FIGURE 1 “Open loop” crop production.
is used to make fundamental farm management decisions such as which crop to plant in each field, which seeds to use, when to plant, how much fertilizer to use, how to till the ground, and what planting pattern and spacing to use in the field. These decisions are made with the goal of optimizing the farm’s operation and maximizing crop production output for the farm. Unfortunately, there are also several dominant external factors that affect crop production—in particular the weather and weed and pest infestations.
With the introduction of Precision Agriculture, including advancements in electronics, computers, software, and sensors, growers now have better tools to manage their crop production. These tools are shown in blue in Figure 2 and are described in more detail below.
The practice of using moisture and grain flow sensors in combine harvesters to measure yield was the first precision agriculture practice to become widely adopted. While the practice of measuring yield on-the-go was introduced in the 1980s, the integration of yield measurements with GNSS in 1994 was a revolution. GNSS-based yield monitors gave farmers a tool to collect site-specific information about their crop production and to generate maps showing in-field yield variability on their farms. Today nearly every combine harvester manufactured and sold in North America includes a yield monitor.
Soil Nutrient Measurements
Nitrogen, phosphorous, potassium, and other soil nutrients are critical to plant health. For thousands of years growers have been aware of the importance of soil