Effect of cutting height and cutting interval on rhizome development, herbage production and herbage quality of Lotus pedunculatus cv. Grasslands Maku

Abstract

Summary. A study was conducted to determine the influence of 3 defoliation intervals (4, 8 and 12 weeks), at 3 harvest heights (2, 6 and 12 cm) on the rhizome development, herbage production and herbage quality of Lotus pedunculatus cv. Grasslands Maku.

An interaction between cutting height and cutting interval was measured for both rhizome number and length. As cutting interval became more frequent, cutting height was more critical, with cutting to 2 cm every 4 weeks producing fewer and shorter rhizomes. Rhizome production increased with increased cutting height and frequent cutting intervals reduced rhizome production. The impact of severe defoliation was greatest during late autumn and winter, when peak rhizome expansion occurred. Although lenient cutting treatments encouraged rhizome development and production it was at the expense of herbage production, with longer cutting intervals and increasing cutting heights resulting in less total herbage and lotus production. Increased rhizome production was also associated with lower in vitro digestibility, lower nitrogen concentration and higher condensed tannin concentration of the lotus herbage.

If long rotations are required to maintain a persistent and competitive lotus sward in temperate and subtropical pasture systems, then L. pedunculatus cv. Grasslands Maku is unlikely to play a major role in intensive grazing systems in eastern Australia. This paper concludes with a discussion of the possible use of strategic grazing practices of Grasslands Maku swards to achieve a balance between rhizome production and herbage production.