This document discusses various methods for scheduling irrigation for crops. It describes approaches based on soil moisture levels like depletion of available soil moisture and soil moisture tension monitored by tensiometers. It also discusses climatological approaches using potential evapotranspiration and cumulative pan evaporation. Additionally, it outlines plant-based indices like visual symptoms of wilting, growth rates, and using indicator plants or increased plant populations to identify water stress. The goal of irrigation scheduling is to minimize crop water stress and maximize yields while reducing costs and inputs.