Soil nitrogenase activity of the Nylsvley Nature Reserve

A dinitrogen fixation rate of 6,3 to 8,5 kg ha− 1 a− 1 was recorded for the Eragrostis pallens – Burkea africana savanna of the Nylsvley Nature Reserve by the acetylene reduction method. The bulk of the activity occurred in the summer and autumn after good rains and appears to be largely the result of legume – Rhizobium symbioses. No evidence of dinitrogen fixation by free-living Cyanobacteria or symbiotic systems involving either actinomycetes or grasses was found.