Presentation on theme: "GPS/GIS Applications in Agriculture Gary T. Roberson Agricultural Machinery Systems."— Presentation transcript:
GPS/GIS Applications in Agriculture Gary T. Roberson Agricultural Machinery Systems
Global Positioning System (GPS) Space and land based information system to determine precise position data. Utilizes military satellites to determine positioning information. Position based on trilateration from know satelite locations. Millions of GPS users worldwide. Most common type of system in agriculture.
Selecting GPS Components Hand Held Backpack Vehicle Mounted Recreational Mapping Surveying
GPS/GIS Applications Guidance Point Guidance Swath Guidance Control Variable rate application Variable depth tillage Variable irrigation Mapping Soil properties Chemical Application Chemical Prescriptions Tillage Maps Yield Mapping Pest Mapping Topographic Maps Planting Maps
What Are Acceptable Accuracy Requirements? Variable fertilizer application (Swath control) Yield mapping Variable herbicide application Spray overlap control Row crop planting Seed bed formation 30 m 1 m 10 m 1 m 10 cm 5 cm
Point Guidance Target point selected on map screen. Cursor location indicates present position, target position highlighted. Cursor provides guidance to target.
Swath Guidance Anchor points established to create base line on map screen. Parallel lines generated at desired swath spacing. Can be used for straight or contour swaths Light bar or similar device used to provide guidance along line. Automatic steering possible.
Field Mapping Position data (georeference data) recorded at predetermined intervals. Other data recorded manually or automatically by monitor, computer, or data logger. Data displayed by geographic information system (GIS) in thematic map format.
Soil Sampling Georeferenced soil samples can be collected Sampling Methods Grid sampling: intensive sampling of entire field Directed sampling: intensive sampling of particular target areas
Grid Sampling Data collected for each cell or point Multiple samples combined into each cell or point sample
Directed Sampling Sampling zones established based on knowledge of field GPS used to locate sample points. Areas of interest intensely sampled, others lightly sampled
Semi-Automatic Soil Sampler
Crop Maze Field Boundary, Vollmer Farm, Bunn, NC
5 acre corn field Creative minds Sub meter DGPS Field computer Mapping software 450 foot tall wolf
Yield Maps Record of spatial yield variability within a field or farm. GPS data coupled with yield data to produce map. Mechanically harvested Hand harvested Useful tool for decision making.
Cotton Yield Map
Field Scouting Fields can be scouted for a variety of pests Pest populations recorded on maps Decision tools can be applied on a site specific basis
Variable Rate Control Application rates designed for needs of small sections of a field GPS determines position of equipment in the field Computer controls use GPS data and prescription files to adjust rate
Summary GPS/GIS hardware and software are valuable management tools. Accuracy requirements should be dictated by task requirements. Hardware and software should be selected to be compatible with the complete system.