Location: Southern Horticultural ResearchTitle: Phytotoxic evaluation of whole pine tree substrates Author
Submitted to: Journal of the Mississippi Academy of Sciences
Publication Type: Abstract Only
Publication Acceptance Date: 12/1/2010
Publication Date: 2/15/2011
Citation: Witcher, A.L., Curry, K.J., Blythe, E.K., Fain, G.B., Spiers, J.M. 2011. Phytotoxic evaluation of whole pine tree substrates. Journal of the Mississippi Academy of Sciences. 56:31. Interpretive Summary:
Technical Abstract: Decreased availability and increased cost of quality substrates are issues facing many horticulture crop producers. Peat moss and pine bark are the most widely used substrate components, yet producers have become more aware of acceptable alternative components. Processed whole pine trees have been identified as an effective substrate component for horticulture crop production, while plant propagation evaluations in such substrates have yielded less desirable results. A simple, direct method for evaluating potential phytotoxicity would be a useful tool for developing alternative substrates, including whole pine tree (WPT) substrates. A PhytotoxKit was used to evaluate root length and calculate percent inhibition of seed germination and root growth for three plant species exposed to a reference soil compared with those in saline pine bark, aged WPT, fresh WPT, aged pine needles, and fresh pine needles. The PhytotoxKit allowed for direct contact of seed and substrate, along with subsequent observation and root measurement of germinated seeds. Saline pine bark produced the greatest inhibition of seed germination and root growth in Sinapis alba, while fresh pine needles resulted in the greatest inhibition of Lepidium sativum and Sorghum saccharatum. Lepidium sativum and Sorghum saccharatum mean root length was greatest in aged WPT, while S. alba mean root length was greatest in the fresh WPT. We discovered fresh pine needles can be phytotoxic to some plant species, yet further research is required to determine whether the presence of pine needles has led to reduced plant growth in WPT substrates.