ARS | Publication request: Milled Paulownia tomentosa as a substrate component in greenhouse annual production

Submitted to: International Plant Propagators Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 1, 2011
Publication Date: N/A

Interpretive Summary: The increase in demand for peat moss and the environmental concerns that is associated with the harvesting of peat bogs providing justification for seeking new alternatives to the industry standards. Two alternatives currently marketed for greenhouse crop substrate use are rice hulls and coconut coir, but recent research has indicated the potential of wood fiber products. Processed Paulownia tomentosa (PT) trees were evaluated as a substrate component for greenhouse-grown annuals. Reduced crop performance was observed in PT substrates compared with a peat-lite substrate. Further research is required to determine what factors (substrate physical properties, nitrogen immobilization, etc.) were responsible for poor performance in PT substrates. This information can be used by researchers in future evaluations of PT substrates.

Technical Abstract: Recent research has indicated the potential of wood fiber products as alternative substrate components. This study was conducted to determine the effects of Paulowinia tomentosa amended substrates on production of greenhouse grown annuals. Paulownia (PT) was used alone (100% PT) and combined with different rates of Canadian sphagnum peatmoss (P) – 2:8 PT:P (v:v), 4:6 PT:P (v:v), 6:4 PT:P (v:v), 8:2 PT:P (v:v) – and compared with a standard peat-lite (PL) mix – 8:2 P: perlite (v:v). Substrates containing 80 to 100% PT had greater Air Space than substrates containing 40% or less of PT. Overall, plants grown in substrates containing PT had lower growth index, bloom count, and root rating compared with plants grown in PL.