With this guide in hand, you’ll learn about the characteristics of selected fertilizers commonly used for fertigation, long- and short-duration strategies, how to calculate injection rates, frequency considerations, how to apply fertilizers uniformly, mixing considerations, injection devices, and how to prevent backflow. You’ll also learn about nitrogen, phosphorus and potassium distribution around drip lines and how and why to inject gypsum. This guide also discusses the environmental effects of chemical applications, and focuses on nitrogen management to reduce groundwater pollution. One of a series of water management handbooks prepared by the UC Irrigation Program.