Yield mapping has called the attention of growers and researchers by demonstrating the degree of yield variability in areas much smaller than whole fields. Although growers recognize that yield varies in their fields, it is difficult to measure and map that variability without a yield monitor. Grain crops, soybean and cotton have led the way when it comes to yield monitoring technology. While yield monitoring has been practiced for approximately 20 years in these commodities, it is not widely used, or is still under development, in other crops like sugarcane, tomatoes, peanuts, sugar beets, pistachios, citrus and coffee. In other crops like alfalfa the technology has not even existed until recently.