Corn Nitrogen Fertilization Algorithm

Corn Nitrogen Fertilization AlgorithmCorn Nitrogen Fertilization Algorithm

ApproachApproach

Predict “Yield Potential” Mid SeasonPredict “Responsiveness to Applied N” Project “N Uptake” Difference (Fertilized & Non Fertilized)Project “N Rate” Based on the Difference

N Rich StripN Rich Strip

Farmer PracticeFarmer Practice

1. Yield Prediction, or YP0 (Farmer Practice)

2. Predict Response Index or RI (NDVI N Rich/NDVI Farmer Practice)

3. Measure CV in Farmer Practice

4. Estimate of Plant Population

5. Yield Achievable with N (YP0*RI)

6. Yield Achievable Adjusted based on CV and Population

7. N uptake Difference using a fixed %N (6 – 1)

8. N rate Determined by Dividing N uptake Difference/ Efficiency Factor

1. Yield Prediction, or YP0 (Farmer Practice)

2. Predict Response Index or RI (NDVI N Rich/NDVI Farmer Practice)

3. Measure CV in Farmer Practice

4. Estimate of Plant Population

5. Yield Achievable with N (YP0*RI)

6. Yield Achievable Adjusted based on CV and Population

7. N uptake Difference using a fixed %N (6 – 1)

8. N rate Determined by Dividing N uptake Difference/ Efficiency Factor

34 Locations, 1998-2004

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 2004

YP0 = 0.254e324.4 INSEY R2=0.54

YP0 + 1Std Dev = 0.359 e324.4 INSEY

NDVI at F5 NDVI at F5 INSEYINSEY

Days from planting to sensing, GDD>0 Days from planting to sensing, GDD>0

Units:

biomass, kg/ha/day where GDD>0

Units:

biomass, kg/ha/day where GDD>0

Winter WheatWinter Wheat

17 Locations, 2002-2004Hybrid Corn, Mexico, Nebraska, Iowa, Oklahoma

V8-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)

CornCorn

NDVI, V8 to V10 NDVI, V8 to V10 INSEYINSEY

Days from planting to sensingDays from planting to sensing

Units: biomass, kg/ha/day Units: biomass, kg/ha/day

Long-Term N Fertilization Experiment in Corn, Mead, NE 1969-1983

Yield Prediction EquationsYield Prediction Equations

17 Locations, 2002-2004Hybrid Corn, Mexico, Nebraska, Iowa, Oklahoma

V8-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)11.311.31978 7.41978 7.4 = 3.8 Mg

= 48.6 kg N

= 3.8 Mg

= 48.6 kg N

8.98.91975 2.51975 2.5 = 6.3 Mg

= 80.0 kg N

= 6.3 Mg

= 80.0 kg N

Difference in Grain N Uptake of 31.4 kg NAt an application efficiency of 50%, 1.25% Grain NN Fertilizer Requirement Differed by 62.8 kg N

Predicting RI in CornPredicting RI in Corn

Relationship between vegetative response (RINDVI) and

RIHARVEST 2004 Corn Trials

y = 1.6395x - 0.5287

R2 = 0.7387

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

0.65 0.75 0.85 0.95 1.05 1.15 1.25

RINDVI

RIHarvest

LCB 113-day V8

LCB 99-day V8

Greenlee 113-day V8

Greenlee 99-day V8

Haskell 113-day V8

Haskell 99-day V8

Perkins 108-day V8

Efaw 113-day V9

YPMAXYPMAX

INSEY (NDVI/days from planting to sensing)INSEY (NDVI/days from planting to sensing)

Gra

in y

ield

Gra

in y

ield

YP0YP0YPNYPN YPNYPN

RI=2.0RI=2.0

RI=1.5RI=1.5

RI-NFOAYPN=YP0 * RIRI-NFOAYPN=YP0 * RI

Nf = (YP0*RI) – YP0))/EfNf = (YP0*RI) – YP0))/Ef

Aug 16, 2002 Aug 28, 2002 Nov 7, 2002

Planting datePlanting datedays from planting to sensingdays from planting to sensing

YP0YP0

Previous Nitrogen Fertilizer Optimization AlgorithmPrevious Nitrogen Fertilizer Optimization Algorithm

1. Establish preplant N Rich Strip(NRS) 4. Determine Response Index (RI)2. NDVI (biomass) =NDVINRS/NDVIFarmer

3. Predict potential yield 5. Predict potential grain yield need # of days from planting to (YP0) with added N, YPN =(YP0*RI) sensing (INSEY = biomass prod./day) 6. Fertilizer Rec = (grain N uptake INSEY vs. Yld eqn. YPN – grain N uptake YP0/0.6)

