ABSTRACT
In colonial America and the new United States, similar practices were adopted as that of ancient peoples with regard to certain crops on certain soils, crop rotation, and the use of manures on worn-out soils. Most of the work in site-specific agriculture conducted since 1920 has concentrated in crop nutrient management. Soil testing has received a great deal of attention, since it was identified as a means of determining the nutrient supplying capacity of soil since the writings of Sprengel. Active-optical sensors have clear advantages over passive light/radiation sensors from satellites or airplanes because they only detect the radiation that they emit. The light emitted by these sensors operates on the same principle as a remote control for a television or an automatic garage-door opener. Site-specific weed control research has received limited research compared with crop nutrients. Site-specific strategies for insects and disease are researched less than even weed control.
