The reduction of mercury uptake and its content in rice (Oryza sativa L.) grains is this research’s aim, particularly on rice grown in mercury-contaminated fields in the Mandailing Natal Regency, Indonesia. The experiment, laid out in a split-split plot design, had three replications and the period from August to December 2023. The main plots included biochar (from coconut shells) modified with Fe3O4 (M1), FeSO4 (M2), dolomite (M3), and unmodified biochar (M0). The subplots were pyrolysis temperatures at two levels, 350 °C (S1) and 550 °C (S2). The sub-sub plots comprised three rice cultivars: IF-16, Inpari-32, and Ciherang. Additionally, the study included three control treatments (without biochar). The results showed biochar modifications with Fe3O4, FeSO4, and dolomite can reduce the mercury content in rice grains below the standard quality threshold. Among the treatments, the IF-16 cultivar combined with biochar modified with Fe3O4 was the most effective in reducing mercury content while significantly increasing production in mercury-contaminated soils. This combination led to an 80.1% increase in rice production with lower mercury content in the grains.
Rice (O. sativa L.), food, gold mine, heavy metals, Hg, tolerance
The results showed rice (O. sativa L.) tolerant cultivar IF-16, combined with modified biochar, can significantly reduce the mercury content in rice grains compared with cultivars Ciherang and Inpari-32 grown by the farming community on mercury-contaminated soils.