scholarly journals Sustainable grazing management for temporal and spatial variability in north Australian rangelands – a synthesis of the latest evidence and recommendations

2014 ◽  
Vol 36 (3) ◽  
pp. 223 ◽  
Author(s):  
Peter O'Reagain ◽  
Joe Scanlan ◽  
Leigh Hunt ◽  
Robyn Cowley ◽  
Dionne Walsh
Keyword(s):  
Key Management ◽  
Rainfall Variability ◽  
Grazing Management ◽  
Economic Modelling ◽  
Infrastructure Development ◽  
Northern Australia ◽  
Wet Season ◽  
Sustainable Grazing ◽  
Patch Burning

Rainfall variability is a major challenge to sustainable grazing management in northern Australia, with management often complicated further by large, spatially-heterogeneous paddocks. This paper presents the latest grazing research and associated bio-economic modelling from northern Australia and assesses the extent to which current recommendations to manage for these issues are supported. Overall, stocking around the safe long-term carrying capacity will maintain land condition and maximise long-term profitability. However, stocking rates should be varied in a risk-averse manner as pasture availability varies between years. Periodic wet-season spelling is also essential to maintain pasture condition and allow recovery of overgrazed areas. Uneven grazing distributions can be partially managed through fencing, providing additional water-points and in some cases patch-burning, although the economics of infrastructure development are extremely context-dependent. Overall, complex multi-paddock grazing systems do not appear justified in northern Australia. Provided the key management principles outlined above are applied in an active, adaptive manner, acceptable economic and environmental outcomes will be achieved irrespective of the grazing system applied.

Bio-economic evaluation of grazing-management options for beef cattle enterprises during drought episodes in semiarid grasslands of northern Australia

2021 ◽  
Vol 61 (1) ◽  
pp. 72
Author(s):  
M. K. Bowen ◽  
F. Chudleigh ◽  
D. Phelps
Keyword(s):  
Beef Cattle ◽  
Management Strategies ◽  
Grazing Management ◽  
Economic Modelling ◽  
Stocking Rate ◽  
Northern Australia ◽  
Management Scenarios ◽  
Management Options ◽  
Herd Management ◽  
Stocking Rates

Context The large inter-annual and decadal rainfall variability that occurs in northern Australian rangelands poses major challenges for the profitable and sustainable management of grazing businesses. Aims An integrated bio-economic modelling framework (GRASP integrated with Breedcow and Dynama (BCD)) was developed to assess the effect of alternative grazing-management options on the profitability and sustainability of a beef cattle enterprise in the central-western Mitchell grasslands of Queensland over a multi-decadal time period. Methods Four grazing-management strategies were simulated over a 36-year period (1982–2017) in the GRASP pasture-growth model, using historic climate records for Longreach in central-western Queensland. Simulated annual stocking rates and steer liveweight-gain predictions from GRASP were integrated with published functions for mortality and conception rates in beef-breeding cattle in northern Australia, and then used to develop dynamic BCD cattle-herd models and discounted cash-flow budgets over the last 30 years of the period (1988–2017), following a 6-year model-equilibration period. The grazing-management strategies differed in the extent to which stocking rates were adjusted each year, from a common starting point in Year 1, in response to changes in the amount of forage available at the end of the summer growing season (May). They ranged from a low flexibility of ‘Safe stocking rate’ (SSR) and ‘Retain core herd’ (RCH) strategies, to a moderate flexibility of ‘Drought responsive’ (DR), to a ‘Fully flexible’ (FF) strategy. The RCH strategy included the following two herd-management scenarios: (1) ‘Retain herd structure’, where a mix of cattle were sold in response to low pasture availability, and (2) ‘Retain core breeders’, where steers were sold before reducing the breeder herd. Herd-management scenarios within the DR and FF strategies examined five and four options respectively, to rebuild cattle numbers and utilise available pasture following herd reductions made in response to drought. Key results Property-level investment returns expressed as the internal rate of return (IRR) were poor for SSR (–0.09%) and the three other strategies when the herd was rebuilt following drought through natural increase alone (RCH, –0.27%; DR, –1.57%; and FF, –4.44%). However, positive IRR were achieved when the DR herd was rebuilt through purchasing a mix of cattle (1.70%), purchasing pregnant cows (1.45%), trading steers (0.50%) or accepting cattle on agistment (0.19%). A positive IRR of 0.70% was also achieved for the FF property when purchasing a mix of cattle to rebuild numbers. However, negative returns were obtained when either trading steers (–2.60%) or agistment (–0.11%) scenarios were applied to the FF property. Strategies that were either inflexible or highly flexible increased the risk of financial losses and business failure. Property-level pasture condition (expressed as the percentage of perennial grasses; %P) was initially 69%P and was maintained under the DR strategy (68%P; average of final 5 years). The SSR strategy increased pasture condition by 25% to 86%P, while the RCH and FF strategies decreased pasture condition by 29% (49%P) and 65% (24%P) respectively. Conclusions In a highly variable and unpredictable climate, managing stocking rates with a moderate degree of flexibility in response to pasture availability (DR) was the most profitable approach and also maintained pasture condition. However, it was essential to economic viability that the property was re-stocked as soon as possible, in line with pasture availability, once good seasonal conditions returned. Implications This bio-economic modelling analysis refines current grazing-management recommendations by providing insights into both the economic and sustainability consequences of stocking-rate flexibility in response to fluctuating pasture supply. Caution should be exercised in recommending either overly conservative safe stocking strategies that are inflexible, or overly flexible stocking strategies, due to the increased risk of very poor outcomes.

