Agricultural Sprayer Automatic Section Control (ASC) Systems

Automatic Section Control (ASC) systems for sprayers can reduce over-application (e.g., of pesticides or fertilizer) by turning off application equipment sections as they pass over previously treated areas. Some systems have the capability to only spray within pre-loaded field boundaries or boundaries recorded by the operator during an initial pass around the field. This “map-based” function ensures that boom sections are always off when passing over areas outside cropped regions of the field. An added benefit of this boundary mapping feature is that some systems allow the operator to map interior field areas to prevent application within grassed waterways or buffer strips. ASC systems operate by map¬ping treated areas in real-time as the sprayer crosses the field. The sprayed areas, also referred to as “as-applied polygons,” are stored using coordinates from the GPS receiver and the active control sections (Figure 1). As the sprayer continues to cover the field, the controller continually checks to determine if any boom sections will pass over previously mapped polygons or beyond a mapped field boundary. When a boom section passes into these areas, that section is turned off; it is turned on when it passes back over unsprayed regions. Most systems also allow the operator to choose the on/off coverage percentage for the boom sections. For a 100% setting, full coverage is ensured (with some overlap) in point-rows, whereas a 50% setting would result in the boom section turning off (or on) when half of that section has entered a previously sprayed zone.