Wastewater Re-Use for Croton in Substrates Amended with Zeolitic Tuff

ABSTRACT

Treated wastewater was compared with tap water for irrigation of croton (Codiaeum variegatum Blume cv. ‘Petra’) in substrates consisting of 1 peat moss: 1 perlite (PP) or 1 soil: 1 sand (SS), alone or supplemented with zeolitic tuff at a ratio of 3:1 (PPZ and SSZ). Substrates were allowed to reach 80% of available water before the plants were irrigated with wastewater or tap water. Results indicated that neither water quality nor substrate affected plant width, leaf area, shoot fresh weight, or root length or weight. Wastewater increased stem diameter; node and leaf number; tissue nitrogen (N); sodium (Na); and chloride (Cl); substrate electrical conductivity (EC); phosphorus (P); Na, Cl, and leachate EC; and concentrations of Na, Cl, NO₃ ⁻, and NH₄ ⁺. Root count, tissue Na, substrate potassium (K) and Na, and leachate pH were higher for zeolite-containing substrates. Shoot dry weight and tissue contents of N and P were the highest for wastewater-irrigated PP and PPZ. Wastewater-irrigated plants in PP and tap water-irrigated plants in PPZ exhibited the highest K content. The highest level of tissue Cl was recorded for SS. Tap water-irrigated PPZ had the highest pH and K concentration. Wastewater-irrigated PP, PPZ, and SS exhibited the highest contents of N, Na, and Cl, respectively. Based on the results, amendment of the substrate with zeolitic tuff is recommended to offset the adverse effect of salinity associated with wastewater.

Keywords:

• Codiaeum variegatum
• zeolite
• salinity
• peatmoss
• perlite
• media

ACKNOWLEDGMENTS

We would like to thank the Deanship of Scientific Research at Jordan University of Science and Technology for funding this research project, No. 151/2002. We would also like to thank Green Technology Group Company for providing the zeolitic tuff used in this study.

Notes

^z Average of 3 replicates.

^z The distance between the substrate surface and the shoot tip.

^y The average of two perpendicular widths.

^x Average of five replicates. Means within columns with different letters are significantly different according to LSD (P ≤ 0.05).

*PP—1 peat moss: 1 perlite; PPZ—3 PP: 1 zeolitic tuff; SS—1 soil: 1 sand; SSZ—3-SS: 1 zeolitic tuff (all, v/v).