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United States Department of Agriculture

Agricultural Research Service

Research Project: Production Management Research For Horticultural Crops in the Gulf South

Location: Southern Horticultural Research

Title: Processed eucalyptus trees as a substrate component for greenhouse crop production

Authors
item Witcher, Anthony
item Fain, Glen -
item Adamczyk, John

Submitted to: International Plant Propagators Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 22, 2012
Publication Date: N/A

Interpretive Summary: Most greenhouse crops are grown in a peatmoss-based substrate, yet fluctuating costs and supplies of peatmoss has led to increased demand for alternative substrate components. Eucalyptus plantings in south Florida are harvested for landscape mulch production, yet this material may have potential as a container substrate for horticulture crop production. In our experiment, processed eucalyptus trees were evaluated as a substrate component for greenhouse-grown petunia and marigold. Eucalyptus was blended with peatmoss at various proportions and compared with two traditional substrates. This study demonstrated substrates composed of up to 80% eucalyptus could be used for petunia and marigold production. Plants grown in eucalyptus substrates had lower chlorophyll content, most likely due to nitrogen immobilization, yet all plants were of marketable size and quality. More research will be required to demonstrate how other plant species perform in eucalyptus substrates and to evaluate nutrient and irrigation requirements for crops grown in eucalyptus substrates.

Technical Abstract: Fast growing eucalyptus species are selected for commercial plantings worldwide and are harvested for a variety of uses. Eucalyptus plantings in south Florida are harvested for landscape mulch production, yet this material may have potential as a container substrate for horticulture crop production. In our experiment, eucalyptus was evaluated as a substrate component for greenhouse-grown petunia and marigold. Eucalyptus (E) was blended with peatmoss (PM) at various volumetric proportions to produce three substrates [E:PM (4:1), E:PM (3:2), and E:PM (2:3)], while two standard substrates were prepared from combinations of PM, pine bark (PB), and/or perlite (P) [PM:P (4:1) and PB:PM:P (3:2:1)]. Substrate pH among all substrates ranged from 4.39 to 5.52 throughout the experiment. Petunia growth index (GI) was similar for E:PM (2:3), PM:P (4:1), and PB:PM:P (3:2:1), while marigold GI was similar among all substrates. Chlorophyll content for petunia and marigold was greater in PM:P (4:1) and PB:PM:P (3:2:1) compared to the other three substrates.

Last Modified: 4/16/2014
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