Grazing studies of a Hyparrhenia hirta (Coolatai grass) pasture in northern New South Wales

2005 ◽  
Vol 45 (12) ◽  
pp. 1603 ◽  
Author(s):  
G. M. Lodge ◽  
L. H. McCormick ◽  
S. Harden
Keyword(s):  
New South ◽  
Basal Area ◽  
Ground Cover ◽  
Experimental Period ◽  
Stocking Rate ◽  
Soil Microbial ◽  
Basal Cover ◽  
South Wales ◽  
Heavy Grazing ◽  
Stocking Rates

Hyparrhenia hirta (L.) Stapf (Coolatai grass) has invaded large areas of grazed native grasslands on the North-West Slopes of New South Wales (NSW) and is widespread along roadsides and travelling stock routes. It is commonly regarded as an invasive, weedy species with low forage value when it is tall and rank, but may be more palatable when kept short, green and leafy. A study (1990–2001) of a naturalised stand of Coolatai grass in the Manilla district of northern NSW examined its herbage mass (kg DM/ha), persistence (basal cover %), and grazing value under 2 contrasting grazing treatments: pastures that had either large amounts of dry, unpalatable herbage [light grazing at 5 dry sheep equivalents (DSE)/ha] or were short, green and leafy (strategic heavy grazing at a stocking rate of 37 DSE/ha). Effects of pre-grazing treatments (slashing, burning, and no defoliation) were also examined and data (litter mass, plant basal area, ground cover, and soil and litter microbial carbon and nitrogen) collected to assess the long term sustainability of these grazing systems. Sheep grazed the light grazing treatment for about 34% of the experimental period, with the strategic heavy grazing treatment being grazed for about 7% of the time. Over the experimental period this equated to 6752 DSE grazing days/ha for the light grazing treatment compared with 10 120 DSE for the heavy grazing treatment. Herbage mass in the heavy grazing treatment declined to <1000 kg DM/ha within 6 months of the start of grazing and remained below this level until December 1998 when stocking rates were switched (i.e. plots previously grazed at low stocking rate were subjected to the heavier rate and vice versa). In contrast, mean herbage mass in the light grazing treatment was generally >3000 kg DM/ha from November 1990–98, but a high proportion of this was dead standing material that carried over from season to season. Mean Coolatai grass basal cover was 9.5% in November 1990, increasing over time to about 25% in both grazing treatments by December 2000. Coolatai grass herbage accumulation was highly seasonal, ranging from as high as 70 kg DM/ha.day in summer to 0 in winter. In both grazing treatments, forage quality was low for both green and dead material, with mean crude protein being 6.0 (green) and 3.4% (dead). Digestible dry matter values ranged from 41 to 62% (green) and 32 to 51% (dead) and mean metabolisable energy values were 7 (green) and 5.3 MJ/kg DM (dead). After 8 years, the heavy grazing treatment had lower (P<0.05) litter mass, ground cover, plant basal area and soil microbial C and N levels than the light grazing treatment, but switching of the stocking rates restored most indicators, except the soil microbial values.

A comparison of the forage value for sheep of buckwheat and sorghum stubbles grown on the Southern Tablelands of New South Wales

1979 ◽  
Vol 19 (98) ◽  
pp. 297 ◽  
Author(s):  
JG Mulholland ◽  
JB Coombe
Keyword(s):  
Organic Matter ◽  
New South ◽  
Experimental Period ◽  
Stocking Rate ◽  
Wool Production ◽  
Weight Losses ◽  
South Wales ◽  
Digestible Organic Matter ◽  
Forage Value ◽  
Stocking Rates

