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Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
Overfertilization in agriculture weakens crops, endangers drinking water quality and harms the soil. Researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB are now developing an alternative fertilizer that is fully biodegradable and only supplies plants with the nutrients they actually need, thus preventing overfertilization.
Around 1.5 million tons of reactive nitrogen are released in Germany every year. These extremely high levels are mainly driven by agriculture. Surplus nitrogen from manure and mineral fertilizers can cause high levels of nitrate contamination in groundwater, soil acidification and massive algal growth in lakes and seas. Overfertilization also damages crops and weakens biodiversity. Moreover, nitrous oxide released during fertilization contributes to global warming.
A team of researchers at Fraunhofer IGB in Straubing is now working on a solution. “As part of the HanAkku project, we are developing a biobased fertilizer that is biodegradable and can be produced in a resource-efficient manner,” explains chemist Melanie Iwanow. “Our customized fertilizer supplies strictly essential nutrients delivered in the quantities the plants actually need.”
Hemp shives form the basis of an environmentally friendly fertilizer
The new material is based on hemp shives, which make up the inner core of the hemp stalk. Until now, hemp fiber factories have treated the shives as a waste product that can only be reused to a limited degree, for example as animal bedding. The researchers now intend to turn hemp residue into a profitable high-quality product. “Because of their highly porous microstructure and material properties, hemp shives can absorb around four times their own weight in water. We aim to transfer this property to novel biobased solvents and use them to load the hemp shives with customized compounds,” says Melanie Iwanow.
Melanie Iwanow and her colleagues start by identifying the nutrients needed by a specific plant. These substances are dissolved in the lab using deep eutectic solvents (DES), environmentally friendly solvents created by mixing solid components and gently increasing the temperature until a liquid forms. Afterwards, the research scientists load the shives from the industrial hemp stalk with the nutrients dissolved in the DES. These absorbed substances are later released in a controlled manner after application, thus ensuring that each plant receives exactly the nutrients it needs.
“Over time, the nutrients dissolve and free up space in the microporous structure of the shives, which can then serve as water reservoirs for the soil. This is a decisive advantage, especially during drought periods,” says Iwanow. During the final stage, the fertilizer breaks down and helps promote the formation of humus.
All this makes HanAkku a biobased, slow-release alternative to standard fertilizers. While conventional products can deliver consistent slow-release fertilization over a period of approx. 14 months, the ingredients often leave behind microplastics and other harmful residues in the soil. Iwanow and her colleagues aim to develop an alternative that achieves comparable long-term fertilization performance but is biodegradable and does not harm the soil.
The HanAkku project ends this year, and the Fraunhofer researchers hope to transfer their product to the agricultural and horticultural sector. The signs are promising: The team has for example succeeded in growing bell pepper seedlings using the new fertilizer. “We have already proven that our fertilizer works very well and are now putting the finishing touches to the final compound to ensure that the nutrients are released as slowly and in as controlled a manner as possible,” says Melanie Iwanow. If successful, the biobased fertilizer may also be suitable for home gardening.
The researchers from Fraunhofer IGB will be presenting a sample of the fertilizer and the results of their experimental trials with plants grown using it at Hannover Messe.
https://www.fraunhofer.de/en/press/research-news/2026/april-2026/customized-fert...
Researchers from Fraunhofer IGB are using hemp shives, the inner core of the hemp stalk, as the basi ...
Copyright: Fraunhofer IGB
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Researchers from Fraunhofer IGB are using hemp shives, the inner core of the hemp stalk, as the basi ...
Copyright: Fraunhofer IGB
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