2. SOILS AND TOPOGRAPHY
3. CLIMATE AND AGRO-ECOLOGICAL ZONES
4. RUMINANT LIVESTOCK PRODUCTION SYSTEMS
5. THE PASTURE RESOURCE
6. OPPORTUNITIES FOR IMPROVEMENT OF PASTURE
7. RESEARCH AND DEVELOPMENT ORGANIZATIONS AND
Australia is the driest inhabited continent with some of the world’s oldest, shallowest and most weathered soils. Over 70% of the land area is classed as either semi-arid (P<0.66E, where P is annual rainfall and E is potential evaporation) or arid – see Figure 2). Of the total land area (762 million ha), barely a tenth is suitable for sown crops and pastures and then only after the addition of fertilizers and/or legumes to ensure the soils are suitable for moderate levels of agricultural production. Australia does have some naturally fertile soils, such as those that occur in the Wimmera area of Victoria and the Darling Downs of Queensland, but there are no tracts as extensive as the deep, fertile soils of the North American prairies or the Ukraine. Furthermore, despite a rich outback (rural) heritage, modern Australia is one of the most urbanised countries in the world, with 90% of the people clustered in towns and cities along the south-western, southern and eastern coasts of the continent. The population at the end of 2009 was 22.2 million (estimated at 21.3 million in July 2009 by World Factbook with a growth rate of 1.195%), boosted in recent decades by a strong inflow of immigrants particularly from Europe and Asia. There are strong ethnic links in horticulture production, such as expatriate Italian communities with viticulture and Asian communities with vegetable production, while cropping and livestock activities are dominated by family farmers who are the descendents of immigrants from the British Isles.
The focus of this profile is on the pasture and forage resources of Australia, collectively called ‘grasslands’, and their use for extensive livestock production. Due to the location of Australia in tropical and temperate latitudes and the relatively low elevation of the continent (mean 330 m), severe winter temperatures do not occur in the grazing lands. Sheep and beef cattle graze pastures and forages year-round – there is no need for housing. There are some intensive, zero-grazing dairies near to major cities and, for high quality markets, cattle and lambs may be finished to prime condition in an intensive feedlot. Animal production in Australia meets the domestic demand for meat, milk and manufactured products, and produces a surplus for export. In 2007-08, Australia exported 45% of total lamb production, 77% of total mutton production, 43% of beef/veal production and 45% of milk production.
Below, a brief history of the agricultural development of Australia is outlined. Then follow sections on the soil resources and climate, the broad agro-ecological zones and the distribution of sheep and cattle across these zones. The following sections on production systems, pasture/fodder resources and future research/development opportunities are considered from a contemporary perspective, drawing selectively on the rich history of the Australian grazing industries and taking into account the likely future trends in climate, global resources, the demand for livestock products and industry policy shifts.
1.2 Agricultural development
A short history of post-settlement agricultural development in Australia was given by Wolfe and Dear (2001). Early in the 19th century, British immigrants explored and occupied rural Australia, partially displacing the Aboriginal people and disrupting the population of grass-eating macropods (kangaroos) with sheep and cattle, which grazed and multiplied on the vast areas of native grasslands. Early development fanned out to occupy a moist crescent around the semi-arid and arid interior of Australia, from the SE sections of South Australia (SA) (300–650 mm median annual rainfall), temperate Victoria (300–900 mm), the central plains, slopes and tablelands of New South Wales (NSW) (350–900 mm), up and down the wetter coast of NSW (900 –1200 mm), and from sub-tropical SE Queensland to the central and eastern tropical areas of Queensland (500 to 1800 mm median annual rainfall). From the 1840s, the SW corner of Western Australia (WA) (300–650 mm median annual rainfall) was developed.