Managing for rainfall variability: impacts of grazing strategies on perennial grass dynamics in a dry tropical savanna

2011 ◽  
Vol 33 (2) ◽  
pp. 209 ◽  
Author(s):  
D. M. Orr ◽  
P. J. O'Reagain
Keyword(s):  
Carrying Capacity ◽  
Rainfall Variability ◽  
Perennial Grasses ◽  
Heteropogon Contortus ◽  
Heavy Grazing ◽  
Average Rainfall ◽  
Sustainable Grazing ◽  
Grazing Strategies ◽  
The Impact

Rainfall variability remains a major challenge to sustainable grazing management in northern Australia with perennial grasses the key to the stability of the resources that maintain a sustainable grazing industry. This paper describes the dynamics of five perennial grasses – Bothriochloa ewartiana (Domin) C.E. Hubb., Chrysopogon fallax S.T. Blake, Aristida spp., Panicum effusum R. Br. and Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult. in relation to three grazing strategies – moderate stocking at long-term carrying capacity, heavy stocking and rotational wet season spelling. The research was conducted in permanent quadrats on the predominant land type in an extensive grazing study in an Aristida-Bothriochloa pasture in north Australia between 1998 and 2010. Summer rainfall was above average for two periods – 1998 – 2001 and 2008 – 2010 with drought and below-average rainfall from 2002 to 2007. Low rainfall affected the dynamics of all grasses by reducing survival and basal area through its effect on plant size; this impact was most noticeable for the shorter-lived Aristida spp., P. effusum and H. contortus. The impact of grazing was greatest on the long-lived B. ewartiana and C. fallax; this effect was accentuated by the 2002–07 drought. Heavy grazing during this period further reduced the survival and size of B. ewartiana in comparison with the moderate stocking and rotational spell treatments. In contrast, the survival of C. fallax was reduced in the moderate stocking and rotational spelling treatment during drought, relative to that under heavy grazing. The density of B. ewartiana declined even under moderate grazing and despite two sequences of above-average rainfall because seedling recruitment failed to offset mature plant death. Results from this study emphasised the importance of maintaining the existing populations of key long-lived species such as B. ewartiana through good management. These results also supported the overall findings from the grazing study indicating that stocking at the long-term carrying capacity is sustainable in managing for climate variability.

