Pasture management in semi-arid tropical woodlands: dynamics of perennial grasses
John G. McIvorCSIRO Sustainable Ecosystems, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, Qld 4067, Australia. Email: john.mcivor@csiro.au
The Rangeland Journal 29(1) 87-100 https://doi.org/10.1071/RJ06031
Submitted: 25 July 2006 Accepted: 15 December 2006 Published: 14 June 2007
Abstract
The effects of a range of pasture management options (introduced legumes and grasses, superphosphate, timber treatment, cultivation before sowing and stocking rate) on the basal cover of perennial grasses were measured from 1982 to 1991 at two sites, ‘Hillgrove’ and ‘Cardigan’, near Charters Towers, in north-east Queensland. Colonisation and survival of eight native and exotic grasses were followed in permanent quadrats in a subset of treatments. Overall, there were significant changes in total basal cover of plots between years and with tree killing, but no significant differences in sown pastures, fertiliser or stocking rate. Basal cover increased when defoliation levels were less than 40% but increases were smaller at higher levels of defoliation and basal cover often declined when defoliation was greater than 60%. Basal cover declined when growing seasons were <10 weeks, remained static with 10–15 weeks growth, and increased when growing seasons were 16 weeks or longer. There was some colonisation in all years but large differences between years. The differences in colonisation between systems were generally small but there was a general trend for higher colonisation at higher stocking rates. Bothriochloa ewartiana (Domin) C.E.Hubb. and Chrysopogon fallax S.T.Blake had low, Heteropogon contortus (L.) P.Beauv. ex Roem.&Schult., Cenchrus ciliaris L. and Aristida spp. had intermediate, and Bothriochloa pertusa (L.) A.Camus and Urochloa mosambicensis (Hack.) Dandy had high colonising ability. Survival of individual species was generally similar at both sites except for Urochloa mosambicensis. Heteropogon contortus and U. mosambicensis at ‘Hillgrove’ were short-lived (<10% survival after 4 years), B. ewartiana, Themeda triandra Forssk. and Aristida spp. had intermediate survival (10–50%), and C. ciliaris, C. fallax, B. pertusa and U. mosambicensis at ‘Cardigan’ were long-lived (>50% survival). Annual survival rates increased with plant age, were higher in good growing seasons than in poor seasons, were higher for large plants than small plants, and were lower at high defoliation levels than where defoliation was less severe. The differences between species in ability to colonise and survive, and the small influence of management compared to seasonal effects on survival, are discussed to explain species performance in pastures.
Additional keywords: colonisation, colonising ability, diet selection, survival, utilisation.
Acknowledgements
I thank Messrs T. H. Mann and R. Porter for the use of their land, Incitec Ltd for supplying superphosphate, Dr C. J. Gardener for contributions to experimental design, Dr M. R. Thomas for statistical advice, Drs K. C. Hodgkinson and D. M. Orr for comments on an earlier draft of this manuscript, and Messrs P. E. J. Allen, W. A. Beyer and L. V. Whiteman for technical assistance.
Andrew M. H.
(1986) Selection of plant species by cattle grazing native monsoon tallgrass pasture at Katherine, N.T. Tropical Grasslands 20, 120–127.
Ash A. J., McIvor J. G.
(1998) How season of grazing and herbivore selectivity influence monsoon tall-grass communities of northern Australia. Journal of Vegetation Science 9, 123–132.
| Crossref | GoogleScholarGoogle Scholar |
Christie E. K.
(1978) Herbage condition assessment of an infertile range grassland based on site production potential. Australian Rangeland Journal 1, 87–94.
| Crossref | GoogleScholarGoogle Scholar |
Deevey E. S.
(1947) Life tables for natural populations of animals. Quarterly Review of Biology 22, 283–314.
| Crossref | GoogleScholarGoogle Scholar |
Gardener C. J., Ash A. J.
(1994) Diet selection in six Stylosanthes-grass pastures and its implications for pasture stability. Tropical Grasslands 28, 109–119.
Gibbens R. P., Beck R. F.
(1988) Changes in grass basal area and forb densities over a 64-year period on grassland types of the Jornada Experimental Range. Journal of Range Management 41, 186–192.
Haydock K. P., Shaw N. H.
(1975) The comparative yield method for estimating dry matter yield of pasture. Australian Journal of Experimental Agriculture and Animal Husbandry 15, 663–670.
Hodgkinson K. C., Muller W. J.
(2005) Death model for tussock perennial grasses: a rainfall threshold for survival and evidence for landscape control of death in drought. The Rangeland Journal 27, 105–115.
| Crossref | GoogleScholarGoogle Scholar |
Hoen K.
(1968) The effect of plant size and developmental stage on summer survival of some perennial grasses. Australian Journal of Experimental Agriculture and Animal Husbandry 8, 190–196.
| Crossref | GoogleScholarGoogle Scholar |
Humphries S. E.,
Groves R. H., Mitchell D. S.
(1991) Plant invasions: the incidence of environmental weeds in Australia. Kowari 2, 1–134.
Jones R. M., Mott J. J.
(1980) Population dynamics in grazed pastures. Tropical Grasslands 14, 218–224.
Jones R. M.,
Jones R. J., Hutton E. M.
(1980) A method for advanced stage evaluation of pasture species: a case study with bred lines of Macroptilium atropurpureum. Australian Journal of Experimental Agriculture and Animal Husbandry 20, 703–709.
| Crossref | GoogleScholarGoogle Scholar |
McCown R. L.
