Grazing management for soil carbon in Australia: A review

The livestock industry accounts for a considerable proportion of agricultural greenhouse gas emissions, and in response, the Australian red meat industry has committed to an aspirational target of net-zero emissions by 2030. Increasing soil carbon storage in grazing lands has been identified as one method to help achieve this, while also potentially improving production and provision of other ecosystem services. This review examined the effects of grazing management on soil carbon and factors that drive soil carbon sequestration in Australia. A systematic literature search and meta-analysis was used to compare effects of stocking intensity (stocking rate or utilisation) and stocking method (i.e, continuous, rotational or seasonal grazing systems) on soil organic carbon, pasture herbage mass, plant growth and ground cover. Impacts on below ground biomass, soil nitrogen and soil structure are also discussed. Overall, no significant impact of stocking intensity or method on soil carbon sequestration in Australia was found, although lower stocking intensity and incorporating periods of rest into grazing systems (rotational grazing) had positive effects on herbage mass and ground cover compared with higher stocking intensity or continuous grazing. Minimal impact of grazing management on pasture growth rate and below-ground biomass has been reported in Australia. However, these factors improved with grazing intensity or rotational grazing in some circumstances. While there is a lack of evidence in Australia that grazing management directly increases soil carbon, this meta-analysis indicated that grazing management practices have potential to benefit the drivers of soil carbon sequestration by increasing above and below-ground plant production, maintaining a higher residual biomass, and promoting productive perennial pasture species. Specific recommendations for future research and management are provided in the paper.

Feedlot growth performance and carcass characteristics of steers backgrounded on buffel grass or buffel-Desmanthus mixed pastures

Feedlot performance and carcass characteristics of tropical beef steers backgrounded on buffel grass (Cenchrus ciliaris) only or buffel grass oversown with desmanthus (Desmanthus spp. ; 11.5% initial sward botanical composition) were evaluated. It was hypothesized that tropical beef cattle steers backgrounded on buffel grass only or buffel grass oversown with desmanthus with similar backgrounding growth performance will not differ in feedlot growth performance and carcass quality. Three hundred and twelve Bos indicus × Bos taurus tropical composite steers, 20-23 months old and weighing 413 ± 24 kg, previously backgrounded on buffel grass only or buffel-desmanthus mixed pastures for 147 days were finished on a concentrate diet in the feedlot for 110 days before slaughter. Buffel-desmanthus backgrounded steers had a slightly higher average daily gain (ADG; 1.8 kg/day) than the buffel grass backgrounded steers that had 1.7 kg/day ADG (p < 0.01). However, the final live weight and dry matter intake were not different (p ≥ 0.59). All the carcass traits measured were not different (p ≥ 0.18). Only 4% buffel grass and 8% buffel-desmanthus backgrounded steers fell short of the Meat Standards Australia (MSA) index, a level that is within the 4-9% reported for cattle produced in Queensland and slaughtered between July 2019 and June 2020. These findings indicate that desmanthus can be used to background beef cattle in northern Australia vertosol soil regions, where there is a paucity of adapted pasture legumes, with no negative impact on feedlot performance and carcass quality. The hypothesis that tropical beef cattle steers backgrounded on buffel grass only pastures or buffel grass oversown with desmanthus with similar backgrounding growth performance will have similar feedlot growth performance and carcass quality was accepted.

Direct and indirect nutritional factors that determine reproductive performance of heifer and primiparous cows

Pregnancy rate is a major determinant of population dynamics of wild ungulates and of productivity of livestock systems. Allocation of feeding resources, including stocking rates, prior to and during the breeding season is a crucial determinant of this vital rate. Thus, quantification of effects and interaction among multiple factors that affect pregnancy rate is essential for management and conservation of pasture-based systems. Pregnancy rate of 2982 heifers and primiparous cows was studied as a function of animal category, average daily gain during the breeding season, stocking rate, pasture type and body weight at the beginning of the breeding season. Data were obtained from 43 experiments conducted in commercial ranches and research stations in the Pampas region between 1976 and 2015. Stocking rate ranged from 200 to 464 kg live weight ha-1, which brackets values for most of the grazinglands in similar regions. Age at breeding was 14-36 months (24.6±7.5 months); initial breeding weights were 129-506 kg and 194-570 kg for heifers and primiparous cows. Pregnancy rate was modeled with an apriori set of explanatory variables where proximate variables (breed, body weight at start of breeding, weight gain during breeding and category) were included first and subsequently modeled as functions of other variables (pasture type, supplementation and stocking rate). This modeling approach allowed detection of direct and indirect effects (through nutrition and body weight) of factors that affect pregnancy rate. Bos taurus breeds (N = 1058) had higher pregnancy rate than B. Taurus x B. indicus crossbreed (N = 1924) females. Pregnancy rate of heifers and primiparous cows grazing in natural grasslands decreased with increasing stocking rate, but no effect of stocking rate was detected in cultivated and improved pastures. Pregnancy rate increased with increasing average daily gain during the breeding season. Use of cultivated or improved natural pastures promotes higher pregnancy rate, as well as allows an increase in stocking rate at the regional level. Body weight at the start of the breeding season is the primary determinant of pregnancy rates in heifer and primiparous cows.

Feral ungulate and macropod responses to resource scarcity and predation risk at savanna waterholes

Abstract

When exotic species are introduced to new environments, they often have a competitive advantage over native species. In northern Australia, pigs, cattle, and water buffalo have established widespread, feral populations. As ungulates have high water requirements, they typically congregate near waterpoints. We used a fencing experiment to test whether native macropods preferentially visited savanna waterholes where large ungulates were excluded. We also investigated whether water scarcity affected the visitation behaviour and temporal activity patterns of herbivores at waterholes and whether increasing prey aggregation at waterholes increased dingo presence. We found that macropods did not use fenced waterholes preferentially over unfenced ones. Cattle presence at waterholes increased as water became scarce, while macropod and pig presence peaked in the middle of the dry season. Macropod activity declined rapidly at the end of the dry season when cattle activity was greatest, suggesting that macropods may avoid waterholes in areas utilised by cattle when competition for resources is high. Macropods and all ungulates visited waterholes more during a drought year compared to an average rainfall year. Despite increasing prey activity, dingo presence at waterholes did not increase when water became scarce. However, dingo presence increased significantly on moonless nights. Our results suggest that competition between macropods and ungulates may intensify during periods of water scarcity. Climate change and pastoral intensification are likely to increase competition for resources between ungulates and macropods in Australian savannas, potentially threatening macropod populations across the landscape in the future.

Significance statement

In northern Australia, feral populations of pigs, cattle, and water buffalo compete with native wildlife for access to water sources. As interspecific competition favours species with a size advantage, we tested whether kangaroos and wallabies (macropods) preferentially use waterholes where large ungulates (cattle and buffalo) were excluded. We found that macropods avoided waterholes when cattle presence was high but did not preferentially use waterholes where livestock were excluded. When water scarcity peaked during a drought, macropods and all three feral ungulate species visited waterholes more. However, increased prey presence at waterholes during the drought did not correspond with increased predator (dingo) presence. Our study advances the understanding of behavioural interactions between invasive and native species at important shared resources, and how this may affect wildlife conservation in an increasingly unpredictable environment.

Soil greenhouse gas emissions and grazing management in northern temperate grasslands

Adaptive multi-paddock (AMP) grazing, a grazing system in which individual paddocks are grazed for a short duration at a high stock density and followed by a long rest period, is claimed to be an effective tool to sustainably manage and improve grasslands and enhance their ecosystem services. However, whether AMP grazing is superior to conventional grazing (n-AMP) in reducing soil greenhouse gas (GHG) emissions is unclear. Here, we measured CO₂, CH₄, and N₂O fluxes between August 2017 and August 2019 in 12 pairs of AMP vs. n-AMP ranches distributed across an agro-climatic gradient in Alberta, Canada. We found that field GHG fluxes did not differ between AMP and n-AMP grazing systems, but instead were regulated by specific management attributes, environmental conditions, and soil properties, including cattle stocking rate, cultivation history, soil moisture content, and soil bulk density. Specifically, we found that seasonal mean CO₂ emissions increased with increasing cattle stocking rates, while CH₄ uptake was lower in grasslands with a history of cultivation. Seasonal mean CO₂ emissions increased while CH₄ uptake decreased with increasing soil moisture content. In addition, CH₄ uptake decreased with increasing soil bulk density. Observed N₂O emissions were poorly predicted by the management, environmental conditions, and soil properties investigated in our study. We conclude that AMP grazing does not have an advantage over n-AMP grazing in reducing GHG fluxes from grasslands. Future efforts to develop optimal management strategies (e.g., the use of sustainable stocking rates and avoided cultivation) that reduce GHG emissions should also consider the environmental conditions and soil properties unique to every grassland ecosystem.

