6. International Palandöken Scientific Studies Congress, Erzurum, Turkey, 24 - 25 June 2023, pp.879-880
Global warming and the increase in agricultural production have caused a decrease in clean water resources and increased the interest in the use of treated domestic wastewater in agriculture. For this purpose, the effects of Advanced Biological Domestic Wastewater diluted with distilled water under controlled conditions on some agricultural properties and nutrient content of crested wheatgrass (Agropyron cristatum Geartn.), hogweed (Dactylis glomerata L.) and alfalfa (Medicago sativa L.) plants were investigated. Wastewater treatment water was diluted with 25%, 50% and 75% pure water and applied to pot according to the field capacity for 4 months with 7 days’ intervals. Wastewater was taken from the discharge point for each irrigation. To simulate heavy grazing, the plants were mown eight times at 3 cm height at 7-day intervals. New wastewater was taken from the discharge point for each irrigation. The effect of wastewater applications on plant height of wheatgrass, orchardgrass and alfalfa was found to be significant. Fresh and dry weights of alfalfa and orchardgrass per pot have increased since the first mows. However, the opposite has been occurring for the wheatgrass. Fresh and dry weights of three plants increased significantly in four irrigation applications, with the most remarkable significant increase in alfalfa. While wastewater rates caused an increase in the nutrient and metal contents of the three plants, it caused a decrease in selenium, except for orchardgrass. Unlike the two grasses, the effect of wastewater application rates on alfalfa Ca content was insignificant. Contrary to other elements, Se decreased significantly in alfalfa and wheatgrass and insignificantly in orchardgrass depending on wastewater dilution rates. In parallel with the dilution rates of wastewater, soil organic matter and EC increased while pH decreased. According to the current findings, depending on the characteristics of the water to be used as irrigation water, the wastewater should be diluted with at least 75% pure water to prevent the risk of salinity. Long-term field studies are recommended for the wastewater dilution rate where the salinity risk threshold can be determined.