Modelling actual evapotranspiration of Ligustrunz japonicum from rooted cuttings to commercially marketable plants in 12 liter black polyethylene containers

Nursery production of woody landscape ornamentals has shifted the past 40 years from in-ground to predominately production in containers for small to medium size shrubs and trees. While nurseries occupy relative small land areas compared to agronomic crops, their consumption of water is quite high, ranging between 1.8 to 2.9 m annually in the Southeastern US. Irrigation frequency and quantity is based on personal experience, and/or increasingly automated time clock systems. While plant water use can vary greatly from day to day, through the course of seasons, and with growth, seldom do these changes invoke irrigation modifications, thus over and under irrigation occur more commonly than correct amounts. In agronomic crops, models that incorporate reference evapotranspiration and crop size function well for predicting irrigation requirements. One avenue to promote precision irrigation for nursery crops is to develop similar models for container produced woody shrubs. A model that predicts actual evapotranspiration for Ligustrum japonicum based on reference evapotranspiration and canopy size was developed. This model was derived during the production of rooted cuttings to commercial market size plants in 12 liter containers under a simulated commercial production situation. With knowledge of local reference evapotranspiration and canopy size, use of this model would permit more accurate and timely changes in irrigation application during container production and water conservation.