Morphology of tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne) plants in pastures under sheep and cattle grazing

Abstract

The effects of contrasting management systems either of infrequent rotational grazing by town milk supply dairy cattle, or of frequent defoliation by continuously grazing sheep and beef cattle, on the morphology of independent plants and populations of ' Grasslands Roa ' tall fescue in mixed pastures, were measured over 1 year (1992\93) in New Zealand. Volunteer perennial ryegrass plants were also measured for comparison.While both species exhibited a similar pattern of clonal growth, tall fescue developed more plants of higher branching complexity than perennial ryegrass, chiefly through maintaining more connective stems, as herbage production was confined to the three youngest branching orders in both species. Greater resistance to microbial degradation of old stems through poorer quality organic matter (wide C : N ratio) compared to perennial ryegrass may be responsible for the greater complexity of fescue plants. In addition, tillering rates in tall fescue were three times lower which was offset by greater longevity and size of leaves and tillers, compared to perennial ryegrass. As a result, seasonal fluctuation in the distribution of plants among the various branching orders in tall fescue was small, producing a more stable population relative to the distinct seasonal changes in the population of perennial ryegrass plants. Grazing management had no effect on the seasonal population structure in either species.Differences in plant structure due to grazing management were small, with only slightly more tillers on sheep-grazed than on cattle-grazed tall fescue plants. The major effect of grazing management was on dry weight or size of plant components. Cattle-grazed tall fescue plants were 120 % heavier, with greater numbers and lengths of stolons and flower heads than those under sheep grazing. For the volunteer perennial ryegrass, the difference was only 65 %, possibly due to competition from the more vigorous tall fescue under rotational cattle grazing.Both species produced stolons throughout the year, although these were primarily associated with reproductive growth in spring. In tall fescue, an additional distinction was made between stolon and rhizome, the latter occurring mainly in the summer-autumn. Their possible functions in plant growth are discussed.

Growth and Senescence of the Successive Leaves on a Cocksfoot Tiller. Effect of Nitrogen and Cutting Regime

“…These results were in agreement with those observed previously: decreasing the cutting height decreases the lamina length (Davies, 1977;Hume and Brock, 1997). The sheath length and its time course could explain these eects.…”

Characterization for industrial purposes of the fibre anatomy of perennial ryegrass and tall fescue stem and leaf at three stages in the primary growth

“…Furthermore, it has also been shown that basal internode extension occurs with advancing stage of maturity (Brock and Fletcher, ). In addition, stem fibre‐cell length was greater for tall fescue compared with PRG, possibly reflecting the greater stem length of tall fescue than PRG (Hume and Brock, ).…”

Growth Strategy of Rhizomatous and Non-Rhizomatous Tall Fescue Populations in Response to Defoliation

“…Primary tillers were removed sequentially from the original clone, recording the nodal position of each successive tiller removed, and associated daughter tillers categorized as either secondary or tertiary tillers. The original intention was to record numbers of tillers forming stolons and rhizomes, as in the study of Hume and Brock [9], but it was found that no clear distinction could be made between stolons and rhizomes. This was due to a continuous gradation in morphology from tillers with a small amount of internode elongation at one or two phytomers to tillers with fully formed rhizomes 100 mm or more in length.…”

“…These buds tended to be those which had been dormant for a period and had taken on a spherical shape. Stolon and rhizome formation on a per plant basis has also been quantified in Grasslands Roa tall fescue [9], however, factors determining rhizome initiation and details of site of initiation and numbers and lengths of internodes comprising each rhizome are largely unknown.…”