Sustainable grazing systems for the Central Tablelands of New South Wales. 5. A bioeconomic framework for assessing the long-term economic benefits of grazing management tactics and implications for sustainability

2006 ◽  
Vol 46 (4) ◽  
pp. 495 ◽  
Author(s):  
R. E. Jones ◽  
P. M. Dowling ◽  
D. L. Michalk ◽  
W. McG. King
Keyword(s):  
Programming Model ◽  
New South ◽  
New South Wales ◽  
Economic Benefits ◽  
Grazing Management ◽  
South Wales ◽  
Grazing Systems ◽  
Sustainable Grazing ◽  
Management Tactics

There have been significant declines in the perennial grass (PG) content in native and sown pastures across temperate Australia. Not only has this reduced agricultural productivity, it has contributed to more serious degradation, such as loss of soil and biodiversity, decreasing water quality, and dryland salinity caused by rising watertables. Results from the Sustainable Grazing Systems Key Program (SGS) research undertaken at Carcoar on the Central Tablelands of New South Wales were reported by Michalk et al. (2003). This research indicated that grazing management tactics can be used to manipulate pasture composition, thereby changing animal production and water-use patterns. The main grazing tactic investigated was termed a summer grazing rest, where resting was imposed in late spring if PG composition was <50%. Reported in this present paper is an economic framework for valuing the long-term benefits of grazing management tactics. The framework involves the development of a bioeconomic modelling system that links a dynamic programming model with biophysical models for water and environmental processes, soil fertility, pasture growth, livestock energy requirements and the change in pasture species composition. The study concludes that long-term economic returns are improved by strategies, e.g. a summer rest, that lead to an increase in PG composition over time. The study also determined that environmental factors, such as deep drainage, runoff and soil loss, are reduced as perenniality is increased.

Improvement in soil structure resulting from sown pastures on degraded areas in the dry savanna woodlands of northern Australia

Soil Research ◽  
1983 ◽  
Vol 21 (1) ◽  
pp. 83 ◽  
Author(s):  
BJ Bridge ◽  
JJ Mott ◽  
WH Winter ◽  
RJ Hartigan
Keyword(s):  
Soil Structure ◽  
Surface Soil ◽  
Northern Australia ◽  
Wet Season ◽  
Stylosanthes Hamata ◽  
Native Grassland ◽  
Townsville Stylo ◽  
Stocking Rates ◽  
High Infiltration

The structure of the surface soil under pastures sown on a former Themada australis native grassland and on degraded areas in the red earths of northern Australia was examined micromorphologically. Heavily grazed pastures containing the legumes Stylosanthes hamata cv. Verano and Alysicarpus vaginalis had more macropore space in the surface soil than arlightly grazed native grassland, while pastures containing S. humilis (Townsville stylo) had as little macropore space as degraded areas. Macropore space in a S. hamata pasture increased between the third and fourth wet seasons after establishment. Where macropore space was high, infiltration measurements showed that sorptivities were as high as those in the native grassland. Where macropore space was low, sorptivities were as low as those in degraded areas. However, all sown pastures showed low hydraulic conductivities equivalent to those in the degraded areas, and this was attributed to trampling during the wet season under the higher stocking rates involved. The improvement and maintenance of soil structure in the S. hamata and A. vaginalis pastures, together with their high sorptivities, indicates that they are stable in the long term.

Implications of retaining woody regrowth for carbon sequestration for an extensive grazing beef business: a bio-economic modelling case study

2016 ◽  
Vol 38 (3) ◽  
pp. 319 ◽  
Author(s):  
Giselle Whish ◽  
Lester Pahl ◽  
Steven Bray
Keyword(s):  
Carbon Sequestration ◽  
Grazing Management ◽  
Economic Losses ◽  
Economic Modelling ◽  
Northern Australia ◽  
Gross Margin ◽  
Modelling Framework ◽  
Grazing Lands ◽  
Financial Losses