Growth Performance and Plasma Metabolites of Grazing Beef Cattle Backgrounded on Buffel or Buffel-Desmanthus Mixed Pastures

Simple Summary

Pasture quality and digestibility decline during the dry season resulting in weight loss or marginal weight gains of grazing cattle in the seasonally dry subtropics of northern Australia. Oversowing grass with legume pastures has shown potential to improve pasture quality and cattle weight gain. This study aimed to evaluate the change in steers’ weight gain and plasma metabolites in response to grazing buffel grass pastures oversown with Desmanthus spp. (Desmanthus), a tropical legume adapted to cracking clay soils, compared to buffel-grass-only pastures. Results showed that Desmanthus at a low botanical composition had no effect on weight gain and plasma metabolites, although pasture yield and stocking rate were 443 kg/ha and 9.5% higher, respectively. Since the productivity of grazing systems depends on cattle annual weight gain and stocking rate, the practical implication of this study is that Desmanthus may improve the profitability of beef production in the dry tropics of northern Australia by improving pasture-carrying capacity with no adverse effect on cattle health status and growth performance.

Abstract

Dietary crude protein and dry matter digestibility are among the major factors limiting feed intake and weight gain of cattle grazing native and improved pastures in the subtropics of Northern Australia during the dry season. Incorporating a suitable legume into grasses improves pasture quality and cattle weight gain, but only a limited number of legume pastures can establish and persist in cracking clay soils. This study aimed to evaluate the effect of Desmanthus inclusion in buffel grass (Cenchrus ciliaris) pastures on the plasma metabolite profile and growth performance of grazing beef cattle during the dry season. We hypothesised that backgrounding steers on buffel grass-Desmanthus mixed pastures would elicit significant changes in plasma glucose, bilirubin, creatinine, non-esterified fatty acids and β-hydroxybutyrate, resulting in higher liveweight gains than in steers on buffel grass only pastures. Four hundred tropical composite steers were assigned to buffel grass only (n = 200) or buffel grass oversown with Desmanthus (11.5% initial sward dry matter) pastures (n = 200) and grazed for 147 days during the dry season. Desmanthus accounted for 6.2% sward dry matter at the end of grazing period. Plasma metabolites results showed that changes in β-hydroxybutyrate, creatinine, bilirubin, glucose and non-esterified fatty acids were within the expected normal range for all the steers, indicating that with or without Desmanthus inclusion in the diet of grazing steers, animal health status was not compromised. It was also evident that Desmanthus inclusion in buffel grass pastures had no impact on the plasma metabolite profile, liveweight and daily weight gain of grazing steers. Therefore, our tested hypothesis of higher changes in plasma metabolite profile and higher liveweight gains due to backgrounding on low-level buffel grass-Desmanthus mixed pastures does not hold.

Opportunities to Apply Precision Livestock Management on Rangelands

Precision livestock management has become a new field of study as the result of recent advancements in real-time global positioning system (GPS) tracking, accelerometer and other sensor technologies. Real-time tracking and accelerometer monitoring has the potential to remotely detect livestock disease, animal well-being and grazing distribution issues and notify ranchers and graziers so that they can respond as soon as possible. On-going research has shown that accelerometers can remotely monitor livestock behavior and detect activity changes that are associated with disease and parturition. GPS tracking can also detect parturition by monitoring the distance between a ewe and the remainder of the flock. Tracking also has the potential to detect water system failures. Combinations of GPS tracking and accelerometer monitoring may be more accurate than either device used by itself. Real-time GPS tracking can identify when livestock congregate in environmental sensitive areas which may allow managers the chance to respond before resource degradation occurs. Identification of genetic markers associated with terrain use, decreased cost of GPS tracking and novel tracking data processing should facilitate development of tools needed for genetic selection for cattle grazing distribution. Precision livestock management has potential to improve welfare of livestock grazing rangelands and forested lands, reduce labor costs and improve ranch profitability and improve the condition and sustainability of riparian areas and other environmental sensitive areas on grazing lands around the world.

Automatic Supplement Weighing Units for Monitoring the Time of Accessing Mineral Block Supplements by Rangeland Cattle in Northern Queensland, Australia

Time spent feeding by grazing cattle is an important predictor of intake and feed efficiency. This study examined the use of automatic supplement weighing (ASW) units for monitoring voluntary access of breeding cows (n = 430) to mineral block supplements in an extensive rangeland of northern Australia. The ASW units (n = 10) were located within each of experimental sites (5 units per site; Bore and Eldons). Over the 62 days of data collection, 85%, 13%, and 2% of cows spent <600, 600–1200, >1200 min accessing supplements, respectively, with between-animal variation (CV) of 107%. A total of 133 cows visited both sites while 142 and 155 cows visited only Bore and Eldons, respectively. Most visits (80–90%) were recorded during the day (800–1700 h), 7–17% during the night (1800–2300 h), and 3% during the dawn (0–700 h). Time spent accessing supplements differed between ASW units across the two sites (p < 0.001) and varied according to the day of visits (p < 0.001). There was a significant relationship between time spent at the ASW units and supplement intake on a herd basis (p < 0.001; R2adj = 0.70). The results showed that the ASW units were capable of monitoring access to mineral block supplements that may reflect the supplement intake of rangeland cattle.

Sustainability of beef production from brigalow lands after cultivation and mining. 2. Acland Grazing Trial pasture and cattle performance

Context Agricultural land used for open-cut coal mining in Queensland is required by law to be returned to a safe, stable and self-sustaining state for agriculture. Aims The aim of this research was to identify whether rehabilitated pastures on post-mine soil at a site near Acland could viably support cattle production. Methods Five years of field data from Botanal pasture assessments, pasture quality, cattle liveweights and faecal observations, plus supplementary cattle liver data, were used to compare pasture and cattle performance from mined and unmined previously cultivated brigalow land. Subtropical pasture species were sown in 2007 (Rehab1, 22 ha), 2010 (Rehab 2, 32 ha) and 2012 (Rehab3, 22 ha) in three rehabilitated paddocks and in 2012 in an unmined (Control, 21 ha) paddock. The paddocks were grazed for 117–190 days of each year by Angus cattle. Key results Mean total standing dry matter in grazed pasture over the five trial years was consistently higher in Rehab 2 (5656 kg/ha) than in the other paddocks. Rehab 1 (3965 kg/ha) and Rehab 3 (3609 kg/ha) performed at an intermediate level and the Control paddock produced less pasture (2871 kg/ha). Grass leaf crude protein was higher in Rehab 2 than in the other paddocks and declined significantly (P &lt; 0.001) across all paddocks as pasture aged. Pasture species remained perennial, palatable and productive in all paddocks; however, pasture yield, quality and composition trends over time suggested that pasture rundown occurred across all paddocks. The mean liveweight gain (LWG) per head when grazing the trial paddocks (trial LWG) was higher (P &lt; 0.05) in the Rehab 2 cohort than the other paddock cohorts in Years 3 and 5, and trial LWG in the Control cohort was not significantly (P &gt; 0.05) different from one or more of the rehabilitated paddock cohorts each year. Cattle production per hectare during the trial grazing periods was also consistently highest in Rehab 2 (5-year mean trial LWG 131 kg/ha) compared with the other paddocks (67–80 kg/ha). Conclusion The rehabilitated pastures in use by the mine were considered at least as productive as the surrounding unmined brigalow landscape. Implications The Acland rehabilitation process was considered successful in establishing pastures that were able to viably support cattle production.

