To make the best use of this procedure, it is important to have a clear ‘picture’ of the amount, condition and location of the natural assets, weeds and pests that need managing in a grazing enterprise. Remember, these resources include:
- Soil: Healthy productive soils, as well as gullies, eroded areas and paddocks that require careful management to improve or maintain condition (e.g. soils that are strongly acid, saline or water repellent)
- Water: The amount, pattern and ability to capture and better utilise annual rainfall (stock water supplies are included here)
- Vegetation: Weeds, native and sown pastures (and their condition), shelter belts, and remnant woody vegetation
- Riparian land: Any land that adjoins a permanent or temporary body of water, be it a river, stream, wetland or farm dam
- Native and feral animals: The species present and their havens
A self-assessment tool (SAT) can be used to audit a farm’s financial, social and environmental sustainability.
Identifying and assessing soil erosion risks
A guide to classifying land capability, in MMFS Module 6 Healthy Soils can be used to assess and record the land classes across a farm. From existing knowledge about the farm and the land classes, identify the key areas at risk of soil erosion and record them on the aerial photo.
Three forms of soil erosion are reasonably common on sheep properties:
- Sheetwash (sometimes called rill or hillslope) erosion is the movement of soil downslope by running water. The key factors are rainfall intensity, ground cover, slope length, gradient and soil erodibility
- Wind erosion is most common in drier areas. Typically, areas subject to wind erosion are exposed dry soils that lack ground cover as a result of overgrazing or cultivation
- Gully erosion is most common in higher-rainfall zones. It occurs from intense rainfall and concentrated run-off from steep ground flowing into cleared drainage lines with unstable soils (e.g. sodic dispersible subsoils). Gullies produce poor quality run-off and, with streambank erosion, are the main sediment sources across southern Australia
Maintaining and/or increasing ground cover can prevent and/or reduce the impact of these erosion processes. Set goals for ground cover in each land class on the farm using the benchmarks outlined in MMFS Module 6 Healthy Soils.
Use the Measuring ground cover and litter levels and Assessing soil health tools in MMFS Module 6 Healthy soils to measure ground cover at the sites with highest erosion risk.
Assessing salinity risk
The primary cause of dryland salinity in Australia has been the replacement of deep-rooted, perennial native vegetation with shallow-rooted, annual crops and pastures that use less water. A 1000 ha farm receiving 500 mm of rainfall has 5000 megalitres of water to manage each year.
Productive pastures, profitable grazing systems and improved sustainability are all about efficient management of the water cycle. The figure below shows the water cycle and the interaction between rainfall, run-off and deep drainage.
Figure 5.1 The ‘water cycle’ on a grazing property
Source: Towards Sustainable Grazing – the Professional Producer’s Guide, adapted by AWI and MLA
Poor management of the water cycle directly impacts on many of our resource management issues, including soil erosion, high nutrient loads in rivers, soil acidity and dryland salinity.
The excess water (often called recharge) not used by plants drains below the root zone causing the water table to rise. It may bring saline groundwater up towards, and eventually into, the root zone, somewhere ‘downslope’ (often called discharge). Sufficient salt in the root zone can restrict or stop plant growth. Contact the relevant regional NRM agency to determine the risk of salinity in the local area. Use the following tools to assess that risk to a given grazing enterprise:
- The Pasture assessment techniques tool in MMFS Module 7 Grow More Pasture can be used to measure the perenniality of a pasture. Compare your result with the benchmarks in the tool
- If areas are salt-affected, the Indicators of saline land tool can be used to rate salinity across paddocks. A range of species identification resources can be used to identify the indicator species listed in the Indicators of saline land tool
Having mainly annual plants means less water use and more potential deep drainage, which contributes to rising groundwater tables. However, some deep drainage is needed to supply water to streams and wetlands.
Acidification of soil can also be greater under annual pastures, as their shorter life spans allow nitrate leaching to occur, leaving behind hydrogen ions, especially at the season break when roots systems aren’t fully developed. Perennial pastures can help prevent soils becoming more acid.
Assessing the condition of native vegetation
It is important to identify what native species are present to inform future management actions. Native pastures provide reliable (because of their diversity) and low input production while helping to maintain healthy soils and ecosystems. Much of Australia’s fine wool comes from native pastures because they provide a persistent, consistent feed supply.
Native grasses are more persistent when they are allowed to recover after grazing. Rotational grazing, with rest for at least part of the year, is an advantage.
Native pastures respond positively to low rates of fertiliser, but higher rates destabilise the pasture, allowing annuals and weeds to crowd out native perennials. This can be partly mitigated through strategic grazing management.
Most regional NRM authorities have tools, access to local experts and information to help sheep producers identify native species.
Several assessment and monitoring tools are available that can help producers quickly and simply assess the condition of their native bush, riparian zones and native pastures and for ongoing monitoring.