A bio-economic modelling framework (GRASP-ENTERPRISE) was used to assess the implications of retaining woody regrowth for carbon sequestration on a case study beef grazing property in northern Australia. Five carbon farming scenarios, ranging from 0% to 100% of the property regrowth retained for carbon sequestration, were simulated over a 20-year period (1993–2012). Dedicating regrowth on the property for carbon sequestration reduced pasture (up to 40%) and herd productivity (up to 20%), and resulted in financial losses (up to 24% reduction in total gross margin). A net carbon income (income after grazing management expenses are removed) of $2–4 per t CO2-e was required to offset economic losses of retaining regrowth on a moderately productive (~8 ha adult equivalent–1) property where income was from the sale of weaners. A higher opportunity cost ($ t–1 CO2-e) of retaining woody regrowth is likely for feeder steer or finishing operations, with improved cattle prices, and where the substantial transaction and reporting costs are included. Although uncertainty remains around the price received for carbon farming activities, this study demonstrated that a conservatively stocked breeding operation can achieve positive production, environmental and economic outcomes, including net carbon stock. This study was based on a beef enterprise in central Queensland’s grazing lands, however, the approach and learnings are expected to be applicable across northern Australia where regrowth is present.

Comparing fixed and flexible stocking as adaptations to inter-annual rainfall variability in the extensive beef industry of northern Australia

2016 ◽  
Vol 38 (1) ◽  
pp. 85 ◽  
Author(s):  
Lester Pahl ◽  
Joe Scanlan ◽  
Giselle Whish ◽  
Robyn Cowley ◽  
Neil MacLeod
Keyword(s):  
Carrying Capacity ◽  
Rainfall Variability ◽  
Full Range ◽  
Herd Size ◽  
Annual Rainfall ◽  
Northern Australia ◽  
Beef Industry ◽  
Growing Seasons ◽  
Stocking Rates

Many beef producers within the extensive cattle industry of northern Australia attempt to maintain a constant herd size from year-to-year (fixed stocking), whereas others adjust stock numbers to varying degrees annually in response to changes in forage supply. The effects of these strategies on pasture condition and cattle productivity cannot easily be assessed by grazing trials. Simulation studies, which include feedbacks of changes to pasture condition on cattle liveweight gain, can extend the results of grazing trials both spatially and temporally. They can compare a large number of strategies, over long periods of time, for a range of climate periods, at locations which differ markedly in climate. This simulation study compared the pasture condition and cattle productivity achieved by fixed stocking at the long-term carrying capacity with that of 55 flexible stocking strategies at 28 locations across Queensland and the Northern Territory. Flexible stocking strategies differed markedly in the degree they increased or decreased cattle stocking rates after good and poor pasture growing seasons, respectively. The 28 locations covered the full range in average annual rainfall and inter-annual rainfall variability experienced across northern Australia. Constrained flexibility, which limited increases in stocking rates after good growing seasons to 10% but decreased them by up to 20% after poor growing seasons, provides sustainable productivity gains for cattle producers in northern Australia. This strategy can improve pasture condition and increase cattle productivity relative to fixed stocking at the long-term carrying capacity, and its capacity to do this was greatest in the semiarid rangeland regions that contain the majority of beef cattle in northern Australia. More flexible stocking strategies, which also increased stocking rates after good growing seasons by only half as much as they decreased them after poor growing seasons, were equally sustainable and more productive than constrained flexibility, but are often impractical at property and industry scales. Strategies with the highest limits (e.g. 70%) for both annual increases and decreases in stocking rates could achieve higher cattle productivity, but this was at the expense of pasture condition and was not sustainable. Constrained flexible stocking, with a 10% limit for increases and a 20% limit for decreases in stocking rates annually, is a risk-averse adaptation to high and unpredictable rainfall variability for the extensive beef industry of northern Australia.

scholarly journals Managing for rainfall variability: effect of grazing strategy on cattle production in a dry tropical savanna

2009 ◽  
Vol 49 (2) ◽  
pp. 85 ◽  
Author(s):  
Peter O'Reagain ◽  
John Bushell ◽  
Chris Holloway ◽  
Angela Reid
Keyword(s):  
Southern Oscillation ◽  
Rainfall Variability ◽  
Cattle Production ◽  
Long Term Effects ◽  
Seasonal Forecasts ◽  
Wet Season ◽  
Variable Environment ◽  
Condition Score ◽  
Stocking Rates