Sustainability of beef production from brigalow lands after cultivation and mining. 1. Sown pasture growth and carrying capacity

Context New Acland coal mine in south-eastern Queensland is seeking to rehabilitate mined land to pastures that are safe, stable and sustainable for beef production. Little is known of the productivity and sustainability of grazing previously mined land in the Darling Downs study region. Additionally, information is required to specify management guidelines for sustainable grazing of regional land types retired from cultivation. Aims Identify pasture growth characteristics, rainfall use efficiencies and long-term carrying capacities of subtropical sown pastures established on lands rehabilitated after open-cut coal mining in comparison to sown pastures established on un-mined but previously cultivated lands. Methods Pasture growth and quality (% nitrogen) were observed using the Swiftsynd methodology in ungrazed exclosures with three sites on rehabilitated lands of the Acland Grazing Trial over a 5-year period (2014–2018), and 13 sites on unmined lands over periods of 2–5 years providing data for modelling pasture growth. Key results Peak pasture yield (TSDM for autumn harvests) averaged for 2017 and 2018 was greater (P &lt; 0.1) on rehabilitated sites than unmined Poplar Box land type sites (5957 and 2233 kg/ha respectively) but similar to Brigalow Uplands and Mountain Coolibah land type sites (3946 and 3413 kg/ha respectively). Pasture rundown was evident, with pasture N uptake decreasing over 5 years at some sites. Soil mineral N supply (potentially mineralisable N and mineral N) in spring was a useful indicator of N uptake over the following growing season. Simulations using the GRASP pasture growth model for the grazing trial period predicted rainfall use efficiencies of 12.0, 7.0, 9.1 and 4.8 kg/ha.mm rainfall for rehabilitated sites and unmined sites on Brigalow Uplands, Mountain Coolibah and Poplar Box land types respectively. Long-term carrying capacities based on estimates of long-term median pasture growth and 30% utilisation were 4.39, 3.58 and 5.92 ha/adult equivalent respectively for the unmined land types, and 2.45 ha/adult equivalent for the rehabilitated lands. Conclusions Rehabilitated land can be as productive as unmined but previously cultivated land. Implications Grazing management plans for sustainable management of mined and unmined lands can be developed using data from the present study. The plans will assist with the transition of rehabilitated lands to commercial agriculture.

Prospects for sustainable use of the pastoral areas of Australia’s southern rangelands: a synthesis

There is growing recognition of the need to achieve land use across the southern Australian rangelands that accommodates changing societal preferences and ensures the capacity of future generations to satisfy their own preferences. This paper considers the prospects for sustainable use of the pastoral lands based either on continued grazing or emerging, alternative land uses. After an overview of the southern rangelands environment, the status of the pastoral industry, its environmental impacts, and key issues for pastoral management, we propose four principles and 19 associated guidelines for sustainable pastoralism. Although some continued withdrawal of land from pastoralism is anticipated, we expect that pastoralism will continue throughout much of the region currently grazed, particularly in the higher rainfall environments in the east. Within these areas, sustainable pastoral land use should be achievable by the application of four broad management principles, as follows: (1) manage grazing within a risk management framework based on the concept of tactical grazing, (2) develop infrastructure to allow best management of both domestic and non-domestic grazing pressure, (3) incorporate management of invasive native scrub, where required, into overall, ongoing property management and (4) manage grazing to enhance biodiversity conservation at landscape scale. Application of these principles and guidelines will require the development of appropriate policy settings, particularly in relation to kangaroo management, climate change, and natural resource governance, together with innovative approaches to research, development and extension. Policy development will also be required if the new industry of carbon sequestration is to deliver socio-ecological benefits without perverse outcomes. Other emerging industries based on renewable energy or ecosystem services appear to have considerable potential, with little risk of adverse ecological consequences.

An online system for calculating and delivering long-term carrying capacity information for Queensland grazing properties. Part 2: modelling and outputs

A combination of field data and models have been used to estimate long-term carrying capacity (LTCC) of domestic livestock in Queensland grazing lands. These methods have been synthesised and coupled with recent developments in science and information technology to provide a fully-automated approach of modelling LTCC through the FORAGE online system. In this study, the GRASP model was used to simulate pasture growth with parameter sets and safe pasture utilisation rates defined for 225 land types across Queensland. Distance to water points was used to assess the accessibility of pastures to livestock. Spatial analysis classified the property into unique areas based on paddock, land type and distance to water points, which estimated pasture growth, pasture utilisation and accessibility at a sub-paddock scale. Thirteen foliage projective cover (FPC) classes were used in modelling the pasture system to deal with the non-linear relationship between tree and grass interactions. As ‘proof of concept’, remotely-sensed individual-date green ground cover data were used to optimise the GRASP model parameters to improve the model performance, and a Monte Carlo analysis provided uncertainty estimates for model outcomes. The framework provides an efficient and standardised method for estimating LTCC. To test the system, LTCCs from 43 ‘benchmark’ properties were compared with simulated LTCCs, and 65% of the modelled LTCCs were within ± 25% of the benchmark LTCCs. Due to uncertainties in model inputs at the property scale and in model simulation, the modelled LTCC should be used as a starting point for further refinement of actual property LTCC.

GrazingFutures: learnings from a contemporary collaborative extension program in rangeland communities of western Queensland, Australia

Producer reliance on drought subsidies instead of proactive planning and timely destocking in low rainfall years has prompted Queensland government investment in promoting business and drought resilience. GrazingFutures (AU$6 million budget, 2016–2022) is an extension project focussed on enhancing business management skills of extensive livestock producers in western Queensland, Australia. The region’s rangelands are in productivity decline, span 1 million km2 and are managed by graziers operating more than 2400 livestock businesses (beef, sheep and goats). The Queensland Department of Agriculture and Fisheries delivers GrazingFutures as a component of the Drought and Climate Adaptation Program, in partnership with regional natural resource management groups and other public and private organisations. Project delivery emphasised upskilling multi-agency staff and livestock producers to promote practice change within three whole of business themes: (1) grazing land management; (2) animal production; and (3) people-business. Three independent surveys (2018, 2019, 2020) indicated positive practice change was occurring in grazing businesses as a consequence of the project. Graziers instigated management changes even under major environmental challenges including extended drought (2013–2020), an extreme flood event in 2019 and the COVID-19 pandemic in 2020. This paper details the rationale, progress against the objectives, challenges and future direction of the GrazingFutures extension project.

Stocking rate affects plant community structure and reproductive strategies of a desirable and an undesirable grass species in an alpine steppe, Qilian Mountains, China

The effects of grazing on species reproduction is a fundamental issue of grassland management. We investigated plant density and dry weight changes at community and species levels, and the reproductive strategies of the dominant desirable Stipa purpurea and the undesirable Achnatherum inebrians grass species in response to stocking rate in an alpine steppe with a 10-year grazing history. Results showed complex patterns of plant community and reproductive strategy. Overall plant density increased with increasing stocking rate and dry weight was significantly higher at light and high stocking rates. Plant density and dry weight of A. inebrians peaked at moderate stocking rates. Higher stocking rate had little impact on S. purpurea density but significantly reduced its dry weight. Both species displayed linearly increasing/decreasing or unimodal/bimodal reproductive effort in response to increased stocking rate. The discrepancies in plant reproductive characteristics between S. purpurea and A. inebrians indicated that: (1) light and moderate grazing may promote an adaption strategy of reproduction by desirable species, which may then contribute to their maintenance in grasslands, and (2) undesirable species presence did not lead to the replacement of desirable species in the grasslands. Therefore, light and moderate stocking rates are recommended to maintain the grasslands and to increase the reproductive outputs of desirable species.

