There are several definitions of precision agriculture. The Precision Ag Institute offers the following:
Precision agriculture, or precision farming, is a farming system that uses technology to allow closer, more site-specific management of the factors affecting crop production. This includes
Global Positioning Systems (GPS) that enable farmers to break fields of crops into smaller units and keep more accurate information on those units through the use of Geographic Information System (GIS) computer software. GPS allows a farmer to accurately return to a specific spot in a field again and again. Special computer-driven equipment can then change the rate at which fertilizer, seed, plant health products and other inputs are used based on the needs of the soil and crop in that smaller unit of the field (this is known as Variable Rate Application or VRA).