Growth and nutrient uptake of Paraserianthes falcataria (L.) as affected by carbonized rice hull and arbuscular mycorrhizal fungi grown in an artificially copper contaminated soil

Potential heavy metal soil-plant transfer due to the disposal of high metal wastes, land application of fertilizers and pesticides and mining activity posed a serious threat to both the environment and human health. Hence, there is a need to limit heavy metal transfer from soil to plant through phytoremediation. This study examines the potential of arbuscular mycorrhizal fungi (AMF) and carbonized rice hull (CRH) application on selected soil chemical properties, plant growth, biomass production, P and Cu uptake of Paraserianthes falcataria grown on soils artificially polluted with Cu. A pot experiment with a total of eight treatment combinations from four different levels of Cu (0, 50, 100, 200 ppm) and two amendment types (unamended, amended (2% CRH + AMF)) was conducted. Results revealed that CRH and AMF inoculation significantly (p < 0.01) increased soil organic carbon (OC) by 17% and soil K by 28% while soil pH reduced by 8% compared to the unamended pots. Shoot and total dry matter production increased by 18% and 13% respectively in plants amended with CRH and AMF under increasing Cu rates. Plant dry biomass in CRH and AMF amended pots were positively correlated with soil pH (p < 0.05; r = 0.976) and tissue P uptake (p < 0.01; r = 0.992). Tissue P concentration significantly reduced by 17% with CRH and AMF inoculation while tissue P uptake was comparable across treatments. Cu concentration and Cu uptake in CRH and AMF in plants were reduced by 23% and 12% respectively, over unamended Cu-treated pots. Results demonstrated the potential of CRH and AMF to improve plant health even if grown under the Cu-stressed soil