scholarly journals Northern Australian pasture and beef systems. 1. Net carbon position

2014 ◽  
Vol 54 (12) ◽  
pp. 1988 ◽  
Author(s):  
Steven Bray ◽  
Natalie Doran-Browne ◽  
Peter O'Reagain
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Management Strategies ◽  
Carbon Stocks ◽  
Grazing Management ◽  
Woody Vegetation ◽  
Stocking Rate ◽  
Beef Industry ◽  
Livestock Emissions ◽  
Stocking Rates

The beef industry in northern Australia manages ~15 million cattle, grazed on 250 million hectares of grassland and savanna woodland. The large size of the beef industry results in significant quantities of greenhouse gases being emitted to the atmosphere through ruminant livestock enteric methane production. However, livestock emissions are only one component of the carbon cycle in which grazing businesses operate. Livestock grazing also affects carbon stocks and fluxes in pasture, woody vegetation, soil and from fire through the consumption of forage and other landscape impacts. Little knowledge is available on the impact of different grazing management strategies on the ‘net carbon position’ incorporating carbon stocks and greenhouse gas emissions when grazing savanna woodlands. The Wambiana grazing trial in northern Queensland, Australia, provides an opportunity to assess carbon stocks and greenhouse gas emissions (reported as t CO2-e) associated with livestock, pasture, woody vegetation, soil and fire under alternative grazing management strategies (moderate and heavy stocking rate) over a 16-year period. The results indicate that tree biomass and woody vegetation dynamics dominate the carbon stocks and fluxes in grazed savanna woodlands. During the trial, both moderate and heavy stocking rate treatments had a positive net carbon balance, with the moderate stocking rate treatment having a better ‘net carbon position’ (19 t CO2-e per ha) than the heavy stocking rate treatment (9 t CO2-e per ha), primarily due to less livestock emissions and greater pasture biomass and soil C. These results add to the previously published benefits on land condition and economic return of grazing at moderate stocking rates, compared with heavy stocking rates.

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.

Post-experimental modelling of grazing systems to improve profit and environmental outcomes using AusFarm

2017 ◽  
Vol 57 (9) ◽  
pp. 1849 ◽  
Author(s):  
K. M. Broadfoot ◽  
W. B. Badgery ◽  
G. D. Millar
Keyword(s):  
Management Strategies ◽  
Grazing Management ◽  
Management Systems ◽  
Stocking Rate ◽  
Management Options ◽  
Experimental Modelling ◽  
Grazing Systems ◽  
Sheep Production ◽  
Flexible Management ◽  
Stocking Rates

Assessments of grazing systems are often constrained by the decisions regarding the management of the grazing systems, including stocking rate, and also the seasonal conditions that occur during the assessment period. These constraints have led to sometimes conflicting results about comparisons of grazing management systems. This paper examines 1-, 4- and 20-paddock (1P, 4P and 20P) grazing management systems to determine how the intensity of grazing management on native pastures influences the financial performance of sheep production systems. The performance of the grazing systems, as part of the Orange EverGraze research experiment, was initially examined using the biophysical data over the 4 years of the experiment and then a more detailed analysis over a longer timeframe was undertaken using the AusFarm simulation modelling software. Flexible management strategies to optimise ewe numbers, sale time of lambs, and adjust ewe numbers based on season, were also assessed to determine which management systems are the most profitable and sustainable. There was higher profit for the 20P grazing system than the 1P system during the experiment. However, when stocking rates were held constant at optimum levels and systems were simulated over 40 years, there was no difference between grazing systems. Modelling strategies used to vary stocking rates showed that flexible management options are better based on optimising ewe numbers and the sale time of lambs rather than changing ewe numbers between years. The sustainability of modelled systems was also assessed using frequency of events where the average herbage mass (0.8 t DM/ha) or ground cover (80%) in autumn dropped below levels that are associated with degradation. Degradation events occurred more so with increasing ewe number than lamb sale time. Overall, the most sustainable systems, when considering profitability and environmental issues, had a stocking rate of 4.2 ewes per ha, with lambs sold in February (2 or 18). Higher stocking rates (5.3 ewes/ha) would need to be run for more intensive grazing management to have higher profitability.

