Authors: Nik Muhamad Majid, Azani M. A.band Arifin Abdu

Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia (UPM), 43400 SerdangSelangor, Malaysia
Faculty of Forestry, Universiti Putra Malaysia (UPM), 43400 Serdang Selangor, Malaysia

Corresponding author: Nik Muhamad Majid

E-mail: [email protected];  | Tel: +603-9769 1882

Abstract

This study measured responses of domestic sewage sludge on tree growth. The study was conducted in the greenhouse at the Faculty of Forestry, Universiti Putra Malaysia using two timber species: Dyera costulataand Cinnamomum iners. A total of 10 levels of sewage sludge treatment were applied to each species replicated four times. A total of 80 seedlings were used for both species and one seedling planted in one pot. The experiment was therefore a 10×2×4 factorial arrangement of treatments. Parameters measured include height growth, diameter increment and foliar nutrient concentrations. The results showed that T7 (70% of sludge by volume) gave the highest height and diameter growth for D. costulatawhile T6 (60% of sludge by volume) was the best rate for C. iners. Thus, the study indicates that the critical nutrient levels for both species correspond to treatments 6 and 7 for C. inersand D. costulata, respectively. However, increasing the volume of sludge per potting mixture at the rate of more than 70% sludge decreased the concentration of Zn in both seedlings. In general, high accumulation of micronutrients such as Fe, Mn, Zn and Cu was found in the leaves in treatments more than 40% sludge by volume. The concentrations of heavy metals in sewage sludge and in the foliage are below the Maximum Permitted Concentration (MPC) of the European Community Standard (ECS) for land application. It is recommended that a field trial of similar species and treatments be conducted to verify the results of this greenhouse experiment.

Keywords: sewage sludge, timber species