1. Establish preplant N Rich Strip(NRS) 4. Determine Response Index (RI)2. NDVI (biomass) =NDVINRS/NDVIFarmer

3. Predict potential yield 5. Predict potential grain yield need # of days from planting to (YP0) with added N, YPN =(YP0*RI) sensing (INSEY = biomass prod./day) 6. Fertilizer Rec = (grain N uptake INSEY vs. Yld eqn. YPN – grain N uptake YP0/0.6)

RIRIYPNYPNMayMay JuneJune AugustAugustCORNCORN

NDVI (sensing date)NDVI (sensing date)

YPMAXYPMAX

INSEY (NDVI/days from planting to sensing)INSEY (NDVI/days from planting to sensing)

Gra

in y

ield

Gra

in y

ield

YP0YP0YPNYPN

RI=2.0RI=2.0

RICV-NFOARICV-NFOA

CVCVCVCV CVlim = 65 (corn)

CVlim = 40 (wheat)

CVlim = 65 (corn)

CVlim = 40 (wheat)

YPN =YP0*RICrCV = (((-0.0003)*POP)+36.315)YPCV = YPN*((65-CV)/(65-CrCV))NRate = ((YPCV-YP0)*0.0125/0.6)

y = 6E-05x + 5.1273

R2 = 0.24

0

2

4

6

8

10

12

14

16

18

20

0 20000 40000 60000 80000 100000

Plant pop, #/ha

Gra

in y

ield

, M

g/h

a

y = -0.1612x + 9.8319R2 = 0.31

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50 60

CV, %Y

ield

, Mg

/ha

RI = NRichStrip/FarmerPracticeYP0 =((1565*EXP((FarmerPractice/Days)*154.7)))RI = (NRichStrip/FarmerPractice)*1.64 - 0.5287YPN =YP0*RICrCV = (((-0.0003)*POP)+36.315)YPCV = YPN*((65-CV)/(65-CrCV))NRate = ((YPCV-YP0)*0.0125/0.6)

Use of Population and CV

y = -0.0003x + 36.315

R2 = 0.42

0

10

20

30

40

50

60

0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000

Plant Pop, #/ha

CV

Rainfed and Irrigated Corn

Condition Crop Year EquationUnits

plus 1 SD Yr’s Loc’ RI Adjustment Equation

Dryland Winter Wheat 2002

YP0=344*EXP(INSEY*267.6

5)kg/ha yes 4 22



5)kg/ha yes 5 26



)kg/ha yes 6 30



)kg/ha yes 7 34

RI Harvest = 1.69(RI-NDVI) -0.70

Irrigated Corn 2003

YP0=2332.9*(EXP(INSEY*1

32.46)kg/ha

Dryland Corn 2003

YP0=1633*(EXP(INSEY*132

.46)kg/ha

Dryland & Irrigated Corn 2004

YP0=1565*(EXP(INSEY*154

.7)kg/ha yes 3 7

RI Harvest = 1.64(RI-NDVI) - 0.5287

IrrigatedCorn (2nd planting, Argentina) 2005

YP0=624*(EXP(INSEY*149.

41)

Irrigated Spring Wheat 2003


1)kg/ha yes 3 6

Irrigated Spring Wheat 2004


5)kg/ha yes 4 11

DrylandSpring Wheat Canada 2005

YP0 = 1659*(exp(732.72*INSEY))

kg/ha yes 1

Dryland Canola Canada 2005YP0=1408.3*exp(744.61*INSEY)

kg/ha yes 1

Yield Prediction Equations

OSU-Precision Sensing Varvel, Schepers, and Francis (1997)

Measurement/Action NDVI NFOA SufficiencyNon-N limiting 0.85 Response Index = 0.85/0.65 = 0.65/0.85 * 100

Farmer Check 0.65 = 1.31 = 76%

Planting date 1.days where GDD >02.days from planting to sensing = 60

Predict Yield Potential = 0.65/ days where GDD>0YP0 = 2334.9 exp(NDVI*2.6493) = 13071 kg/ha

Grain N uptake YP 0 = 13071 * 1.25%N163

Grain N uptake YP N = 13071 * 1.31 * 1.25%N214

N Recommendation = (214-163)/0.70 + N if <95%73 Rate = 30 lb N/ac

checked every 7 daysapplied N all the way to R3At max uptake (5 lb N/ac/day)

Sufficiency <90%, Max yields not achieved with in-season N, as yield potential had already been reduced.corn grain = 1.25%N

Response Index vs. Sufficiency

Corn Nitrogen Fertilization Algorithm

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