Pot experiment of treated domestic wastewater re-use for irrigation of Chinese cabbage

Water quality and irrigation schedule restrict the development of wastewater irrigation. Two water quality treatments(clean water and wastewater), and four lower limits of soil moisture for irrigation(60%fc, 70%fc, 80%fc, 90%fc), eight treatments in total were set in pots experiment. Influences of different lower limits of soil moisture on the growth and quality of Chinese cabbage were analyzed with wastewater irrigation. Results show that domestic wastewater irrigation reduce the yield gently, increase nitrate and chlorophyll content of vegetable leaves, and enhance heavy metal accumulation. Lower limits of irrigation impacted growth and quality dramatically, and the varieties of crop and soil as irrigation limitation changes under wastewater irrigation are different with that under clean water irrigation, which indicates that proper lower limit of irrigation under wastewater irrigation can not refer to the index of clean water irrigation. Integrated analysis indicate that Chinese cabbage has higher yield, water use efficiency, chlorophyll, and lower nitrate, lower heavy metal accumulation under irrigation with 80% field capacity of soil moisture as lower limit. Therefore, 80%fc soil moisture and 9.3% of leaf cell sap concentration relatively are determined to be the proper lower limit of soil moisture for wastewater irrigation on Chinese cabbage.