Precision Agriculture GPS Ag Science Fall 2000 Introduction

Precision Agriculture & GPS Ag Science Fall 2000

Introduction • Precision farming: • managing each crop production input on a site specific basis. • Example inputs: –fertilizer –pesticides --lime -- 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 • p. H

Fast changers: • nitrate level • moisture content • pest population Slow changers: • topography • texture • p. H

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