Cadmium stress poses a significant challenge to plant growth by disrupting vital physiological and biochemical processes. It hampers nutrient uptake, resulting in stunted growth and reduced biomass. Additionally, cadmium generates reactive oxygen species, leading to oxidative stress that damages cell components such as lipids, proteins, and DNA. This stress lowers chlorophyll levels, complicating photosynthesis and further hindering development. Cadmium's toxicity also disrupts hormone balance, enzyme activity, and cell structure, culminating in poor plant growth and diminished agricultural yields.
To tackle this issue, acidified biochar (BC) emerges as a promising solution. Biochar, with its high cation exchange capacity and oxygen-containing functional groups, aids in immobilizing heavy metals in soil through surface complexation and precipitation. Acid treatment of biochar exposes more adsorption sites, enhancing cadmium immobilization. This approach significantly boosts plant growth by improving soil structure, promoting water retention, and enhancing microbial activity, acting as a slow-release nutrient source.
A study explored the effects of biochar amendments on spinach, under both cadmium stress and non-stress conditions. Four treatments—control, 0.45BC, 0.90BC, and 1.20BC—were applied using a completely randomized design with four replications. The results were promising: the 1.20BC treatment led to substantial increases in shoot fresh weight (86.21%), root fresh weight (96.20%), shoot dry weight (223.24%), and root dry weight (42.38%) compared to the 0BC treatment under 20 mg Cd/kg soil contamination. There were also significant improvements in total soluble sugar (16.05%) and total soluble protein (54.70%).
Moreover, the 1.20BC treatment enhanced chlorophyll a (121.26%), chlorophyll b (10.91%), and total chlorophyll (32.12%) levels compared to the control under cadmium stress, demonstrating its potential effectiveness. A notable increase in nitrogen, phosphorus, and potassium concentrations in both the shoot and root of spinach further validated the superiority of 1.20BC over 0BC under cadmium stress. The study concludes that applying 1.20BC can effectively mitigate cadmium-induced stress in spinach, offering a viable strategy for improving crop resilience and productivity in contaminated environments.
Sheikh, L., Naz, N., Oranab, S., Younis, U., Alarfaj, A. A., Alharbi, S. A., & Ansari, M. J. (2025). Minimization of cadmium toxicity and improvement in growth and biochemical attributes of spinach by using acidified biochar. Scientific Reports, 15(1), 1-16. https://doi.org/10.1038/s41598-025-90746-1
Source: Nature