The effect of soil carbon on symboitic nitrogen fixation and symbiotic Rhizobium populations in soil with Trifolium repens as host plant
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Date
Authors
Swanepoel, Pieter Andreas
Botha, P.R. (Philippus Rudolph)
Truter, Wayne Frederick
Surridge-Talbot, A.K.J. (Angela Karen Joanna)
Journal Title
Journal ISSN
Volume Title
Publisher
NISC and Taylor & Francis
Abstract
Soil organic carbon (SOC) is the main attribute of high-quality soil. The amount of nitrogen fixed by Rhizobium symbiotically
with Trifolium repens (white clover) is ultimately determined by the quality of the soil environment. The effect of SOC on the total
number of symbiotic and saprophytic rhizobia was determined. Subsequently, the amount of nitrogen (N) fixed was assessed by
using the N difference technique. Most Rhizobium was detected between a SOC content of 2.03% to 3.80% in both inoculated and
non-inoculated soils. Inoculation increased the number of rhizobia in soil. Most N was fixed in the soil with the lowest SOC content.
Although the amount of N fixed increased as the level of SOC decreased, the efficiency of N fixation decreased proportionally to
SOC. Subsequently, more N was rhizodeposited. It was concluded that symbiotic rhizobia introduced by the inoculant were more
efficient than free-living rhizobia in soils with higher carbon content, which highlights the importance of inoculation in improving
the sustainable production of T. repens pastures.
Description
Keywords
Colony forming units, Most probable number, Plant infection technique, Symbiotic nitrogen fixation, Trifolium repens
Sustainable Development Goals
Citation
P A Swanepoel, P R Botha, W F Truter & A KJ Surridge-Talbot (2011): The effect of soil carbon on symboitic nitrogen fixation and symbiotic Rhizobium populations in soil with Trifolium repens as host plant', African Journal of Range & Forage Science, 28:3, 121-127.