Pasture management in semi-arid tropical woodlands: dynamics of perennial grasses

2007 ◽  
Vol 29 (1) ◽  
pp. 87 ◽  
Author(s):  
John G. McIvor
Keyword(s):  
Perennial Grasses ◽  
Individual Species ◽  
Stocking Rate ◽  
Pasture Management ◽  
Management Options ◽  
Exotic Grasses ◽  
Heteropogon Contortus ◽  
Basal Cover ◽  
Growing Seasons ◽  
North East

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.

Land Condition in the Tropical Tallgrass Pasture Lands. 1. Effects on Herbage Production.

1995 ◽  
Vol 17 (1) ◽  
pp. 69 ◽  
Author(s):  
John G. Mcivor ◽  
Andrew J. Ash ◽  
Garry D. Cook
Keyword(s):  
Basal Area ◽  
Nutrient Status ◽  
Condition Index ◽  
Perennial Grasses ◽  
Individual Species ◽  
Growing Seasons ◽  
North East ◽  
Linear Relationships ◽  
Run Off ◽  
Land Condition

A quantitative condition index based on vegetation (botanical composition and basal area of perennial grasses) and soil characteristics (erodibility, nutrient status and availability, partitioning of rainfall into infiltration and run-off) was developed for tropical tallgrass pastures near Charters Towers (north-east Queensland) and Katherine (Northern Territory). Herbage growth and the responses of individual species at 10 sites over two growing seasons were related to the index. At all sites there were significant linear relationships between herbage growth and condition index although the values differed between sites. Annual grasses increased and most perennial grasses decreased as condition declined but Bothriochloa pertusa and Bothriochloa ewartiana were most abundant at intermediate condition levels. The response of Chrysopogon fallax varied widely between sites. The lower herbage production on poor condition sites will result in lower carrying capacity.

Beef production from native pastures sown to fine-stem stylo in the Burnett region of south-eastern Queensland

1979 ◽  
Vol 19 (97) ◽  
pp. 140 ◽  
Author(s):  
EJ Bowen ◽  
KG Rickert
Keyword(s):  
Stocking Rate ◽  
Management Options ◽  
North West ◽  
Heteropogon Contortus ◽  
South Eastern ◽  
Continuous Grazing ◽  
Weight Gains ◽  
The Mean ◽  
Native Pastures ◽  
Stocking Rates

At Gayndah, south-eastern Queensland, a native Heteropogon contortus pasture, sown to fine-stem stylo (Stylosanthes guianensis var. intermedia), and invaded by red natal grass (Rhynchelytrum repens), was grazed by weaner steers from June 1 in three treatments : heavy and light put-and-take grazing for five years from 1971, and set-stocked at 1.37 animals ha-1 for two years from 1974. Weight gains in the put-and-take treatments were not significantly different. The mean annual liveweight gain was 167 kg animal-1 at a mean equivalent stocking rate of 1.47 animals ha-1. Over the same period unsown native pasture, cleared of timber, gave a gain of 62 kg animal-1 at 0.62 animals ha-1. In all seasons except summer, weight gains declined linearly with stocking rate and in 1972-73, with a mean equivalent stocking rate of 2.66 animals ha-1, the annual gain was almost halved. When equivalent stocking rates were 0.9, 0.9, 1.8 and 1.2 animals ha-1 in winter, spring, summer and autumn, the respective gains were 4, 73, 65 and 45 kg animal-1. The set-stocked treatment had a mean annual gain of 147 kg animal-1. At another site 116 km north-west of Gayndah, two paddocks of Heteropogon contortus and fine-stem stylo were set-stocked with weaners over four years. One paddock had four applications of superphosphate of 250 kg ha-1. The mean annual liveweight gains were significantly different, being 154 and 143 kg animal-1 in the fertilized and unfertilized paddocks at mean stocking rates of 0.83 and 0.74 animals ha-1, respectively. In a grazing protection experiment the density of fine-stem stylo declined exponentially with an accumulation of pasture dry matter in spring and summer. Heavy continuous grazing, an annual hay cut and an accidental fire all increased the density of fine-stem stylo. Management options to maintain the density of fine-stem stylo and the relative importance of the legume and grass to animal production are discussed.

