Global warming is causing droughts to increase worldwide. Around 60 percent of the world’s grain farmers practice pure rain-fed agriculture – without artificial irrigation. This endangers the food supply for the world’s population, especially in regions already affected by famine. But agriculture in western regions is also coming under increasing pressure from climate change: Tropical heatwaves are leading to slumps in harvests and extreme rainfall is eroding fertile soils. In addition, water consumption for agricultural irrigation already accounts for more than 70 percent of total freshwater resources. Organic hydrogel could significantly mitigate the effects of rising temperatures and declining rainfall.
Hydrogel is usually applied to soils in granular form. It can absorb large amounts of water and releases it slowly back into the environment. But available hydrogel technologies often still contain synthetic raw materials and may not be used in agriculture. Based on fossil raw materials, their decomposition releases toxic acrylic acid, explains Dr. Gibson Stephen Nyanhongo, founder of Agrobiogel and head of the Biomaterial Technology Research Group at BOKU Vienna. Synthetic hydrogels were developed for agriculture in the 1960s but were unsuitable because their performance fell short of expectations. The problem is that synthetic hydrogels bind water but barely release it. That’s why they are now used in products that require the absorption of liquids, such as medical and hygiene products.
Existing technologies for biological hydrogel are not yet powerful enough to be marketable.
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Nyanhongo is the founder of the start-up Agrobiogel, developer of an organic hydrogel based on natural raw materials that is completely biodegradable. The idea originated in a university research project seeking solutions to the global problem of climate change. Soil mixed with this hydrogel can absorb up to 95 percent of the water that seeps in, reducing irrigation requirements up to 40 percent.
As a so-called superabsorber, Agrobiogel absorbs rainwater and nutrients from fertilizers in the soil, stores them and releases them back into the environment during dry periods. As a result, it can counteract droughts and compensate for irregular or reduced water supplies. As such, it could help overcome dry spells worldwide and reduce freshwater consumption.
A technological leap
Agrobiogel represents a technological leap forward compared to conventional fossil-based hydrogels and complies with the EU Fertilizer Regulation ((EU) 2019/1009), which takes effect in July 2022. The regulation contains technical specifications on permissible feedstocks, process conditions, quality requirements and quality management system requirements.
Increased soil productivity
Agrobiogel is a granulate that is applied to agricultural land by spreading. Only when water is added does it turn into gel. The granules are made from lignified plants that incorporate biopolymers into the plant cell wall to store exceptionally high amounts of water. Nyanhongo explains, “The manufacturing process for our hydrogel is secret, but we use residues from the bio-distillery and pulp and paper processing.”
Agrobiogel is biodegradable. Wood is a natural precursor to humus, decomposing over the years and then resulting in more fertile soils. Even sandy soils become productive again. Since the wood comes from waste wood from the timber industry, the product is also suitable for a functioning circular economy.
The organic hydrogel also promotes soil fertility and root growth. Plant roots grow larger, have better soil retention and produce stronger and healthier plants. This can increase crop yields and prevent crop failure in dry years.
Protection from leaching
Agrobiogel can be used alone or in combination with any type of irrigation. It helps save water by reducing the frequency of irrigation. Also, any added agricultural chemicals such as fertilizers are retained in the soil instead of being washed out. “Many farmers spread fertilizer in excess, and that harms the environment and is expensive,” explains Nyanhong.
Durable and water-absorbent
Compared to other organic hydrogels, Agrobiogel has a much higher water absorption capacity and stays in the soil much longer. It takes up to 20 years for the wood-based granules to decompose in the soil and become humus. Tests have proven that after three years it still has a water absorption capacity of 89 percent. This also allows it to be applied more sparingly, Nyanhongo says: “If 40 grams of hydrogel per liter of soil is already enough to achieve the desired effect in the first year, then you only need to apply about 10 to 20 grams of hydrogel per liter of soil in subsequent years.”
Organic hydrogel can be applied in open fields as well as in greenhouses and other artificial agricultural systems. There are virtually no limits to the areas of application. The launch is scheduled for as early as spring 2022. Hydrogel will then be available worldwide via wholesalers at an affordable price for amateur gardeners as well as farmers. Production will take place in Tulln near Vienna, Austria. The start-up is currently working on expanding production, as demand is already exceeding production capacity. The next step will be to add fertilizers to the hydrogel that are tailored to specific plant types.
This spin-off from the University of Natural Resources and Applied Life Sciences Vienna (BOKU) is funded by the Austria Wirtschaftsservice and ACCENT Startup Incubator Lower Austria and supported by the Austrian Centre of Industrial Biotechnology. The founding team consists of Gibson Nyanhongo, Johannes Paul Schwarz and Enrique Nacif.
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