Many valuable timbers in southern areas of Africa are in danger thanks to the risk of fire or excessive use. This also includes African teak (of which the latin name is Pterocarpus angolensis). The wood of this tree is the most harvested in the southern regions of Africa – it is stable, easy to work with, and aesthetically pleasing. Teak is also appreciated locally as a shade tree and for traditional medicine. Natural rejuvenation or reforestation with nursery plants are difficult, as the germination rate and the chances that the seedlings will survive in the ground that is usually lacking in nutrients are low.
Plants Are “Fertilized Biologically”
A team from the University of Bremen found out whilst carrying out investigations in Namibia and Angola in 2020 that there are bacteria that can help to make the cultivation of these trees in nurseries successful. The tree belongs to the legume family, of which many can enter into symbioses with bacteria: Nodule bacteria fix atmospheric nitrogen into a usable form in special root nodules and then deliver it to the plant. Which plant species cooperates with which bacteria can sometimes be highly specific. The researchers spent several years screening nodule bacteria and were able to for the first time ever find bacteria that enter into such a symbiosis with this tree species. Based on these findings “organic fertilizer” can be developed. Bacteria that have been multiplied in a laboratory can be added to the seeds so that the symbiosis can hopefully occur quickly in nurseries and thus simplify the cultivation of seedlings.
Professor Barbara Reinhold-Hurek, microbiologist at the University of Bremen: “The plants are biologically fertilized by the bacteria. This means that they can also grow in soil that has little of the nutrients that are needed by seedlings. With our research, we wish to contribute to the possibility of sustainably cultivating the popular plant. A sustainable handling of resources is imperative.” The working group has also spent several years working on the topics of sustainability and yield increase in smallholder agriculture through the implementation of microbial fertilizer for legumes. The German Federal Ministry of Education and Research is funding the project.