Chemigation Safety Measurers

Chemigation is the process of applying an agricultural chemical (fertilizer or pesticide) to the soil or plant surface with an irrigation system by injecting the chemical into the irrigation water. Depending on the type of agricultural chemical being applied, chemigation may be referred to as fertigation, herbigation, insectigation, fungigation, etc. Chemigation, like other chemical application methods, has its advantages, limitations and risks that a farm manager must consider in deciding which method of application is the best choice. The greatest risk of chemigation is the potential for accidental backflow of all or part of the chemical into the irrigation water source if the system is not properly set up, operated and maintained. Chemigation can be an effective and safe way of applying certain agricultural chemicals to some irrigated crops if the proper irrigation system and antipollution safety devices to protect the water source are utilized. Application of a portion of a crop's nitrogen requirement with irrigation water is a recognized best management practice to reduce nitrate leaching losses by both University of Minnesota and Minnesota Department of Agriculture crop specialists for high nitrogen use crops grown on coarse textured soils. The 1987 Minnesota Legislature mandated that chemigation regulations and a permit program be developed for pesticide application and expanded the law in 1989 to include fertilizers. Both laws granted administration responsibilities to the Minnesota Department of Agriculture (MDA), Agronomy Services. The MDA initiated the pesticide chemigation regulations in January 1989 and adopted regulations in fall of 1992 for fertilizer chemigation. The Minnesota Department of Health (MOH) also has rules associated with chemical storage tanks, chemigation systems and water wells (irrigation, potable & public water systems) that are referenced in the MDA regulations. This publication does not discuss the protection requirements ror chemigation systems connected to a potable well or public water supply system. The purpose of this publication is to describe the general chemigation safety measures and management practices. These practices minimize the potential risk of accidentally allowing any injected chemical to flow back into the irrigation well, surface water source or to discharge onto the land where not intended, possibly creating a public health problem. Specific details on the sarety devices and measures should be obtained from the MDA before installing any chemigation equipment.