Calf loss in northern Australia: a systematic review

Calf mortality is a key issue for the north Australian beef industry; however, the sector faces several challenges that preclude the detection and reduction of calf mortality rates. A systematic literature review methodology was employed to explore scientific literature describing the scope of calf loss in northern Australia. Online databases were used to locate articles reporting on beef calf mortality rates within the north Australian region. Articles (n=43) consisting of 668 beef cattle cohorts were retrieved that reported calf mortality between 1936 and 2014. Of these, 13 different observation periods were identified. Most cohorts (n=201) examined mortality between the pregnancy to weaning period, whereas only 20 cohorts in four studies were located that investigated calf mortality in the perinatal and postnatal periods. A broad seasonal and regional influence was identified, however, the dilution of the datasets due to the high number of timeline variations, prevented robust statistical analysis and the further examination of influential factors, such as breed. The results of the systematic literature review indicate that the resolution of the data available does not allow for producers or researchers to accurately target the occurrence or cause of calf mortality. Experimental protocols for future research pertaining to reproductive efficiency and calf loss in northern Australia should be standardised. Consistency in reporting factors and periods must first occur for robust statistical analyses to be achieved.

Can extension programs improve grazing management in rangelands: a case study in Australia

A key challenge in reducing sediment moving from grazing lands into the Great Barrier Reef in Australia is to encourage beef cattle producers to improve management practices. Excessive grazing pressures cause land degradation, leading to both increased sediment runoff and lower future profits. Although higher grazing rates may be possible (and profitable) in better seasons, slow rates of adjustment to poorer seasons can lead to overgrazing and negative impacts on land condition. For policymakers the challenge is to find mechanisms that encourage or signal producers to be more precise in their management and avoid overstocking. Some of the most common options include extension programs, grant programs that use financial incentives, and regulation. In this paper we outline a conceptual framework that shows why extension may be a more powerful driver of management change than incentive programs, and then test this through an evaluation of a case study program conducted with beef cattle producers in catchments of the Great Barrier Reef, Australia. The pathway involving landholders to implement management change was through improved efficiency and productivity, as these are the issues that drive ongoing participation in broader environmental programs. The results present multiple lines of evidence to infer positive outcomes of an extension program in terms of changed management practices, which may be expected to generate improved productivity and better water quality outcomes. These can be grouped into three key areas. First, outcomes show positive improvement relative to the Grazing Water Quality Risk framework for the Great Barrier Reef catchments, which is designed to assess the links between land management and water quality. This indicates that resource condition is likely to improve and sediment emissions should be reduced over time. A second outcome is increased landholder engagement and improved understanding of their business and engagement in future programs, which should underpin ongoing adoption. A third outcome is improved management of risk and developing the skills to do this through data collection and monitoring, which should improve management responses in drought years.

Challenges, solutions and research priorities for sustainable rangelands

Australia’s rangeland communities, industries, and environment are under increasing pressures from anthropogenic activities and global changes more broadly. We conducted a horizon scan to identify and prioritise key challenges facing Australian rangelands and their communities, and outline possible avenues to address these challenges, with a particular focus on research priorities. We surveyed participants of the Australian Rangeland Society 20th Biennial Conference, held in Canberra in September 2019, before the conference and in interactive workshops during the conference, in order to identify key challenges, potential solutions, and research priorities. The feedback was broadly grouped into six themes associated with supporting local communities, managing natural capital, climate variability and change, traditional knowledge, governance, and research and development. Each theme had several sub-themes and potential solutions to ensure positive, long-term outcomes for the rangelands. The survey responses made it clear that supporting ‘resilient and sustainable rangelands that provide cultural, societal, environmental and economic outcomes simultaneously’ is of great value to stakeholders. The synthesis of survey responses combined with expert knowledge highlighted that sustaining local communities in the long term will require that the inherent social, cultural and natural capital of rangelands are managed sustainably, particularly in light of current and projected variability in climate. Establishment of guidelines and approaches to address these challenges will benefit from: (i) an increased recognition of the value and contributions of traditional knowledge and practices; (ii) development of better governance that is guided by and benefits local stakeholders; and (iii) more funding to conduct and implement strong research and development activities, with research focused on addressing critical knowledge gaps as identified by the local stakeholders. This requires strong governance with legislation and policies that work for the rangelands. We provide a framework that indicates the key knowledge gaps and how innovations may be implemented and scaled out, up and deep to achieve the resilience of Australia’s rangelands. The same principles could be adapted to address challenges in rangelands on other continents, with similar beneficial outcomes.

Effects of cutting height managements on yield and composition of different annual pastures

ABSTRACT This study aimed to evaluate the effects of different pre-cutting and residual heights of Pearl millet, Sudangrass, and Sorghum pastures on yield, morphological and chemical composition. The experimental design was the randomized blocks, with four experimental units per treatment. It was evaluated three species of forage: 1) Pearl millet (MIL; Pennisetum americanum); 2) Sudangrass (SUD; Sorghum sudanense); and 3) Sorghum (SOR; Sorghum bicolor); and two cutting managements: I) 50:20 - cutting height at 50 cm and 20 cm residual height; and II) 85:10 - cutting height at 85 cm and 10 cm residual height. Managements of cutting height affected neither forage yield per cut nor total forage yield. Sudangrass had less cuts than MIL and SOR when submitted to the 50:20 management. The 85:10 management increased stem proportion and leaf to stem ratio, and reduced leaf proportion in comparison with the 50:20 management. The 50:20 management reduced forage contents of fiber and organic matter, and increased forage contents of crude protein and total digestible nutrient. Sorghum exhibited greater nutritive value due to increased leaf proportion. The 50:20 management increased number of cuts and improved nutritive value of forages, regardless of species evaluated in this study.

Riparian health improves with managerial effort to implement livestock distribution practices

Optimising the spatial distribution of free-ranging livestock is a significant challenge in expansive, grazed landscapes across the globe. Grazing managers use practices such as herding (i.e. droving), strategic placement of off-stream livestock drinking water and nutritional supplements, and strategic fencing in attempts to distribute livestock away from sensitive streams and riparian areas. We conducted a cross-sectional survey of 46 cattle-grazed riparian areas and associated stream reaches embedded in rugged range landscapes to examine relationships between implementation of these management practices, stocking rate, and riparian health. We determined in-stream benthic invertebrate assemblages at each site to serve as an integrative metric of riparian health. We also collected information from the grazing manager on stocking rate and implementation of livestock distribution practices at each site over the decade before this study. Off-stream livestock drinking-water sources were implemented at just two sites (4.3%), indicating that this was not a common distribution practice in these remote management units. We found no significant relationship of riparian health (i.e. invertebrate richness metrics) with stocking rate (P ≥ 0.45 in all cases), or with the simple implementation (yes/no) of off-stream nutritional supplements, fence maintenance, and livestock herding (P ≥ 0.22 in all cases). However, we did find significant positive relationships between riparian health and managerial effort (person-days spent per year for each individual practice) to implement off-stream nutritional supplements and fence maintenance (P ≤ 0.017 in all cases). Livestock herding effort had an apparent positive association with riparian health (P ≥ 0.2 in all cases). Results highlight that site-specific variation in managerial effort accounts for some of the observed variation in practice effectiveness, and that appropriate managerial investments in grazing distributional practices can improve riparian conditions.

