Variable Nitrogen Management for Cereal Production USA and Mexico

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Variable Nitrogen Management for Cereal
Production USA and Mexico
precision SENSING
Oklahoma State University
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• Sense and treat every 0.4m2
• Application rates of 0-88 kg/ha in 12 kg
  increments

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• Sense and treat every 2 plants
• Application rates of 0-88 kg/ha in 12 kg
  increments

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Strategies1. Basing Algorithm on Predicted
Yield2. Response Index3. Spatial Variability
and VRT Resolution4. Integrating
Components Predicted Yield Response Index5.
Coefficient of Variation6. Results
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Strategies

• Voss (1998) Greatest recent improvement in
  fertilizer recommendations is the soil nitrate
  test
• Cabrera and Kissel (1988) Improved N
  recommendations using N mineralized from soil
  organic matter
• Mulvaney et al. (2001) Use of amino sugar N to
  partition responsive from non-responsive sites
• Yield Goal
• 33 kg N/ha for every 1Mg wheat (Johnson, 2000)
• 20 kg N/ha for every 1Mg corn (Schmitt et al.,
  1998)
• RISK of predicting the environment (good or bad
  year) placed on the producer

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Strategies (cont.)

• Chlorophyll meter readings and end-of-season
  stalk NO3-N helped partition fields with
  different levels of residual N (Fox et al.,
  2001).
• SPAD-502 readings at V10 and mid-silk were good
  predictors of corn grain yield (Wood et al.,
  1992)
• Light reflectance near 550nm had promise as a
  technique to detect N deficiencies in corn
  (Blackmer et al., 1994)
• Chlorophyll meter readings used to compute a
  sufficiency index, N applied when less than 95
  (Varvel et al., 1997)
• If sufficiency indices were below 90 at V8,
  maximum yields could not be achieved (Varvel et
  al., 1997)
• Reflectance in the near-infrared (NIR) and blue
  regions was found to predict early season P
  stress between growth stages V6 and V8 (Osborne
  et al., 2002)

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1. Basing Algorithm on Predicted Yield

• Grain N
• Wheat 2.13 N (Tkachuk, 1977)
• Corn 1.23 N (Tkachuk, 1977)
• Wheat
• 33 kg N, 1Mg/ha (2 lb/bu) (Johnson 2000)
• Corn
• 20 kg N, 1Mg/ha (1.2 lb/bu) (Schmitt et al.,
  1998)

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1. Basing Algorithm on Predicted Yield N
Removed

• Wheat
• Yield Goal 4 Mg/ha 0.0213 85.2 kg N/ha
• 33 kg N/Mg 132 kg N/ha
• 85.2-42.642.6/132 0.32 NUE
• ½ N from soil rain (Keeney, 1982)
• Corn
• Yield Goal 8 Mg/ha 0.0123 98.4 kg N/ha
• 20 kg N/Mg 160 kg N/ha
• 98.4-49.249.2/160 0.31 NUE
• ½ N from soil rain (Keeney, 1982)

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WINTERWHEAT
NDVI at F5

INSEY
days from planting to F5, GDDgt0
Good predictor of final grain yieldRequires
only one sensor readingWorks over different
regions/biotypes
Units N uptake, kg ha-1 day-1 where GDDgt0
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1. Basing Algorithm on Predicted Yield
8 sites 12 sites 10 sites
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SPRING WHEAT
NDVI at F5

INSEY
days from planting to first node
Good predictor of final grain yieldRequires
only one sensor reading
Units N uptake, kg ha-1 day-1
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• Fixed height readings using a portable
  bike-mounted GreenSeeker sensor and a shaft
  encoding device to monitor distance (0.5cm)
• By-plant NDVI
• CV by-plant

