Hostname: page-component-77c89778f8-vpsfw Total loading time: 0 Render date: 2024-07-19T05:32:55.617Z Has data issue: false hasContentIssue false
  • English
  • Français

Summer-growing components of a pasture system in a subtropical environment. 1. Pasture growth, carrying capacity and milk production

Published online by Cambridge University Press:  27 March 2009

G. J. Murtagh ,
A. G. Kaiser ,
D. O. Huett  and
R. M. Hughes
G. J. Murtagh
Affiliation:
Agricultural Research Centre, Wollongbar, N.S.W. 2480, Australia
A. G. Kaiser
Affiliation:
Agricultural Research Centre, Wollongbar, N.S.W. 2480, Australia
D. O. Huett
Affiliation:
Agricultural Research Centre, Wollongbar, N.S.W. 2480, Australia
R. M. Hughes
Affiliation:
Agricultural Research Centre, Wollongbar, N.S.W. 2480, Australia
Get access Rights & Permissions [Opens in a new window]

Summary

The leaf growth, carrying capacity and dairy production of four summer-growing pastures were measured in a subtropical area of Australia. The growing season was subdivided into ten 4-week periods and the production was estimated for each period. Carrying capacities were determined by rotationally grazing four paddocks of each pasture over the 4-week period, and varying the stocking density so that a target weight of leaf material remained on the pasture at the conclusion of each grazing.

A non-limiting rate of nitrogen fertilizer increased total leaf production of kikuyu by 97% over a control treatment without nitrogen, but the response was not evenly distributed throughout the season. It fell to 50% during autumn when growth on the nitrogen-fertilized pastures was restricted following heavy defoliation during late summer. The use of the tropical legumes, siratro and glycine, in a mixed sward with kikuyu, did not increase leaf production over a kikuyu control pasture. The legumes grew poorly and this appeared to be due to the combined effects of their poor adaptability to the krasnozem soil, a high plant mortality especially during the first winter after sowing, the 4-week grazing interval and strong grass competition.

The carrying capacity of the nitrogen-fertilized pasture was 1·3–5·3 cows/ha at the beginning (September–October) and end (April–mid June) of the growing season, and increased to a peak of 7·4–9·7 cows/ha during February-mid March. Nitrogen fertilizer increased the carrying capacity by an average of 131% over that on a kikuyu pasture without nitrogen. The carrying capacities were similar on kikuyu and on a mixed carpet grass-kikuyu pasture, both without nitrogen, but were less on a tropical legume-kikuyu pasture which was grazed at a lighter grazing intensity during autumn to aid legume persistence.

Reflecting the experimental method of adjusting the stocking density according to the pasture available, differences in dairy production per cow were small relative to differences in the carrying capacity. Consequently seasonal variation in total dairy production/ha mirrored the carrying capacity. Nitrogen fertilizer increased the average production of 4% fat-corrected milk to 13·2 t/ha/40 weeks, an increase of 133% over the control without nitrogen.

The results illustrate the marked seasonal imbalance in growth and carrying capacity for a given pasture, and emphasize the need to use mixed feeding systems to provide a uniform level of nutrition for a fixed number of cows.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 94 , Issue 3 , June 1980 , pp. 645 - 663
Copyright
Copyright © Cambridge University Press 1980