The original native grasslands comprised tall warm-season perennial grasses (e.g. Themeda triandra, Poa labillarderi, Austrostipa aristiglumis and Heteropogon contortus) which, depending on rainfall and grazing intensity, gave way towards shorter native species such as redgrass (Bothriochloa macra), bluegrass (Dichanthium sericeum), the wallaby grasses (Austrodanthonia spp.) and windmill grass (Chloris truncata) (Moore, 1970). In southern Australia, a range of species from around the Mediterranean were introduced accidentally and became naturalised; these included several cool-season annual grasses (Bromus, Hordeum, Vulpia spp.), forbs (Arctotheca calendula, Echium plantagineum) and annual legumes (Trifolium spp., Medicago spp.).
During the first century of exploration and exploitation (Shaw, 1990), the expanding flocks of grazing livestock (Table 1) were sustained by way of a combination of activities, such as clearing trees and shrubs, the regular burning of the open woodland-grassland and scrub-grassland communities, the granting of grazing rights and eventual land tenure, fencing/yards and the provision of reliable water supplies, better techniques of animal breeding and husbandry, investment and banking services that followed the discovery of gold in the 1850s, and the building of the Australian railway system from 1855. By 1891, when most of the railway system was in place, more sheep were grazing the Australian landscape than occur today (Table 1); however, the numbers of sheep and cattle were reduced during the next decade by a general economic depression and by the ‘Federation drought’, which began in the mid 1890s and reached its devastating climax in late 1901 and 1902.
Scientific agriculture began late in the 19th century with the establishment of experimental farms, which during the early 20th century helped to promote a consolidation phase comprising new techniques of dry farming, purposeful wheat breeding, superphosphate fertilizer and mechanisation (Barr and Cary, 1992). To counteract the depletion of soil organic matter, a technique of ley farming with annual pasture legumes was developed for slightly acidic soils in Victoria (with subterranean clover, Trifolium subterraneum) and alkaline soils in SA (with annual medics, Medicago spp.). However, because of the depression and then war, there was little change in on-farm practices and outputs between 1930 and 1950, and land degradation (erosion of croplands, overgrazing of pasture lands with livestock and rabbits) continued. A highlight during the 1940s was the discovery of several trace element deficiencies (copper, molybdenum, zinc and cobalt) that affected the growth and nitrogen fixation of legumes on large tracts of soils in coastal SA and WA (copper, zinc and cobalt) and in south-eastern Australia (molybdenum) (Williams and Andrew, 1970).
There was a rapid expansion in improved pastures from 1950 (5 000 000 ha of improved pastures) until 1975 (>20 million ha), based on prior investments in agricultural research, a wool boom in the early 1950s, incentives for investment in agriculture (taxation concessions, a superphosphate bounty) and the advent of aerial agriculture. However, once again, this expansion was accompanied by problems that were evident during the 1970s and 1980s, including a widespread decline in the productivity of pasture legumes due in part to the occurrence of new plant diseases, insect pests and weeds; a worsening cost-price squeeze; and land degradation phenomena such as eucalyptus tree dieback, soil acidification and salinisation. The collective marketing scheme for wool collapsed and a steep decline in sheep numbers began from 1975.
Table 1. Agricultural development in Australia, 1820-2005*
The concept of sustainable production developed in Australia from the 1980s, concentrating on liming to correct soil acidity, the replacement of plant nutrients, the use of alternative crops to cereals, tackling soil erosion and compaction problems through reduced tillage and tree planting on farms. In the pastoral and high-rainfall zones, livestock numbers were adjusted to more conservative levels. In the main mixed farming zone (the wheat-sheep belt, see Figure 14) during the last two decades, the decline in sheep numbers has continued due to crop specialisation and a declining/ageing workforce in the agricultural industries. A run of dry seasons in 2001-09 (impacting on crop production), plus the threat of climate change and strong demand recently in the domestic and export markets for sheep meat may soon encourage a return of more sheep to the wheat-sheep belt. Over the same time period, water storage levels in the Murray-Darling Basin of south-eastern Australia have currently reached historical low levels due to over-allocation of water rights, competition for irrigation water between agricultural, environmental and community users, and a restricted supply due to ongoing drought conditions. Overall, Australian dryland and irrigated farms are now going through a painful period of adjustment in response to the underlying unprofitability of most family farms, animal care concerns and global/local resource issues. This readjustment process is threatening the social wellbeing of rural communities.
