Effect of cutting on production and tillering in prairie grass (Bromus willdenowii Kunth) compared with two ryegrass (Lolium) species. 1. Vegetative plants
1991
Hume, D.E.
Effects of cutting to 3 or 6 cm stubble height at frequencies of 1, 2 or 4 weeks were investigated in young, vegetative, spaced plants of prairie grass (Bromus willdenowii Kunth), a tetraploid Westerwolds ryegrass (Lolium multiflorum Lam.) and perennial ryegrass (Lolium perenne L.). Plants were grown for 8 weeks on nutrient solution in a growth cabinet at day/night temperatures of 15/10 degrees C and in a short photoperiod. Leaf appearance, site filling and tiller numbers were all reduced by both increased cutting frequency and a lower cutting height. The extent of these reductions was least in prairie grass and greatest in Westerwolds ryegrass. Relative growth rates in all species responded in a similar manner with more frequent cutting and a lower cutting height. Cutting frequency had the greatest effect on growth rates, although the effect of cutting height increased with time. Results confirm general recommendations of long intervals between defoliations to achieve high yields for vegetative prairie grass, but the relative amounts of dry matter harvested under the different cutting regimes may be no different to that obtained in ryegrass. Stubble height was of lesser importance in determining yields. A typical U-shaped curve for depletion and recovery in water-soluble carbohydrates occurred after defoliation in all species, but levels remained low at frequent cutting. Water-soluble carbohydrate levels in stubble and roots were higher in prairie grass. Regrowth at the end of the experiment was highly correlated with total stubble and root weights (r = 0.84), while regrowth per tiller showed a good correlation with water-soluble carbohydrate content, although the response varied between species.
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