It is important to discuss and record the collective vision for areas of native bush, riparian vegetation and native pastures, what changes could be made to protect areas at risk (e.g. make them larger, denser, more diverse, etc.), and when these risks will be addressed.
Surveying birds as ‘focal’ species
Birds receive more attention than any other animal group when designing landscapes for environmental outcomes. Birds are a popular choice for several reasons:
- Birds are mobile — they move across the landscape at the planning scale of hectares (paddocks) and kilometres (properties)
- Birds are relatively easy to survey, being abundant and visible during the day
- Birds are placed well towards the top of food chains — an ibis can eat 250 grasshoppers per day and a magpie can eat 40 scarab beetle larvae per day
- A diverse range of bird species inhabiting the ground, the understorey layers and mature trees indicates the remnant vegetation is healthy
Native birds are perhaps the most useful ‘indicator’ group. A farm with a rich diversity of birds will also have a relatively high diversity of trees, shrubs, mammals, reptiles, frogs and invertebrates. If small birds are missing, there is something wrong with the habitat. Too many larger birds or noisy miners indicate a lack of balance.
The Quickchecks tool accounts for the fact that different parts of the farm will have different bird groups, highlighting the fact that a variety of habitats is required across the farm.
Alternatively, property owners and managers can keep a small notebook in the ute or make a list on their phone and record birds and native animals as they come across them in an ordinary day’s work. All family members can record what they see and where and later add them to a master list.
It is important to identify changes that can be made to vegetation on farm to improve bird populations, and when these changes will be implemented.
Assessing the prevalence of weeds
Pests and weeds threaten both pasture productivity and natural resources. The threat posed to biodiversity by weeds is ranked second only after land clearing.
Successful weed management is much more than ad hoc weed control. It is important to work out why weeds are a problem, set realistic goals for both pasture and weed management, undertake the appropriate weed management practices on time, every time, check whether weed management has been successful, and adapt the weed management plan as needed. Weeds can spread from adjoining properties, so neighbours may need to be involved to get the best results.
This approach of deliberation, diversity and diligence is called the ‘3Ds of weed management’. Each step has key decisions and critical actions. The deliberation table allows producers to compare a stocktake of their current weed problems (species and density in key paddocks) and agree on priorities for action based on what they want the weed level to be. It is important to record the changes that could be made to weed populations and establish a timeframe for change.
Assessing invertebrate pests
Invertebrate pests, including insects and mites, can significantly reduce pasture productivity throughout the year.
Across Australia, redlegged earth mite (RLEM) infest 20 million hectares of pasture, causing $200 million damage to the wool industry alone.
The first step is to correctly identify the pest. A local agronomist can help identify the species present. Other sources of information include CSIRO Entomology, state departments of primary industries and Cesar Australia.
Determine the acceptable pest level to be, and the changes could be made to reduce and keep pest populations small.
It is important to choose the appropriate tools to manage each pest, using multiple approaches and not just insecticides (integrated pest management or IPM) and to monitor the effectiveness of any approach taken.
Different pests require different management strategies. For example, RLEM and blue oat mite (BOM) look similar but have different lifecycles. This difference means the timing of pesticide spraying using TIMERITE® works for RLEM, but not for BOM.
Assessing vertebrate pests
A variety of vertebrate pests affect sheep farms across Australia, including introduced pests such as goats, deer, rabbits, pigs, foxes and wild dogs. Native browsers, such as kangaroos, wallabies and wombats, can also sometimes cause issues for livestock and cropping production systems.
Many of the habitats that support native animals and birds on farm also favour the vertebrate pests. Producers have to find the balance that suits their situation.
Rabbits damage vegetation by ringbarking trees and shrubs, prevent regeneration by eating seeds and seedlings, and degrade the land through burrowing and reducing ground cover leading to erosion. Selective grazing by rabbits changes the composition of the vegetation.
Where rabbits have caused the slow decline of, say, bulokes on roadsides in western Victoria, there are fewer food trees for species such as the red-tailed black cockatoo that have declined as a result, though clearly not from ‘direct competition’ from the rabbits.
The impact of rabbits often increases during and immediately after drought or fire, when food is scarce and they eat whatever remains or re-grows. Populations as low as 2–3 rabbits per hectare aresufficient to severely depress the regeneration of native shrubs and trees.
Spotlight transect counts (the number of rabbits seen along a set route or transect) are an accurate way to monitor rabbit populations, though the number of rabbits seen in the car headlights when driving home provides a good enough indicator of rising or falling rabbit numbers.
