ABSTRACT
Precision farming with automatic control of inputs and monitoring of corn and soybean yields began in the early 1990s in the Midwest. Automated technologies were developed to permit variable rate fertilizer application in response to variable soil nutrient test levels across fields. Innovators had been using measuring tapes or wheels and flags to break fields into grids before electronic guidance tools, such as the Global Positioning System (GPS), were publicly available. As GPS technology became available, it quickly replaced earth-based electronic location systems. The earth-based systems used triangulation to electronic repeating-beacons placed in fields by operators as they entered. Early adopters, such as Ted Macy in Indiana, used components to put systems together in the early 1990s that allowed them to vary seed and fertilizer inputs and record the results (Macy, 1993). This resulted in savings of almost $35 per ha ($14 per acre), primarily for corn, by optimizing inputs of fertilizer and seed, with small savings on herbicide as well. Macy was interested in site-specific management for almost ten years before the concept could be implemented with automatic controllers in 1991.
