Quote from the magazine 'Forst&Technik - Issue 9/2023':
Establishing forests is becoming increasingly challenging in times of prolonged drought. Especially on large calamity areas, plant failures are almost inevitable. A new glimmer of hope comes from Austria and agricultural research. What is behind the product name Agrobiogel?
What to do when there is no rain for weeks, and the painstakingly planted, supposedly climate-resistant mixed forest is at risk of withering in the first few months? Many forest owners have even broken a taboo: Until a few years ago, no one would have seriously considered irrigating forest plantations. However, this is increasingly being practiced nowadays, sometimes even with permanent irrigation systems on the area.
Retaining water
Another strategy is the use of so-called superabsorbents. These are hygroscopic substances that can store multiple times their initial volume of water and gradually release it to their surroundings. However, the well-known products like Stockosorb, Polyter, etc. are not entirely uncontroversial because, despite containing natural ingredients (cellulose, potassium), they also include certain proportions of polyacrylates, i.e., plastics. Even though manufacturers emphasize that these materials still biodegrade completely within a few years, there remains some skepticism among many.
Completely organic
Agrobiogel (ABG) is currently emerging as a potential alternative in the market. In this case, the base material is lignosulfonate, a byproduct of the sulfite process in pulp production. This byproduct is then combined with enzymes.
The finished granulate ultimately contains only natural components. It can store 10 to 15 g of water per gram. It remains effective for three to five years until complete carbon degradation. The concept was developed at the University of Natural Resources and Life Sciences (Boku) in Vienna. As the name suggests, it was initially designed for agriculture, particularly for specialty crops such as vegetables, fruits, or vineyards."
The inventor, Prof. Gibson Nyanhongo, hails from Zimbabwe in Africa and experimented from the beginning on extremely dry, sandy soils. Notably, Agrobiogel has already been approved by the Research Institute of Organic Agriculture (FiBL) for all certifications in organic farming, including Bioland and Demeter, as a soil conditioner. However, scientific studies for the forestry sector are still largely lacking.
In Germany, initial experiments were conducted in a private forest in Baden-Württemberg this spring. The plants, approximately 1000 in number, were set with relatively high effort. This involved initially pre-drilling each hole with a 20-cm planting auger, adding 100g of Biogel granules to each hole, and then mixing the soil substrate and the aid substance a bit with the auger before finally placing the bare-rooted bird cherries, chestnuts, Douglas firs, and larches.
In addition to a control group without any aid substance, plants were also treated with a conventional superabsorbent. In the first check after twelve weeks, the trees treated with Agrobiogel showed better root development compared to the control treatments. However, experiments on spruce with a significantly higher amount of Agrobiogel (200g per plant) yielded a negative result: the root zone was excessively saturated, the plants were chlorotic, and showed minimal growth. It appears that excessive application can have adverse effects.
How can we address water scarcity on our cultivated areas?
These initial results appear to be quite promising. Regarding the high effort involved in adding the aid substance before planting, the manufacturer states that standard procedures with planting hoes and spades can, of course, also be used. However, the best chemotactic stimuli on the root system, ultimately stimulating growth, arise with good mixing. This applies to all types of superabsorbents.
For further in-depth research into the effectiveness of Agrobiogel, the company is in contact with various universities, forestry research institutions, and major forestry enterprises in Germany. Discussions are also underway with manufacturers of planting machines to incorporate the granules into the soil using mechanized methods as much as possible.
Market Entry
Worldwide, there are still 35 pulp mills operating under the sulfite process. According to the company Agrobiogel, industrial production is set to commence next year in Hallein, Austria. In the next step, there is a potential partner in Southwest Germany. The calculated selling price is €5000 per ton of granules. This would mean material costs of 50 cents per plant with a dosage of 100 grams.
We are curious to see how the further development at Agrobiogel will unfold. There is already a distribution in Germany: the Deutsche Bodenhilfsstoff GmbH based in Waldbrunn in the Odenwald.
Heinrich Höllerl
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