Growth of tropical grass introductions in mixed swards with ryegrass and clover under mowing

Abstract

Six tropical grass introductions were compared with Pennisetum clandestinum as pasture components under lax mowing in Northland for 3 years. All were in mixed swards with perennial ryegrass and white clover. A control treatment of ryegrass/clover alone was included. The mixed swards were relatively stable on a moisture-retentive soil at Kaitaia, but were unstable on a drought-prone soil at Sweetwater where ryegrass and clover did not persist. At a heavy frost site at Kaikohe, the tropical species were frost-damaged and either failed to persist or were minor sward components. Long-term evaluation of the tropical species in mixed swards was possible only at Kaitaia. Hemarthria altissima was planted only at this site where it persisted in mixed swards, whereas Aeroeeras maerum, Cynodon daetylon, Digitaria pentzii, D. sealarum, and Setaria sphacelata gradually disappeared as they were suppressed by ryegrass, clover, and volunteer species. Pennisetum clandestinum persisted as almost a pure stand by excluding other sward components. Compared with P. clandestinum, the mixtures containing the introductions were faster growing in winter and spring, and were often of similar productivity in summer-autumn. Over. 3 years, mixtures containing H. altissima, A. maerum, C. daety/on, and S. sphaelata} were significantly higher yielding than P. clandestinum. Mixtures containing the introductions had higher summer-autumn growth rates and higher annual yields than ryegrass/clover alone.

Keywords:

• tropical grasses
• mixed pastures
• evaluation
• Aeroeeras
• Cynodon
• Digitaria
• Hemarthria
• Pennisetum
• Setaria
• kikuyu grass
• ryegrass
• white clover
• Gramineae