Effect of winter herbage cover on survival and spring growth of tropical grasses in a temperate environment

Winter herbage covers were investigated as a means of protecting 5 tropical grasses from frost. Paspalum dilatatum, Pennisetum clandestinum, Cynodon dactylon, Digitaria scalarum and Setaria anceps were grown in small plots and overwintered under the following treatments: (1) tall stubble oftheir own herbage, (2) a short sward, (3) overdrilled lupin, and (4) overdrilled perennial ryegrass. During frosts grass stern-base mimimum temperatures under the heavy cover oftall stubble were 2°C warmer than under the short sward, but there were no significant differences in plant survival between the short sward and tall stubble. Stern-base temperatures were above O°C even during severe frosts in all treatments, but some plants died, especially in Setaria, even through meristems at soil level were not frozen. Chilling injury, as distinct from frost injury, may have killed them. Overdrilled lupin and ryegrass both failed to produce sufficient herbage by early winter from a 25 March sowing date to protect the...