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

Brockington, N. R. (1972). A mathematical model of pasture contamination by grazing cattle and the effects of herbage intake. Journal of Agricultural Science, Cambridge 79, 249–257.Google Scholar
Bryan, W. W. (1970). Tropical and sub-tropical forests and heaths. In Australian Grasslands (ed. Moore, R. M.), pp. 102–122. Canberra: Australian National University Press.Google Scholar
Bryan, W. W. & Sharpe, J. P. (1965). The effect of urea and cutting treatments on the production of Pangola grass in south-eastern Queensland. Australian Journal of Experimental Agriculture and Animal Husbandry 5, 433–441.Google Scholar
Colman, R. L. (1964). Nitrogen fertilisation of Paspalum dilatatum Poir. in relation to the feed requirements of dairy cattle on the north coast of New South Wales. M.Sc.Agr. thesis, University of Sydney.Google Scholar
Colman, B. L. (1971). Fertilizers and irrigation for intensification of pasture production. In Intensive Pasture Production (ed. Lazenby, A. and Swain, F. G.), pp. 176–196. Sydney: Angus and Robertson.Google Scholar
Colman, R. L. & Kaiser, A. G. (1974). The effect of stooking rate on milk production from kikuyu grass pastures fertilized with nitrogen. Australian Journal of Experimental Agriculture and Animal Husbandry 14, 155–160.Google Scholar
Colman, R. L. & Mears, P. T. (1975). Regional pasture development and associated problems. IV. Northeastern New South Wales. Tropical Grasslands 9, 101–108.Google Scholar
Conway, A. G. (1973). Voluntary intake and stocking rate equivalents for grazing cattle. Irish Journal of Agricultural Research 12, 193–204.Google Scholar
Cowlishaw, S. J. (1969). The carrying capacity of pastures. Journal of the British Grassland Society 24, 207–214.Google Scholar
Henzell, E. F. & Oxenham, D. J. (1973). The relation between growth and leaf nitrogen concentration in Nandi setaria and some other tropical grasses. Communications in Soil Science and Plant Analysis 4, 147–154.Google Scholar
Ivory, D. A., Stobbs, T. H., McLeod, M. N. & Whiteman, P. C. (1974). Effect of day and night temperatures on estimated dry matter digestibility of Cenchrus ciliaris and Pennisetum clandestinum. The Journal of the Australian Institute of Agricultural Science 40, 156–158.Google Scholar
Johnson, R. I. (1962). Pasture sampling machine. Agricultural Gazette, New South Wales 73, 607–608.Google Scholar
Jones, R. J. (1974). Effects of previous cutting interval and of leaf area remaining after cutting on regrowth of Macroptilium atropurpureum cv. Siratro. Australian Journal of Experimental Agriculture and Animal Husbandry 14, 343–348.Google Scholar
Klingman, D. L., Miles, S. R. & Mott, G. O. (1943). The cage method for determining consumption and yield of pasture herbage. Journal of the American Society of Agronomy 35, 739–746.Google Scholar
McGarity, J. W. (1956). The soils of the Richmond-Tweed region. A study of their distribution and genesis. M.Sc.Agr. thesis, University of Sydney.Google Scholar
Mears, P. T. & Humphreys, L. R. (1974 a). Nitrogen response and stocking rate of Pennisetum clandestinum pastures. I. Pasture nitrogen requirement and concentration, distribution of dry matter and botanical composition. Journal of Agricultural Science, Cambridge 83, 451–467.CrossRefGoogle Scholar
Mears, P. T. & Humphreys, L. R. (1974 b). Nitrogen response and stocking rate of Pennisetum clandestinum pastures. II. Cattle growth. Journal of Agricultural Science, Cambridge 83, 469–478.Google Scholar
Murtagh, G. J. (1963). Herbicides as an aid to the establishment of sodsown Glycine javanica. Australian Journal of Experimental Agriculture and Animal Husbandry 3, 173–176.Google Scholar
Murtagh, G. J., Kaiser, A. G. & Huett, D. O. (1980). Summer-growing components of a pasture system in a subtropical environment. 2. Relations between pasture and animal production. Journal of Agricultural Science, Cambridge 94, 665–674.Google Scholar
Rowell, J. G. & Walters, D. E. (1976). Analysing data with repeated observations on each experimental unit. Journal of Agricultural Science, Cambridge 87, 423–432.Google Scholar
Spedding, C. R. W. (1971). Grassland Ecology, pp. 120–127. Oxford: Clarendon Press.Google Scholar
Stobbs, T. H. (1971). Quality of pasture and forage crops for dairy production in the tropical regions of Australia. 1. Review of the literature. Tropical Grasslands 5, 159–170.Google Scholar
Stobbs, T. H. (1975). The effect of plant structure on the intake of tropical pasture. III. Influence of fertilizer nitrogen on the size of bite harvested by Jersey cows grazing Setaria anceps cv. Kazungula swards. Australian Journal of Agricultural Research 26, 997–1007.CrossRefGoogle Scholar
Wheeler, J. L., Burns, J. C., Mochrie, R. D. & Gross, H. D. (1973). The choice of fixed or variable stocking rates in grazing experiments. Experimental Agriculture 9, 289–302.Google Scholar