Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-27T20:38:29.132Z Has data issue: false hasContentIssue false

Seasonal variation in the morphology of perennial ryegrass (Lolium perenne) and cocksfoot (Dactylis glomerata) plants and populations in pastures under intensive sheep grazing

Published online by Cambridge University Press:  27 March 2009

J. L. Brock
Affiliation:
Ag Research, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand
D. E. Hume
Affiliation:
Ag Research, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand
R. H. Fletcher
Affiliation:
Ag Research, Grasslands Research Centre, Private Bag 11008, Palmerston North, New Zealand

Summary

The morphology of independent plants of ‘Grasslands Ruanui’ perennial ryegrass (Lolium perenne L.) and three cultivars of cocksfoot (Dactylis glomerata L.) (‘Grasslands Apanui’, ‘Grasslands Kara’ and ‘Grasslands Wana’) in mixed pastures under intensive sheep grazing was studied at Palmerston North, New Zealand during 1991/92.

Both perennial ryegrass and cocksfoot exhibited a similar pattern of clonal growth and population structure. Distribution of plants among various orders of branching showed a relatively stable pattern through most of the year except in spring, when stem decay and plant fragmentation exceeded apical growth and regeneration, causing an increase in the proportion of small plants and a corresponding decrease of larger plants. This pattern was similar to that previously reported for white clover (Trifolium repens L.). Nevertheless, seasonal variation in plant structure (number of leaves, tillers and stems per plant) was small, but variation in organ size (DW or length) was greater. Stolon formation through elongation of internodes occurred throughout the year, but was associated primarily with flowering.

Grazing management caused no differences in plant structure between species or among the cocksfoot cultivars, but did affect the size of organs, and hence plants. Cocksfoot plants were 50–60% heavier than perennial ryegrass under rotational grazing. Under set stocking, only perennial ryegrass and Wana cocksfoot exhibited sufficient phenotypic plasticity to survive, both Kara and Apanui cocksfoot failed to persist. The only consistent difference between the species was greater flowering in perennial ryegrass than in cocksfoot, in both the proportion of plants flowering, and the number of flowering tillers per plant. Both species produced stolons throughout the year, although perennial ryegrass and Wana cocksfoot had a higher proportion of plants with stolons than Apanui and Kara cocksfoot. Length and DW of stolons per plant were similar in both species.

As there was little variation in plant structure and plant density, length of stolons per unit area tended to parallel seasonal changes in pasture tiller density. The role of grazing management in the survival of tillers and plants, and subsequent performance of grass species in pastures is discussed.

