A working draft of resources and reports from an NSF-sponsored project intended to strengthen the role of mathematics in Advanced Technological Education (ATE) programs. Intended as a resource for ATE faculty and members of the mathematical community. Comments are welcome by e-mail to the project directors: Susan L. Forman or Lynn A. Steen.
Computer tools such as spreadsheets and technology such as Global Positioning Systems (GPS) have begun to transform agriculture to a precision, high-performance industry where data are used to minimize costs and optimize yields. Farmers use tractor-mounted GPS receivers to record location both when they take soil chemistry readings and when they apply fertilizer and herbicides. In precision agriculture, these GPS data are then combined with other data such as pH, moisture content, weed density, and crop yield in a computer spreadsheet or a Geographic Information System (GIS). Careful use of such data, combined with comparison information from other farms and earlier years, enables farmers to minimize waste and optimize yield. The investment required of farmers for GPS receivers and associated computer equipment is about $20,000 which is cost effective for farmers who use it for 1000 acres or more.
Using data on yield gathered either from previous years or from databanks of information on similar farms, the GIS system can be used to prepare "prescription maps" of fields that indicate how much fertilizer, herbicide, and water is needed in each small patch of land. Additional soil analysis combined with market information about predicted crop prices can help farmers make wise decisions about crop rotation and planting schedules. Regular use of such systems can optimize crop yield and minimize costs, thus increasing the chance of profit for the farm.
Because farmers need GPS data that are more accurate than the normal range of 50-100 meters provided by standard receivers, they rely on supplementary data from ground-based stations that transmit estimates of the current error from satellite signals in that region. By combining this information with that of the GPS satellites--using the error as a new unknown and adding data from a fourth satellite--the tractor-based GPS receivers can calculate position to within approximatley 8-10 meters.
Sophisticated use of GPS and GIS data also requires some information, however tentative, on market conditions for various possible crops. With these data, optimization tools such as linear programming can be used to help decide how much of which crop to plant on which field in order to maximize the likelihood of profit.
Precision Farming National Project (Georgia)
Precision Agriculture Education Network (PrAEN)
AgInnovator OnLine News.
Trimble Precision Agriculture
Feder, Barnaby F. "From Amber Waves of Data." New York Times, (May 4, 1998) C1,C4.
Committee on Assessing Crop Yield. Precision Agriculture in the 21st Century : Geospatial and Information Technologies in Crop Management. Washington, DC: National Academy Press, 1998.
Copyright © 1999.
Last Updated: October 12, 1999.
Susan L. Forman or
Lynn A. Steen.