Catching rhizobia to introduce high protein containing soybean for sustainable agriculture in Flanders

General introduction

With the help of 1,200 citizens and their gardens, we successfully identified native rhizobia (beneficial soil bacteria) in Flemish soils that are capable of efficiently nodulating soybean plants. Soybean is not an indigenous crop in Western Europe, thus it requires inoculation with nitrogen-fixing bacteria to establish a productive symbiosis and benefit from atmospheric nitrogen fixation. Currently, most of these bacteria are exotic strains imported from North or South America. Replacing these with local strains that are better adapted to Belgian and Northwestern European environmental conditions could optimize soybean yields and enhance protein content. 

Research approach

Soybean plants were grown in 1,200 Flemish gardens as part of a citizen science initiative. In the lab, researchers examined the roots for nodules. In total, 267 nodules were found and 34 of which colored red, indicating the presence of nitrogen-fixing bacteria. These bacteria were isolated and thoroughly studied. After laboratory testing, the most promising strains were trialed in greenhouses and later in field conditions. The results showed that these native strains performed as well as, or better than, the exotic strains currently used.

Further research will focus on understanding which conditions are most favorable for these native bacteria and how they can be effectively applied to improve soybean cultivation. This innovative approach could lead to more sustainable and locally adapted agricultural practices in the region.

Relevance/Valorisation

Soybean (Glycine max) is one of the most important protein sources for food and feed. Belgium is dependent on imported soy and its derived products: approximately 800,000 tons annually. Of this, 65% is imported from countries such as Argentina and Brazil that are associated with high risks for deforestation and forest degradation. Local soybean production would help to reduce this dependency and to develop socially responsible protein products. Additional knowledge about soil bacteria and fungi will support the success of Flemish soy cultivation.