Influence of N and K fertilization and growth temperature on 13C/12C ratios of timothy (Phleum pratense L.).

Measurements have been reported of carbon isotope ratios of timothy grown at different temperatures and with varying nitrogen and potassium supplies. Both total plant tissue and extracted plant tissue have been analyzed. The 13C/12C ratios were found to vary both with temperature and with nutrient level; the highest values of δ13C were found under the most optimum growth conditions.