Precision Agriculture & GPS
Precision Agriculture & GPS
Introduction
• Precision farming:• managing each crop production
input on a site specific basis.• Example inputs:
–fertilizer --lime
–pesticides -- seed
Objectives of Precision Farming
• Reduce waste
• Increase profit
• Maintain environment
Comparison• Pre-mechanization:• Farmers dealt with each seed &
plant
• Post-mechanization:• Farmers dealt with entire fields
Variable Rate Application
• Applying different amounts of input while going across field
Variable Rate Technology
• Tools and equipment that allows for variable rate application
Variability in the Field
• Soil fertility• Moisture content• Soil texture• Topography• Pest population• pH
Fast changers:
• nitrate level
• moisture content
• pest population
Slow changers:
• topography
• texture
• pH
Fertilizers
• 97% of corn acres applied with N
• ~25% cash production costs
• Consider environmental impact
Pesticides
• $7 billion spent annually
• 98% of corn & soybean acres
• Environment is concern
Seed
• 1900 -- 1 farmer fed 8 people• 1990 -- 1 farmer feeds >100
people
• We can change plant population as we plant
Components of Precision Farming
• Tillage - depth & residue
• Planting - seed rate & depth
• Spraying - certain area
• Crop scouting - problem area
• Harvesting - yield monitor
Where on Earth are We?
• Dead reckoning
• Land-based positioning
• Satellite-based positioning
Dead Reckoning
• Uses starting point
• Speed
• Travel time
• Number of passes to determine location
Land-Based Positioning
• Uses radio towers
• Must have three towers
Satellite-Based Positioning
• AKA
• Global Positioning System
• GPS for short
GPS
• Constellation of satellites
• Developed by Department of Defense
• Used 24 hrs./day anywhere on Earth
Uses
• Military
• Industrial
•Commercial•Civilian
Segments of GPS
• Space
• User
• Control
Space
• 24 satellites
• 12,000 miles above Earth
• Orbit twice daily
• Always have at least 4 satellites in view
• “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
User Segment
• GPS Units & Receivers
• Free of charge usage of signals
Control Segment
• Track & monitor satellites
• Master Control Station - AFB in Colorado Springs