Foxes are significant predators of native wildlife. While they are also known to prey heavily on rabbits at certain times of the year, evidence suggests foxes are a primary cause in the decline and extinction of many small-sized and medium-sized rodent and marsupial species in Australia. They also prey on many bird species. While foxes are known to scavenge and remove dead or mismothered lambs, fox predation has also been identified as the primary cause of death in studies conducted across the country. Predation rates vary between production settings and landscapes however the average rate of primary predation on lambs varies between 5–10% but can be as high as 22% in some circumstances.
The average density for foxes in Australia in most landscapes is around four per square kilometre, but estimates as high as seven per kilometre have been recorded in from areas, for example around Orange in NSW. Fox territories range from 2–5 km2 across which there might be numbers of 8–20 foxes. Foxes are highly mobile and will continue to migrate and establish new territories after the breeding season so monitoring fox populations in the lead-up to lambing is essential, however managing foxes throughout the year benefits native fauna and biodiversity.
Delivery of fox management programs in conjunction with rabbit control also benefits production and biodiversity protection so foxes don’t focus their predation pressure on to lambs and native animals when rabbit populations have been reduced through annual biological control outbreaks or management activities.
Feral pigs are distributed across many of the sheep regions across Australia and continue to spread into new areas, both naturally and through illegal dumping. They cause agricultural damage by preying on newborn lambs, reducing crop yields, damaging fences and water sources, and competing with stock for feed by consuming or damaging pasture, and cause extensive damage to natural habitats by turning over vast areas of soil when rooting for food. They also wallow and foul up water sources, trample and consume native vegetation, and facilitate the spread of weeds and Phytophthora (a plant pathogen causing dieback in native plants and trees). Feral pigs also host serious diseases with the potential to devastate livestock operations including foot and mouth disease (FMD).
Identify the prevalence of vertebrate pests and their location on your farm, what you would like the pest level to be and what changes could be made to reduce and keep numbers down.
Assessing stock water supplies
Most of Australia’s livestock drink from water that falls on the property, but stock water can come from a variety of sources including rivers, creeks and channels, dams, ground tanks, wells or bores. Whatever the source, the suitability of water available now and the water needed forthe future depends on its quantity, quality and reliability.
A variety of measures can improve water use efficiency (WUE) in sheep grazing systems, including creating additional watering points, using troughs to improve water quality and reduce evaporation and maintaining healthy soils to minimise run-off.
Healthy soil drives higher pasture productivity and benefits the environment through greater use of water and nutrients in the paddock reducing the risk of run-off, erosion and deep drainage (see MMFS Module 6 Healthy Soils).
Like the feed budgeting tool in MMFS Module 8 Turn Pasture into Product, the stock water requirements tool helps to calculate stock water requirements by determining how much water is currently available, how much stock need, and how long a dam or water supply will last.
Consider the following resources when auditing stock water supplies:
- source (groundwater, rain fed)
- quantity
- quality
- reliability and amount of ongoing monitoring required
- water requirements of livestock – daily and maximum
- location and proximity to other sources
- costs (time and labour) associated with providing water stock
- impacts of non-domestic animals on watering points
- condition of source and its associated infrastructure, and delivery mechanisms
- risk assessment (i.e. consider the likelihood and consequence of various risks, such as equipment failure, or blue-green algal bloom, or lack of rainfall).
Use the stock water requirements tool to complete a stock water audit of the quantity, quality and reliability of stock water supplies.
Assessing a farm’s carbon footprint
The Earth’s surface temperature depends on the balance between incoming and outgoing radiation. The main greenhouse gases (GHG) — water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and ozone — absorb and re-radiate much of the infrared radiation released by the Earth’s surface.
All of these gases occur naturally and are essential to producing a natural greenhouse effect, maintaining the temperature of the Earth’s surface some 33°C warmer than it would otherwise be and making Earth inhabitable. Together, these GHG make up less than 1% of the atmosphere, which is comprised mainly of nitrogen and oxygen.
When looking at global (and Australian) GHG emissions, carbon dioxide contributes the largest proportion, while methane and nitrous oxide make up a smaller part.
Australian GHG emissions by gas
Source: Australian Greenhouse Emissions Information System, Department of the Environment and Energy (May, 2020), adapted by AWI and MLA
These emission estimates account for multiple sectors: National GHG Inventory Total, Energy, Fuel Combustion, Transport, Fugitive Emissions from Fuels, Industrial Processes, Agriculture, Land Use, Land-Use Change and Forestry KP, Waste, Other
The main emissions from agricultural production are carbon dioxide, methane and nitrous oxide, as shown below. These emissions are measured in carbon dioxide equivalents (CO2e) to allow for comparison in terms of the quantity and potency of emission sources, as each gas has a different capacity to contribute to global warming. For example, methane (the largest source of livestock emissions) is a more potent GHG than carbon dioxide. Between 1750 and 2019, global methane concentrations rose by 150% and nitrous oxide by 22% (CSIRO global methane and nitrous oxide trackers).
Sources of major farm greenhouse gas (GHG) emissions.