Offsets required to reduce the carbon balance of sheep and beef farms through carbon sequestration in trees and soils

2018 ◽  
Vol 58 (9) ◽  
pp. 1648 ◽  
Author(s):  
Natalie Doran-Browne ◽  
Mark Wootton ◽  
Chris Taylor ◽  
Richard Eckard
Keyword(s):  
Carbon Sequestration ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Carbon Balance ◽  
Livestock Production ◽  
Tree Cover ◽  
Stocking Rate ◽  
Gas Emissions ◽  
Carbon Neutral ◽  
Stocking Rates

The sustainability of farming is important to ensure that natural resources remain available into the future. Ruminant livestock production generates more greenhouse gas emissions than other types of agricultural production and most livestock mitigation options to date have a modest greenhouse gas reduction potential (<20%). Trees and soils, by comparison, can sequester large amounts of carbon depending on the availability of land. Previous studies on carbon neutral livestock production have shown that farms with a stocking rate of 8 dry sheep equivalents (DSE)/ha can be carbon neutral or carbon positive by sequestering more carbon than is emitted from the farm. However, the carbon offsets required by farms with higher stocking rates (>20 DSE/ha) has yet to be studied in Australia. The challenge is to sequester enough carbon to offset the higher level of emissions that these higher stocked farms produce. This study calculated the carbon balance of wool, prime lamb and beef enterprises using a range of stocking rates (6–22 DSE/ha) and levels of tree cover in two agroecological zones. Emissions from livestock, energy and transport were offset by the carbon sequestered in trees and soils. Additionally, the carbon balance was calculated of a case study, Jigsaw Farms, an intensive sheep and beef farm in south-eastern Australia. The methods used to calculate emissions and carbon stocks were from the Australian National Greenhouse Gas Inventory. The majority of stocking rates were carbon positive over a 25-year period when 20% of the sheep or beef enterprises were covered with trees. This study demonstrated that substantial reductions can be made in greenhouse gas emissions through the use of carbon sequestration, particularly in trees. The results showed that from 2000 to 2014 Jigsaw Farms reduced its emissions by 48% by sequestering carbon in trees and soil. The analysis of different stocking rates and tree cover provides an important reference point for farmers, researchers and policy analysts to estimate the carbon balance of wool, prime lamb and beef enterprises based on stocking rate and the area of tree cover.

Improving grassland/forage quality and management to reduce livestock greenhouse gas emissions

2021 ◽  
pp. 209-230
Author(s):  
Michael O’Donovan ◽  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Condensed Tannin ◽  
Management Strategies ◽  
Grazing Management ◽  
Gas Emissions ◽  
Measurement Issues ◽  
Clover Content

This chapter reviews grazing management strategies that can contribute to reducing livestock greenhouse gas emissions. Strategies discussed include grazing season length and timing as well as sward structure and quality, including dry matter and clover content. The chapter also discusses the use of condensed tannin legumes such as chicory and plantain, as well as measurement issues including life cycle assessment.

Management of grazing systems

1989 ◽  
pp. 117-122 ◽  
Author(s):  
J. Hodgson
Keyword(s):  
Management Practices ◽  
Management Control ◽  
Grazing Management ◽  
Relative Importance ◽  
Stocking Rate ◽  
Pastoral Systems ◽  
Starting Point ◽  
Alternative Means ◽  
Grazing Systems ◽  
Stocking Rates

Recent assessments of the relative importance of stocking rate. stocking policy and grazing management on the output from pastoral systems are used as a starting point to argue the need for objective pasture assessments to aid control of livestock enterprises to meet production targets. Variations in stocking rates, stocking policy and other management practices all provide alternative means of control of pasture conditions which are the major determinants of pasture and animal performance. Understanding of the influence of pasture conditions on systems performance should provide a better basis for management control and for Communication between farmers, extension officers and researchers. Keywords: Stocking rate, pasture condition, pasture cover

scholarly journals A geographical assessment of vegetation carbon stocks and greenhouse gas emissions on potential microalgae-based biofuel facilities in the United States

2016 ◽  
Vol 221 ◽  
pp. 270-275 ◽  
Author(s):  
Carlos Quiroz Arita ◽  
Özge Yilmaz ◽  
Semin Barlak ◽  
Kimberly B. Catton ◽  
Jason C. Quinn ◽  
...  
Keyword(s):  
United States ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
The United States ◽  
Carbon Stocks ◽  
Gas Emissions ◽  
Vegetation Carbon

