Amelioration effect of a new type amendment based on iron tailings on saline-alkali soil in Songnen Plain

Songnen Plain is characterized by extensive areas of saline-alkali soil, whose adverse physical and chemical properties hinder crop growth, thereby severely restricting agricultural production in the region. Although various amendments have been used to ameliorate saline-alkali soil with some success, the high cost of most amendments limits their widespread application. Iron tailings, a byproduct of the steel industry, possesses soil-amending properties and is inexpensive. If developed for soil improvement, they could not only realize the resourceful utilization of waste but also reduce the cost of soil amendment. This study investigated the effects of a novel composite amendment based on iron tailings on the properties of saline-alkali soil and the growth of maize. A field plot experiment was conducted with six treatments: a control group (CK), a cow manure control group (CK+CM), and four groups combining cow manure with iron tailings-based amendments (T13+CM, T14+CM, T16+CM, T22+CM). Soil physicochemical properties, nutrient content, and maize growth parameters were measured at different growth stages. The results show that the iron tailings-based amendments significantly reduces soil pH (the maximum reduction is 8.86%) and bulk density (the maximum reduction is 0.29 g·cm⁻³), but increases soil organic matter, total nitrogen, nitrate nitrogen, ammonium nitrogen, total phosphorus, and available phosphorus contents. Under the T14+CM treatment, maize emergence rate reaches 92.2%, which is significantly higher than the control group. Plant height, stem diameter, biomass, and yield components are all significantly improved, with the highest yield of 6268 kgˑhm⁻² achieved under the T22+CM treatment. This study demonstrates that iron tailings-based amendments provide an environmentally sustainable and economically feasible solution for saline-alkali soil amelioration while enhancing maize yield.