Source: CN30 Roadmap
Australia’s livestock industry (including dairy) produces 10% of Australia’s total GHG emissions (compared, for example, with energy sector generation, which represents 37% of Australia’s GHG emissions).
Most of the emissions from Australia’s livestock industry are methane (56%). Typical Australian beef and sheep systems have been estimated to emit around 85% of their GHG as methane. Methane is also emitted during the production and transport of coal, natural gas, and oil, and by the decay of organic waste (e.g. municipal solid waste landfills). Enteric (occurring in the intestines) methane arises from ruminant digestion and manure management.
Nitrous oxide emissions arise predominantly from manure excretion and fertiliser application.
Carbon dioxide emissions arise from fossil fuels used for lime and urea inputs, transport, machinery and other uses on-farm, and can also arise from the manufacture of purchased inputs such as fertiliser and feed. Carbon dioxide emissions or removals (storage) can also occur from changes in soil and vegetation carbon levels.
Typical GHG emission breakdown in beef and sheep systems
Source: Wiedemann et al., 2015; Wiedemann et al., 2016, adapted by AWI and MLA
Note: the exact contributions can vary by ±10% for methane and by about ±5% for nitrous oxide and carbon dioxide
Methane emissions occur as a result of ruminant digestion and methane is released into the atmosphere via belching. It represents a major energy loss for the animal, as methane has an energy content of 55.65MJ per kilogram (much the same as that of natural gas).
In grazing ruminants, energy losses from methane are in the order of 6–10% of gross energy intake. Assuming a pasture with metabolisable energy (ME) of 7. 3–11.7 MJ/kg DM, this loss equates to between 10–16% of ME.
Reducing these emissions would substantially increase the amount of energy available for growth and reproduction. For this reason, it could be a major productivity gain if solutions or improvements were found for methane production.
Methane production per animal has a linear relationship to dry matter intake (DMI). This is true for most pasture types, but a small number of specific feed types have been shown to produce less methane per kilogram of DMI. When assessing emissions for a herd or flock, the key determinants that influence the level of these emissions are:
- livestock numbers
- livestock seasonal weights and mature weights
- growth rates and reproductive status (the factors that influence feed intake).
The importance of this issue is progressing at a rate faster than policy can be developed. Some graziers are keen to investigate what can be done on farm to reduce their carbon footprint. Whether this is to investigate potential carbon trading, offsets, insets, marketing opportunities or personal goals, calculation of farm emissions is a good place to start working out how emissions might be reduced and more carbon stored on farm.
A number of emissions calculators are available to estimate a farm’s annual GHG emissions (both at the individual enterprise activity level and for a farm business as a whole) and to examine the financial impacts different GHG mitigation options may have on farm business profitability.
A life cycle assessment (LCA) of sheep meat and wool production in south-eastern Australian production systems measured emissions intensity of 6.8 kg CO2e per kilogram of liveweight and 26.8 kg per kilogram of greasy wool.
Assessing climate change impacts
Australian sheep producers have always dealt with a variable climate and its associated droughts and floods. Climate change scenarios suggest this variability will increase.
In the sheep industry, climate change is likely to impact on:
- Pasture and fodder crop production: Production could increase under higher carbon dioxide concentrations, however, this increase may be offset by lower nutrient content, higher temperatures, and lower rainfall.
- Water resources: Water supplies will decline in some areas because of increased evaporation, reduced run-off into storages, and decreased and more variable rainfall.
- Wool production and quality: Reduced wool production and quality in some marginal areas where pasture growth is reduced. There might be increased productivity in areas of high rainfall.
- Animal health and reproduction: Increased heat and water stress and possibly changes in the spectrum of pests and diseases that affect sheep. Indications of effects of heat stress on reproduction include reduced conception rates during periods of prolonged heat during joining.
- Land stewardship: Increased pressure from the community for agriculture to reduce the impacts of climate change.
- Competition from other agricultural activities: Increased competition from other agricultural industries (particularly for cropping).
- National and international markets: For example, in New Zealand and China, sheep producers are likely to be advantaged as warmer and wetter regional conditions extend their grazing zones.
- Product contamination and discounting: Vegetable matter and dust contamination in wool and grass seed contamination in carcases could increase where pasture composition changes, particularly if weeds and bare ground increase.
Sheep producers now face not only the continued challenge of managing production of food and fibre, given the variability in climatic conditions, but the new challenges created by the community’s desire to see reductions in carbon emissions.
View predictions for changes in seasonal rainfall, temperature, wind speed and solar radiation under future GHG emissions scenarios (known as ‘Representative Concentration Pathways changes’, where RCP4.5 is low emissions and RCP8.5 is the highest emissions pathway) at https://climatechangeinaustralia.gov.au/en/changing-climate/state-climate-statements/.