Seasonal Changes of Daily Increase in Extended Sward Height, Dry Matter, Bulk Densities and Digestible Dry Matter of Temperature Grasses

Under a regime of frequent cutting, seasonal changes of the daily increase in extended sward height, dry matter (OM) bulk densities and digestible dry matter (DOM) of perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata L.) and Kentucky bluegrass (Poa pratensis L.) were followed for 5 years. Seasonal changes of the daily increase in extended sward height, DM bulk densities (daily increase in OM/daily increase in extended sward height) and DOM (daily increase in DOM/daily increase in extended sward height) of the grasses had 3 peaks and 2 troughs, as the height and densities were depressed around 30% by dry weather in the middle of June (low precipitation and high radiation) and · August (low precipitation and high air temperature).