Increasing ewe genetic fecundity improves whole-farm production and reduces greenhouse gas emissions intensities: 2. Economic performance

2014 ◽  
Vol 54 (9) ◽  
pp. 1248 ◽  
Author(s):  
C. K. M. Ho ◽  
T. Jackson ◽  
M. T. Harrison ◽  
R. J. Eckard
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Net Present Value ◽  
Stocking Rate ◽  
Present Value ◽  
Gas Emissions ◽  
High Fecundity ◽  
Farm Profit ◽  
Baseline System

Ewes with the fecundity Booroola (FecB) gene produce more lambs per ewe on average than ewes without the gene and offers a potential way to decrease greenhouse gas emissions (net and per unit animal product) without reducing lamb production if the lambs can be reared to market weights. Using a case study farm in south-west Victoria, a biophysical modelling study has previously showed that increased ewe fecundity from 1 to 1.5 lambs per ewe increased production by 27% and reduced net farm emissions by 21% for the same long-term stocking rate. In this study, a whole-farm economic analysis was used to investigate the relative merit of the same case study farm, with high-fecundity ewes, compared with a baseline system that represented a typical prime lamb enterprise in the region. An additional system comprising ewes with high fecundity at a lower stocking rate than the case study farm was also examined. The analysis was undertaken to establish which farm systems represented the most economically efficient use of all the resources that are employed over a run of years, and involved estimating the net present value of annual profits earned by the farm in each scenario, taking into account the total value of capital used. The potential revenue from the sale of carbon credits through the Carbon Farming Initiative was also investigated. After accounting for the additional costs involved, increasing ewe fecundity resulted in an increase in annual whole-farm profit compared with the baseline system, but risk, considered as the variability in farm profit, also increased. Decreasing stocking rate for the high-fecundity system reduced annual operating profit and net present value at a 5% discount rate, but had less risk compared with the higher stocking rate system. While both systems that incorporated high-fecundity ewes reduced greenhouse gas emissions, revenue from the sale of carbon credits was small compared with revenue from the sale of lambs, wool and culled ewes. Despite this, and assuming the required increases in fertility and weaning rates could be achieved consistently on-farm, ewes with high fecundity may offer producers the opportunity to increase production and profit as well as decrease greenhouse gas emissions.

The inter-relationships of grazing method and stocking rate in the efficiency of pasture utilization by dairy cattle

1963 ◽  
Vol 61 (2) ◽  
pp. 147-166 ◽  
Author(s):  
C. P. McMeekan ◽  
M. J. Walshe
Keyword(s):  
Dairy Cows ◽  
Large Scale ◽  
Age Distribution ◽  
Grazing Management ◽  
Vanishing Point ◽  
Stocking Rate ◽  
Rotational Grazing ◽  
Continuous Grazing ◽  
Grazing System ◽  
Stocking Rates

1. A large-scale grazing management study comparing rotational grazing and continuous grazing with dairy cows at two stocking rates over four complete production seasons is described.2. The four treatments were: (i) controlled grazing, light stocking rate; (ii) controlled grazing, heavy stocking rate; (iii) uncontrolled grazing, light stocking rate; (iv) uncontrolled grazing, heavy stocking rate.Each treatment involved 40 cows for a first 2-year phase and 42 cows for the following 2 years. Each herd had a normal age distribution pattern and seven 2-year-old first lactation heifers (17% of total herd) were introduced each year to maintain this pattern.3. Stocking rate was the more important factor affecting the efficiency of pasture utilization as measured by per acre output of milk and butterfat. In general, high stocking was associated with higher outputs per acre despite lower yields per animal.4. Grazing method was of less importance. In general, controlled rotational grazing was superior to uncontrolled continuous grazing, both per animal and per acre, but the average influence even of these extremes of management was only half that of stocking rate.5. Significant interactions between stocking rate and grazing method existed. Under continuous grazing a point was reached where production per acre declined to the vanishing point with increased stocking rate due to excessive depression of per cow yield: this point was not reached under rotational grazing at the same high stocking levels.6. The results suggest that optimum stocking rate under rotational grazing occurs at a level some 5–10% higher than under continuous grazing. A depression of 10–12% in per cow yield, compared with more lenient grazing, corresponds with optimum stocking level irrespective of the grazing system. This estimate is suggested as a guide line in applying the principles involved.

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