(1973) An evaluation of the influence of available soil water storage capacity on growing season length and yield of tropical pastures using simple water balance models. Agricultural Meteorology 11, 53–63.
| Crossref | GoogleScholarGoogle Scholar |
McIntyre S., Filet P.
(1997) Choosing appropriate taxonomic units for ecological survey and experimentation: the response of Aristida to management and landscape factors as an example. The Rangeland Journal 19, 26–39.
| Crossref | GoogleScholarGoogle Scholar |
McIvor J. G.
(1985) The growth of Urochloa accessions in grazed swards with Stylosanthes near Townsville, north Queensland. Australian Journal of Experimental Agriculture 25, 61–69.
| Crossref | GoogleScholarGoogle Scholar |
McIvor J. G.
(2001) Pasture management in semi-arid tropical woodlands: regeneration of degraded pastures protected from grazing. Australian Journal of Experimental Agriculture 41, 487–496.
| Crossref | GoogleScholarGoogle Scholar |
McIvor J. G., Gardener C. J.
(1990) Soil and vegetation characteristics of dry tropical rangelands for predicting pasture regeneration in exclosures. Proceedings of the Ecological Society of Australia 16, 273–277.
McIvor J. G., Gardener C. J.
(1995) Pasture management in semi-arid tropical woodlands: effects on herbage yields and botanical composition. Australian Journal of Experimental Agriculture 35, 705–715.
| Crossref | GoogleScholarGoogle Scholar |
McKeon G. M.,
Day K. A.,
Howden S. M.,
Mott J. J.,
Orr D. M.,
Scattini W. J., Weston E. J.
(1990) Northern Australian savannas: management for pastoral production. Journal of Biogeography 17, 355–372.
| Crossref | GoogleScholarGoogle Scholar |
Mott J. J.,
Ludlow M. M.,
Richards J. H., Parsons A. D.
(1992) Effects of moisture supply in the dry season and subsequent defoliation on persistence of the savanna grasses Themeda triandra, Heteropogon contortus and Panicum maximum. Australian Journal of Agricultural Research 43, 241–260.
| Crossref | GoogleScholarGoogle Scholar |
Olson K. C.,
White R. S., Sindelar B. W.
(1985) Response of vegetation of the northern Great Plains to precipitation amount and grazing intensity. Journal of Range Management 38, 357–361.
Orr D. M.
(2004) Dynamics of plant populations in Heteropogon contortus (black speargrass) pastures on a granite landscape in southern Queensland. 4. The effects of burning on H. contortus and Aristida spp. populations. Tropical Grasslands 38, 77–87.
Orr D. M.,
Evenson C. J.,
Lehane J. K.,
Bowly P. S., Cowan D. C.
(1993) Dynamics of perennial grasses with sheep grazing in Acacia aneura woodlands in south-west Queensland. Tropical Grasslands 27, 87–93.
Orr D. M.,
Paton C. J., Lisle A. T.
(1997) Using fire to manage species composition in Heteropogon contortus (black speargrass) pastures 1. Burning regimes. Australian Journal of Agricultural Research 48, 795–802.
| Crossref | GoogleScholarGoogle Scholar |
Orr D. M.,
Paton C. J., Reid D. J.
(2004b) Dynamics of plant populations in Heteropogon contortus (black speargrass) pastures on a granite landscape in southern Queensland. 1. Dynamics of H. contortus populations. Tropical Grasslands 38, 17–30.
Orr D. M.,
Paton C. J., Playford C.
(2004c) Dynamics of plant populations in Heteropogon contortus (black speargrass) pastures on a granite landscape in southern Queensland. 3. Dynamics of Aristida spp. populations. Tropical Grasslands 38, 65–76.
Royston J. P.
(1982) An extension of Shapiro and Wilk’s W test for normality to large samples. Applied Statistics 31, 115–124.
| Crossref | GoogleScholarGoogle Scholar |
Samuel M. J., Hart R. H.
(1995) Observations on spread and fragmentation of blue grama clones in disturbed rangeland. Journal of Range Management 48, 508–510.
Shaw N. H.
(1957) Bunch spear grass dominance in burnt pastures in south-eastern Queensland. Australian Journal of Agricultural Research 8, 325–334.
| Crossref | GoogleScholarGoogle Scholar |
Snyman H. A., Fouche H. J.
(1993) Estimating seasonal herbage production of a semi-arid grassland based on veld condition, rainfall and evapotranspiration. African Journal of Range and Forage Science 10, 21–24.
Tothill J. C.
(1969) Soil temperatures and seed burial in relation to the performance of Heteropogon contortus and Themeda australis in burnt woodland pastures in eastern Queensland. Australian Journal of Botany 17, 269–275.
| Crossref | GoogleScholarGoogle Scholar |
Virgona J. M., Bowcher A.
(2000) Effects of grazing interval on basal cover of four perennial grasses in a summer-dry environment. Australian Journal of Experimental Agriculture 40, 299–311.
| Crossref | GoogleScholarGoogle Scholar |
Walker B., Weston E. J.
(1990) Pasture development in Queensland – a success story. Tropical Grasslands 24, 257–268.
Whiteman P. C., Gillard P.
(1971) Species of Urochloa as pasture plants. Herbage Abstracts 41, 351–357.
1 Nomenclature according to Henderson (2002).