Ecophysiological Responses of Plants After Sewage Sludge Compost Applications

Composting is one of the most appropriate methods to recycle sewage sludge. Sewage sludge compost is a suitable solution for improving the quality of barren soil at landfill. Therefore, it is important to investigate the effects of sewage sludge compost on plants. Different compost application methods (mixing and scattering over reclaimed soil) on sawtooth oak (Quercus acutissima) and Japanese red pine (Pinus densiflora) have been tested. The application of sewage sludge compost markedly increased soil moisture and nitrogen content. Compost treatments resulted in significant increases in both plant height and biomass as compared to controls. Compost treatments led to a significant increase in the N content of plant leaves. Compost treatments resulted in significant increases in the chlorophyll content and photosynthetic rates of the plants. The scattering of compost over reclaimed soil (compost 2) resulted in lower total antioxidant activity and superoxide dismutase activity than mixing the compost with the reclaimed soil (compost 1), or in the control treatment. Since the growth rates, N content, and photosynthetic rates in compost 2 treatment were not markedly different from compost 1 treatment, it (compost 2) would be a better application method from both an ecological and economic perspective.