Recycling agricultural waste into carbon-stable materials offers an eco-friendly path to support plant development and reduce chemical fertilizer dependence. In this investigation, the researchers explored how processing sunflower husks at three different temperatures alters their physical properties and biological impacts. Using a highly sensitive aquatic indicator species, the team verified that these thermal products cause no toxic effects. Instead, the resulting amendments serve as robust growth stimulators, with outcomes heavily determined by both the specific manufacturing temperature and the final concentration applied to the plants.

The research demonstrates that higher manufacturing temperatures produce the most outstanding growth responses in floating vegetation. When plants received a small dose of ten milligrams per ten milliliters of biochar produced at five hundred degrees Celsius, vegetative reproduction expanded dramatically. This treatment caused total frond counts to jump by more than fifty percent compared to the untreated control group within a ten-day period. This significant increase confirms that properly processed agricultural residues can actively accelerate plant development rather than merely acting as inert soil fillers.

This remarkable developmental boost is driven by structural and chemical modifications that occur during high-temperature biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More conversion. Increasing processing temperatures to five hundred degrees Celsius breaks down the dense, organized cell walls of raw husks, causing the internal hemicellulose network to decompose. This complete structural collapse leaves behind a highly porous carbon network featuring extensive surface voidage, cracks, and deep microscopic channels. This expanded porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More dramatically increases the specific surface area, providing an optimal interface for nutrient exchange and physical plant interaction.

Simultaneously, the thermal production process concentrates essential mineral nutrients within the porous solid mass. Quantitative spectrometer analysis showed that higher treatment temperatures systematically multiply key elements required for plant health. Potassium content within the material increased from 1.494 percent in raw biomass to an impressive 6.098 percent at the highest temperature. Magnesium content grew nearly tenfold, rising from 0.269 percent up to 2.475 percent, while total phosphorus levels expanded from 0.083 percent to 0.744 percent, providing an abundant supply of macronutrients.

Physiological testing confirmed that these enriched carbon amendments preserve high plant vitality and photosynthetic efficiency. Chlorophyll index monitoring revealed steady pigment accumulation, with all treated groups remaining well above thresholds associated with environmental stress. Additionally, chlorophyll fluorescence measurements demonstrated excellent maximum quantum efficiency within the plant photosystem, remaining near perfect baseline health values throughout the experiment. These healthy physiological markers prove that sunflower husk biochar functions as a safe, highly efficient component for clean, waste-derived plant fertilizers.

Source: Osmanska, J., Szufa, S., Romanowska-Duda, Z., Mohammad, O., Unyay, H., Wozniak, C., Piersa, P., Czerwinska, J., Kazimierski, P., Regkouzas, P., Stefanakis, A., Panek, B., & Onwudili, J. A. (2026). High-value biochar from sunflower husk pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More enhances growth and physiological performance of Spirodela polyrhiza. Scientific Reports, 16, Article 243.