|Proven phosphorus retention <br> Retained phosphorus is stable||May harm plants<ref>Logsdon SD, Sauer PA. Iron Filings Cement Engineered Soil Mix. Agron J. 2016;108(4):1753. doi:10.2134/agronj2015.0427.</ref> <br> Removal efficiency declines with increased concentration of incoming phosphorus | |Proven phosphorus retention <br> Retained phosphorus is stable||May harm plants<ref>Logsdon SD, Sauer PA. Iron Filings Cement Engineered Soil Mix. Agron J. 2016;108(4):1753. doi:10.2134/agronj2015.0427.</ref> <br> Removal efficiency declines with increased concentration of incoming phosphorus |