How Rice Husk Biochar Affects Fertilizer Emissions and Cabbage Growth

Jim Crocker
9th March, 2024

How Rice Husk Biochar Affects Fertilizer Emissions and Cabbage Growth

Image Source: Natural Science News, 2024

Key Findings

  • In South Korea, neutral pH biochar reduced ammonia emissions from fertilized fields
  • Basic pH biochar increased Chinese cabbage growth the most
  • Biochar's effectiveness depends on its pH level, influenced by production methods
In the quest for sustainable agriculture, scientists at Chungnam National University have been exploring the use of biochar, a carbon-rich product derived from organic materials, as a means to improve crop growth and reduce environmental pollutants, particularly those associated with nitrogen (N) loss. Biochar has gained popularity for its potential to sequester carbon, thus mitigating climate change, and for its ability to enhance soil health[1]. Agricultural fields, especially those treated with urea-based fertilizers, are known to emit ammonia (NH3), a gas that can lead to environmental pollution and the loss of valuable nitrogen from the soil. The latest research from Chungnam National University has honed in on the effects of rice husk biochar, with varying pH levels, on NH3 emissions and crop growth, using Chinese cabbage as a test crop. The study found that the pH level of the biochar, which can vary based on how it is produced (pyrolysis conditions), plays a significant role in its effectiveness. Among the biochars tested, the one with a neutral pH of 7.10 stood out. It significantly reduced NH3 volatilization, especially under high nitrogen application rates (640 kg N ha-1). This reduction is attributed to the biochar's high surface area (6.49 m2 g-1), which provides more sites for NH3 adsorption. Interestingly, while the neutral biochar excelled in reducing NH3 emissions, the basic biochar (pH 11.01) was most effective in boosting crop yield, with the Chinese cabbage reaching an impressive 4.00 kg plant-1 when combined with high nitrogen rates. This suggests that while all biochar amendments improved crop growth, the basic biochar had an edge in terms of agronomic performance. These findings are in line with earlier research that has shown biochar's capacity to influence soil nitrogen transformations. For instance, one study indicated that biochar amendments could accelerate the mineralization of organic nitrogen to ammonium (NH4+), which is a more plant-accessible form of nitrogen[2]. However, the same study also noted that the effects of biochar on nitrogen cycling can be land-use specific, highlighting the importance of tailoring biochar use to the specific conditions of the soil and crop[2]. The combination of biochar with other amendments has also been explored. An experiment assessing the co-application of zeolite and biochar found that this combination could significantly reduce NH3 and methane (CH4) emissions from arable land while improving soil chemical properties[3]. This suggests that the synergistic use of different soil amendments can enhance the environmental benefits of biochar. Biochar's role in pollution remediation and greenhouse gas emission reduction has also been recognized, with the type of feedstock used for its production influencing its properties and suitability for specific pollutants[4]. For example, biochars produced from crop residue and woody biomass are more suitable for organic pollution remediation and greenhouse gas emission reduction[4]. The current study by Chungnam National University contributes to this growing body of knowledge by demonstrating that the pH level of biochar is a critical factor in its effectiveness for reducing NH3 emissions and improving crop yield. Moreover, it underscores the necessity of selecting the right type of biochar for specific agricultural purposes. In summary, the research indicates that neutral pH biochar is most effective at mitigating NH3 emissions in urea-fertilized fields, while basic pH biochar enhances the growth of Chinese cabbage. This insight could prove invaluable for farmers and policymakers aiming to optimize the use of biochar in agriculture, ensuring environmental protection while also enhancing crop production. As the global agricultural community continues to seek out sustainable practices, the strategic application of biochar tailored to specific crop and soil needs could be a key component of future farming systems.

EnvironmentPlant ScienceAgriculture

References

Main Study

1) Pyrolysis temperature and time of rice husk biochar potentially control ammonia emissions and Chinese cabbage yield from urea-fertilized soils.

Published 8th March, 2024

https://doi.org/10.1038/s41598-024-54307-2


Related Studies

2) Biochar application can mitigate NH3 volatilization in acidic forest and upland soils but stimulates gaseous N losses in flooded acidic paddy soil.

https://doi.org/10.1016/j.scitotenv.2022.161099


3) Mitigating Ammonia and Greenhouse Gaseous Emission From Arable Land by Co-application of Zeolite and Biochar.

https://doi.org/10.3389/fpls.2022.950944


4) Effects of different feedstocks-based biochar on soil remediation: A review.

https://doi.org/10.1016/j.envpol.2021.118655



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