Early field performance of Acacia koa seedlings grown under subirrigation and overhead irrigation

Koa (Acacia koa A. Gray [Fabaceae]) seedlings were grown with subirrigation and overhead irrigation systems in an effort to characterize post-nursery field performance. One year following outplanting, we found no differences in seedling height or survival, but root-collar diameter was significantly larger for subirrigated seedlings. This indicates that koa seedlings, with equal or better morphological quality compared with overhead irrigated seedlings, can be effectively produced using subirrigation systems, thus allowing for potential reductions in water use and wastewater during nursery culture.