Rainfall variability is a challenge to sustainable and profitable cattle production in northern Australia. Strategies recommended to manage for rainfall variability, like light or variable stocking, are not widely adopted. This is due partly to the perception that sustainability and profitability are incompatible. A large, long-term grazing trial was initiated in 1997 in north Queensland, Australia, to test the effect of different grazing strategies on cattle production. These strategies are: (i) constant light stocking (LSR) at long-term carrying capacity (LTCC); (ii) constant heavy stocking (HSR) at twice LTCC; (iii) rotational wet-season spelling (R/Spell) at 1.5 LTCC; (iv) variable stocking (VAR), with stocking rates adjusted in May based on available pasture; and (v) a Southern Oscillation Index (SOI) variable strategy, with stocking rates adjusted in November, based on available pasture and SOI seasonal forecasts. Animal performance varied markedly over the 10 years for which data is presented, due to pronounced differences in rainfall and pasture availability. Nonetheless, lighter stocking at or about LTCC consistently gave the best individual liveweight gain (LWG), condition score and skeletal growth; mean LWG per annum was thus highest in the LSR (113 kg), intermediate in the R/Spell (104 kg) and lowest in the HSR (86 kg). Mean LWG was 106 kg in the VAR and 103 kg in the SOI but, in all years, the relative performance of these strategies was dependent upon the stocking rate applied. After 2 years on the trial, steers from lightly stocked strategies were 60–100 kg heavier and received appreciable carcass price premiums at the meatworks compared to those under heavy stocking. In contrast, LWG per unit area was greatest at stocking rates of about twice LTCC; mean LWG/ha was thus greatest in the HSR (21 kg/ha), but this strategy required drought feeding in four of the 10 years and was unsustainable. Although LWG/ha was lower in the LSR (mean 14 kg/ha), or in strategies that reduced stocking rates in dry years like the VAR (mean 18 kg/ha) and SOI (mean 17 kg/ha), these strategies did not require drought feeding and appeared sustainable. The R/Spell strategy (mean 104 kg/ha) was compromised by an ill-timed fire, but also performed satisfactorily. The present results provide important evidence challenging the assumption that sustainable management in a variable environment is unprofitable. Further research is required to fully quantify the long-term effects of these strategies on land condition and profitability and to extrapolate the results to breeder performance at the property level.

scholarly journals Resting Subtropical Grasslands from Grazing in the Wet Season Boosts Biocrust Hotspots to Improve Soil Health

Agronomy ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Wendy J. Williams ◽  
Susanne Schmidt ◽  
Eli Zaady ◽  
Bruce Alchin ◽  
Than Myint Swe ◽  
...  
Keyword(s):  
Best Practice ◽  
Rainfall Variability ◽  
Soil Health ◽  
Extreme Rainfall ◽  
Wet Season ◽  
Ecosystem Integrity ◽  
Landscape Function ◽  
Eastern Australia ◽  
Stocking Rates

Effective grazing management in Australia’s semi-arid rangelands requires monitoring landscape conditions and identifying sustainable and productive practice through understanding the interactions of environmental factors and management of soil health. Challenges include extreme rainfall variability, intensifying drought, and inherently nutrient-poor soils. We investigated the impacts of grazing strategies on landscape function—specifically soil health—as the foundation for productive pastures, integrating the heterogenous nature of grass tussocks and the interspaces that naturally exist in between them. At Wambiana—a long-term research site in north-eastern Australia—we studied two soil types, two stocking rates (high, moderate), and resting land from grazing during wet seasons (rotational spelling). Rotational spelling had the highest biocrust (living soil cover), in interspaces and under grass tussocks. Biocrusts were dominated by cyanobacteria that binds soil particles, reduces erosion, sequesters carbon, fixes nitrogen, and improves soil fertility. Rotational spelling with a moderate stocking rate emerged as best practice at these sites, with adjustment of stocking rates in line with rainfall and soil type recommended. In drought-prone environments, monitoring the presence and integrity of biocrusts connects landscape function and soil health. Biocrusts that protect and enrich the soil will support long-term ecosystem integrity and economic profitability of cattle production in rangelands.