Grazing pressure and tree competition affect cattle performance and native pastures in Eucalypt woodlands of Queensland, north-eastern Australia

Context Well managed grazing pressure will optimise animal and pasture production, and preserve the soil to maintain a viable beef business on native pastures in eucalypt woodlands. Aims A cattle grazing experiment was established to measure animal and pasture performance under management practices used in the Aristida/Bothriochloa native pastures in central Queensland. Methods Performance of Brahman-cross steers and pastures were measured in an experiment with three grazing pressures by two tree densities in a Eucalyptus populnea woodland in north-eastern Australia over 8 years in paddocks of 4–18 ha. Key results At low grazing pressure with trees killed by herbicide (‘cleared’), stocking rate increased 35% as pasture composition and biomass improved over 8 years. At low grazing pressure where treed, stocking rate remained constant, however, at high grazing pressure where treed, it was reduced after 4 years. The annual liveweight gain increased from 0.37 to 0.45 to 0.51 kg/head.day as grazing pressure was reduced from high to medium to low grazing pressure respectively, and across grazing pressures it decreased from 0.49 where cleared to 0.39 kg/head.day where treed. Liveweight gain per hectare increased under low grazing pressure and declined at medium and high pressures. Body condition scores responded positively to lower grazing pressure and a lack of tree competition to pastures. This treatment combination also produced higher animal sale values. Pasture biomass, basal area and ground cover were all affected negatively by increasing grazing pressure. Conclusions Grazing 25% of autumn pasture improved dry matter production, species composition and land condition, and increased steer growth rates, body condition and their market value. This grazing pressure produced an increasing trend in stocking rates relative to the decline at higher grazing pressures. Higher liveweight gain/ha was produced initially at high grazing pressure (75% utilisation), however, after 4 years animal condition and pastures deteriorated, requiring a reduction in stocking rate to maintain the condition of both the remaining animals and the pastures. Managing tree competition to pastures is necessary to maintain the higher animal production potential. Implications This objective information demonstrates the benefits for cattle, pastures and long-term economic outcomes of managing for conservative grazing pressure and controlling tree competition to pasture in this woodland. Applying these findings can improve beef business outcomes and provide management groups with objective educational resources.

Diet and Genetics Influence Beef Cattle Performance and Meat Quality Characteristics

A comprehensive review of the impact of tropical pasture grazing, nutritional supplementation during feedlot finishing and fat metabolism-related genes on beef cattle performance and meat-eating traits is presented. Grazing beef cattle on low quality tropical forages with less than 5.6% crude protein, 10% soluble starches and 55% digestibility experience liveweight loss. However, backgrounding beef cattle on high quality leguminous forages and feedlot finishing on high-energy diets increase meat flavour, tenderness and juiciness due to improved intramuscular fat deposition and enhanced mono- and polyunsaturated fatty acids. This paper also reviews the roles of stearoyl-CoA desaturase, fatty acid binding protein 4 and fatty acid synthase genes and correlations with meat traits. The review argues that backgrounding of beef cattle on Desmanthus, an environmentally well-adapted and vigorous tropical legume that can persistently survive under harsh tropical and subtropical conditions, has the potential to improve animal performance. It also identifies existing knowledge gaps and research opportunities in nutrition-genetics interactions aimed at a greater understanding of grazing nutrition, feedlot finishing performance, and carcass traits of northern Australian tropical beef cattle to enable red meat industry players to work on marbling, juiciness, tenderness and overall meat-eating characteristics.

Linking Prohibited Grazing Policy to Farmers’ Subjective Well-Being: A Case Study in Yanchi County, China

Since the launch of a prohibited grazing policy (PGP) in 2002, the ecological environment in North China has improved markedly. The aims of PGP are to improve the ecological environment without reducing farmers’ well-being in rural areas. Hence, after the implementation of the policy for more than 16 years, the effect of this policy on farmers’ subjective well-being (SWB) has become a question that needs to be studied. In this paper, the survey data in Yanchi County was used to explore the relationship between the perception of the policy and farmers’ SWB using structural equation modelling (SEM). The results showed that there was a full mediation effect in the relationship between the perception of the PGP and farmers’ SWB through economic status, neuroticism, and extraversion. However, the mediation effect through the perception of the ecological environment was not significant. These findings suggest that it is important to continue to implement this policy.

Overcoming drought vulnerability in rangeland communities: lessons from central-western Queensland

Drought and climate variability are an increasing global problem, especially in rangelands which may lack robust socioeconomic systems. Vulnerability is being applied in drought and climate change policy theory, by describing exposure and sensitivity factors, and adaptive capacity. In this paper we examine these vulnerability factors in central-western Queensland (CWQ), Australia, as a case study to test the idea that vulnerability and resilience must be considered together to build strong and enduring rangeland communities. The region’s economy and employment are strongly coupled with rain-fed agriculture. Drought is a key risk to CWQ communities, with 13 extended droughts recorded since 1898. The region has been officially in drought since 2013 following well below-average rainfall, and remains in drought in 2019. The impact has led to reductions in town business turnover of 30–60%, loss of livelihoods and outmigration of 20%. Outmigration corresponds to the recent periods of drought. Social networks have been destabilised, highlighting that the cascading impacts of drought are complex, interrelated and affect the whole community. Regionally led responses have helped to re-build social cohesion, provide mental health support and stimulate economic activity and employment. These actions provide examples of a systemic, whole-of-community approach, that (1) captures place-based advantages; (2) enhances internal and external socioeconomic networks; (3) engages meaningfully through multi-level consultation; and (4) seeks to build sustained financial investment. A common theme of success is partnerships which provide external support for regionally-identified issues and solutions. There has been considerable investment of public, philanthropic and private funds in drought relief and infrastructure programs. This has occurred through a whole-of-community approach, and suggests a move towards policy which aims to build long-term regional resilience. CWQ has linked vulnerability and resilience by asking of both internally and externally led drought relief ‘will this action build or undermine community resilience’. This approach could also be applied to the design of drought policies and responses in other rangeland regions.

Should I stay or should I go? Indirect effects of livestock on bird nest-site selection in arid environments

Introduced livestock may indirectly affect bird species by decreasing vegetation structure and affecting the selection of nesting sites. This is especially true for birds that use shrubs as the raw material for nest construction or for nest placement. Nesting in inadequate supporting structures or the use of inadequate raw material for nest building may increase nest vulnerability (e.g. increasing structure weakness, falling and nest exposure to predation). Accordingly, bird species show a great variation in the selectivity of nesting sites and the raw material they use. Furnariidae family members exhibit an extraordinary diversity in nest placement and structure, which allows them to survive in different arid environments. I report here on a study of nest site selection of two common furnariid species, Leptasthenura aegithaloides and Pseudoseisura gutturalis, across a grazing gradient composed by nine independent paddocks within the same arid habitat. These species use large closed-nests (&gt;40 cm long) built with thorny branches, placed on spiny shrubs. I measured nest abundance and supporting plants characteristics, vegetation structure, browsing intensity and compared the plants selected by the birds with the surrounding vegetation. These bird species used only few plant species for nest building and location. Livestock significantly reduced vegetation cover of the species used to build and place the nests, affecting nest site selection and reducing nest abundance. As livestock density increased, both species selected aggregated plants and the tallest plants for nesting, which may increase nest exposure. Therefore, livestock may indirectly affect nest-site selection of birds ultimately affecting their nesting ecology. This work illustrates how domestic livestock, through decreasing plant cover, may affect native biota with consequences on key species within an ecosystem.

Optimising cattle grazing distribution on rangeland: a systematic review and network analysis

Optimising beef cattle (Bos taurus and Bos indicus) distribution, both spatially and temporally, is one of the most significant challenges associated with managing extensive grazed rangelands. Landscape variability and behavioural patterns of cattle may lead to non-uniform and inefficient forage utilisation, damage to critical habitats, and water quality impairment. In order to overcome these distribution challenges, a large suite of tools have been developed and researched to optimise grazing patterns. The objectives of this synthesis paper are 2-fold: (i) to survey and categorise distribution tools; and (ii) to analyse the connectivity of existing research across academic disciplines to identify and isolate knowledge gaps. A systematic literature review revealed specific types of tools and strategies to improve cattle distribution, which were categorised as either ‘animal’ or ‘environmental manipulations’. Animal manipulations utilise aspects of individual behaviour and herd dynamics to alter grazing patterns, whereas environmental manipulations involve transforming aspects of the animal’s surroundings to overcome challenges associated with inefficient distribution. This review reveals that strategies are overwhelmingly studied in isolation, and that there is potential to increase efficacy by integrating multiple strategies to achieve a desired outcome. Motivated by these findings, an author collaboration network analysis was conducted to investigate connectivity within and among author fields of expertise to understand why more integrated management strategies are not currently studied. Authors were classified into five fields of research: animal behaviour science, animal production science, biophysical rangeland science, economics, and other. The network analysis revealed that communities of authors contributing to papers on enhancing cattle distribution are disjointed. These results suggest that in order to fulfil knowledge gaps about the efficacy and cost of management strategies, there needs to be interdisciplinary engagement with particular attention to strategies that integrate animal and environmental manipulations to enhance cattle grazing distribution on extensively grazed landscapes.

