Fertilized soils enhance the efficiency of phytoremediation by tropical grasses in cadmium-contaminated soils

The effectiveness of phytoremediation in Cd-contaminated soils is crucial for enhancing nutrient availability and plant tolerance to Cd. We simulated soil contamination with varying textures and fertilization conditions. Two experiments were conducted: one without liming and fertilization and another with soil fertilization for grasses. The soil types used were Oxisol and Entisol, and the grasses tested were <i>Megathyrsus maximus</i> and <i>Urochloa brizantha</i> at three Cd levels: 0 mg kg^-1 (Control), 2 mg kg^-1 (Low), and 12 mg kg^-1 (High). Soil amendments and fertilization did not significantly change Cd availability. Soil chemical attributes were unaffected by Cd contamination but were influenced by fertilization, which kept the pH below optimal levels. Cd availability was higher in more contaminated soils, with Entisol showing greater concentrations than Oxisol. Dry matter production of the grasses decreased with higher contamination, with <i>U. brizantha</i> being more productive than <i>M. maximus</i> in fertilized soils. Cd accumulation was higher in highly contaminated soils, particularly for <i>U. brizantha</i>. The bioconcentration factor was higher in Entisol, while the translocation factor exceeded 1.0 only for <i>M. maximus</i> in low-contamination Oxisol. Fertilization can mitigate Cd contamination effects, with <i>U. brizantha</i> showing greater tolerance and accumulation capacity in fertilized soils.