By-Plant Prediction of Corn Forage Biomass and Grain Yield at Various Growth Stages using NDVI and Plant Height

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By-Plant Prediction of Corn Forage Biomass and
Grain Yield at Various Growth Stages using NDVI
and Plant Height

• K. Freeman, B. Raun, K. Martin, R.Teal, D.
  Arnall, M. Stone, J. Solie

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Introduction

• Stone el al., 1996 found that N uptake could be
  predicted in winter wheat using NDVI.
• Varvel et al., 1997 noted that corn N status
  could be monitored using chlorophyll meters.
• Muchado et al., 2002 stated that in dry years,
  plant height can explain 90 and 61 of the
  variation of total dry and grain yield,
  respectively.

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Introduction
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Introduction

• Prediction of Corn Forage Biomass
• Avenue for predicting final grain yield
• Estimate Corn Silage in the Field
• Prediction of Corn Forage N Uptake
• Prediction of Corn Grain Yield
• Ability to predict corn grain yield will help to
  prescribe N rates mid-season
• These rates can be predicted on a by-plant basis

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Objective

• To determine the feasibility of by-plant sensor
  data collected at various stages of corn
  development for predicting corn forage biomass, N
  uptake, and corn grain yield.

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Methods

• INSEY_DFP NDVI / Days from Planting to Sensing
• INSEY_GDD NDVI / Cumulative GDD from Planting
  to Sensing
• GDD (Tempmin Tempmax /2) 40 F
• Regression analysis performed using an
  exponential model

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Methods

• A GreenSeeker Sensor was mounted on a bicycle
• A shaft encoder was used to assign distance to
  each sensor reading
• Readings were taken once per centimeter

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Methods

• Plant Height measurements were taken at each
  sensor reading and clipping
• Heights were measured by extending the last
  collared leaf upright

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Methods
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2
3
10cm
30cm
Area Calculation for Plant 2 ? Area ½(10)
½(30) Row Spacing Then, Area (5 cm 15cm)
76cm 1520 cm2
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Results
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Results
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Results
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Results
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Results
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Results
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Results
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Results
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Results
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Results
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Results
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Results
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Conclusions

• NDVI was a better predictor of forage yield at
  early growth stages
• N uptake was correlated with NDVI at early and
  later growth stages
• The product of NDVI and Plant Height improved the
  ability to predict forage and N uptake

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Conclusions

• Final grain yield was accurately predicted at the
  V10 and V8 growth stages.
• INSEY was slightly better than NDVI alone for
  predicting final grain yield.
• There was no difference between INSEY_DFP and
  INSEY_GDD.

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http//www.soiltesting.okstate.edu/SBNRC/SBNRC.php
http//www.nue.okstate.edu
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By-Plant Prediction of Corn Grain Yield with
Sensor Reading taken from V8-R6 Growth Stages in
2004
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By-Plant Prediction of Corn Forage N Uptake at
V8-V11 Growth Stage using NDVI in 2003 2004
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Results
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Results
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By-Plant Prediction of Corn Forage N uptake at
V8-V11 Growth Stage using Plant Height in 2003
2004
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By-Plant Prediction of Corn Forage N Uptake at
V8-V11 Growth Stage using NDVIHeight in 2003
2004