Effect of GPS sample interval and paddock size on estimates of distance travelled by grazing cattle in rangeland, Australia

The distance travelled by an animal, when determined by using global positioning system (GPS) coordinates, is usually calculated assuming linear movement between the recorded coordinates. When using long sample intervals, some movement may be overlooked if linear movement between each recorded position is assumed, because of the tendency of livestock to move in meandering paths. Conversely, overestimation of the true distance travelled could occur with short sample intervals because of the accumulation of extra distance due to GPS measurement error. Data from 10 experiments were used to explore the effect of paddock size and GPS sampling rate on the calculation of distance travelled by free-ranging cattle. Shortening the sample interval increased apparent distance travelled according to a power function. As paddock size increased from <1 ha to >450 ha, distance travelled increased according to a logarithmic relationship; however, other variation between experiments could have affected these results. It was concluded that selecting an optimal GPS sampling interval is critical to accurately determining the distance travelled by free-ranging cattle.

Spring fire effects on two Aristida/Bothriochloa native pastures in central Queensland, Australia

Controlled burns are commonly used to suppress woody plant regrowth and to remove accumulated unpalatable pasture from rangelands and occasionally to alter pasture composition in native pastures in central Queensland, Australia. Outcomes can be somewhat unpredictable and short-term, and reliable evidence is needed to confirm the likely long-term efficacy of such fires. We imposed a regime of repeated spring burns on native Aristida/Bothriochloa pastures growing in two contrasting eucalypt woodlands of central Queensland to determine the effects on pasture composition, ground cover, landscape stability and woody plant recruitment, all in the absence of grazing. The sites selected were a silver-leaved ironbark (Eucalyptus melanophloia F.Muell.) woodland and a poplar box (E. populnea F.Muell.) woodland. Weather conditions precluded spring burns in 3 years out of 7 at the silver-leaved ironbark site and in 2 years out of 8 at the poplar box site. The burn intensity was variable, and frequent fires produced a marked change in abundance of only a few pasture species. Depending on the site, fires significantly increased the frequency of Enneapogon spp., Bothriochloa bladhii (Retz.) S.T.Blake and Dichanthium sericeum (R.Br.) A.Camus and reduced the frequency of some minor components such as Cymbopogon spp., Panicum effusum R.Br., Cenchrus ciliaris L. and, ephemerally, that of some forbs. Contrary to expectation, only Aristida calycina R.Br. declined in abundance among the many Aristida species present, and the abundance of Heteropogon contortus (L.) P.Beauv. ex Roem. & Schult. barely increased under regular spring fires. The total germinable seeds of herbaceous species in the soil each spring was significantly reduced by burning in the previous spring. Repeated spring fires rarely reinforced any initial change induced by burning, and slightly lowered average ground cover as well as various indices of landscape stability and ecosystem functionality. Changes produced were not always consistent across the two communities. Though prescribed burning is often important for maintaining grazing productivity and landscape values, very regular use is not recommended.

Influence of climate variability and stocking strategies on greenhouse gas emissions (GHGE), production and profit of a northern Queensland beef cattle herd

Previous studies of greenhouse gas emissions (GHGE) from beef production systems in northern Australia have been based on models of ‘steady-state’ herd structures that do not take into account the considerable inter-annual variation in liveweight gain, reproduction and mortality rates that occurs due to seasonal conditions. Nor do they consider the implications of flexible stocking strategies designed to adapt these production systems to the highly variable climate. The aim of the present study was to quantify the variation in total GHGE (t CO2e) and GHGE intensity (t CO2e/t liveweight sold) for the beef industry in northern Australia when variability in these factors was considered. A combined GRASP–Enterprise modelling platform was used to simulate a breeding–finishing beef cattle property in the Burdekin River region of northern Queensland, using historical climate data from 1982–2011. GHGE was calculated using the method of Australian National Greenhouse Gas Inventory. Five different stocking-rate strategies were simulated with fixed stocking strategies at moderate and high rates, and three flexible stocking strategies where the stocking rate was adjusted annually by up to 5%, 10% or 20%, according to pasture available at the end of the growing season. Variation in total annual GHGE was lowest in the ‘fixed moderate’ (~9.5 ha/adult equivalent (AE)) stocking strategy, ranging from 3799 to 4471 t CO2e, and highest in the ‘fixed high’ strategy (~5.9 ha/AE), which ranged from 3771 to 7636 t CO2e. The ‘fixed moderate’ strategy had the least variation in GHGE intensity (15.7–19.4 t CO2e/t liveweight sold), while the ‘flexible 20’ strategy (up to 20% annual change in AE) had the largest range (10.5–40.8 t CO2e/t liveweight sold). Across the five stocking strategies, the ‘fixed moderate’ stocking-rate strategy had the highest simulated perennial grass percentage and pasture growth, highest average rate of liveweight gain (121 kg/steer), highest average branding percentage (74%) and lowest average breeding-cow mortality rate (3.9%), resulting in the lowest average GHGE intensity (16.9 t CO2e/t liveweight sold). The ‘fixed high’ stocking rate strategy (~5.9 ha/AE) performed the poorest in each of these measures, while the three flexible stocking strategies were intermediate. The ‘fixed moderate’ stocking strategy also yielded the highest average gross margin per AE carried and per hectare. These results highlight the importance of considering the influence of climate variability on stocking-rate management strategies and herd performance when estimating GHGE. The results also support a body of previous work that has recommended the adoption of moderate stocking strategies to enhance the profitability and ecological stability of beef production systems in northern Australia.

Emerging opportunities for developing a diversified land sector economy in Australia’s northern savannas

We explore sustainable land sector opportunities for Australia’s 1.2 million km2 northern savanna rangelands where extensive beef cattle pastoralism is the predominant contemporary land use. Our focal region is characterised by mean annual rainfall exceeding 600 mm, ecologically bountiful wet season water availability followed by 6–8 months of surface water deficit, mostly nutrient-poor soils, internationally significant biodiversity and carbon stock values, very extensive dry season fires in pastorally unproductive settings, a sparse rural population (0.14 persons km–2) comprising a high proportion of Indigenous people, and associated limited infrastructure. Despite relatively high beef cattle prices in recent seasons and property values escalating at a spectacular ~6% p.a. over the past two decades, long-term economics data show that, for most northern regions, typical pastoral enterprises are unprofitable and carry significant debt. Pastoral activities can also incur very significant environmental impacts on soil and scarce dry season water resources, and greenhouse gas emissions, which currently are not accounted for in economic sustainability assessments. Over the same period, the conservation sector (including National Parks, Indigenous Protected Areas) has been expanding rapidly and now occupies 25% of the region. Since 2012, market-based savanna burning projects aimed at reducing greenhouse gas emissions occur over a further 25%. Returns from nature-based tourism focussed particularly on maintaining intact freshwater systems and associated recreational fishing opportunities dwarf returns from pastoralism. The growth of these latter industries illustrates the potential for further development of profitable ‘ecosystem services’ markets as part of a more environmentally and socially sustainable diversified regional land sector economy. We outline some of the imminent challenges involved with, and opportunities for developing, this new industry sector.

Optimisation of fuel reduction burning regimes for carbon, water and vegetation outcomes

Fire plays a critical role in biodiversity, carbon balance, soil erosion, and nutrient and hydrological cycles. While empirical evidence shows that fuel reduction burning can reduce the incidence, severity and extent of unplanned fires in Australia and elsewhere, the integration of environmental values into fire management operations is not well-defined and requires further research and development. In practice, the priority for fuel reduction burning is effective mitigation of risk to life and property. Environmental management objectives, including maintenance of high quality water, reduction of CO₂ emissions and conservation of biodiversity can be constrained by this priority. We explore trade-offs between fuel reduction burning and environmental management objectives and propose a framework for optimising fuel reduction burning for environmental outcomes.