Steer gains, pasture yield and pasture composition on native pasture and on native pasture oversown with Indian couch (Bothriochloa pertusa) at three stocking rates

1997 ◽  
Vol 37 (7) ◽  
pp. 755 ◽  
Author(s):  
R. J. Jones
Keyword(s):  
Perennial Grasses ◽  
Grass Species ◽  
Stocking Rate ◽  
Pasture Grass ◽  
Pasture Production ◽  
Heteropogon Contortus ◽  
Native Pasture ◽  
Unit Increase ◽  
Stocking Rates ◽  
Pasture Yield

Summary. Pasture production and steer liveweight gain were compared on native pasture (Bothriochloa decipiens, Heteropogon contortus, Themeda triandra and Chrysopogon fallax) and on native pasture oversown with Indian couch or Indian bluegrass (Bothriochloa pertusa). This grass was not a planned introduction to the area but is spreading in Central and North Queensland and its value as a pasture species is questioned by graziers. There were 3 nominal stocking rates of 0.3, 0.6 and 0.9 steers/ha. Each paddock was stocked with 3 steers of stratified ages. The experiment was sown in March 1988 and terminated in June 1993. The experiment, sited 50 km south of Townsville in eucalypt woodland on a solodic-solodised-solonetz soil, was sown in March 1988 and terminated in June 1993. Increases in stocking rate resulted in a linear decline in both pasture yield (by 3–5 t/unit increase in stocking rate) and steer gains (by more than 100 kg/unit increase in stocking rate). Differences between pastures were apparent only at the medium and high stocking rates where, over time, Indian couch gave higher pasture yields and steer gains. Younger steers gained far more weight than older steers. Mean gains over 3 years were weaners 125 kg/year, yearlings 93 kg/year and 2-year-old steers 46 kg/year. Native pasture remained fairly stable botanically at the low stocking rate, but the tufted perennial grass species declined at both the medium and high stocking rates. Sowing Indian couch hastened the botanical changes due to stocking rate, and it became the dominant species at these higher stocking rates. At the low stocking rate, the contribution of Indian couch declined from initial values indicating that this is not an invasive species in the area at a low stocking rate. Contribution of Indian couch to pasture yield was linearly related to stocking rate. Nutritional quality of the Indian couch was similar to the other native perennial grasses though calcium concentration was higher. Increased steer gains were related to higher yield on Indian couch pastures at the higher stocking rates rather than to improved quality. Maximum liveweight gain/ha was achieved at about 0.6 steers/ha. Stocking at 0.9 steers/ha was not sustainable. Even at the low stocking rate, steers would need to spend about 2.8 years on the pastures after weaning to reach 500 kg liveweight. It was concluded that B. pertusa is a useful pasture grass in this environment giving steer gains equal to, or higher than, the gains from the native pasture which it replaced.

Learning From History to Survive in the Future: Management Evolution on Trafalgar Station, North-East Queensland.

1998 ◽  
Vol 20 (1) ◽  
pp. 104 ◽  
Author(s):  
RG Landsberg ◽  
AJ Ash ◽  
RK Shepherd ◽  
GM Mckeon
Keyword(s):  
Financial Management ◽  
Climatic Variability ◽  
Simulation Modelling ◽  
Perennial Grasses ◽  
Production Environment ◽  
Pasture Management ◽  
Diverse Range ◽  
Management Philosophy ◽  
Advantages And Disadvantages ◽  
North East

Managing rangeland enterprises requires balancing socio-economic goals within a production environment characterised by ecological complexity and large climatic variability. Trafalgar Station in north-east Queensland, has been trying to maintain this balance over a period of 80 years and three generations of the one family. This paper explores how management on Trafalgar Station has gone through four evolutionary phases and examines the advantages and disadvantages of each of these stages of development. The first 50 years of management was a technologically constrained era of low stock numbers and poor productivity but there were few resource management problems. Next followed a 20 year period of production maximisation which was made possible by improved cattle genetics and nutritional technologies. With drought feeding occurring more frequently and loss of perennial grasses and soil becoming more evident, there came the realisation that this high stocking strategy was unsustainable. The management of Trafalgar then embarked on a new philosophy based on conservative stocking (similar to historical levels) and increased emphasis on herd, pasture and financial management. This new management philosophy required a transitional phase where stock numbers. and income, were very low to allow pasture condition to improve. Current herd management focuses on maintaining quality rather than quantity, strategic use of supplements for production, and developing a diverse range of markets for sale cattle. Conservative stock numbers have increased opportunities in pasture management with 15 to 20% of the property now annually rested from grazing. Fire has been reintroduced to restrict "thickening" of native woody plants and to control exotic woody weeds. Together with long-term financial planning, these improvements in management are reducing economic risk. The perceived benefits of the current management philosophy are supported by simulation modelling studies of pasture and animal production and analyses of property economics.