Two grazing experiments were conducted to evaluate buckwheat and sorghum stubbles as forage for sheep. The stubbles were stocked by young crossbred wethers at 10 and 20 ha-1 for 55 days on the buckwheat and 81 days on the sorghum. Measurements were made at regular intervals of the availability and composition of plant material, diet selection, the intake of digestible organic matter (DOM) and liveweight change, while wool production was measured over each experimental period. More than one-third of the sheep grazing buckwheat stubble were affected by fagopyrism (buckwheat poisoning) and this probably reduced both liveweight gain and wool production. Buckwheat residues had a similar nitrogen content to sorghum (1 .0% vs 0.87%), but a lower organic matter digestibility (43.7% vs 57.1%). Mature buckwheat plants were not eaten readily. Mean liveweights of sheep on buckwheat stubble declined throughout the experimental period and overall changes were -3.8 and -7.0 kg for the low and high stocking rates, respectively. Corresponding values for sheep on sorghum stubble were 0.3 and -4.6 kg, although weight losses at the higher stocking rate did not occur until after 40 days grazing. For the same length of grazing as the buckwheat (55 days) the liveweight changes for sorghum were 0.2 and -1.2 kg, respectively. Wool growth rate was low for both stubbles but was more than 60% higher for sheep on the sorghum. Values for each stocking rate were 3.86 and 2.67 (g clean dry wool day-1) for the buckwheat, and 5.39 and 4.33 for the sorghum. It was concluded that sorghum stubble is a useful source of grazing for sheep on the Southern Tablelands but buckwheat stubble, because of its low acceptability, poor nutritional value and the risk of fagopyrism, is of very limited value.

Effects of grazing, slashing and burning on Aristida ramosa and sheep productivity in northern New South Wales

1999 ◽  
Vol 39 (6) ◽  
pp. 685 ◽  
Author(s):  
G. M. Lodge ◽  
B. J. Gogel ◽  
K. A. Archer ◽  
B. R. Cullis
Keyword(s):  
Dry Matter ◽  
New South ◽  
New South Wales ◽  
Fibre Diameter ◽  
Wool Fibre ◽  
Dry Matter Yield ◽  
Basal Cover ◽  
South Wales ◽  
Heavy Grazing ◽  
Stocking Rates

Summary. Studies were conducted on a natural pasture dominated by Aristida ramosa (wiregrass) in northern New South Wales. In each of the 4 studies, treatments were designed to reduce wiregrass presence by grazing, using stocking rates up to 12.5–15.0 dry sheep equivalents (dse/ha) in summer and autumn (1983–88), slashing (1984–86), or burning (2 studies, 1985–88; 1986–88) in spring before heavily grazing in summer–autumn. Effects of these treatments on A. ramosa dry matter yield and basal cover, Danthonia linkii (wallaby grass) basal cover, sheep liveweight change and fleeceweight were measured for the different time periods. Wool quality was determined from mid-side samples taken in 1983–85. All treatments reduced A. ramosa dry matter yield and basal cover and increased D. linkii basal cover, compared with control plots continuously grazed at 5 dse/ha. From 1983 to 1988, A. ramosa dry matter yields in the control plots increased from about 1000 to 3500 kg/ha and its basal cover increased from 7 to 13%. In contrast, A. ramosa dry matter yields in heavily grazed, and spring burnt and heavily grazed treatments were <500 kg/ha, with basal cover levels of A. ramosa <0.3% while those of D. linkii were about 5%. Slashing before heavy grazing (1984–86) also reduced A. ramosa dry matter yields and basal cover compared with the control, but higher levels of A. ramosa (800 kg/ha dry matter, 1% basal cover) remained at the end of these studies. Heavy grazing of wiregrass led to significant negative liveweight changes, compared with sheep in control plots. Slashing or burning of wiregrass to remove dead material and increase green leaf before grazing at high stocking rates, markedly reduced rates of liveweight decline. Both grazing at high stocking rate and slashing in spring followed by heavy grazing, significantly reduced the amount of wool grown in the spring–winter period and significantly decreased either wool fibre diameter, strength or point-of-break. In the long term, sheep in wiregrass control plots lost more weight than those in treatment plots at equivalent stocking rates. Results suggest that on-farm control strategies based on late winter or spring burning, and heavy summer grazing should reduce the presence of wiregrass in similar pasture system.

An economic analysis of a 10 year rate of stocking trial with fine-wool

1978 ◽  
Vol 18 (92) ◽  
pp. 370 ◽  
Author(s):  
JM George ◽  
RA Pearse
Keyword(s):  
New South ◽  
Climatic Conditions ◽  
Stocking Rate ◽  
Labour Costs ◽  
South Wales ◽  
Wide Range ◽  
Wool Yield ◽  
Stocking Rates ◽  
Price Relationships ◽  
Clover Pasture

Merino ewes were grazed for 10 years at stocking rates of 8, 12 and 16 ha-1, lambing in winter, spring or summer on a phalaris/white clover pasture on the Northern Tablelands of New South Wales. Wool production, wool yield and count, and lambing and weaning rates were established for the wide range of climatic conditions experienced. A spring lambing is indicated under the within-year price relationships experienced. Under a wide range of wool and lamb prices the optimum stocking rate varied from 12 to 16 ewes ha-1 depending on labour costs.

