S05 - Session P2 - Investigation of optimum substrate volumetric water content for potted eucalyptus production

Authors: Seong Kwang An *, Jongyun Kim

The potted eucalyptus has been increasingly popular recently with interest in home interiorscaping in Korea. Since eucalyptus is usually grown in soil for outdoor as trees in natural habitats, information related to water management is insufficient for growing eucalyptus as a potted plant. This study was conducted to investigate the optimal substrate volumetric water content (VWC, m 3 ·m -3 ) to produce high-quality eucalyptus using a soil moisture sensor-based automated irrigation system. FDR soil moisture sensor (EC-5, Meter Group) was installed in a pot filled with growing mix (Sunshine Mix #4) on each experimental unit, and plants were grown under four different VWC levels (0.3, 0.4, 0.5, and 0.6 m 3 ·m -3 ) with four blocks. Although the treated VWC was well maintained for six weeks, there were no significant differences in most growth parameters. However, differences between treated VWC and actual VWC values were occurred during the experimental period, despite the plants receiving the same amount of irrigation to maintain the specific VWC depending on sensor measurement. Thus, all data were reanalyzed based on the actual VWC of each pot measured at harvest. The plants were grown around 0.4 m 3 ·m -3 of actual VWC showed the widest plant width with a quadratic response ( p = 0.01 and 0.02 at 3 and 6 WAT, respectively). Leaf area, fresh and dry shoot weights also showed a quadratic response ( p = 0.01, 0.02, and 0.03 at 6 WAT, respectively), displaying decreased growth under higher or lower than VWC at 0.4 m 3 ·m -3 . Overall, approximately 0.4 m 3 ·m -3 of actual VWC provided appropriate moisture levels for high-quality potted eucalyptus production, indicating that the growth of potted eucalyptus can be reduced by drought and overwatering conditions. This study was supported by RDA Korea (PJ016184).