Cattle landscape selectivity is influenced by ecological and management factors in a heterogeneous mountain rangeland

Few studies addressing drivers of cattle selectivity focus on the combination of ecological (biotic and abiotic) and management factors such as rotational systems, paddock sizes and paddock shapes. As a consequence, it is difficult to prioritise management practices integrating information of different driving factors. In a heterogeneous mountain rangeland in Central Argentina we established a total of 419 square study plots of 1 ha located in 18 paddocks with differing sizes, shapes and cattle grazing management. Plots were small samples of landscapes, covering all existing variability in vegetation and physiography. For each plot we estimated the annual cattle use, average seasonal cattle density, forage types and abiotic characteristics. We used general linear models to show that selectivity was mainly driven by biotic variables. Cattle selected landscapes dominated by short palatable plants, but the strength of this influence differed among paddocks. Selectivity was strongest in paddocks with low abundance of lawns dominated by short palatable plants and low annual stocking rate. As stocking rate and the availability of lawns increased, selectivity strength decreased. Abiotic variables had far less influence than biotic variables, showing that cattle tended to avoid rough landscapes with steep terrain in the wet-warm season; and to be attracted by permanent water sources during the dry-cold season. Seasonal stocking density and paddock size had no detectable influence on cattle selectivity and distribution. Paddock shape influenced distribution but not the strength of forage selectivity. We conclude that in our system, cattle selectivity is mainly driven by biotic factors, and the most effective methods of changing the consequent distribution pattern is by manipulating forage types and paddock shape. The role of stocking rate remains controversial as it was correlated with the proportion of lawns in the paddock.

Seasonal hogget grazing as a potential alternative grazing system for the Qinghai-Tibetan plateau: weight gain and animal behaviour under continuous or rotational grazing at high or low stocking rates

The traditional transhumance grazing system on the Qinghai-Tibetan Plateau (QTP) is being replaced by a system in which pastoralists are allocated fixed areas for grazing. In this context, we conducted experiments to evaluate a possible change to seasonal grazing of young animals for weight gain, and the effects of grazing management (continuous grazing (CG) vs rotational grazing (RG)) and stocking rate (SR) on the performance and behaviour of Oura-type Tibetan sheep. In Experiment 1 (June–December 2014), 72 Tibetan sheep (initial bodyweight (BW) 32.2 ± 3.37 kg) were allocated to one of three treatments: (1) CG24 – eight sheep grazed continuously in a single 2-ha plot for the entire duration of the experiment; (2) RG24 – eight sheep grazed in a 1-ha plot from June to September (growing season), and then moved to a new plot for September–December grazing (early cold season); (3) RG48 – eight sheep grazed in a 0.5-ha plot, but otherwise as for RG24. All treatments had three replicates. In Experiment 2 (September–December 2014), 48 Tibetan sheep (initial BW 46.3 ± 1.62 kg) were used to repeat the RG24 and RG48 treatments imposed in the early cold season of the Experiment 1. In both experiments, increasing SR significantly reduced bodyweight gain (BWG) per head and increased BWG per ha in the RG treatments. In Experiment 1, RG, compared with CG, did not significantly affect BWG per head, BWG per ha, or feed utilisation efficiency. In both experiments weight gain was small or negative in the early cold season. These results indicate that removal of sheep at the onset of the cold season will be important for retention of the weight gain achieved in the growing season but choice between a CG and RG grazing system is unimportant for the production efficiency in the proposed grazing system of Tibetan sheep.

The effect of earlier mating and improving fertility on greenhouse gas emissions intensity of beef production in northern Australian herds

Approximately 5% of Australian national greenhouse gas (GHG) emissions are derived from the northern beef industry. Improving the reproductive performance of cows has been identified as a key target for increasing profitability, and this higher efficiency is also likely to reduce the GHG emissions intensity of beef production. The effects of strategies to increase the fertility of breeding herds and earlier joining of heifers as yearlings were studied on two properties at Longreach and Boulia in western Queensland. The beef production, GHG emissions, emissions intensity and profitability were investigated and compared with typical management in the two regions. Overall weaning rates achieved on the two properties were 79% and 74% compared with typical herd weaning rates of 58% in both regions. Herds with high reproductive performance had GHG emissions intensities (t CO2-e t–1 liveweight sold) 28% and 22% lower than the typical herds at Longreach and Boulia, with most of the benefit from higher weaning rates. Farm gross margin analysis showed that it was more profitable, by $62 000 at Longreach and $38 000 at Boulia, to utilise higher reproductive performance to increase the amount of liveweight sold with the same number of adult equivalents compared with reducing the number of adult equivalents to maintain the same level of liveweight sold and claiming a carbon credit for lower farm emissions. These gains achieved at two case study properties which had different rainfall, country types, and property sizes suggest similar improvements can be made on-farm across the Mitchell Grass Downs bioregion of northern Australia.

Climate Clever Beef: options to improve business performance and reduce greenhouse gas emissions in northern Australia

The Rangeland Journal – Climate Clever Beef special issue examines options for the beef industry in northern Australia to contribute to the reduction in global greenhouse gas (GHG) emissions and to engage in the carbon economy. Relative to its gross value (A$5 billion), the northern beef industry is responsible for a sizable proportion of national reportable GHG emissions (8–10%) through enteric methane, savanna burning, vegetation clearing and land degradation. The industry occupies large areas of land and has the potential to impact the carbon cycle by sequestering carbon or reducing carbon loss. Furthermore, much of the industry is currently not achieving its productivity potential, which suggests that there are opportunities to improve the emissions intensity of beef production. Improving the industry’s GHG emissions performance is important for its environmental reputation and may benefit individual businesses through improved production efficiency and revenue from the carbon economy. The Climate Clever Beef initiative collaborated with beef businesses in six regions across northern Australia to better understand the links between GHG emissions and carbon stocks, land condition, herd productivity and profitability. The current performance of businesses was measured and alternate management options were identified and evaluated. Opportunities to participate in the carbon economy through the Australian Government’s Emissions Reduction Fund (ERF) were also assessed. The initiative achieved significant producer engagement and collaboration resulting in practice change by 78 people from 35 businesses, managing more than 1 272 000 ha and 132 000 cattle. Carbon farming opportunities were identified that could improve both business performance and emissions intensity. However, these opportunities were not without significant risks, trade-offs and limitations particularly in relation to business scale, and uncertainty in carbon price and the response of soil and vegetation carbon sequestration to management. This paper discusses opportunities for reducing emissions, improving emission intensity and carbon sequestration, and outlines the approach taken to achieve beef business engagement and practice change. The paper concludes with some considerations for policy makers.

Is land condition a useful indicator of soil organic carbon stock in Australia’s northern grazing land?

The grazing lands of northern Australia contain a substantial soil organic carbon (SOC) stock due to the large land area. Manipulating SOC stocks through grazing management has been presented as an option to offset national greenhouse gas emissions from agriculture and other industries. However, research into the response of SOC stocks to a range of management activities has variously shown positive, negative or negligible change. This uncertainty in predicting change in SOC stocks represents high project risk for government and industry in relation to SOC sequestration programs. In this paper, we seek to address the uncertainty in SOC stock prediction by assessing relationships between SOC stocks and grazing land condition indicators. We reviewed the literature to identify land condition indicators for analysis and tested relationships between identified land condition indicators and SOC stock using data from a paired-site sampling experiment (10 sites). We subsequently collated SOC stock datasets at two scales (quadrat and paddock) from across northern Australia (329 sites) to compare with the findings of the paired-site sampling experiment with the aim of identifying the land condition indicators that had the strongest relationship with SOC stock. The land condition indicators most closely correlated with SOC stocks across datasets and analysis scales were tree basal area, tree canopy cover, ground cover, pasture biomass and the density of perennial grass tussocks. In combination with soil type, these indicators accounted for up to 42% of the variation in the residuals after climate effects were removed. However, we found that responses often interacted with soil type, adding complexity and increasing the uncertainty associated with predicting SOC stock change at any particular location. We recommend that caution be exercised when considering SOC offset projects in northern Australian grazing lands due to the risk of incorrectly predicting changes in SOC stocks with change in land condition indicators and management activities for a particular paddock or property. Despite the uncertainty for generating SOC sequestration income, undertaking management activities to improve land condition is likely to have desirable complementary benefits such as improving productivity and profitability as well as reducing adverse environmental impact.