Wool production, ground cover and botanical composition of pastures grazed by Merino wethers in central western New South Wales. 2. Barrel medic pasture

1973 ◽  
Vol 13 (64) ◽  
pp. 510 ◽  
Author(s):  
H Brownlee
Keyword(s):  
Agricultural Research ◽  
New South ◽  
Ground Cover ◽  
Additional Treatment ◽  
Research Station ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Barrel Medic ◽  
South Wales ◽  
Pasture Area

Two grazing experiments were performed between 1965 and 1969 at the Agricultural Research Station, Condobolin, to determine the carrying capacity of Jemalong barrel medic (Medicago truncatula) pasture. In each experiment the pasture was set stocked with Merino wethers at 3.1, 4.1 and 6.2 ha-1. An additional treatment stocked at 6.2 ha-1 was included in which two-thirds of the pasture area was saved during autumn or periods of feed shortage while stock were confined to the other one-third. In both experiments the pasture supported 3.1 wethers ha-1 under set stocking for three years with little supplementary feeding and regenerated successfully each year. No major changes in botanical composition were recorded, and Jemalong medic remained the major component of the pasture. Autumn saving at 6.2 ha-1 mitigated the effects of the high stocking rate on both animal and pasture, but did not result in worthwhile animal production increases.

Evaluation of natural annual pastures at Trangie in central western New South Wales. 1. Sheep production

1973 ◽  
Vol 13 (62) ◽  
pp. 238
Author(s):  
RJ Campbell ◽  
DG Saville ◽  
GE Robards
Keyword(s):  
New South ◽  
Management Strategies ◽  
New South Wales ◽  
Grazing Pressure ◽  
Stocking Rate ◽  
Wool Production ◽  
South Wales ◽  
Sheep Production ◽  
Stocking Rates ◽  
Sheep Wool

Natural annual pasture at Trangie, New South Wales, was set stocked from August, 1967 to December 1970 at rates of 2.5, 3.7, and 4.9 merino wethers per ha to determine an optimum stocking rate for the pasture type. All stocking rates were supported without the necessity to hand feed any sheep. Wool production per head was reduced significantly by increased stocking rate in 1968, but not in 1969 and 1970. The suppression of barley grass at the higher stocking rates appeared to benefit animal production in 1969. Substitution of portion of the natural annual pasture with areas of lucerne or natural perennial pasture was also investigated and found to be ineffective in increasing wool production per head above that of wethers at similar rates of stocking on natural annual pasture alone. Possible reasons for the apparent failure of the grazing supplements, particularly lucerne, are discussed in terms of grazing pressure and management strategies.

Effect of time of application of herbicides on the long-term control of St. John's wort (Hypericum perforatum var. augustifolium)

1979 ◽  
Vol 19 (101) ◽  
pp. 746 ◽  
Author(s):  
MH Campbell ◽  
JJ Dellow ◽  
AR Gilmour
Keyword(s):  
Hypericum Perforatum ◽  
New South ◽  
Ground Cover ◽  
Experimental Period ◽  
Time Of Application ◽  
St John’S Wort ◽  
St John's Wort ◽  
South Wales ◽  
Long Term Effect

The effect of time of application of herbicides on the long-term control of St. John's wort was investigated at Tuena, New South Wales. The herbicides used were: 2,4-D, 2,4,5-T, 2,4-D -i- 2,4,5-T, picloram + 2,4-D, and glyphosate. Each of these was applied in February, May, August and November, 1976, and regrowth of wort monitored until February 1978. The percentage ground cover of unsprayed St. John's wort varied between 75% and 85% over the experimental period. Initially all herbicides reduced the ground cover of St. John's wort from over 75% to less than 15%. Thereafter the regrowth of wort depended on the long-term effect of the herbicides. At the final assessment in February 1978, the most effective herbicide treatments were: from the February and May applications, glyphosate and picloram + 2,4-D; from the August application, picloram + 2,4-D; and from the November application, picloram + 2,4-D, 2,4-D + 2,4,5-T and 2,4-D.

