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OSU Corn AlgorithmOSU Corn Algorithm

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Can Yield Potential (similar to “yield goals”) be Predicted MID-SEASON?Is it better than a preplant N decision?

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43 Locations, 1998-2006

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01

INSEY

Gra

in y

ield

, M

g/h

a

PKNP 1998PKSN 1998TPSN 1998PKNP 1999222 1999301 1999EFAA 1999801 1999502 1999PKNP 2000222 2000301 2000EFAA 2000801 2000502 2000HNAA 2000PKNP 2001222 2001301 2001EFAA 2001801 2001PKNP 2002222 2002301 2002EFAA 2002801 2002HNAA 2002502 2003222 2003EFAA 2003PKNP 2004222 2004301 2004502 200420052006

YP0 = 0.409e258.2 INSEY R2=0.50

YP0 + 1Std Dev = 0.590 e258.2 INSEY

NDVI at F5 INSEY

Days from planting to sensing, GDD>0

Units: biomass, kg/ha/day, where GDD>0

Winter WheatWinter Wheat

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Predicting Yield Potential in Corn NDVI, V8 to V10

INSEY Days from planting to sensing

20 Locations, 2002-2005Hybrid Corn, Mexico, Nebraska, Iowa,

Oklahoma, Virginia, OhioV8-V10 (44 to 69 days)

y = 19583x1.7916

R2 = 0.71

0

2

4

6

8

10

12

14

16

18

20

0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018

INSEY

Gra

in y

ield

, M

g h

a-1

104-day (2003)

107-day (2003)

111-day (2003)

99-day (2004)

113-day (2004)

105-day (2002)

109-day (2002)

113-day (2002)

113-day (OFIT)

108-day (OFIT)

Efaw (2003)

LCB (2003)

Efaw (2004)

LCB 2004

Mexico (2002)

Shelton (2004)

Ames (2004)

OhioCORNCORN

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Exp. 502, 1971-2006

0

10

20

30

40

50

60

70

80

901

97

11

97

21

97

41

97

51

97

61

97

71

97

81

97

91

98

01

98

11

98

21

98

31

98

41

98

51

98

61

98

71

98

81

98

91

99

01

99

11

99

21

99

31

99

41

99

51

99

61

99

71

99

81

99

92

00

02

00

12

00

22

00

32

00

42

00

52

00

6

Gra

in y

ield

, b

u/a

c

0-40-60

100-40-60

Long-Term Winter Wheat Grain Yields, Lahoma, OK

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0

20

40

60

80

100

120

140

1971

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

Op

tim

um

N R

ate,

lb

/ac

Exp. 502, 1971-2006

Optimum N Rate Max YieldAvg. 49 lb N/ac +/- 39 Avg. 43 bu/ac +/- 13

Response to Fertilizer N, Long-Term Winter Wheat Experiment, Lahoma, OK

Response to Fertilizer N, Long-Term Winter Wheat Experiment, Lahoma, OK

“After the FACT” N Rate required for “MAX Yields” Ranged from 0 to 140 lbs N/ac

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Can RI be Predicted in Wheat?.... YES

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

2.75

3.00

3.25

0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75RINDVI

RI H

arve

st

67 Locations, 1998-2004y= -0.70 + 1.69X (x<1.72)y= 1.13 + 0.45X (x>1.72)

R2 = 0.53

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Can RI Be Predicted in Corn?... YES

MullenAgronomy Journal 95:347-351 (2003)Winter Wheat

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Improved Prediction of Yield Potential

SuperPete to the Rescue

Improved Prediction of Yield Potential

SuperPete to the Rescue

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All Equations

0

5

10

15

20

25

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

NDVI

Yie

ld, M

g/h

a

538 680 797 910 988 1206

All GDD Class Yield Prediction Equations for Corn

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550-650 (V5-V6)

y = 6766.8e1.291x

R2 = 0.36

0

5000

10000

15000

20000

25000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

NDVI

Yie

ld, M

g/h

a

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850-950 (V8 - V9)

y = 2359.9e2.0459x

R2 = 0.43

0

5000

10000

15000

20000

25000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

NDVI

Yie

ld, M

g/h

a

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950-1050 (V9-V10)

y = 832.4e3.5488x

R2 = 0.83

0

5000

10000

15000

20000

25000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

NDVI

Yie

ld, M

g/h

a

> 1050 (V10 - V12)

y = 684.44e3.1401x

R2 = 0.54

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

NDVI

Yie

ld, M

g/h

a

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y = -0.000000055x3 + 0.000144228x2 - 0.118267442x + 31.779941626

R2 = 0.88

y = 0.000000101x3 - 0.000267038x2 + 0.218075180x - 51.146352373

R2 = 0.97

0

1

2

3

4

5

6

7

8

500 700 900 1100Sum GDD

Co

ef A

0

0.5

1

1.5

2

2.5

3

3.5

4

Co

ef B

Coef A

Coef B

CubicMg/ha kg/ha

NDVI FP NDVI N Rich Sum GDD CoefA CoefB Pred. Yield0.51 0.71 700 5.300654 1.175651 9.65438571 9654.386

