Growth of Several Tree spp. in Containers in Response to N Loading, Fertilizer Type and Substrate Open Access

Two studies were conducted to determine if Comtil, a composted municipal sewage sludge, could be used as a substrate component and a slow release N source in a containerized whip production system and to determine the growth potential of nine tree species not widely grown in the industry. Also, in the second study the effects of fertilizer type on five oak species were studied. In the first study, total N from Comtil was estimated to be 64 gm per No. 3 nursery container, representing between 48 and 100% of the N loading. Despite the potential high N loading from Comtil, tree height was unaffected. No simple fertilizer treatment consistently produced the tallest plants for the four species studied. Fertilizer type affect growth of only two species (Q. macrocarpa and Q. muehlenbergii) and then only in the first year of the two year study. There were significant differences in height growth among the six Q. alba sources. The nine tree species in this study could be grown in 3:1 (by vol) pine bark: coir and pine bark: Comtil substrates.