Biochar and soil properties limit the phytoavailability of lead and cadmium by Brassica chinensis L. in contaminated soils

Abstract

The current study investigated the effect of biochars derived from cinnamomum woodchip, garden waste and mulberry woodchip on soil phytoavailable lead (Pb), cadmium (Cd) pools, and their uptake by Chinese cabbage (Brassica chinensis L.). The biochars were produced at 450 °C of pyrolysis temperature. The contaminated soils were collected from Yunfu (classified as Udept), Jiyuan (Ustalf) and Shaoguan (Udult) cities in China at the depth of 0–20 cm and amended with biochars at the rate of 3% w/w. After mixing the soil with biochar for 14 days, the Chinese cabbage was planted in the amended soils. Then, it was harvested on the 48th day after sowing period. In Udult soil, Chinese cabbage died 18 days after sowing period in control and soils amended with cinnamomum and mulberry biochars. Although only plants grown with the garden waste biochar treatment survived in Udult soil, amendment of garden waste or mulberry biochars at 3% w/w (450 °C) to Udult soil significantly increased (4.95–6.25) soil pH compared to other biochar treatments. In Udept and Ustalf soils, the application of garden waste and mulberry biochars significantly improved plant biomass compared to control, albeit it was dependent on both biochar and soil properties. Garden waste biochar significantly decreased soil Cd phytoavailable concentration by 26% in the Udult soil, while a decrease of soil Cd phytoavailable concentration by 16% and 9% was observed in Ustalf and Udept soils, respectively. The available phosphorus in biochar and soil pH were important factors controlling toxic metal phytouptake by the plant. Thus, the amendment of soil with biochar at 3% can effectively reduce the mobility of Cd and Pb in soil and plant uptake. However, biochar and soil properties should be well-known before being used for soil toxic metal immobilization.

Corncob biochar combined with Bacillus subtilis to reduce Cd availability in low Cd-contaminated soil

“…The spectra clearly showed new peaks of Cd compounds formed via Cd adsorption on CB@B and the decrease in intensity of the SiO 2 peak. The adsorption process may involve precipitation 63 within the solution and on the surfaces. The adsorption process oen proceeds synergistically with other mechanisms such as ion exchange, electrostatic interaction, and surface complexation 53 because of the direct interaction between chemical compounds containing carbonates (e.g., SiO 2 ) and O-functional groups (e.g., O-H and COOH) on CB@B and Cd.…”

An integrated remediation approach using combinations of biochar, Rhizobium leguminosarum, and Vigna radiata for immobilizing and dissipating cadmium contaminants from the soil–mustard plant system

“…Some co-combination techniques have been adapted to analyze their mutual benefits comprising toward the crop, including the bacterial strain of species (Rhizobium leguminosarum), biochar produced from (Wheat husk), and Co-planting with legume plant (Vigna radiata). This study also provides data to investigate the root architecture of plants grown under Cd stress ( Nedjimi and Daoud, 2009 ; Huang et al., 2010 ; Houssou et al., 2022 ).…”

“…Various plants and crops cannot survive under Cd stress; for this reason, scientists are working to develop biological approaches that can effectively overcome Cd toxicity, including intercropping, bioremediation using microbes, and soil amendments using biochar ( Tang et al., 2020 ; Houssou et al., 2022 ; Taye et al., 2022 ). Intercropping is a method of cultivation of two or more crop species in the same field, and it can enhance plant productivity and biodiversity and provide biocontrol against pests and pathogens.…”

Reducing cadmium bioaccumulation in Theobroma cacao using biochar: basis for scaling-up to field

“…The immobilization mechanisms and their effectiveness depend on several factors e.g. soil pH ( Xiao et al., 2019 ) and material characteristics (ash, basic cation, and P content) ( López et al., 2020 ; Houssou et al., 2022 ). Soil pH is among the most critical parameters influencing the effectiveness of biochar in Cd mitigation ( Xiao et al., 2019 ).…”