ARS | Publication request: Alternative substrates in production of trees in 25-gallon containers

Submitted to: Southern Nursery Association Research Conference
Publication Type: Proceedings
Publication Acceptance Date: October 12, 2011
Publication Date: January 18, 2012
Citation: Murphy, A.M., Gilliam, C.H., Fain, G.B., Torbert, H.A., Gallagher, T.V., Sibley, J.L., Marble, S.C. 2012. Alternative substrates in production of trees in 25-gallon containers. In: Proceedings of the Southern Nursery Association Research Conference. 57:55-59.

Interpretive Summary: Pine bark supplies have wavered in availability over the past couple of years due to a shift in-field harvesting where bark is used as a biofuel material. Research in alternative potting substrates has continued across the country in an attempt to identify inexpensive, and logistically available, substrate options that could offset any lapses in pine bark availability. Two high wood content, pine based, substrates have been identified as potential amendments or replacements to pine bark in soilless media. Whole Tree (WT) (approx 80% wood particles, 15% bark, and 55% needles) consists of the entire pine tree harvested from pine plantations, and Clean Chip Residue (CCR) (approx 50%, wood, 40% bark, and 10% needles) was evaluated as an alternative to peat in greenhouse substrates. These products were also evaluated as an alternative to PB in the production of six woody ornamental species in full gallon containers including lantana spirea, azalea, tea olive, ligustrum and holly. Treatments consisted of 100% PB, WT, and CCR, and then treatments with either 25, 50, or 75% CCR or WT mixed with PB. Data from the study showed that after 365 days, five of the six species tested showed no difference in growth indices of any treatment compared to the PB standard.

Technical Abstract: Pine bark supplies have wavered in availability over the past couple of years due to a shift in-field harvesting where bark is used as a biofuel material. Research in alternative potting substrates has continued across the country in an attempt to identify inexpensive, and logistically available, substrate options that could offset any lapses in pine bark availability. Two high wood content, pine based, substrates have been identified as potential amendments or replacements to pine bark in soilless media. Whole Tree (WT) (approx 80% wood particles, 15% bark, and 55% needles) consists of the entire pine tree harvested from pine plantations, and Clean Chip Residue (CCR) (approx 50%, wood, 40% bark, and 10% needles) was evaluated as an alternative to peat in greenhouse substrates. These products were also evaluated as an alternative to PB in the production of six woody ornamental species in full gallon containers including lantana spirea, azalea, tea olive, ligustrum and holly. Treatments consisted of 100% PB, WT, and CCR, and then treatments with either 25, 50, or 75% CCR or WT mixed with PB. Data from the study showed that after 365 days, five of the six species tested showed no difference in growth indices of any treatment compared to the PB standard.