OICC Press International Journal of Recycling of Organic Waste in Agriculture 2251-7715 13 5 2024 10 03 Cymbopogon citratus biochar as a fertilizing and remediating agent for soils with high copper content 10.57647/ijrowa-zetg-p321 EN Vanessa Susana Rech Bisi Postgraduate Program in Processes Engineering and Technologies (PGEPROTEC), University of Caxias do Sul, Caxias do Sul, RS, Brazil https://orcid.org/0000-0002-7526-5770 Wendel Paulo Silvestre Postgraduate Program in Processes Engineering and Technologies (PGEPROTEC), Course of Agronomy, and Laboratory of Soil-Plant Studies (LESPA), University of Caxias do Sul, Caxias do Sul, RS, Brazil https://orcid.org/0000-0002-9376-6405 Marcos Henrique Tramontin Course of Agronomy and Laboratory of Soil-Plant Studies (LESPA), University of Caxias do Sul, Caxias do Sul, RS, Brazil https://orcid.org/0009-0001-5569-8405 Elaine Damiani Conte Course of Agronomy, University of Caxias do Sul, Caxias do Sul, RS, Brazil https://orcid.org/0000-0002-6523-7100 Marcelo Godinho Postgraduate Program in Processes Engineering and Technologies (PGEPROTEC), University of Caxias do Sul, Caxias do Sul, RS, Brazil https://orcid.org/0000-0001-8630-1995 Gabriel Fernandes Pauletti Postgraduate Program in Processes Engineering and Technologies (PGEPROTEC), Course of Agronomy, and Laboratory of Soil-Plant Studies (LESPA), University of Caxias do Sul, Caxias do Sul, RS, Brazil https://orcid.org/0000-0001-9850-3682 Journal Article 2024 10 03 Purpose: The use of biochar and its products has been increasing in recent years. However, although being studied, most of the potential of biochar to be used as a remediating and fertilizing agent is still unclear. Given this, the present work aimed to assess the effect of different concentrations of Cymbopogon citratus (lemongrass) biomass applied to soil contaminated with Cu. Method: Using natural soil, seven treatments were tested, with three replicates each: soil pH 4.7 (T1), soil pH 6.0 (T2), soil pH 6.0, and adding 5 wt.% biochar (T3), soil with 50 mg∙kg-1 Cu (T4), soil at pH 6.0 with 50 mg∙kg-1 Cu (T5), soil with 50 mg∙kg-1 Cu and addition of 5 wt.% biochar (T6) and soil with 50 mg∙kg-1 Cu and addition of 10 wt.% biochar (T7). The treatments were incubated for 30 days in 30 cm³ containers. Afterward, the soil and the leached solution were analyzed. Subsequently, the incubated soil was transferred to recipients, and seedlings of Catharantus roseus were transplanted, totaling twelve plants per treatment. After 60 days, the plants were evaluated according to the biometric parameters of plant size and root size, root volume, and fresh and dry mass of the plant and roots. The contents of macronutrients and Cu in plant tissue were also determined. Results: The data showed that C. citratus biochar acted as a soil acidity-neutralizing agent at 5 wt.% and 10 wt.%. Adding biochar increased all biometric parameters of C. roseus seedlings. Using the biochar also reduced the Cu levels in the plant tissue, although the treatment with 10 wt.% biochar had the highest copper content in the leachate. Conclusion: According to this study, C. citratus biochar has the potential to be used as soil fertilizer and remediating agent. Research Highlights: Lemongrass biochar was applied in the soil at 5 wt.% and 10 wt.%. Biochar had a soil acidity-neutralizing property, similar to lime. The addition of biochar enhanced the growth of Catharantus roseus Biochar addition reduced Cu uptake by plants, although it increased Cu content in the leachate. Lemongrass biochar can be envisaged as a potential soil fertilizer and remediating agent.