Establishment and development of surface sown pasture species in a nitrophilous weed association: effect of herbicide rate

1981 ◽  
Vol 21 (112) ◽  
pp. 531 ◽  
Author(s):  
MH Campbell ◽  
AR Gilmour ◽  
DT Vere
Keyword(s):  
Festuca Arundinacea ◽  
New South ◽  
Basal Area ◽  
Ground Cover ◽  
Weed Suppression ◽  
Perennial Grasses ◽  
Herbicide Treatment ◽  
South Wales ◽  
Annual Grasses ◽  
Association Effect

In an experiment carried out between 1976 and 1979 near Orange, New South Wales, the effects of four rates of glyphosate (0.1 25, 0.25, 0.5 and 1.0 kg/ha active ingredient (a.i.)) and three rates of amitrole (0.5, 0.75, 1.0 kg/ha a.i. in association with 2.5 kg/ha a.i. 2,2-DPA) on the suppression of a nitrophilous weed association (broadleafed plants, annual grasses, native perennial grasses, annual legumes) and the resultant establishment and development of surface sown pastures species (Medicago sativa, Phalaris aquatica, Dactylis glomerata, Festuca arundinacea) were measured. The length of weed suppression in the year of spraying (1976) was the most important factor in the eventual development of the sown species. Glyphosate at 1.0 kg/ha a.i. gave better weed suppression for longer (up to and beyond 23 weeks after spraying) than any other herbicide treatment and allowed sown species to establish and survive the first summer better and thus produce a better pasture three years later. Weed suppression between 8 and 19 weeks after spraying affected the initial establishment of sown species; in general, establishment was better on herbicide treatments that reduced ground cover of the weed association to less than 30% in this period. Rate of weed suppression had no effect because no sown species germinated in the eight weeks after spraying. Three years after treatment the ground cover of the nitrophilous weed association was 31% on the best herbicide treatment (glyphosate, 1.0 kg/ha a.i.) and 83% on the unsprayed control; the respective ground cover of sown species was 60% and 7%. The increase in ground cover of sown species during the three years was on most treatments almost entirely due to the increase in basal area of P. aquatica.

Effects of grazing and management on herbage mass, persistence, animal production and soil water content of native pastures. 2. A mixed native pasture, Manilla, North West Slopes, New South Wales

2003 ◽  
Vol 43 (8) ◽  
pp. 891 ◽  
Author(s):  
G. M. Lodge ◽  
S. R. Murphy ◽  
S. Harden
Keyword(s):  
Soil Water ◽  
New South ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Litter Mass ◽  
Wool Production ◽  
Basal Cover ◽  
South Wales ◽  
Continuous Grazing ◽  
Over Time

As part of the Sustainable Grazing Systems (SGS) National Experiment a study was conducted on a native pasture in the Manilla district of northern New South Wales to examine the effects of 5 grazing treatments on total herbage mass, litter mass, basal cover, ground cover, sheep liveweight, wool production and soil water content (SWC, mm) at different depths. The pasture was a mixture of native perennial grasses, with redgrass (Bothriochloa macra) and wiregrass (Aristida ramosa) dominant on a red Chromosol soil type and bluegrass (Dichanthium sericeum) on a brown Vertosol. Wallaby grasses (Austrodanthonia richardsonii and A. bipartita) were common on both soils. Plots were grazed with Merino wethers and data collected from spring 1997 to spring 2001 were analysed to determine the effect of treatments on both production and sustainability. Five grazing treatments were applied in a randomised 3 replicate design. Grazing treatments were: continuous grazing at 3.1 and 6.2�sheep/ha (C3 and C6), continuous grazing at 9.2 sheep/ha, with subterranean clover (Trifolium subterraneum) oversown and fertiliser applied (C9+sub) and rotational grazing at an annual stocking rate of 3.1 sheep/ha with pasture grazed for 4 weeks and rested for 4 weeks (R4/4), or rested for 12 weeks (R4/12). Over time, treatments had no significant effect on either total pasture herbage mass (compared with the C3�control) or the basal cover of the major perennial grasses. Treatments had inconsistent significant effects on ground cover, litter mass, sheep liveweight and wool production (kg/head) over time. Compared with all other treatments ground cover was less (P<0.05) in the C6 treatment in only May and September 2000 and litter mass less (P<0.05) in only December 1998 and March 1999. Treatment sheep liveweights were not significantly different from the C3 treatment from September 1997 to 1999. However, from October 1999 to October 2001 sheep liveweight in the C6 treatment was significantly less than in the C3 treatment, while in the C9+sub and R4/12 treatments it was significantly greater than the control. In 1999, wool production per head was higher (P<0.05) in the C9+sub and R4/12 treatments compared with all other treatments but treatment differences were not significant in all other years. Significant differences in SWC only occurred at the 0–30 cm depth between the C3 and the C6 and R4/12 treatments, but were predicted to be <1.5 mm/year. A sustainability index derived from economic [equivalent annual net return ($/ha) for a 10-year period], animal production, pasture, soil health and soil water data indicated that the overall indices were lowest for the C3, C6 and C9+sub treatments and highest for the R4/4 and R4/12 treatments.

