Effect of modified basic oxygen furnace slag on the controlled release of nitrate nitrogen and the functional microbial community in soil

Abstract The specific surface area and active adsorption sites of basic oxygen furnace (BOF) slag increase after BOF modification. The addition of modified BOF slag to the soil may enable the control of nitrate nitrogen (NO3–N) leaching and also affect the functional microflora in the soil. In this study, soil column leaching experiments were conducted to explore the effects of adding modified slag to the soil on the controlled release of NO3–N and the main functional microbial communities involved in nitrification and denitrification processes. The experimental design included seven column groups: a soil control group (CT); soil groups with 2.5%, 5%, and 10% raw slag (S1, S2, S3); and soil groups with 2.5%, 5%, and 10% modified slag (MS1, MS2, MS3) that were subjected to three cycles of leaching, each of which were comprised of five leaching treatments. After the three cycles of leaching, significantly less NO3–N had leached from the modified slag group compared to the CT and the raw slag groups (P