Growth of Chrysanthemum with Ground Automobile Tires Used as a Container Soil Amendment

Abstract

<jats:p>A study was conducted to determine the potential for using ground automobile tires as a container medium amendment. Rooted cuttings of chrysanthemum <jats:italic>[Dendranthema</jats:italic> × <jats:italic>grandiflorum</jats:italic> (Ramat.) Kitamura] were planted in 1.56-liter pots containing 1 sand:2 sawdust (v/v) or media in which coarsely or finely ground particles of rubber substituted for 33%, 67%, or 100% of the sawdust. Amendment with the coarse material decreased total porosity and container capacity and increased air-filled porosity and bulk density relative to the sawdust control. Amending the medium with the fine material did not appreciably alter total porosity, container capacity, or bulk density, but did increase air-filled porosity. Plant height, fresh weight, dry weight, and number of open flowers were reduced significantly in rubber-amended media compared to sawdust controls. Rubber amendment reduced shoot tissue concentrations of N, P, K, Ca, Mg, and Cu, but increased Zn as much as 74-fold over control values. There was no accumulation of other heavy metals (Cd, Cr, Ni, Pb) or Na in the tissue due to rubber amendment. This study demonstrates that ground tires might be used as a component of container media in the production of greenhouse chrysanthemums. However, growth reductions and the potential for Zn toxicity may limit the usefulness of ground tires as a substitute for conventional organic amendments.</jats:p>

Kinetics of zinc release from ground tire rubber and rubber ash in a calcareous soil as alternatives to Zn fertilizers

“…Foliar levels of zinc have been previously shown to be high in plants grown on ground rubber (Bowman et al 1994;Zhao 1995).…”

“…Plants grown in soilless potting media containing ground tire rubber showed elevated Zn concentration in their tissues (Bowman et al 1994;Evans and Harkess 1997). Adequate levels of foliar zinc for most crops is from 4 to 200 mg/kg (Jones et al 1991), yet the zinc level for most plants grown in acidic media containing waste tire was greater than 200 mg/kg.…”

Zinc toxicity from tire rubber in soilless potting media

“…It might be possible to include tire rubber in media for some chrysanthemums (Bowman et al, 1994). Some other horticultural species might also tolerate such an inclusion.…”

“…Thus, the inclusion of 0.7 to 21 g/kg of ground tire rubber in a sand growing medium produced linear decreases in shoot weights in Phaseolus vulgaris (Schulz, 1987), which were attributed to Zn toxicity. More recently (Bowman et al, 1994), it has been claimed that chrysanthemums could be grown in a soilless medium amended with tire rubber. This claim was made despite the fact that Dendranthema x grandiflorum (Ramat.)…”

“…This claim was made despite the fact that Dendranthema x grandiflorum (Ramat.) Kitamura growing in such media showed slow establishment, wilting, discolored leaves, and very high tissue Zn levels (Bowman et al, 1994). Plants differ widely in their tolerance of high concentrations of Zn (Bradshaw, 1975;Handreck, 1991).…”