Petunia Growth and Maintenance in the Landscape as Influenced by Alternative Irrigation Strategies

Abstract

Petunia ×hybrida Vilm. `Midnight' plants were grown in drainage lysimeters to evaluate growth in response to alternative irrigation strategies. Irrigation treatments were tensiometer-regulated automatic irrigation systems, regularly scheduled irrigation using an automated controller, and human perception of plant irrigation need (manual watering). Mean irrigation volumes were reduced by manual watering and tensiometer-regulated treatments, compared to the automated controller. Total mean irrigation volume applied by the automated controller (460 L) was significantly greater than received by the manually watered (293 L) or tensiometer-regulated (286 L) treatments. Regularly scheduled irrigation using an automated controller resulted in higher assimilation rates, final shoot dry mass, final biomass, shoot to root ratios, and growth indices compared to other irrigation methods tested. Assimilation rates were significantly higher for tensiometer-controlled irrigation than the manually watered treatment, but no differences were reported between these two treatments for growth parameters. Visual observations indicated aesthetic quality was compromised among tensiometer-regulated and manually watered treatments relative to the automated controller treatment.