Research note:

The use of Lolium multiflorum and uninoculated Trofolium subterraneum as reference crops in nitrogen fixation studies

  • M Trytsman Range and Forage Institute, Agricultural Research Council, Private Bag X05, Lynn East, 0039 Republic of South Africa
  • WD Stock Department of Botany, University of Cape Town, Private Bag, Rondebosch, 7700 Republic of South Africa
  • CJ Otto Plant Protection Research Unit, Agricultural Research Council, Private Bag X134, Pretoria, 0001 Republic of South Africa
Keywords: botany, crops, <i>Lolium multiflorum</i>, nitrogen fixation, nodulation, Roodeplaat Research Station, ryegrass, South Africa, subterraneum clover, <i>Trifolium subterraneum</i>, Woogenellup, <sup>15</sup>N


The 15N natural abundance and15 N dilutions methods were used to determine the viability of using either Lolium Multiflorum (annual ryegrass) or uninoculated Trifolium subterraneum (subterrenean clover), as non-fixing reference crops in N2-fixation studies. The δ15 N values for the15 N natural abundance method and atom% 15N values for the 15N dilution method for plant and soil samples are presented. The ryegrass pastures showed the least variation in δ15N and atom%15N values between experimental plots. This crop appeared to be a more appropriate choice in such studies, but further investigation is needed to confirm this observation. The use of uninoculated subterranean clover as a reference crop seemed problematic, since inoculation with effective rhizobia could not be prevented. Relatively high variation in δ15N values for inoculated for subterranean clover was obtained compared to the atom% 15N values. This result indicated that the use of the 15N natural abundance method should be evaluated for other pasture legume species.

Keywords: botany; crops; Lolium multiflorum; nitrogen fixation; nodulation; Roodeplaat Research Station; ryegrass; South Africa; subterraneum clover; Trifolium subterraneum; Woogenellup; 15N

African Journal of Range and Forage Science 1995, 12 (1):46–48

Journal Identifiers

eISSN: 1727-9380
print ISSN: 1022-0119