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

Abstract

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 tropical grasses from severe frosts in late May. By late winter the overdrilled species had produced a heavy yield of herbage. The order of species survival (excluding lupin and ryegrass treatments) was: Paspalum and Pennisetum (complete survival), Cynodon (slight mortality), Digitaria (up to 40% plant death), and Setaria (almost complete plant death). Spring growth was related to species survival and to plant survival in the cover treatments. Thus.Paspalum and Pennisetum were the most productive species, and the tall stubble and short sward the most productive treatments. There was little difference in growth between these two treatments, except in Cynodon where the tall winter cover increased spring production 9-fold.

Evaluation of five introductions of the subtropical grassHemarthria altissimaat a frost-prone site in Northland

“…Our observations suggest that the superior winter survival of PI 364884 and PI 364891 was based on two attributes: first, slightly higher frost tolerance; and second, denser swards and therefore larger amounts of stem material at the soil surface. As shown by Davies & McNaughton (1980), stem material at soil level under stubble can escape frost. Oakes (1980) and Quesenberry (pers.…”

The role of C4grasses in New Zealand pastoral systems

“…Longer regrowth intervals of 4-6 weeks result in more pasture growth than with a 2-week interval (Goold 1979), but feed quality inevitably suffers. 2,3,4,5,6,7,11 1,2,3 1,2,3,4,5,8,11 1,2,3,4,5,11 1,2,3,8 2,3,4,5 3,4,5 1, Taylor et al (1976a); 2, Taylor et al (1976b);3, Taylor et al (1976c);4, Forde et al (1976a);5, Forde et al (1976b);6, Percival & Couchman (1979);7, Percival et al (1979);8, Rumball (1991);9, Davis & Hunt (1989); 10, ; 11, Davies & McNaughton (1980). Managing the switch from autumn dominance or co-dominance of C 4 grasses to C 3 dominance for cool-season growth is critical for successful farming of C 4 grasses in New Zealand.…”