
%0 Journal Article
%A Vickery, PJ 
%A Wheeler, JL 
%A Mulcahy, C 
%T Factors affecting the hydrogen cyanide potential of white clover (<I>Trifolium repens</I> L.)
%J Australian Journal of Agricultural Research
%D 1987/12/01
%V 38
%N 6
%P 1053-1059
%K 
%R https://doi.org/10.1071/AR9871053
%U https://www.publish.csiro.au/paper/AR9871053 
%X Pot experiments were used to determine the effects of age, light, temperature, mineral nutrition and wilting on the HCN potential (HCNp ) of white clover (Trifolium repens L.). HCNp, adjusted for pre-expenmental HCNp, was reduced by higher light intensity (505 v. 220 mg HCN kg-1 DM), by increased temperature (408 v. 317 mg HCN kg-1 DM) and by phosphorus application (382 v. 343 mg HCN kg-1 DM). These effects were largely explained by the hypothesis that HCNp diminished as the size and vigour of the plant increased, and the use of dry matter production as a covariate on HCNp removed the significant effects of light, temperature and phosphorus. In two experiments wilting plants prior to harvest increased HCNp by 15 and 24%, and reduced dry matter yield by 9 and 13%. HCNp declined curvilinearly as the white clover aged. The conditions shown to favour high HCNp, namely, immaturity, moisture stress, low light intensity, cool temperature, and inadequate P supply, are those which occur periodically in the late autumn and early spring of temperate climates. Sheep in late pregnancy at this time, could, if white clover comprises a substantial proportion of their diet, experience thiocyanate absorption as a consequence of HCN detoxication and hence increase the risk of goitri to the lamb. 
