Treated wastewater reuse and its impact on soil properties and potato and corn growth

Water scarcity is a growing challenge in semi-arid regions. Many farmers have resorted to treated wastewater (TWW) as an available and low-cost water source. This study investigated the impact of irrigating potato (Solanum Tuberosum) and corn (Zea mays) with tertiary-treated (TW) and secondary-treated (SW) wastewater compared to freshwater, over two years. We studied the impact of TWW reuse on soil properties, soil microbes, crop yield, and potato tuber health. Irrigation of both corn and potato with TW significantly increased organic matter (OM) content; on average across both years and crops OM increased by about 35 % under SW and 42 % under TW. TWW irrigation also increased cation exchange capacity (CEC) by the second year under SW and TW in potato (average 67 %), and by the second year under TW in corn (average 13 %). TWW also enhanced soil fertility with no heavy metals contamination. However, potato field irrigated with SW showed high levels of total and thermotolerant coliforms in soil, exceeding predefined thresholds, in the second season. No microbial contamination was recorded in TW-irrigated fields, however, it raised salinity concerns compared to control with 935 mg Na /kg in TW soil compared to 465 mg/kg in control soil during the first season in potato soil. Significant increases in potato tillers, number of tubers (average 6 tubers/plant in TW vs 3 tubers/plant in the control), and tuber weight were recorded in season two under TW irrigation. Both SW and TW increased corn biomass during both seasons. In conclusion, TW is a sustainable alternative water source that enhances crop yields and improves soil quality. This study highlighted the critical role of TWW management and monitoring to address challenges such as salinity and microbial contamination. Further research is required to optimize TWW long-term reuse sustainable agriculture, balancing crop benefits while safeguarding human health.