Short-Term Effects of Irrigation with Wastewater from Treatment Plant on the Development and Some Metal and Metalloid Contents of White Clover (Trifolium repens L.) + Kentucky Bluegrass (Poa pratensis L.) Mixture

In this study, the issue of irrigation of a mixture of white clover (Trifolium repens L.) and kentucky bluegrass (Poa pratensis L.) plants with different concentrations of the effluent of Van Edremit Advanced Biological Wastewater Treatment Plant in Turkey is discussed. In this context, the research was carried out to investigate the effect of wastewater on the growth of plants sole and in mixtures. In addition, it was aimed to determine the short-term effects of wastewater on some metal and metalloid content in soil and plants. The experiment was carried out in three replications according to the randomized plots trial design in pots in the climate room in 2018. Applications in the study were 100% pure water control (100S), 25% wastewater + 75% pure water (25A75S), 50% wastewater + 50% pure water (50A50S) and 75% wastewater + 25% pure water (75A25S). The plant height of the plants increased depending on the amount of wastewater application in all forms. The highest average plant height of 10.70 cm was obtained from 75A25S in white clover, and 11.42 cm and 11.21 cm in kentucky bluegrass from control and 75A25S applications, respectively. The fresh and dry weight of white clover increased depending on wastewater applications, but the effect of wastewater applications was not observed in kentucky bluegrass. The metal and metalloid content of plants and post-harvest soil generally increased depending on the applications. The metal and metalloid contents, except molybdenum (Mo) in the kentucky bluegrass and copper in the white clover, reached the highest values in the 75A25S application. There was no change in Mo, lead, and cadmium contents in the soil after harvest, but other metal and metalloid contents increased. It was determined that there was a decrease in pH value with wastewater applications in soil samples taken after harvest. It was determined that the electrical conductivity value of the soil increased as the wastewater application concentrations increased. In the light of these results, the positive effects of the wastewater used on plant growth and development were determined, but it was concluded that long-term studies are needed for its effects on the soil.