Tim Sharp

1. Beltwide Cotton Conference Use of Multispectral Imagery for Variable Rate “Application-zone” Identification in Cotton Production Tim Sharp January 6-10, 2003

2. 1. Introduction • Researchers have been trying to identify the correct management zones based mainly on the variability of the crop yield. • Airborne multispectral imaging of cotton can provide important spatial information • Spatial variations in crop vigor can be observed in green, red and near infrared wavebands • Multispectral images can be used to monitor the spatial and temporal changes in the growth of crops

3. Objective • The purpose of this study was to investigate the use of multispectral imagery • As a tool to map cotton vigor zones • Test the hypothesis that imagery from one year would map the zones in subsequent years (Zones are stable in time and space) • Could these maps be a tool for variable rate application prescriptions in the following year

4. 2. Material & Methods • Positioning System • GPS NAVMAN / IPAQ • Softwares • COTMAN • Farm Site Mate • ERDAS Image • SSToolbox • SAS • Imagery Acquisition • Duncan’s camera (Green, Red, Near Infrared bands) • 0.5 to 1.5 meter resolution images were utilized

5. Field Data Collected • Standard Data by productivity zone • Stand • Height • Total Nodes • Total Bolls • Yield Map Data • Total Final Plant Maps

6. 3. Results and Discussion IMAGE x NDVI - Barn- Moose Lodge- Traveler Rest

7. 3. Results and Discussion Barn 9 - 2001 Low Low Medium Medium High High

8. NDVI x NDVI – Barn NDVI 2001 NDVI 2002

9. 3. Results and Discussion Moose Lodge 2 - 2002 Low High Low High Medium Medium

10. NDVI x NDVI – Moose Lodge NDVI 2001 NDVI 2002

11. 3. Results and Discussion Traveler’s Rest 1 - 2002 High High Medium Medium Low Low

12. NDVI x NDVI – Traveler’s Rest NDVI 2001 NDVI 2002

13. 3. Results and Discussion Wildy 4 – 2002 (Irrigated) Medium Medium High High Low Low

14. NDVI x Yield – Wildy (Irrigated) Yield 1998 NDVI 2002

15. 3. Results and Discussion Year 2001 vs Year 2002- Stand- Height- Total Nodes- Total Bolls

16. 3. Results and Discussion STAND 2001 vs 2002 BARN TRAVELERS REST MOOSE LODGE Tukey's Studentized Test with alpha at 5% - Means with the same letter are not significantly different.

17. 3. Results and Discussion BARN HEIGHT 2001 vs 2002 TRAVELERS REST MOOSE LODGE Tukey's Studentized Test with alpha at 5% - Means with the same letter are not significantly different.

18. 3. Results and Discussion TOTAL NODES 2001 vs 2002 BARN TRAVELERS REST MOOSE LODGE Tukey's Studentized Test with alpha at 5% - Means with the same letter are not significantly different.

19. 3. Results and Discussion BARN TOTAL BOLLS 2001 vs 2002 TRAVELERS REST MOOSE LODGE Tukey's Studentized Test with alpha at 5% - Means with the same letter are not significantly different.

20. Summary and Conclusions

21. Summary and Conclusions • Some researchers have reported in other areas of the country that zones change position. • May be due to wet soil conditions • May not have enough total variability in the field to fully express zone identity • In our study the medium zones may or may not be significantly different from either the low or high zone from one year to the next

22. In West Tennessee • Zones did not move from year to year. • With over 100 fields studied across three years • Final Plant Map data were collected from each of the five NDVI classed zones in each field • We never found that the low classed NDVI zone or the High Classed NDVI zone were incorrectly identified • Confirmation plots agreed completely with research site data

23. Implications • NDVI classed maps obtained after 550 DD60 NAWF 5 but prior to defoliation • Will accurately map the productivity zones for the following years • Will allow for the opportunity to plan Variable Rate Applications based on those classed maps in subsequent years • Correctly maps and predicts the cotton vigor to be expressed in those areas

24. Acknowledgements • National Cotton Council • National Science Foundation