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Kent Martin, M.S. Student
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CORN
Kent Martin, M.S. Student
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BERMUDAGRASS
y 133.85e1846x R2 0.64
Jagadeesh Mosali, Ph.D Candidate
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2. Response Index
Response to Fertilizer NLong-Term Winter Wheat
Experiment 502, Lahoma, OK, 1971-2003
min 1.0max 4.1avg 1.7
Gordon Johnson
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Response to Fertilizer NLong-Term Corn
ExperimentMead, NE, 1969-1983
Gordon Johnson
Prof. R.A. Olson
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Matt Steinert, Covington, OK (March 20, 2003)
Predicted yieldwith N fertilization(YPN)
RI
Response Index 0.75/0.57 1.31
N-Rich Strip
Farmer Practice
Planting date
Predicted yieldwith no added Nfertilization
(YP0)
days from planting to sensing
NDVI (sensing date)
INSEY (NDVI/days from planting to sensing where
GDDgt0)YPN YP0 RIFertilizer N (Grain N
uptake at YPN Grain N uptake at YP0)/0.7
Jim SchepersDennis Francis
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2. Response Index
Robert Mullen
Gordon JohnsonKyle FreemanPaul Hodgen
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3. Spatial Variability and VRT Resolution
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Yield per plant, based on area occupied
Biomass, g 100 20
120 5X
Distance, cm 10 40 44
20 4X
52025 202242 221032
Yield, g/l-cm 4 0.5
3.8 8X
Recognize and Manage Spatial Variability
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Integrating Componentsa. Predicted Yield b.
Response Index
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RI-NFOAYPNYP0 RI
YP0
YPN
YPN
YPMAX
RI1.5
RI2.0
Grain yield
INSEY (NDVI/days from planting to sensing)
Nf (YP0RI) YP0))/Ef
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Nitrogen Fertilizer Optimization Algorithm
Aug 16, 2002
Aug 28, 2002
Nov 7, 2002
1. Establish preplant N Rich Strip(NRS) 4.
Determine Response Index (RI)2. NDVI (biomass)

NDVINRS/NDVIFarmer3. Predict potential yield
5. Predict potential
grain yield need of days from planting to
(YP0) with added N, YPN (YP0RI)
sensing (INSEY biomass prod./day) 6.
Fertilizer Rec (grain N uptake INSEY vs.
Yld eqn. YPN
grain N uptake YP0/0.7)
CORN
YPN
RI
May
June
August
NDVI (sensing date)
YP0
Planting date
days from planting to sensing (GDDgt0)
WHEAT
November
March
June
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Max Yield-NFOA
YP0
YPMAX
Grain yield
INSEY (NDVI/days from planting to sensing)
Nf (YPMAX-YP0)/Ef
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Ivan Ortiz-MonasterioKen SayreCiudad Obregon,
Mexico
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RICV-NFOA
RI2.0
YP0
YPN
YPMAX
CV
Grain yield
CV
INSEY (NDVI/days from planting to sensing)
Nf ((YP0RI)(100-CV/100-CVlim)) YP0/EfCVlim
40 (wheat)CVgt40, YP0RI cannot increase
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5. Coefficient of Variation
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• Fixed height readings using a portable
  bike-mounted GreenSeeker sensor and a shaft
  encoding device to monitor distance (0.5cm)
• By-plant NDVI
• CV by-plant

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Kent Martin, M.S. Student
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Yield, Mg/ha
CV,
INSEY
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By-plant-yield (entire plants, stalkear
harvested at the base) over 6 m of row, and
corresponding NDVI sensor readings collected from
this exact same area at the 7 leaf and 10 leaf
growth stages, 87 and 70 days earlier, Texcoco,
Mexico, 2002.
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RI-CV Demonstration
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Corn, Oklahoma
y 447.03e0.0199x R2 0.78
Kyle Freeman, Ph.D. Student
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http//www.soiltesting.okstate.edu/SBNRC/SBNRC.php
http//www.dasnr.okstate.edu/nitrogen_use
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Procedure
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Grain yields could be predicted from mid-season
NDVI readings (Agron J. 93131), divided by the
number of days from planting to sensing where GDD
gt0 Nitrogen Fertilization based on mid-season
estimates of yield potential and a response index
increased NUE by gt15, when fertilizing each 1m2
area independently (Agron J. 94815)
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Summary of Results - 10 Field Trials
GreenSeekerTM Field Sprayer (OSU Wheat)
Treatment Pre-Trt. N, lb/ac Trt. N, lb/ac Total N, lb/ac Yield, bu/ac Net Rtn, /ac
N-Rich Strip 94 0 94 44.6 110
Var. Rate 56 23 79 39.8 100
Fixed Rate A 56 35 91 37.3 91
Fixed Rate B 58 24 82 35.4 85
Field Rate 73 20 92 34.6 82