Effects of continuous grazing and seasonal closures on the performance and persistence of some sown temperate perennial grasses, North-West Slopes New South Wales

2002 ◽  
Vol 42 (4) ◽  
pp. 431 ◽  
Author(s):  
G. M. Lodge
Keyword(s):  
Festuca Arundinacea ◽  
Perennial Grass ◽  
Basal Area ◽  
Trifolium Subterraneum ◽  
Perennial Grasses ◽  
Individual Species ◽  
North West ◽  
Basal Cover ◽  
Crown Density ◽  
Plant Frequency

A split-plot experiment was sown at Tamworth in 1992 to examine the effects of continuous sheep grazing and seasonal closures (autumn, spring, spring + autumn, and summer + winter) on the herbage mass, plant frequency and basal cover of 5 perennial grasses, when sown as monocultures or with a perennial (Trifolium repens cv. Haifa) or annual legume (Trifolium subterraneum var. subterraneum cv. Seaton Park). Plant basal area and crown density data were also collected. The perennial grasses were Phalaris aquatica cv. Sirosa, Festuca arundinacea, cv.� Demeter, Lolium perenne cv. Kangaroo Valley, Austrodanthonia richardsonii (syn. Danthonia richardsonii) cv.�Taranna, and A. bipartita (syn. D. linkii) cv. Bunderra. There was no significant effect of legume presence on the herbage mass or persistence of the perennial grasses. The only treatment that had a significant effect (P< 0.05) on either herbage mass, plant frequency or basal cover data was the grazing treatment × perennial grass interaction in each of the years 1993-98, except for herbage mass in December 1993 and basal cover in October 1998. In all of the grazing treatments examined, Kangaroo Valley ryegrass failed to persist after spring 1994; Demeter fescue had failed by spring 1997 and Sirosa phalaris by spring 1998. Six years after sowing the only temperate grass cultivars that were persisting in all grazing treatments were the native perennials, Taranna and Bunderra. Hence, the data represent the entire stand life from sowing to eventual failure for the 3 introduced cultivars. While grazing treatment effects within years for individual species were significant, overall grazing had little effect on the rate of decline in herbage mass and persistence of Kangaroo Valley, Demeter and Sirosa. By 1998, grazing treatment had no significant effect on the herbage mass and basal cover of Taranna and Bunderra, but their plant frequencies were lowest in the spring rest and summer + winter rest treatments.

Pasture yield and composition changes in a Central Queensland black speargrass (Heteropogon contortus) pasture in relation to grazing management options

2001 ◽  
Vol 41 (4) ◽  
pp. 477 ◽  
Author(s):  
D. M. Orr ◽  
W. H. Burrows ◽  
R. E. Hendricksen ◽  
R. L. Clem ◽  
M. T. Rutherford ◽  
...  
Keyword(s):  
Total Yield ◽  
Individual Plant ◽  
Stocking Rate ◽  
Management Options ◽  
Heteropogon Contortus ◽  
Diet Supplements ◽  
The Stability ◽  
The Individual ◽  
Stocking Rates ◽  
Pasture Yield

