2001
EFAA 2001
801 2001
PKNP 2002
222 2002
301 2002
EFAA 2002
801 2002
HNAA 2002
502 2003
222 2003
EFAA 2003
PKNP 2004
222 2004
301 2004
502 2004
2005
2006
80
1971
1972
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
Grain yield, bu/ac
90
0-40-60
Exp. 502, 1971-2006
100-40-60
70
60
50
40
30
20
10
0
Response to Nitrogen, Long-Term Winter
Wheat Experiment, Lahoma, OK
140
Exp. 502, 1971-2006
Optimum N Rate, lb/ac
120
Optimum N Rate
Avg. 49 lb N/ac +/- 39
Max Yield
Avg. 43 bu/ac +/- 13
100
80
60
40
20
19
71
19
74
19
76
19
78
19
80
19
82
19
84
19
86
19
88
19
90
19
92
19
94
19
96
19
98
20
00
20
02
20
04
20
06
0
“After the FACT” N Rate required for “MAX Yields” Ranged from 0 to 140 lbs N/ac
Why a RAMP or N Rich Strip
Because N Response Index Varies
from year to year and field to field.
It’s like filling up your gas tank, do
you put in 20 gallons of gas in every
time you fuel up no matter what?
Take Home Message:
60 5. Two lbs./ac. actual N doesn’t usually equal a
one bu./ac. wheat yield
50
40
30
20
10
0
1971
1972
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
Grain yield, bu/ac
1. Wheat’s Response to N Changes Year to Year
2. Demand for N Fertilizer Changes Year to Year
90
3. Without a RAMP or
N502,
Rich
Strip it is impossible
Exp.
1971-2006
0-40-60
80 to accurately determine how much N is needed
100-40-60
4. Applying
N “When it is Needed” Feekes 5 near
70 “FHS” is the best method to improve NUE
QUESTIONS