Irrigation and Water Management

Irrigation is the application of water to the soil to sustain or improve crop production. Irrigation management considers the method of water application, the timing of water application, and how much water to apply. This chapter deals with forage irrigation and water management. It focuses on the need of irrigation, sources of water, forage water use, and forage responses to irrigation. Measuring or estimating forage water use is important for proper irrigation management. The measurement can be done by soil water budgets, direct measurements using weighing lysimeters, vapor flux measurement using instrumentation, and using remotely sensed thermal and spectral data. The chapter discusses the issues of soil fertility and yield relationships as well as outlines some basic terms associated with irrigation scheduling. Salinity control usually requires a two-step process; reclamation leaching removes accumulated salts (applicable to new ground or neglected soils), while maintenance leaching removes salts as they accumulate in the soil.