Dam sediment as a soil amendment enhances plant antioxidant responses and suppresses bacterial wilt

Dam sediment accumulates in reservoirs worldwide, yet its fine fractions are rarely reused. To explore the functional benefits of sediment application in agriculture, we evaluated its effects on soil properties, plant physiological responses, and bacterial wilt suppression in Micro-Tom (Solanum lycopersicum 'Micro-Tom'). Potting soil was amended with dam sediment at 0%, 4%, or 8% (wet basis), and plants were inoculated with Ralstonia pseudosolanacearum. The 8% sediment treatment markedly reduced both the progression and final severity of bacterial wilt; no plants exceeded the disease threshold, whereas all plants in the control treatment became diseased. At day 21, disease incidence (DS ≥ 3) was 100% (4/4) at 0% sediment and 0% (0/4) at 8% sediment (p = 0.0286). Sediment amendment was associated with changes in soil nutrient status and increased carotenoid accumulation in tomato leaves, suggesting a potential enhancement of antioxidant capacity. Peroxidase activity also increased with sediment addition, indicating potential enhancement of constitutive defense metabolism. Phenylalanine ammonia-lyase activity showed weaker differences at the late sampling time, consistent with its known role as an early-response enzyme. Hydrogen peroxide levels remained stable across treatments, suggesting that sediment-mediated resistance does not involve excessive oxidative stress. These results demonstrate that dam sediment can enhance both basal and inducible components of plant defense, contributing to reduced wilt severity. The findings highlight the potential of dam sediment as a biostimulant that promotes plant resilience while supporting sustainable resource recycling from watershed management to agriculture.