The presence of abundant oil palm residues in Malaysia prompted the need to utilize this waste to avoid environmental pollution. This waste was abundant at the oil palm mill and accounted for almost 50% of production. The study was conducted to determine the morphological effect of Palm Oil Mill Effluent (POME) sludge on the maize growth performance and gas exchange. Physicochemical, growth morphology and gas exchange was measured after treated with POME sludge from different treatment pond systems: Mixing, anaerobic, facultative, algae and dumping. The results indicated the pH, C, and CEC of mixing the < anaerobic < facultative < algae < dumping ponds. There was a significant presence of macronutrient (N, Mg, Ca, Fe, S) in the treated POME sludge, contrary to the presence of heavy metal (Cd, Cu, Ni and Pb) elements which were not significantly different in all the treatments and lower than WHO/FAO standard. Root Shoot Ratio (RSR) and Specific Leaf Area (SLA) indicated significant difference in biomass accumulation and yield compared to the control. The gas exchange variable was a significant difference on stomata conductivity (Gs) and transpiration rate (E). However, the POME sludge from the facultative, algae and dumping ponds showed positive correlations between net photosynthesis, stomata conductivity and transpiration rate. Indeed, the increased transpiration rate (E) was correlated with stomata conductance (Gs) after treatment with anaerobic, facultative, algae and dumping ponds. In conclusion, the POME sludge amendment was able to increase the maize biomass and yield.

Background: Transforming the abundance of palm oil mill effluent (POME) sludge into beneficial substances such as an organic amendments is vital in the recycling of waste. Vermicomposting from treated POME sludge (TPS) was evaluated on the effect of soil physicochemical properties, crop performances and to determine the best treatment effect on the biomass of the hybrid grain maize (Zea mays L.). Methods: The experimental layout was designed in a randomized complete block design (RCBD). The grain maize cultivated in Bungor series soil (Ultisol) comprising of (T1) control (NPK fertilizer), (T2) 1 kg of vermicompost, (T3) 2 kg vermicompost, (T4) 1 kg TPS and T5 (2 kg TPS) with six replications, for a period of 100 days from June to September 2019. Half of the NPK fertilizer dosage applied from the recommended practices. Result: The treatments with 50% reduction of NPK rate significantly (p less than 0.05) affected soil physicochemical properties. The dry matter production, crop performance analysis (net photosynthesis, stomata conductance and transpiration rate) and root weight density were also increased significantly using 2 kg of vermicompost treatment. Vermicompost application demonstrated the best treatment effect on soil properties and grain maize productivity. Utilization of POME sludge waste into organic amendment through vermicomposting approach would become very crucial practices to be adopted in reducing the abundance waste.