An experiment was set up to determine the effect of time and rate of nitrogen fertilization and stage of growth at first cut on yield and digestibility of dry matter and protein content of two timothy (Phleum pratense L.) cultivars, at each of two cuts, No difference in yield or chemical composition was found between cultivars. Highest yields and crude protein contents were measured at rates of nitrogen fertilizer of 112 and 224 kg/ha. Higher yield and protein content were obtained with NH4NO3 applied totally or in split applications in the spring than with urea in the fall. Dry matter digestibility (DDM) was not affected by nitrogen at rates of 56, 112 and 224 kg/ha. First cut was taken at two different stages of growth, and the second cut was taken on the same day in all the plots. At anthesis, yields were higher than at the head stage but DDM and protein content were lower. The opposite was found at the second cut. Except in 1973, total dry matter yield was not affected by the stage of growth at first cut.
