Effect of Hg pollution in ex-gold mining soil ameliorated with bamboo biochar on vegetative growth of corn (Zea mays L.)

Abstract Gold mining has caused negative impacts on the environment, especially Hg contamination and pollution in the soil system. This study aims to assess the effect of Hg pollution on ex-gold mining soil in Dharmasraya West Sumatra ameliorated with bamboo biochar (B-B) on corn (Zea mays L.) plants in polybags (15 kg soil polybags −1 ). The research was conducted at the Wire House, Agriculture Faculty Andalas University in a completely randomized design (CRD) with three replications of five doses of bamboo biochar application namely 0, 10, 20, 30, and 40 t ha −1 . The application of 40 t ha −1 bamboo biochar (300 g B-B 15kg soil −1 ) can improve the chemical properties of ex-gold mining soil contaminated with Hg which can increase soil pH by 3.10, organic matter by 0.46% C, CEC by 3.34 cmol(+) kg −1 , total N by 0.031% N, available P by 3.06 ppm, K-exch by 0.21 cmol(+) kg −1 ; Ca-exch by 0.0016 cmol(+) kg −1 , and Mg-exch by 0.328 cmol(+) kg −1 and can inactivate Hg pollution with a decrease in total Hg of 1.52 mg kg −1 , compared to the control. The application of 40 t ha −1 (300 g B-B 15 kg soil −1 ) on ex-gold mining soil contaminated with Hg can also increase plant height to 81.66 cm, plant dry weight of 68.65 g, an increase in nutrient levels of 0.033% N, 0.001% P, and 0.134% K, and a decrease in plant Hg up to 1.12 mg kg −1 , compared to the control.