Biochar from Waste Boosts Tomato Plant Growth

Jenn Hoskins
24th April, 2024

Biochar from Waste Boosts Tomato Plant Growth

The synthesis process converts raw licorice root waste into biochar by first grinding and sieving the material (a, b) before pyrolyzing it under anoxic conditions (c, d).

Image adapted from: Rosa et al. / CC BY (Source)

Key Findings

  • Researchers in Rome developed a slow-release fertilizer from licorice waste that boosts tomato growth
  • The biochar-based fertilizer, especially at lower temperatures, provides nutrients steadily over time
  • This new fertilizer increased tomato plant health, indicated by 38% more chlorophyll and 15% more carotenoids
In the quest to find sustainable ways to enhance agricultural productivity, researchers from Sapienza University of Rome have made a significant breakthrough using a byproduct of the licorice industry[1]. They've developed a novel slow-release fertilizer from licorice processing waste that could potentially revolutionize how we nourish plants, particularly tomatoes, scientifically known as Solanum lycopersicum. Plants, like any living organism, require certain nutrients to thrive. Macronutrients such as nitrogen (N), phosphorus (P), and potassium (K) are vital for their growth and development, and they usually absorb these from the soil[2]. However, the conventional fertilizers that supply these nutrients often release them too quickly, leading to wastage and environmental pollution. The researchers at Sapienza University aimed to address this by creating a biochar-based fertilizer that releases nutrients gradually. Biochar is a carbon-rich material produced through the pyrolysis of biomass, such as plant residues[3]. It has been recognized for its soil conditioning properties and its ability to help with carbon sequestration. The study focused on transforming licorice waste into biochar at two different temperatures, 500°C and 700°C, to investigate how these conditions affect the nutrient release properties of the resulting biochars, named BC500 and BC700, respectively. The produced biochars were then enriched with NPK, the essential macronutrients, using an impregnation method. This process aimed to create a slow-release system that would provide a steady supply of nutrients to plants. The effectiveness of these biochars as fertilizers was measured by observing their nutrient desorption rates in aqueous solutions at different pH levels. Desorption is the process by which nutrients detach from the biochar and become available to plants. The study found that the biochar produced at the lower temperature, BC500, had a slower release of nutrients, attributed to its smaller pore size. It took 14 days for BC500 to reach nutrient release equilibrium, compared to 10 days for BC700. Interestingly, the initial pH of the solution did not significantly alter the release kinetics, meaning the biochar would be effective in various soil types. Further tests were conducted to determine the optimal dosage and nutrient ratio for use as a soil conditioner. The researchers discovered that a 25% application of BC500 with a nutrient ratio of 4:1:3 (N:P:K) was most beneficial. This particular treatment increased the total chlorophyll content by 38% and carotenoids by 15% in tomato plants, indicating a healthier and potentially more productive plant compared to the control. The implications of this study are far-reaching. By utilizing waste from the licorice industry, the researchers at Sapienza University of Rome have not only found a use for a byproduct that might otherwise go to waste but also created a product that could help farmers grow more nutritious tomatoes while reducing environmental impact. The slow-release nature of the biochar-based fertilizer aligns with previous understandings of plant nutrient requirements and uptake mechanisms[2], and it addresses the issue of biochar's influence on soil microbial activity and enzyme function noted in earlier research[4]. While the study represents a promising step forward in sustainable agriculture, the long-term effects and practical applications of this biochar-based fertilizer in diverse agricultural settings remain to be fully explored. Nonetheless, the research conducted by Sapienza University of Rome opens up new possibilities for waste recycling and presents an innovative solution to a global agricultural challenge.

AgricultureSustainabilityPlant Science

References

Main Study

1) Functionalized biochar from waste as a slow-release nutrient source: Application on tomato plants.

Published 30th April, 2024 (future Journal edition)

https://doi.org/10.1016/j.heliyon.2024.e29455

Related Studies

2) Physiological functions of mineral macronutrients.

https://doi.org/10.1016/j.pbi.2009.04.003

3) Organic and inorganic contaminants removal from water with biochar, a renewable, low cost and sustainable adsorbent--a critical review.

https://doi.org/10.1016/j.biortech.2014.01.120

4) Molecular characterization of biochars and their influence on microbiological properties of soil.

https://doi.org/10.1016/j.jhazmat.2014.06.074


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