Biochar combined with reduced nitrogen fertilizer enhances sustainable tobacco production in tobacco-rice rotation systems

A research team demonstrated that applying biochar at 30 t·ha^-1 combined with a 10%-20% reduction in nitrogen fertilizer significantly improved nitrogen utilization efficiency and the nitrogen harvest index in tobacco plants, compared to conventional nitrogen application. These findings indicate that biochar's impact on soil health and nitrogen cycling genes, such as nxrA, nifH, and UreC, supports sustainable tobacco production. The study suggests that reducing nitrogen usage by 10%-20% alongside biochar application can maintain optimal crop performance, offering a sustainable approach for long-term tobacco-rice rotation fields.

Tobacco cultivation suffers from continuous cropping issues, leading to increased disease, decreased yield, and reduced quality, particularly in Fujian Province, China, where tobacco-rice rotation is common. Prolonged rotation worsens soil health due to autotoxin secretion and poor soil aeration, prompting excessive nitrogen fertilizer use, which degrades soil further. Although biochar shows promise in improving soil conditions and nitrogen utilization, the optimal nitrogen reduction ratio in tobacco-rice systems remains unclear.

A research article (DOI: 10.48130/TIA-2023-0012) published in Technology in Agronomy on 31 October 2023, aims to determine the best nitrogen reduction strategy with biochar to enhance tobacco production sustainability.

In this study, the research utilized a combination of biochar application and reduced nitrogen fertilizer to examine their effects on nitrogen accumulation and utilization in flue-cured tobacco plants. The study found that the treatments with 10% (T2) and 20% (T3) nitrogen reduction combined with biochar (30 t∙ha⁻¹) significantly enhanced nitrogen accumulation in tobacco plants, with nitrogen uptake efficiency and the nitrogen harvest index showing notable increases over two years. Specifically, biochar improved nitrate nitrogen content during the vigorous growing period while reducing ammonium nitrogen, and significantly increased soil pH, organic matter content, porosity, and field water-holding capacity. Additionally, the T2 and T3 treatments increased the abundance of genes related to nitrification, nitrogen fixation, ammoniation, and organic nitrogen synthesis, such as nxrA, nifH, UreC, and gdh. Regression analysis further revealed a strong correlation between soil organic matter, pH, and the abundance of these functional genes, indicating that biochar's impact on soil conditions plays a crucial role in improving nitrogen uptake efficiency in tobacco plants. This study highlights the potential of biochar in optimizing nitrogen utilization while maintaining soil health in tobacco-rice rotation systems.

According to the study's lead researcher, Jinwen Huang, “This experiment suggests that under the condition of full-surface application of biochar (30 t·ha^-1), a reduction of 10%−20% in nitrogen fertilizer can be achieved compared to conventional nitrogen application, thus sustainably promoting the production of tobacco.”

In summary, the study found that applying biochar combined with a 10%-20% reduction in nitrogen fertilizer significantly improves nitrogen utilization efficiency and the nitrogen harvest index in tobacco plants. This approach enhances soil properties and boosts key nitrogen cycling genes, making it a sustainable strategy for tobacco production. Looking ahead, these findings suggest potential for broader applications in crop systems, promoting sustainable agriculture by reducing nitrogen usage while maintaining high crop yields.

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References

DOI

10.48130/TIA-2023-0012

Original Source URL

https://doi.org/10.48130/TIA-2023-0012

Funding information

This research was supported by the Fujian Branch of China National Tobacco Corporation, China (2019350000240143).

About Technology in Agronomy

Technology in Agronomy (e-ISSN 2835-9445) is an open access, online-only academic journal sharing worldwide research in breakthrough technologies and applied sciences in agronomy. Technology in Agronomy publishes original research articles, reviews, opinions, methods, editorials, letters, and perspectives in all aspects of applied sciences and technology related to production agriculture, including (but not limited to): agronomy, crop science, soil science, precision agriculture, and agroecology.