Type
Crops and Soils
Copyright
Copyright © Cambridge University Press 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Barnard, C. (Ed.) (1964). Grasses and Grasslands. London: Macmillan.CrossRefGoogle Scholar
Brock, J. L. (1986). Some observations of pasture management effects on grassgrub, Porina and earthworm populations. Proceedings of the New Zealand Grassland Association 47, 273278.CrossRefGoogle Scholar
Brock, J. L. & Fletcher, R. H. (1993). Morphology of perennial ryegrass (Lolium perenne) plants in pastures under intensive sheep grazing. Journal of Agricultural Science, Cambridge 120, 301310.CrossRefGoogle Scholar
Brock, J. L. & Thomas, V. J. (1991). The pasture ryegrass plant, what is it? Proceedings of the New Zealand Grassland Association 53, 111116.CrossRefGoogle Scholar
Brock, J. L., Hay, M. J. M., Thomas, V. J. & Sedcole, J. R. (1988). Morphology of white clover (Trifolium repens L.) plants in pastures under intensive sheep grazing. Journal of Agricultural Science, Cambridge 111, 273283.CrossRefGoogle Scholar
Carlson, G. E. (1966). Growth of white clover leaves, after leaf removal. In Proceedings of the X International Grassland Congress, pp. 134136. Helsinki, Finland: Finnish Grassland Association.Google Scholar
Cooper, J. P. & Saeed, S. W. (1949). Studies on growth and development in Lolium. I. Relation of the annual habit to head production under various systems of cutting. Journal of Ecology 37, 233259.CrossRefGoogle Scholar
Cowie, J. D. (1978). Soils and agriculture of Kairanga County, North Island, New Zealand. New Zealand Soil Bureau Bulletin 33.Google Scholar
Curll, M. L. & Wilkins, R. J. (1982). Frequency and severity of defoliation of grass and clover by sheep at different stocking rates. Grass and Forage Science 37, 291297.CrossRefGoogle Scholar
Evans, P. S. (1973). The effect of repeated defoliation to three different levels on root growth of five pasture species. New Zealand Journal of Agricultural Research 16, 3134.CrossRefGoogle Scholar
Harris, W., Pandey, K. K., Gray, Y. S. & Couchman, P. K. (1979). Observations on the spread of perennial ryegrass by stolons in a lawn. New Zealand Journal of Agricultural Research 22, 6168.CrossRefGoogle Scholar
Hay, M. J. M., Brock, J. L. & Thomas, V. J. (1989). Density of Trifolium repens plants in mixed swards under intensive grazing by sheep. Journal of Agricultural Science, Cambridge 113, 8186.CrossRefGoogle Scholar
Hoglund, J. H. & Brock, J. L. (1978). Regulation of nitrogen fixation in a grazed pasture. New Zealand Journal of Agricultural Research 21, 7382.CrossRefGoogle Scholar
Hume, D. E. & Barker, D. J. (1991). Natural reseeding of five grass species in summer dry hill country. Proceedings of the New Zealand Grassland Association 53, 97104.CrossRefGoogle Scholar
Hunt, W. F. (1989). Grazing management effects on perennial ryegrass and white clover tiller populations. In Proceedings of the XVI International Grassland Congress, pp. 10551056. Nice, France: The French Grassland Society.Google Scholar
Jacques, W. A. & Edmond, D. B. (1952). Root development in some common New Zealand pasture plants. V. The effect of defoliation and root pruning on cocksfoot (Dactylis glomerata) and perennial ryegrass (Lolium perenne). New Zealand Journal of Science and Technology 34A, 231248.Google Scholar
Jacques, W. A. & Schwass, R. H. (1956). Root development in some common New Zealand pasture plants. VII. Seasonal root replacement in perennial ryegrass (Lolium perenne), Italian ryegrass (L. multiflorum) and tall fescue (Festuca arundinacea). New Zealand Journal of Science and Technology 37A, 569583.Google Scholar
Korte, C. J. & Harris, W. (1987). Stolon development in grazed ‘Grasslands Nui’ perennial ryegrass. New Zealand Journal of Agricultural Research 30, 139148.CrossRefGoogle Scholar
Lancashire, J. A. & Brock, J. L. (1983). Management of new cultivars for dryland. Proceedings of the New Zealand Grassland Association 44, 6173.CrossRefGoogle Scholar
Matthew, C. (1992). A study of seasonal root and tiller dynamics in swards of perennial ryegrass (Lolium perenne L.). PhD thesis, Massey University, New Zealand.Google Scholar
Matthew, C., Quilter, S. J., Korte, C. J., Chu, A. C. P. & Mackay, A. D. (1989 a). Stolon formation and significance for sward tiller dynamics in perennial ryegrass. Proceedings of the New Zealand Grassland Association 50, 255259.CrossRefGoogle Scholar
Matthew, C., Xia, J. X., Hodgson, J. & Chu, A. C. P. (1989 b). Effect of late spring grazing management on tiller age profiles and summer–autumn pasture growth rates in a perennial ryegrass (Lolium perenne L.) sward. In Proceedings of the XVI International Grassland Congress, pp. 521522. Nice, France: The French Grassland Society.Google Scholar
Matthew, C., Chu, A. C. P., Hodgson, J. & Mackay, A. D. (1991). Early summer pasture control: what suits the plant? Proceedings of the New Zealand Grassland Association 53, 7377.CrossRefGoogle Scholar
Mitchell, K. J. (1956). Growth of pasture species under controlled environment. I. Growth at various levels of constant temperature. New Zealand Journal of Science and Technology 38A, 203216.Google Scholar
Rumball, W. (1982 a). ‘Grasslands Kara’ cocksfoot (Dactylis glomerata L.). New Zealand Journal of Experimental Agriculture 10, 4950.CrossRefGoogle Scholar
Rumball, W. (1982 b). ‘Grasslands Wana’ cocksfoot (Dactylis glomerata L.). New Zealand Journal of Experimental Agriculture 10, 5152.CrossRefGoogle Scholar
Vickery, P. J., Bennett, I. L. & Nicol, G. R. (1980). An improved electronic capacitance meter for estimating herbage mass. Grass and Forage Science 35, 247252.CrossRefGoogle Scholar
Whitehead, D. C. (1970). Carbon, nitrogen, phosphorus and sulphur in herbage plant roots. Journal of the British Grassland Society 25, 236241.CrossRefGoogle Scholar