A grazing study commenced in 1988 at Calliope, Central Queensland, measured the effects of stocking rate, legume over-sowing and animal diet supplements/burning on pasture and animal production in a native black speargrass (Heteropogon contortus) pasture. This paper reflects on changes in yield and pasture composition between 1988 and 1996, during which time the seasonal rainfall was below average. At the pasture community scale, the highest stocking rate of 1 steer/2 ha reduced pasture yield but had little impact on pasture composition. The frequency of H. contortus showed no clear differences due to stocking rate although there was a slight overall trend for it to decline with time. The frequency of increaser species such asChloris divaricata was highest at the highest stocking rate. At the individual plant scale, the density of H. contortus plants declined at high stocking rate. The proportion of the sown legume Stylosanthes scabra cv. Seca increased with time reaching a density of 15 plants/m 2 and contributing 33% to the total yield in the legume treatments. Burning has reduced the occurrence of H. contortus compared with that in unburnt native pasture and this may be due to the stocking rates being too high following the fire. These results indicate the stability of pasture composition across a 4-fold range of stocking rates from 1988 to 1996. This study needs to continue, at least through a period of above average rainfall, to determine further effects of stocking rate and pasture type on pasture composition.

Pasture management in semi-arid tropical woodlands: effects on herbage yields and botanical composition

1995 ◽  
Vol 35 (6) ◽  
pp. 705 ◽  
Author(s):  
JG McIvor ◽  
CJ Gardener
Keyword(s):  
Perennial Grasses ◽  
Percentage Increase ◽  
Botanical Composition ◽  
Pasture Management ◽  
Management Options ◽  
Stylosanthes Hamata ◽  
Large Yield ◽  
Native Pastures ◽  
Growing Conditions ◽  
Yield Responses

The effects of pasture management options (introduced legumes and grasses, superphosphate, timber treatment, cultivation before sowing, stocking rate) on the yield and botanical composition of pastures were measured from 1982 to 1992 at 2 sites, Hillgrove (extractable phosphorus, 50 mg P/kg) and Cardigan (extractable P, 6 mg/kg), near Charters Towers, northeastern Queensland. Despite generally poor establishment and growing conditions, some sown species (Stylosanthes hamata, S. scabra, Cenchrus ciliaris, Urochloa mosambicensis) established and persisted at both sites. The initial sown grass populations were small but yields increased markedly towards the end of the experiment. There were no yield responses by the native pastures to superphosphate, but the sown pastures responded at Cardigan, although not at Hillgrove. There were large yield responses to tree killing. The percentage increase in herbage yield following tree killing increased as the available water in the soil during the growing season decreased, and was greater at the higher fertility Hillgrove site. Overall, the native pastures were dominated by perennial grasses, but annual grasses and forbs increased on plots with live trees and high stocking rates towards the end of the trial. sown grasses, particularly C. ciliaris, became dominant (and are likely to remain so) at Hillgrove and on plots with superphosphate at Cardigan, especially where the trees were killed. Productive, mixed pastures with reasonable proportions of both grass and legume were maintained under live trees.

Impacts of grazing management options on pasture and animal productivity in a Heteropogon contortus (black speargrass) pasture in central Queensland. 3. Diet composition in autumn

2010 ◽  
Vol 50 (4) ◽  
pp. 276 ◽  
Author(s):  
R. E. Hendricksen ◽  
D. J. Myles ◽  
D. J. Reid ◽  
D. M. Orr
Keyword(s):  
Diet Composition ◽  
Plant Density ◽  
Stocking Rate ◽  
Management Options ◽  
Heteropogon Contortus ◽  
Native Pasture ◽  
Stylosanthes Scabra ◽  
Animal Diet ◽  
Palatable Species ◽  
Stocking Rates

The diet selected in autumn by steers fistulated at the oesophageous was studied in a subset of treatments in an extensive grazing study conducted in a Heteropogon contortus pasture in central Queensland between 1988 and 2001. These treatments were a factorial array of three stocking rates (4, 3 and 2 ha/steer) and three pasture types (native pasture, legume-oversown native pasture and animal diet supplement/spring-burning native pasture). Seasonal rainfall throughout this study was below the long-term mean and mean annual pasture utilisation ranged from 30 to 61%. Steers consistently selected H. contortus with levels decreasing from 47 to 18% of the diet as stocking rate increased from 4 ha/steer to 2 ha/steer. Stylosanthes scabra cv. Seca was always selected in legume-oversown pastures with diet composition varying from 35 to 66% despite its plant density increasing from 7 to 65 plants/m2 and pasture composition from 20 to 50%. Steers also selected a diet containing Chrysopogon fallax, forbs and sedges in higher proportions than they were present in the pasture. Greater availability of the intermediate grasses Chloris divaricata and Eragrostis spp. was associated with increased stocking rates. Bothriochloa bladhii was seldom selected in the diet, especially when other palatable species were present in the pasture, despite B. bladhii often being the major contributor to total pasture yield. It was concluded that a stocking rate of 4 ha/steer will maintain the availability of H. contortus in the pasture.

