How Biochar and Eco-Friendly Mulch Reduce Soil Metals in Tobacco Farming

Greg Howard
25th March, 2024

How Biochar and Eco-Friendly Mulch Reduce Soil Metals in Tobacco Farming

Image Source: Natural Science News, 2024

Key Findings

  • In a Chinese study, combining biochar and biodegradable mulch reduced soil chromium by 34.21-37.92%
  • This combination also increased tobacco plant growth, including height, leaf size, and root mass
  • The dual application suggests a sustainable way to enhance crops and reduce heavy metal risks
In agriculture, the use of additives to improve soil quality and crop yield is a common practice. However, the accumulation of heavy metals, such as chromium (Cr), in soil is a growing concern due to its potential to enter the food chain and negatively impact human health. Researchers at Guizhou Medical University have conducted a study[1] to evaluate the combined effects of two soil amendments—biochar (BC) and biodegradable mulch film (BMF)—on the mobility of Cr in soil and the growth of flue-cured tobacco, a valuable agricultural product. Biochar is a carbon-rich product derived from the burning of organic materials in a low-oxygen environment. Its application in soil has been known to improve soil quality and reduce the bioavailability of heavy metals[2]. Biodegradable mulch films, on the other hand, are used to cover soil to conserve moisture and improve crop yield, and they are designed to break down over time, reducing plastic pollution[3]. While the individual effects of BC and BMF have been studied before, this new research explores their combined impact on reducing Cr contamination and enhancing tobacco plant growth. The study involved a pot experiment where BMF, BC, and a combination of both (CMB) were applied to the soil in which tobacco plants were grown. The results were promising: the combined application of BMF and BC significantly reduced the concentration of Cr that could be extracted from the soil by 34.21-37.92%. This is crucial because the lower the concentration of extractable Cr, the less likely it is to be taken up by plants and enter the food chain. The reduction in Cr bioavailability was attributed to the increased adsorption of Cr onto soil particles and enhanced soil enzyme activity, which limits the mobility of Cr. Furthermore, the study demonstrated that the co-application of BMF and BC not only reduced Cr uptake by the tobacco plants but also improved various growth parameters. The plants were taller, had thicker stems, larger leaf areas, and more extensive root systems when grown in soil treated with CMB. These changes translated into an increase in leaf and root biomass by 11.40-67.01% and 23.91-50.74%, respectively, indicating a potential for higher crop yield and quality. The findings of this study align with earlier research[4], which suggested that biodegradable mulches could reduce the bioavailability of heavy metals like cadmium (Cd) and arsenic (As) in soil. The mechanisms proposed included the stabilization of heavy metals through complexation with functional groups on the surface of aged mulches. In a similar vein, the research[5] on the biocontrol agent Bacillus amyloliquefaciens WS-10 showed that introducing beneficial microorganisms could suppress soilborne diseases and positively alter the microbial community structure in the rhizosphere, the zone of soil surrounding plant roots. The combined use of BMF and BC appears to offer a dual benefit: mitigating the risk of heavy metal contamination in crops and enhancing plant growth. This approach can be seen as a step towards sustainable agriculture, where the goal is to produce food in a way that protects the environment and human health. It also highlights the importance of considering the interactive effects of different soil amendments, as they may offer synergistic benefits that are not observed when they are applied separately. In conclusion, the study from Guizhou Medical University provides valuable insights into the combined application of BMF and BC as a strategy to reduce Cr contamination in soil and improve the agronomic characteristics of flue-cured tobacco. This research could have broader implications for the management of heavy metal pollution in agriculture and the promotion of sustainable farming practices.

SustainabilityPlant ScienceAgriculture

References

Main Study

1) Combined effects of biochar and biodegradable mulch film on chromium bioavailability and the agronomic characteristics of tobacco.

Published 22nd March, 2024

https://doi.org/10.1038/s41598-024-56973-8

Related Studies

2) Method and mechanism of chromium removal from soil: a systematic review.

https://doi.org/10.1007/s11356-022-19452-z

3) Effect of Long-Term Biodegradable Film Mulch on Soil Physicochemical and Microbial Properties.

https://doi.org/10.3390/toxics10030129

4) Polyethylene and poly (butyleneadipate-co-terephthalate)-based biodegradable microplastics modulate the bioavailability and speciation of Cd and As in soil: Insights into transformation mechanisms.

https://doi.org/10.1016/j.jhazmat.2022.130638

5) Plant-Microbe Interaction: Mining the Impact of Native Bacillus amyloliquefaciens WS-10 on Tobacco Bacterial Wilt Disease and Rhizosphere Microbial Communities.

https://doi.org/10.1128/spectrum.01471-22


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