Growth, nitrogen use efficiency, and leachate comparison of subirrigated and overhead irrigated pale purple coneflower seedlings

Pale purple coneflower [Echinacea pallida (Nutt.) Nutt.] was grown within three container volumes (90, 105, and 340 cm3) under subirrigation and overhead irrigation treatments. Subirrigated coneflowers showed increased seedling quality with more biomass (14%), better nitrogen use efficiency (13%), greater nitrogen content (N; 11%), more height (15%), and lower mortality compared with overhead-irrigated seedlings. Plants also showed increasing height, biomass, and N content with increasing container volume. Overhead irrigated coneflowers had more leachate compared with subirrigated seedlings, which produced none. Leachate electrical conductivity and N were monitored throughout the growing season and decreased at similar rates, whereas subirrigation effluent levels remained constant. Subirrigation offers a viable alternative to traditional overhead irrigation systems by producing this native plant with equal or better quality without discharging potentially harmful leachate into the environment.