Effects of soil bulk density and strength on seedling growth of annual ryegrass and tall fescue in controlled environment

• Published in: Grass and forage science Vol. 65; no. 3; pp. 348 - 357
• Main Authors: Bartholomew, P.W, Williams, R.D
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.09.2010; Blackwell Publishing Ltd
• Subjects: Festuca arundinacea; Italian ryegrass; leaf measurements; Lolium; Lolium multiflorum; soil compaction; tall fescue; tiller number
• ISSN: 0142-5242; 1365-2494
• DOI: 10.1111/j.1365-2494.2010.00753.x

Grasses sown with minimal tillage commonly exhibit slower establishment and lower herbage yield than those sown into a conventionally tilled seedbed. Some of the difference in performance may be attributed to differences in bulk density between tilled and untilled ground. It is not known if performance rankings of grass cultivars established in clean-tilled ground remain valid in more compacted soil characteristic of no-till seeding. Seedlings of five cultivars of Italian ryegrass (Lolium multiflorum Lam.) [IRG] and five cultivars of tall fescue [Festuca arundinacea Schreb. also known as Lolium arundinaceum Schreb. (Darbysh.)] [TF] were grown in pots of Coyle or Stephenville series soils (sandy loam and loamy sand respectively) packed to 0·75, 0·88 or 1·00 of maximum packing densities, established as 1·47 and 1·68 g cm⁻³ for Coyle and Stephenville soil respectively. Leaf appearance was measured until seedling harvest at 540 growing degree days after emergence. Increased bulk density decreased leaf appearance rates, reduced final leaf and tiller numbers and aerial and root biomass at harvest in both IRG and TF. Among cultivars within species, there was no difference (P > 0·05) in response to measured parameters to change in bulk density. Seedling growth and development of IRG were consistently greater than that of TF but showed greater reduction in response to increased soil bulk density. Soil strength provided a better indicator of likely seedling response to soil compaction than bulk density. The results suggest that cultivar rankings obtained under conventional tillage are likely to be valid with no-till planting.