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Remote Sensing of Aphid-Induced Stress in Wheat

Remote Sensing of Aphid-Induced Stress in Wheat. BAE/SOIL 4213- Precision Agriculture Oklahoma State University Victor W. Slowik April 20, 2001. Remote Sensing of Aphid-Induced Stress in Wheat.

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Remote Sensing of Aphid-Induced Stress in Wheat

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  1. Remote Sensing of Aphid-Induced Stress in Wheat BAE/SOIL 4213- Precision Agriculture Oklahoma State University Victor W. Slowik April 20, 2001

  2. Remote Sensing of Aphid-Induced Stress in Wheat • Experimental Hypothesis:Reductions in yield can be associated with insect stress at varied infestation rates. • Experimental Premise • NDVI correlated with biomass and yield • NDVI associated with plant health • Stress adversely impacts plant health • Reductions in NDVI as a result of plant stress can be related to yield reductions.

  3. Remote Sensing of Aphid-Induced Stress in Wheat • Study Objectives • Collect data from infested plots. • Incorporate data from parent study • Climatic data from weather station • Greenbug and parasite counts • Wheat yield data • Determine relationships in data • Statistical Analyses • Literature Review of similar work • Present Results and Conclusions

  4. Remote Sensing of Aphid-Induced Stress in Wheat • Remotely sense data for infested plots. • Equipment List: • Exotech 100BX Radiometer • 4 bands filtered to emulate LandSat TM Bands 1 through 4 (Blue to NIR) • Laptop for data collection • National Instruments DAQ-500 card for radiometer-computer interaction • ExoCollect – a Visual Basic program to control data collection activities.

  5. Remote Sensing at Perkins Research Station

  6. ExoCollect Data Collection Program

  7. Remote Sensing of Aphid-Induced Stress in Wheat • Data collected for each plot sample: • Plot Identifier from tag* • Date* • Time* • Sensor configuration • Instrument height (sensed area) • Field of View (sensed area) • Gain setting for each of the four channels • Voltage for each of the four channels* required to identify unique sample

  8. Exotech 100BX Radiometer Bandwidths

  9. Remote Sensing of Aphid-Induced Stress in Wheat • Compute reflectance for plot sample: • For Each of the four bands: • Refl = Voltage * Area * (SERE)*10exp • Refl – Reflectance in Watts • Voltage – Volts • Area – cm2 • Source Equivalent Radiant Emittance*(W/cm2/Volt) • Exp – exponent** from Radiometer Calibration Table

  10. Remote Sensing of Aphid-Induced Stress in Wheat • Eighty plots are sampled: • Two cultivars • Four replications for each cultivar • Ten plots per replication • Five infestation rates (0 through 4) • 0 = control (no infestation) • one each for Fall and Spring

  11. Remote Sensing at Perkins Research Station

  12. Remote Sensing of Aphid-Induced Stress in Wheat • Study Objectives • Incorporate Climatic Data from Parent Study • Temperature • Precipitation • Incident Radiation • Incorporate Insect Data • Greenbug counts • Parasite counts (mummies and wasps) • Wheat Yield Data • Grain counts (extrapolate to estimate yield)

  13. Weather Station at Perkins Research Station

  14. Remote Sensing of Aphid-Induced Stress in Wheat • Challenges • Radiometer Data • Spatial Scale (1m vs. 30m data) • Normalization (Incident Radiation) • Climatic Data • Temporal resolution (hourly averages) • Cause / Effect Lag • Non-linear responses • Wheat Yield Data • Error introduced by extrapolation

  15. Remote Sensing of Aphid-Induced Stress in Wheat • Summary • The basic challenge is to isolate plant stress caused by greenbugs from other factors that affect NDVI. • I do not expect explicit success due to experimental problems with spatial, radiometric and temporal scales.

  16. Sample Plot of Raw Data

  17. Remote Sensing of Aphid-Induced Stress in Wheat • Conclusion • Eventually, studies of this type could be technically and economically feasible as remote sensing methods becomes more sophisticated. • Extent must increase • Grain (spatial resolution) must decrease • Spectral resolution must improve • Radiometric resolution must improve • Spatial pattern recognition incorporated (GIS)

  18. Remote Sensing of Aphid-Induced Stress in Wheat • References • Model 100BX Hand-Held Radiometer Instruction Manual, Exotech Incorporated. • Lillesand, T.M., Kiefer, R.W. Remote Sensing and Image Interpretation, Third Edition, John Wiley & Sons, Inc., New York, 1994. • Riedell, W.E., Blackmer, T. M., Leaf Reflectance Spectra of Cereal Aphid-Damaged Wheat, Crop Science, 39: 1835-1840, 1999. • Riedell, W.E. et al., Leaf and Canopy Reflectance Indicators for Remote Sensing of Greenbug Damage, Proceedings of 1999 Entomological Society of America Symposium, Oklahoma State University, 2000.

  19. Remote Sensing of Aphid-Induced Stress in Wheat • Acknowledgements • Dr. Norm Elliott, ARS Research Scientist, provided access to an ongoing study in greenbug population dynamics as the basis for this study. • Dr. Stuart Phinn, Professor of Geography at the University of Queensland (Australia), provided compiled code of a data collection program for the 100BX. It facilitated the creation of ExoCollect.

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