TopSoil

Low crop productivity is a general problem of smallholder agriculture in sub-Saharan Africa.

In the Kavango and North-Western region of Namibia, agricultural production is dominated by smallholder farmers who produce very low yields without irrigation and due to lack of fertilizer or other inputs. Low yields are associated with declining soil fertility. Soil analyses indicate that agricultural productivity is particularly affected by a prevailing deficiency in plant-available nitrogen.

Pulses, forage legumes and other Fabaceae can access nitrogen from air by nitrogen-fixing nodule symbioses with rhizobia. They can provide protein- and nutrient-rich food and feed with good agricultural management practices. In addition, plant residues can be added to the soil to increase its nitrogen and organic matter content and thus also improve soil fertility.Consequently, nitrogen fixation by nodule symbioses could provide an important input of nitrogen and organic matter to local agricultural systems, but this management option is hardly targeted in our research region Namibia. In addition, the target region is expected to be severely affected by increases in temperature and decreases in precipitation as climate change progresses.

Therefore, an interdisciplinary team of soil scientists, microbiologists, molecular biologists, biotechnologists, and economists intends to introduce adapted rhizobial inoculant for legumes that should be suitable under projected drought and temperature increases.

Previous results suggest that some rhizobia in the target region are particularly well adapted to such harsh conditions. Field experiments with cowpea will test the efficiency of bacterial symbiont strains. Promising other legumes that are particularly drought resistant have hardly been tested or used in Kavango: chickpea and alfalfa. One aim is to test whether they are suitable for the climatic and soil conditions, and to find suitable symbiotic bacteria. To this end, master's students from Namibia will collaborate scientifically in the project and also visit the German partner laboratories. In order to foster  anchoring the knowledge-based technologies in the target country, broad-participation courses are be held in Namibia. They are held jointly for students from both Namibian universities, UNAM (University of Namibia) and NUST (Namibia University of Science and Technology).