1. Precision Agriculture & GPS

3. Introduction Precision farming:
managing each crop production input on a site specific basis.
Example inputs:
fertilizer --lime
pesticides -- seed

4. Objectives of Precision Farming
Reduce waste
Increase profit
Maintain environment

5. Comparison Pre-mechanization: Farmers dealt with each seed & plant
Post-mechanization:
Farmers dealt with entire fields

6. Variable Rate Application
Applying different amounts of input while going across field

7. Variable Rate Technology
Tools and equipment that allows for variable rate application

8. Variability in the Field
Soil fertility
Moisture content
Soil texture
Topography
Pest population pH

9. Fast changers:
nitrate level
moisture content
pest population
Slow changers:
topography
texture pH

10. Fertilizers 97% of corn acres applied with N
~25% cash production costs
Consider environmental impact

11. Pesticides $7 billion spent annually 98% of corn & soybean acres
Environment is concern

12. Seed 1900 -- 1 farmer fed 8 people
farmer feeds >100 people
We can change plant population as we plant

16. Components of Precision Farming
Tillage - depth & residue
Planting - seed rate & depth
Spraying - certain area
Crop scouting - problem area
Harvesting - yield monitor

17. Where on Earth are We? Dead reckoning Land-based positioning
Satellite-based positioning

18. Dead Reckoning Uses starting point Speed Travel time
Number of passes to determine location

19. Land-Based Positioning
Uses radio towers
Must have three towers

20. Satellite-Based Positioning
AKA
Global Positioning System
GPS for short

21. GPS Constellation of satellites Developed by Department of Defense
Used 24 hrs./day anywhere on Earth

22. Uses
Military
Industrial
Commercial
Civilian

23. Segments of GPS
Space
User
Control

24. Space 24 satellites 12,000 miles above Earth Orbit twice daily
Always have at least 4 satellites in view

25. “In view” = above horizon
Each satellite sends & receives radio signals
Radio signals travel ~183,000 miles per second
Satellites equipped with atomic clock for accuracy

30. User Segment
GPS Units & Receivers
Free of charge usage of signals

31. Control Segment Track & monitor satellites
Master Control Station - AFB in Colorado Springs