chemigation

Chemigation is the application of chemicals through an irrigation system by dissolving or carrying them in the irrigation water. It is used to apply fertilizers (fertigation) and pesticides, herbicides, fungicides, or other agrochemicals in a controlled manner. By injecting chemicals into the irrigation flow, growers aim to deliver active ingredients directly to the root zone and through the crop canopy as irrigation occurs.

The system typically includes an irrigation distribution system, a chemical injection device (such as a venturi injector, positive-displacement pump, or metering pump), a chemical storage or mixing tank, filtration, and a backflow prevention device. An automated controller or timer may regulate injection according to irrigation run time and flow rate. Proper mixing and filtration help prevent clogging of emitters and ensure a uniform concentration in the irrigation water.

Chemigation covers a range of products, including soluble fertilizers and agricultural pesticides. The exact chemicals used, rates, and timing depend on crop type, growth stage, water quality, soil conditions, and regulatory requirements. Accuracy in dosage and uniform distribution are essential to achieve target effects while minimizing waste and environmental impact.

Safety and environmental considerations are central to chemigation. Backflow prevention is often required to avoid contamination of the water supply. Injection rates must be calibrated to irrigation flow, and labels or regulatory guidelines followed to prevent crop injury, non-target effects, or groundwater contamination. Regular maintenance and monitoring of water quality, equipment, and soil or tissue status help optimize outcomes.