Fixation and transfer of nitrogen by white clover to ryegrass

Abstract. 15 N 2 was used in a sealed controlled environment chamber to investigate the transfer of fixed nitrogen from white clover to perennial ryegrass growing in soil in pots. There was no difference in the 15 N content of roots and shoots of clover plants after exposure to 15 N. No labelled fixed nitrogen was detected in ryegrass plants growing with the clover plants for a period of 129 days. There was therefore no evidence of rapid direct transfer (excretion) of fixed nitrogen from clover to ryegrass.