Impact of phosphorus application and sheep grazing on the botanical composition of sown pasture and naturalised, native grass pasture

2004 ◽  
Vol 55 (12) ◽  
pp. 1213 ◽  
Author(s):  
J. O. Hill ◽  
R. J. Simpson ◽  
A. D. Moore ◽  
P. Graham ◽  
D. F. Chapman
Keyword(s):  
Trifolium Subterraneum ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Annual Species ◽  
Basal Cover ◽  
Grazing Systems ◽  
P Application ◽  
Phosphorus Application ◽  
Stocking Rates

Botanical composition (basal cover) was measured in 4 replicated pasture treatments based on Phalaris aquatica and Trifolium subterraneum at Hall, ACT (unfertilised with low and high stocking rate; fertilised with low and high stocking rate) and in 2 unreplicated pasture treatments based on native perennial grasses (Austrodanthonia spp. and Microlaena stipoides) and T. subterraneum at Bookham, NSW (unfertilised and low stocking rate; fertilised and high stocking rate). Current economic pressures are encouraging graziers to increase their use of phosphorus (P) fertiliser and to adopt higher stocking rates. The objective of the research was to determine the changes in botanical composition that may result from these changes in grazing systems management. At Hall, annual species differed in their responses to P fertility. Notably, basal cover of Bromus spp. increased significantly with P application, whereas Vulpia spp. decreased significantly. Basal cover of T. subterraneum also increased significantly with P application when stocking rate was high, but was reduced by P application if stocking rate was low. Basal cover of perennial grasses (P. aquatica and Holcus lanatus) was significantly higher at low stocking rate when P was applied. The botanical composition of high stocking rate treatments was relatively stable over time, which contrasted with less stable composition at low stocking rate. At Bookham, fertilised pasture in unreplicated paddocks appeared to have a higher basal cover of productive annual species (i.e. Bromus spp. and T. subterraneum), but native perennial grasses appeared to have lower basal cover in comparison with the unfertilised area. These results indicated that in some cases, the influence of P fertiliser and high stocking rates on botanical composition was favourable (i.e. increased basal cover of P. aquatica and T. subterraneum) and in others it could be detrimental (i.e. lower basal cover of native perennial grasses).

Changes in the Quantitative Floristics in Some Astrebla Spp. (Mitchell Grass) Communities in South-Western Queensland in Relation to Trends in Seasonal Rainfall

1981 ◽  
Vol 29 (5) ◽  
pp. 533 ◽  
Author(s):  
DM Orr
Keyword(s):  
Relative Abundance ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Seasonal Rainfall ◽  
Individual Species ◽  
Botanical Composition ◽  
Basal Cover ◽  
Wide Range ◽  
Annual Grasses

Seasonal changes in the quantitative floristics at a wide range of Astrebla grassland sites in south-western Queensland were monitored between 1972 and 1980 with a wheel point apparatus. Changes in the floristics were measured in terms of both relative abundance and basal cover. A large increase in the relative abundance of perennial grasses, particularly Aristida latifolia, Astrebla spp. and Dichanthium sericeum, occurred between 1972 and 1976. This increase was at the expense of annual grasses and forbs which declined in both relative abundance and number of genera present. The relative abundance of perennial grasses declined between 1978 and 1980 and this was associated with a large increase in the forbs such as Daucus glochidiatus and Plantago spp., particularly at southern sites. The contribution of annual grasses to botanical composition remained low throughout the period. Total basal cover differed between years although these differences were not significant. As perennial grass, particularly Astrebla spp., was the major vegetation component of total basal cover, changes in the latter were associated mainly with changes in the basal cover of Astrebla spp. Changes in the contribution of individual species to total basal cover were related to changes in the relative abundance of those species. Changes in botanical composition in Astrebla grassland may be influenced more by trends in seasonal rainfall than by grazing pressure.

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