Precision Farming in the South East NESPAL & UGA BIO & AG ENGINEERING

What is Precision Farming ? n A management strategy which identifies, analyses and manages within field variability for increased profit and reduced environmental impact n farming by the foot, farming by satellite, site specific management, prescription farming……...

Technologies behind PF n Global Positioning System (GPS) n Yield Monitoring n Variable Rate Technology (VRT) n Remote sensing n Geographic Information system (GIS)

GPS - What is it ? n Navigation device which lets you pinpoint your location on the earths surface n accurate to within a tennis court (SA off)

n 24 orbiting satellites emitting radio signals n Messages picked up by GPS receiver GPS - How does it Work ?

Differential Correction n Correcting your normal GPS to give you accuracies down to below 1 meter (about 3 feet) n Achieved by using a stationary base station GPS or subscription to commercial satellite broadcast service

Satellite Base Station Receiver

What is yield monitoring ? n Sensors mounted on the combine measuring yield as the crop is harvested n Coupled with a GPS logging location, data can be mapped

Grain Crops n Corn, Wheat, Canola, Soybean GPS Computer display

Peanut

PYMS Components 5k load cells Omnistar DGPS antenna palmtop computer swath width indicator junction box

Cotton Emitters

Two Ways to a Profit Map aerial photo 08 July 1998 yield map October 1998 profit map classified image

What does a yield map tell you ? n “Report card” for field n Quantifies variability within a field n directs sampling to explain yield differences

Corn 1995 Soybean 1995 Peanut 1997

Variable Rate Technology n Refers to any equipment designed to allow the rate of farm inputs to be precisely controlled and varied while the machine is in operation

VRT - Sensor Based System n Real time sensing and control n Bowman Scan Ray

VRT Fertilizer spreader Computer display Application map

Variable rate system Application Map Sprayer/Spreader/ Planter ControllerGPS On-the-go sensing Sprayer/Spreader Controller As Applied Map As Applied Map

What is Remote Sensing n Using satellite and aerial photography to see the “big picture” n highlights variability within a field

Color film imageInfrared image n Images may be made from color or infrared film

Ground control point GPS antenna Data logger Ground Control Points n Ground control points are the longitude and latitude of a specific target n These target locations are later used to georeference an image

What is georeferencing ? n matching a specific longitude and latitude to a targeted location n There are usually many targets within a field

What is the advantage to georeferencing ? n Georeferencing allows the image to be used as a map within the field n a scout may go out to a field with a GPS and navagate to problem areas in the photo Weed patches

GPS Terms n S/A – Selective Availability n Receiver n Differential Correction n Lat/Lon and UTM n Landmarks/Waypoints n Coast Guard Beacon n WAAS (Wide-Area Augmented System)

Specific uses for GPS n Differential (1 m accuracy) –Yield Monitoring –Variable Rate Applications –Field Scouting n Non-Differential (Handheld) –Dependent on accuracy n Dependent on receiver, clear view of satellites, atmospheric disturbances) –Field Scouting

Handheld GPS n Initialization n Navigation Screens n Storing Landmarks n Routing –GOTO –Tracking –Multi-Leg Route

Initialization n Let’s Receiver know where it is n Input time and date data n Must be re-initialized if receiver has travelled more than xx miles from home, while off –XX miles for Magellan 315 –XX- 500 miles for Garmin GPS III Plus n Set-up

Landmarks/Waypoints n Position stored in memory n Usually input by pressing “Mark” button –Can be renamed, comments and messages –Takes time because without keyboard, spelling words takes a while n Can mark position of: –Home, campsites, tree stands, fishing holes –Field positions known to have recurrent insect, disease or nutrient problems.

Routing n GOTO –Usually have a GOTO button –Select waypoint/landmark and receiver begins providing distance and bearing to landmark n Tracking –Turn tracking on (always on with Garmin GPS III) –Store tracking into a route, can then backtrack to first spot, following trail used to get there n Multi-Leg Routes –Put waypoints in route and receiver will navigate to each point in order

Routing n Informational screens, navigation screens, pages n Magellan has up to 9 screens and Garmin has up to 6 pages n Each page provides information on position and/or distance and direction to a waypoint/landmark

Routing n Status Screen (page) –Shows number of satellites tracked and their position in the sky ° Horizon You EPE – Estimated position Error DOP – Degree of Precision Require 3 satellites for 2-D position and 4 satellites if 3-D (include altitude) Ephemeris – position and speed of satellites N

Routing n Compass screen (page) –Shows number of satellites tracked and their position in the sky Heading – Direction of Travel Bearing – Direction should be going if navigating to a position E W N N

Routing n Position Screen (page) –Lat/Lon or UTM position –Time –Speed –Distance traveled –Access to secondary coordinate

GPS Scenarios for USE n Finding field areas of interest –History of disease, low soil fertility, insect pressure –Mark area and give location a name.

Routing n Navigation screen(s) –Basically same as compass screen –BRG – Bearing to spot you want to got to –HDG – Direction you are traveling –SPD, XTE, DST n Plot screen (map page) –From Plot screen, it is easy to see landmarks already stored, tracks if tracking history is on, distance to landmarks –Zoom in and out with arrow right and left key (page in and out)

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