Sensing system and method for direct injection systems on agricultural sprayers

A direct injection agricultural spray system, the system comprising:

• a chemical tank configured to store a chemical for application;
• a carrier tank configured to store a carrier fluid;
• a primary sensor that senses chemical concentration in a chemical injection line downstream of the chemical tank;
• a plurality of nozzle assemblies, wherein at least two of the plurality of nozzle assemblies separately comprises a carrier flow meter on a carrier flow line, an injection point downstream of the carrier flow meter that receives the carrier flow line and a chemical injection line, and a secondary sensor downstream of the injection point that senses carrier concentration, and a nozzle downstream of the secondary sensor;
• and
• a control system that controls flow from the chemical tank and the carrier tank to target a predetermined chemical concentration at the plurality of nozzle assemblies, wherein the primary sensor establishes a maximum chemical concentration and a calibration curve for the chemical concentration and using this calibration curve, the chemical concentration is determined and controlled based on the output of the secondary sensor.