Precision technologies: maximising the value of irrigation

Precision irrigation, by definition, reduces water losses and increases water productivity from irrigated land. This is required as global freshwater scarcity continues to escalate. The concept of precision irrigation can be applied simply and without technology in lower income regions. However, research shows that significant benefits are gained when precision sensor mapping is used to define soil spatial variability, derive management classes, guide placement of sensors for monitoring, and provide timely information for precision irrigation scheduling.

Results from research trials on commercial farms using variable-rate sprinkler irrigation systems with individual nozzle and speed control, used with sensor mapping and monitoring technologies indicate water savings (typically 5–30%, depending on the degree of variability), a major reduction of irrigation-related drainage events, and positive or neutral impact on crop yield. The systems are also used innovatively by farmers for flexible management (e.g. multiple crops under one system; pasture renovation of small irregular areas, precision grazing). This paper presents a case study to demonstrate how precision irrigation practices can be used for best management of irrigation onto variable soils to enhance crop yield and minimise irrigation-related drainage losses.