CoefA CoefA = 6E-08x3 - 0.0002x2 + 0.1122x - 18.731 E GDD Coef A Coef BCoefB CoefB = -5E-08x3 + 0.0001x2 - 0.1183x + 31.78 538 6.766 1.291YP0 = (CoefA * EXP (CoefB * NDVI)) 680 5.144 1.2787x = cummulative GDD 797 4.5975 1.2442

910 2.3599 2.0459988 0.8324 3.54881206 0.6844 3.1401

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Yield Prediction Curve Coefficients, kg/ha

y = -0.0003x2 + 0.0816x - 2.7337R2 = 0.99

y = 0.3231x2 - 77.8x + 5405.7R2 = 0.99

0

500

1000

1500

2000

2500

0 20 40 60 80 100 120 140 160 180

GDD

"A"

0

0.5

1

1.5

2

2.5

"B"

"A"

"B"

GDD "A" "B"52 2232 0.59481 1222 1.544

105 819 2.018125 707 2.09154 1094 1.584

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YPMAX

INSEY (NDVI/days from planting to sensing)

Gra

in y

ield

YP0YPN YPN

RI=2.0RI=2.0

RI=1.5RI=1.5

RI-NFOAYPN=YP0 * RI

Nf = (YP0*RI) – YP0))/Ef

The mechanics of how N rates are computed are really very simple

1. Yield potential is predicted without N

2. The yield achievable with added N is #1 times the RI

3. Grain N uptake for #2 minus #1 = Predicted Additional N Need

4. Fertilizer Rate = #3/ efficiency factor (usually 0.5 to 0.7)

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Problems: Extremely early season prediction of

yield can be overestimated (Feekes 4, wheat) (V6, corn)

Inability to reliably predict yield potential at early stages of growth should be accompanied by more risk averse prediction models (small slope)

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Combined RI = (NDVI-N Rich Strip/NDVI-Farmer Practice) CoefA = (0.323123*Gdd2 - 77.8* Gdd + 5406) CoefB = -0.0003469*Gdd2 + 0.08159*Gdd - 2.73372 YP0 = (CoefA * exp(CoefB * NDVI-FP)) If ((NDVI-N Rich Strip/NDVI-FP)< 1.72) RI = (NDVI-N Rich Strip/NDVI-FP)*1.69 - 0.7 If (RI<1) RI=1 YPN = YP0*RI; NRate = ((YPN-YP0)*0.0239/0.6) Determine based on %N in the grain

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Variable Rate Technology Treat Temporal and Spatial Variability Returns are higher but require larger investment

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Just remember boys, you can always trust SuperPete!

Just remember boys, you can always trust SuperPete!

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ORGANICMATTER

MESQUITERHIZOBIUMALFALFASOYBEAN

BLUE-GREEN ALGAEAZOTOBACTERCLOSTRIDIUM

PLANT AND ANIMAL RESIDUES

R-NH2 + ENERGY + CO2

R-NH2 + H2O

R-OH + ENERGY + 2NH3

MATERIALS WITH NCONTENT < 1.5% (WHEAT STRAW)

MATERIALS WITH NCONTENT > 1.5%(COW MANURE)

MICROBIAL

DECOMPOSITION

HETEROTROPHICAMINIZATION

BACTERIA (pH>6.0)FUNGI (pH<6.0)

AMMONIFICATION

GLOBAL WARMING

pH>7.0

2NH4+ + 2OH-

FIXED ONEXCHANGE SITES

+O2

Nitr

osom

onas

2NO2- + H2O + 4H+

IMMOBILIZATION

NH3 AMMONIA -3NH4

+ AMMONIUM -3N2 DIATOMIC N 0N2O NITROUS OXIDE 1NO NITRIC OXIDE 2NO2

- NITRITE 3NO3

- NITRATE 5

OXIDATION STATES

ATMOSPHERE

N2ONON2

N2O2-

NH3

SYMBIOTIC NON-SYMBIOTIC

+ O2Nitrobacter

FERTILIZATION

LIGHTNING,RAINFALL

N2 FIXATION

DENITRIFICATION

PLANTLOSS

AMINOACIDS

NO3-

POOL

LEACHING

AMMONIAVOLATILIZATION

NITRIFICATION

NH2OH

Pseudomonas, Bacillus,Thiobacillus Denitrificans,and T. thioparus MINERALIZATION

+ NITRIFICATION

IMMOBILIZATION

NO2-

MICROBIAL/PLANT SINK

TEMP 50°F

pH 7.0

LEACHING LEACHING

DENITRIFICATIONLEACHING

LEACHINGVOLATILIZATIONNITRIFICATION ADDITIONS

LOSSES

OXIDATION REACTIONS

REDUCTION REACTIONS

HABER BOSCH

3H2 + N2 2NH3

(1200°C, 500 atm)

Joanne LaRuffaWade ThomasonShannon TaylorHeather Lees

Department of Plant and Soil SciencesOklahoma State University

INDUSTRIALFIXATION

15-40 kg/ha

10-80 kg/ha

0-40 kg/ha

0-50 kg/ha