Plant-Based Irrigation Scheduling

Irrigation scheduling is the process of deciding when to irrigate and how much water to apply to a crop in order to obtain the most “crop per drop.” Proper irrigation scheduling can help mitigate the negative environmental, societal, and economic impacts of excessive irrigation while preventing yield-limiting water deficit stress, thereby improving water use efficiency. Typically, if scheduling methods are used, a water balance approach to scheduling irrigation is employed. This approach couples estimates of soil water holding capacity, rooting depth, and crop evapotranspiration to determine irrigation timing and amount. Additionally, a number of different soil moisture sensors are available and can provide estimates of the need for irrigation. It is important to note that that the cotton crop, as with any other crop, integrates its total environment such that any site-specific differences in soil moisture, rooting depth, and evaporative water losses will be manifested in the water status of the plant. The current review explores the potential use of direct and indirect measurements of plant water status for more efficient irrigation scheduling in cotton. Specifically, recent efforts to deploy plant-based irrigation scheduling in the humid southeastern United States are highlighted.