Biochar and microbial synergy: enhancing tobacco plant resistance and soil remediation under cadmium stress

Abstract

The increasing contamination of soil with heavy metals, particularly cadmium, poses a significant threat to agricultural productivity, especially in tobacco cultivation. The primary objective of this study is to explore the impacts of biochar combined with microorganisms on tobacco resistance and soil remediation under cadmium stress. The experiment consisted of four treatments: namely, G0C0 (no cadmium or biochar added), G1C0 (cadmium 130 mg added, no biochar added), G1C1 (cadmium 130 mg added, 10 g kg⁻¹ biochar added), and G1C2 (cadmium 130 mg added, 10 g kg⁻¹ biochar added, and 1% microbial inoculant added). The influence of each treatment on tobacco growth and development, cadmium uptake by tobacco, soil biological characteristics, and components of soil microbial communities was investigated. The study revealed that cadmium stress had a negative impact on tobacco net photosynthesis. Notably, biochar was found to be effective in alleviating this effect. The results demonstrated that Apparent Quantum Yield (AQY), Maximum Photosynthetic Rate (Pmax), and Light Saturation Point (LSP) in G1C1 increased by 1.69%, 80.50%, and 30.76%, respectively, compared to G1C0. Similarly, AQY, Pmax, and LSP in G1C2 increased by 3.39%, 86.84%, and 62.35%, respectively. Following cadmium contamination, the levels of soil urease, catalase activity, and microbial biomass nitrogen and carbon were reduced. However, the application of biochar significantly enhanced urease and catalase activities by 12.42–63.89% and 13.03–14.17%, respectively. Additionally, the carbon and nitrogen content of microbial biomass increased by 46.42–76.27% and 21.56–28.12%, respectively, compared to the G1C0 treatment. The combined application of biochar and Trichoderma exhibited a synergistic effect, enhancing soil microbial diversity and community structure while increasing the abundance of beneficial genera such as Mucoromycota, Chaetomium, and Bacillus. Additionally, biochar effectively restricted the upward transport of cadmium in tobacco plants. These findings suggest that co-applying biochar and microorganisms offers a sustainable strategy to enhance tobacco plant resilience under cadmium stress, improve soil ecology, and promote soil remediation in contaminated environments.

Keywords

Biochar / Cadmium stress / Rhizosphere soil micro-ecology / Micro-ecological balance

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Funding

key research and development projects(2021YFD1700900)

Shanghai Tobacco Group Science and Technology Project (2022310000140536)

Key Science and Technology Project of Sichuan China Tobacco Industry Co., Ltd. (2021611000270042)

Ministry of Higher Education, Malaysia(63933)

RIGHTS & PERMISSIONS

The Author(s)