Doctoral candidate makes unusual discovery to help farmers
University of Venda final year doctoral candidate in the School of Agriculture, Francina Bopape recently discovered a novel type of soil bacterium which has huge potential for producing organic nitrogen fertiliser.
LIMPOPO – Because of its novelty and significance, the finding was published by the American Society for Microbiology in January and part of Bopape’s research project is aimed at helping small-scale farmers who produce bean crops.
She explained that some field crops, particularly the bean types such as soybean, are unique in the sense that they take up nitrogen gas (from the air) and convert it into nitrogen fertiliser. All field crops require this fertiliser for growth and ultimately the production of grain yield.
“Farmers apply commercial chemical nitrogen fertiliser (which is quite expensive) on crops. The bean types of plants can however circumvent the need for this expensive fertiliser if they are grown in a soil that harbours indigenous bacteria (called soil Rhizobia) which then forms small round structures on the roots which enables the manufacturing of the organic nitrogen fertiliser by the plant,” she said.
During planting, commercial farmers often mix (or inoculate) the bean seed with commercially available soil bacteria in order to enhance the subsequent manufacturing of the nitrogen fertiliser by the plants as they grow from seedlings to adult plants. This means that farmers save on the cost of inputs for producing the crop.
Using local soil samples, Bopape trapped the indigenous soil bacteria in the seedlings of a bean type of plant called pigeonpea. She then harvested the nodules and squeezed out the bacteria in the laboratory before purifying them for the next stage that identifies the genes that are responsible for the nitrogen fertiliser manufacturing process, among other genes. The novel strain of bacterium involved did not possess the common key genes found in other Rhizobia that are necessary in the process of nitrogen fertiliser manufacturing, suggesting that there is an alternative method.
Prof Eastonce Gwata of Univen’s Department of Crop Science commented that the results from Bopape’s work have several positive implications particularly for bio-inoculant technology. The next step in the study is to understand the mechanism at work in the strain before attempting its genetic enhancement for the benefit of farmers.
