Abstract:Rhizobox culture method was employed to investigate the effects of biochar and pectin on nutrient and heavy metals migration in soil-plant system irrigated by reclaimed water. The results showed that reclaimed water irrigation did harm to the plant growth. Plant grew better in pectin treatments than biochar though there was no significant difference between the both. When irrigated with reclaimed water, the shoot biomass in pectin treatments were 59.32% higher than CK. Compared with distilled water irrigation, reclaimed water irrigation increased the soil pH. When the irrigation water was same, the soil pH of pectin treatments was a little lower than the biochar treatments. Both the biochar and pectin treatments raised the soil nutrient contents, and pectin performed better for the increase in soil available nitrogen, available phosphorous and organic matter, while biochar resulted in the higher increase in soil available potassium. Biochar enhanced the plant nutrient contents, and pectin improved the transport capacity of nutrients. Bichoar decreased the soil available Fe, Mn, Cu, and Ni contents, but pectin increased the soil available Fe, Mn, Cu, Pb, Ni contents. The heavy metals contents in plant roots under pectin treatments were generally higher than that of biochar treatments. Take the distilled water irrigation for example, the Fe, Mn, Cu, Zn, Pb, Cd, Ni contents in plant roots of pectin treatments were 165.29%, 113.01%, 21.16%, 92.74%, 14.61%, 26.86% and 53.43% higher than that of biochar treatments. Fortunately, the translocation factors of Cu, Zn, Pb, Cd, Ni in pectin treatments were lowest. This study could provide the theoretical basis for the agricultural safe utilization of biochar and pectin in north alkaline soil with reclaimed water irrigation.