Aboveground and belowground carbon dynamics in response to fire regimes in the grazed rangelands of northern Australia: initial results from field studies and modelling

The world’s rangelands are often seen as offering considerable potential as a carbon (C) sink, which could contribute to the management of atmospheric C levels, but there are often few data available to assess this potential or to inform the type of management regimes that would be necessary. This paper reports on a review of the literature, a field study and modelling of C stocks under a selection of experimental fire regimes in two plant communities in Australia’s northern rangelands. The field study on an open eucalypt savanna woodland and a savanna grassland-open shrubland suggested that fire regime had no effect or an inconsistent effect on aboveground C stocks. However, modelling using the Century model for the open woodland site showed that increasing fire frequency was associated with reduced aboveground and soil C stocks. Thus, while infrequent fires allowed C stocks to increase (10-yearly fire) or remain stable (6-yearly fire) over a modelled 58-year period, a regime of more frequent fires (4- and 2-yearly fires) reduced C stocks over time. Simulation of C dynamics over 93 years of pastoral settlement suggested that total C stocks had increased by 9.5 t ha–1, largely due to an increase in C in woody vegetation following a reduction in fire frequency associated with pastoral settlement. Frequent burning, as recommended to maintain low woody density and promote pasture production for grazing, will, therefore, reduce aboveground and to a lesser extent soil C stocks where there has been a history of infrequent fire. The opportunities for pastoralists to increase C stocks will depend on the frequency of fire and vegetation type, especially its woodiness or potential woodiness. Reducing fire frequency in woody rangelands will increase C stocks but may have adverse effects on pasture and livestock production. Reducing grazing pressure or destocking might also increase C stocks but may be relevant only when a property is overstocked or where relatively unproductive land could be taken out of livestock production. Any C gains from altering fire and grazing management are likely to be modest.

Fire and carbon management in a diversified rangelands economy: research, policy and implementation challenges for northern Australia

Burning of savanna is a globally important source of greenhouse gas (GHG) emissions. In Australia, burning of savanna contributes between 2% and 4% annually of the nation’s reportable emissions. Complete removal of this source of emissions is unrealistic because fire is a ubiquitous natural process and important land-management tool. In the rangelands of northern Australia, fire is used to manage habitat for conservation, control woodland thickening, manipulate pastures for grazing and is an essential component of indigenous cultural and land-management practice. There has been a concerted attempt in recent times to move away from complete fire suppression and its consequence: frequent, extensive and high intensity wildfires occurring late in the dry season. In fire-adapted vegetation types, prescribed early dry season fires help reduce the incidence of late season wildfires and consequently the amount of GHG emissions produced. The emergence of a carbon economy affords a potential opportunity for land managers to diversify their livelihoods by adopting fire-management practices that reduce GHG emissions and increase carbon sequestration. However, in order to realise benefits from this emerging economy, there is a need to identify and address a range of barriers affecting community participation. The papers in this Special Issue document current scientific knowledge, policy issues and pathways to participation, with particular reference to Australia’s savanna rangelands. This introductory paper outlines how northern Australia has both the opportunity and requirement to develop a diversified rangelands economy to realise multiple conservation, economic and emissions outcomes.

EcoFire: regional-scale prescribed burning increases the annual carrying capacity of livestock on pastoral properties by reducing pasture loss from wildfire

Prescribed burning is an important management tool in the extensive pastoral lands in northern Australia. It can be used to influence grazing patterns, increase the nutritive value of pastures, reduce the density of woody shrubs and reduce the risk of damaging wildfires. The consequences of regional-scale prescribed burning on pasture availability and annual carrying capacities of pastoral properties in northern Australia were examined using EcoFire, a fire management program in the Kimberley Region of north-west Australia, as an example. Theoretical long-term carrying capacities of land systems, and fire scar imagery from years before (2004–06) and during EcoFire (2007–11) were used to model the impact of the program on the seasonality and extent of fire-induced losses in annual carrying capacity, and the likelihood of properties experiencing catastrophic losses in a given year. Over the 5 years that EcoFire has been running, it has resulted in a progressive reduction in the loss of annual carrying capacity caused by the burning of pasture, and shifted the season that annual carrying capacity is lost to fire from predominantly the late to the early dry season. Most notably, the established program has reduced the probability of experiencing catastrophic loss (defined here as >50% of annual carrying capacity removed due to fire) from 18 incidences to three incidences within a 3-year period. These outcomes have the potential to deliver economic benefits to pastoralists via increased annual carrying capacity and by improvements in pasture condition, provided stocking rates and pasture utilisation are managed carefully.

Virtual herding for flexible livestock management – a review

Free-ranging livestock play a pivotal role globally in the conversion of plant tissue into products and services that support man’s many and changing lifestyles. With domestication came the task of providing livestock with an adequate plane of nutrition while simultaneously managing vegetation for sustainable production. Attempting to meld these two seemingly opposing management goals continues to be a major focus of rangeland research. Demand for multiple goods and services from rangelands today requires that livestock production make the smallest possible ‘negative hoof-print’. Advancements in global navigation satellite system, geographic information systems, and electronic/computing technologies, coupled with improved understanding of animal behaviour, positions virtual fencing (VF) as an increasingly attractive option for managing free-ranging livestock. VF offers an alternative to conventional fencing by replacing physical barriers with sensory cues to control an animal’s forward movement. Currently, audio and electrical stimulation are the cues employed. When VF becomes a commercial reality, manual labour will be replaced in large part with cognitive labour for real-time prescription-based livestock distribution management that is robust, accurate, precise and flexible. The goal is to manage rangeland ecosystems optimally for soils, plants, herbivores in addition to the plant and animal’s microflora. However, maximising the benefits of VF will require a paradigm shift in management by using VF as a ‘virtual herder’ rather than simply as a tool to manage livestock within static physical barriers.

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

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.

Resting pastures to improve land condition in northern Australia: guidelines based on the literature and simulation modelling

Pasture rest is a possible strategy for improving land condition in the extensive grazing lands of northern Australia. If pastures currently in poor condition could be improved, then overall animal productivity and the sustainability of grazing could be increased. The scientific literature is examined to assess the strength of the experimental information to support and guide the use of pasture rest, and simulation modelling is undertaken to extend this information to a broader range of resting practices, growing conditions and initial pasture condition. From this, guidelines are developed that can be applied in the management of northern Australia’s grazing lands and also serve as hypotheses for further field experiments. The literature on pasture rest is diverse but there is a paucity of data from much of northern Australia as most experiments have been conducted in southern and central parts of Queensland. Despite this, the limited experimental information and the results from modelling were used to formulate the following guidelines. Rest during the growing season gives the most rapid improvement in the proportion of perennial grasses in pastures; rest during the dormant winter period is ineffective in increasing perennial grasses in a pasture but may have other benefits. Appropriate stocking rates are essential to gain the greatest benefit from rest: if stocking rates are too high, then pasture rest will not lead to improvement; if stocking rates are low, pastures will tend to improve without rest. The lower the initial percentage of perennial grasses, the more frequent the rests should be to give a major improvement within a reasonable management timeframe. Conditions during the growing season also have an impact on responses with the greatest improvement likely to be in years of good growing conditions. The duration and frequency of rest periods can be combined into a single value expressed as the proportion of time during which resting occurs; when this is done the modelling suggests the greater the proportion of time that a pasture is rested, the greater is the improvement but this needs to be tested experimentally. These guidelines should assist land managers to use pasture resting but the challenge remains to integrate pasture rest with other pasture and animal management practices at the whole-property scale.