Yields and nitrogen uptake of grain sorghum in various rotations, including lucerne, annual legume and long fallow

1989 ◽  
Vol 40 (2) ◽  
pp. 255 ◽  
Author(s):  
ICR Holford
Keyword(s):  
Nitrogen Uptake ◽  
Grain Sorghum ◽  
Grazing Management ◽  
First Year ◽  
Red Clay ◽  
Beneficial Effects ◽  
South Wales ◽  
Establishment Method ◽  
Soil Evidence

Long-term yields, nitrogen uptake and responsiveness of grain sorghum following three lucerne rotations, an annual legume rotation, long fallowing, and continuous wheat growing were measured on a black earth and red clay in northern New South Wales. The three lucerne rotations compared two methods of lucerne establishment (with or without a cover crop) and two methods of grazing management (short or extended grazing).There were large beneficial effects of lucerne leys on the first grain sorghum crop, whether they were measured as grain yield, nitrogen content of the foliage and grain, or nitrogen uptake. The effect was much smaller in the second year but it increased in the third and fourth years, in direct relation to the rainfall during the sorghum flowering period. The effect was larger on the black earth than on the red clay, reflecting the much higher lucerne yields on the former soil. Evidence indicated that the nitrogen contribution from lucerne after the first year was no greater than the nitrogen accumulated by long fallowing, and this was attributed to very low rainfall and lucerne yields during the four year ley period.The annual legume rotation suffered from drought and insect damage in most years, and following sorghum yields tended to be lower than those achieved by long fallowing.Differences in the effects of establishment method and grazing management on total lucerne yields were reflected in the differences in subsequent grain sorghum yields. Largest differences were on the black earth where extended grazing lowered the total yields of lucerne and subsequent grain sorghum. Sowing lucerne under wheat had little effect on total yields of lucerne or sorghum.

Adaptation of Medicago rigidula to a cereal–pasture rotation in north-west Syria

1986 ◽  
Vol 107 (1) ◽  
pp. 179-186 ◽  
Author(s):  
A. M. Abd El-Moneim ◽  
P. S. Cocks
Keyword(s):  
North Africa ◽  
Farming System ◽  
Livestock Production ◽  
Grazing Management ◽  
North West ◽  
Selection Programme ◽  
Ley Farming ◽  
Medicago Rigidula ◽  
Subsequent Regeneration

SUMMARYThe ley-farming system (integrated cereal and livestock production in which cerealsrotate with self-regenerating pastures) is considered to be of great potential benefit to north Africa and west Asia. In the colder parts of this region (of which north Syria is typical) its application is limited by poor adaptation of commercial medic cultivars (mainly Medicago truncatula and M. littoralis). An extended selection programme hag identified M. rigidula as adapted to the soils and climate of the region but nothing is known of its adaptation to the ley-farming system itself.An experiment which included 23 selections of M. rigidula and one each of M. rotata and M. noeana was conducted over 3 years during which herbage production, seed yield, and the fate of seeds were observed during the 1st year when pastures were established, the 2nd year when wheat was sown, and the 3rd year when the pasture regenerated. Of the 400–800 kg seed/ha produced in the 1st year an average of 87% remained in the soil in spring of the 3rd year. The weight of seed regenerating in the 3rd year varied from 30 to nearly 170 kg/ha, and herbage production, especially in winter, depended heavily on the number of regenerating seedlings. The most productive regenerating pastures produced nearly 2 t/ha of dried herbage by 1 January, and more than 6 t/ha for the whole growing season.The results showed that there was sufficient residual and newly produced seed at the end of the 3rd year to be sure that subsequent regeneration would result in similar herbage yields in the 5th year, and that the pasture was assured of long-term persistence. The significance of this for livestock production is discussed, and it is concluded that the results should encourage further investigation of grazing management and socioeconomic factors seen as constraints to introducing the ley-farming system to north Syria.

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