Evaluation of natural annual pasture at Trangie in central western New South Wales. 3. Effect of stocking rate on annual-dominated and perennial-dominated natural pastures

1978 ◽  
Vol 18 (92) ◽  
pp. 361 ◽  
Author(s):  
GE Robards ◽  
DL Michalk ◽  
RJ Pither
Keyword(s):  
New South ◽  
Perennial Grass ◽  
New South Wales ◽  
Perennial Grasses ◽  
Stocking Rate ◽  
Wool Production ◽  
South Wales ◽  
Natural Pasture ◽  
Ewe Lamb ◽  
Stocking Rates

A four year experiment is reported during which breeding Merino ewes grazed two natural pasture types at three stocking rates at Trangie in central-western New South Wales. Initially, the pasture on a red brown soil was dominated by cool season annual species, particularly Hordeum leporinum, Erodium species and Medicago species. The pasture on a heavier grey soil was dominated by the perennial grasses Chloris acicularis, C. truncata and Stipa variabilis. Clean wool production of ewes grazing the annual-dominated pasture was significantly (P< 0.05) higher than that of ewes grazing the perennial grass-dominated pasture even though the wool of the ewes grazing perennial pasture had a higher percentage clean yield (P < 0.05). The ewes on the annual-dominated pasture were significantly heavier in autumn and winter, and had a faster rate of wool growth in each season except spring, than ewes grazing perennial pasture. Number of lambs born per ewe, lamb birth weight and lamb growth rate were not affected by pasture type or stocking rate. Stocking rate had a small but statistically significant effect on clean wool production and only small effects on ewe liveweight, regardless of pasture type. When hand feeding of the pregnant ewes became necessary in the poor winters of 1971 and 1972 all stocking rates had to be commenced simultaneously. The significance of perennial grasses in these natural pastures is discussed in relationship to animal production, stocking rate, pasture and soil stability, and regeneration of grasses following favourable seasons.

Effect of superphosphate, white clover and stocking rate on the productivity of natural pastures, Northern Tablelands, New South Wales

1976 ◽  
Vol 16 (79) ◽  
pp. 209 ◽  
Author(s):  
GG Robinson ◽  
A Lazenby
Keyword(s):  
White Clover ◽  
New South ◽  
Animal Production ◽  
First Year ◽  
Stocking Rate ◽  
Bare Ground ◽  
Species Frequency ◽  
South Wales ◽  
Stocking Rates ◽  
Different Levels

The species frequency, pasture availability and animal production on natural pastures oversown with white clover were examined over the five year period 1968-73. Superphosphate was applied annually at different levels (0, 250 and 500 kg ha-1) and the plots were grazed continuously at two stocking rates (7.8 and 15.6 wethers ha-1). An increase in the frequency of white clover (Trifolium repens) and a decrease in bare ground, Panicum spp-Eragrostis spp. and Sporobolus elongatus (in the case of the latter two the effect was particularly evident at the low stocking rate) followed the application of superphosphate. Increasing stocking rate resulted in a reduction in white clover and an increase in the frequency of Panicum spp.-Eragrostis spp. and bare ground. Pasture availability and animal production were increased by superphosphate. Apart from the first year, when the season was unusually dry, supplementary feeding was minimal on all topdressed treatments but was essential at the high stocking rate where no superphosphate was applied. Over the five year period animals on the pastures receiving superphosphate averaged 15 per cent heavier and gave 18 per cent more wool than those that were unfertilized. Wool production at the high stocking rate averaged 17.8 kg ha-1 (49 per cent) more than that from the low stocking rate.

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