Optimizing Plant Growth and Water Use by Modifying Cyclic Irrigation Timing in Container Nursery Production

In container nursery production, managing irrigation is critical for reducing agrichemical runoff. Slender deutzia (Deutzia) plants grown in 1-gal containers were conservatively irrigated using an on-demand irrigation system based on a specific substrate moisture content derived from the relationship between substrate moisture and photosynthetic rate. Unfortunately, commercial nurseries have not readily adopted senor-based irrigation systems partly due to expense and reliability of the sensors. The objective of the present study was to evaluate easily accessible weather variables (light integrals and vapor pressure deficit) as a substitute for substrate moisture sensors to predict irrigation timing based using the on-demand irrigation system. It was determined that light integral, which is simpler to calculate compared to vapor pressure deficit, better simulated on-demand irrigation scheduling and was chosen for further validation in the proposed research.