Effects of Temperature, Nitrgoen Fertilizer, and Cutting Height on Regrowth and Dry Matter Production

Orchardgrass (Dactylis glomerata L.) is used extentively in South Korea for green-chop and pasture mixtures. Maintaining orchardgrass stands over summer is a major problem in South Korea. Orchardgrass was grown in soil in growth chambers to evaluate the effect of temperature (day/night:20/JO, 27/17 and 3S/25°C), nitrogen (N) application (0, 5 and 10 kg/ha) and cutting height (5 and IO cm) on plant height, above­and below-ground dry matter yield, and leaf area accumulation. High temperatures (35/25°C) greatly reduced plant height, DM yields and leaf area expansion, Cutting to 10 cm gave greater DM yields and leaf areas, compared to cutting to 5 cm, but there were no differences between N fertiliser levels. High temperature is thought to be partially responsible for the commonly observed summer depression of orchardgrass growth and cutting to a greater height could improve DM yield and minimise stand losses during hot summers.