Akademik Veri Yönetim Sistemi
Journal of Soil Science and Plant Nutrition, 2025 (SCI-Expanded)
This study evaluated the potential of biological wastewater treatment sludge (BWTS) from a municipal sewage facility as a soil amendment for urban landscaping by assessing its effects on physiological and biochemical parameters in selected tree species. Saplings of yellow pine (Pinus sylvestris), birch (Betula pendula), and elm (Ulmus glabra) were cultivated for six months under greenhouse conditions. Pots contained different BWTS-soil mixtures (0%, 25%, 50%, 75%, 100%). Leaf relative water content (RWC), photosynthetic pigments, soluble carbohydrates, phenolic compounds, reactive oxygen species (ROS) such as O2.− and H2O2, lipid peroxidation (LPO) levels, as well as the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), and glutathione S-transferase (GST) were measured. BWTS at 25 and 50% did not significantly alter RWC, whereas 100% caused marked reductions. Chlorophyll and carotenoids were stable at 25% but declined at higher levels. Soluble carbohydrates rose at 75–100% BWTS yet decreased in pine and elm at lower doses. Phenolic content decreased in all treatments in birch; increased at low-to-medium doses in pine, and showed a steady increase in elm. ROS levels decreased at 25% BWTS but increased sharply at higher doses, accompanied by elevated LPO, indicating that oxidative stress was specifically enhanced under its high doses. SOD activity increased at low doses in birch and pine, but decreased at high doses. In elm, however, an increase in SOD was observed in all applications. CAT activity declined under high BWTS. GPX and APX showed species-dependent trends, while GST declined under BWTS in all plants. BWTS exhibited both dose-and species-specific effects. Low application (25%) promoted physiological performance, while high doses led to stress-related damage. BWTS appears suitable for urban landscaping at low to moderate levels (≤ 50%), provided species-specific tolerances are considered.