|2. TOPOGRAPHY AND SOILS
2.1 Main topographical features
2.2.1 History of soil formation and degradation
Natural cycles of erosion (water, wind) and deposition (water, wind, lava flows) have further shaped Australian landscapes. However, the human population has had the most impact. The use of fire by the Aboriginal people decreased the vegetation cover and marginally increased the loss of soil nutrients and rate of soil erosion. With the arrival of British convicts, colonists and immigrants from 1788, “the severity of soil degradation, particularly in the 100 years after 1850, was extreme” (McKenzie et al., 2004). Activities and their negative impacts on Australian soils included clearing the deep-rooted native vegetation (loss of cover, changes in hydrology, loss of nutrient cycling, erosion, salinisation), mining (landscape disruption, nil or inadequate repair, sediment damage and pollution of waterways), overgrazing by livestock and rabbits (vegetation cover and type, soil erosion, surface sealing, nutrient removal), excessive cultivation (oxidation of organic matter, soil erosion, surface sealing and compaction, increased wind and water erosion, nutrient losses), machinery and vehicular traffic (loss of cover, compaction), excavation and construction activities on sensitive soils (e.g. acid sulphate soils) and contamination of soil and groundwater systems with fertilizers and chemicals.
During the last half-century, the promotion of sustainable production by research organizations, industry bodies and farmers has lowered the rate of soil degradation through understanding the degradation processes and the implementing more sustainable farming systems and practices. These practices include a reduction in sheep numbers, the control of rabbits, the use of fertilizers and legumes to enhance soil fertility, the adoption of reduced tillage, liming to counteract soil acidity, gypsum treatment for sodic soils, the increased use of perennial plants for reducing groundwater accessions and caps to the allocation of water resources. In urban environments, too, there is a renewed focus on land use, subdivision and site development/management policies, stormwater management and waste disposal systems. The implementation of improved processes for agricultural and urban environments is an ongoing process, now stimulated by the phenomena of climate change, greenhouse gas management, dwindling oil reserves and the supply/demand situation for food.
Isbell (1992) outlined the history of soil classification in Australia. Until the 1970s, the Great Soil Group classification (e.g. podzols, red-brown earths, black earths) was the general system used for describing soils in land surveys and for educating agricultural scientists. For an Atlas of Australian Soils project (1960-68), a factual key developed by K.H. Northcote was used, a key that classified soils into 4 divisions (organic O, uniform U, gradational G and duplex D) according to their organic matter content and texture change down the profile; subdivisions were based on features such as texture (U profiles), limestone content (G profiles) and colour of the B horizon (D profiles). However, neither of these classifications incorporated the vast amount of soils knowledge acquired after the 1960s, particularly in northern Australia. Consequently, an Australian Soils Classification system was developed, published and adopted from the 1990s. This system comprises 14 soil orders (Figure 4).
The soils that occur in the main agricultural zones are:
In southern Australia, there is no clear delineation of land use (grazing, cropping, horticulture) according to soil type – location (proximity to major cities), topography (steep/non-arable, undulating/arable, level for irrigation), rainfall amount/distribution and ease of tree/shrub clearing were more important determinants of land use. Within rather than between agro-ecological zones (Figure 7), soil types help determine agricultural practices and the selection of pasture species, and these matters are dealt with in subsequent sections. For example, vertosols that store moisture from rainfall prior to the beginning of the growing season in either winter or summer, are favoured not only for crop production in moderate rainfall country in eastern Australia but also for native grasslands (especially Mitchell grass, Astrebla lappacea) in inland northern Australia.
|3. CLIMATE AND AGRO-ECOLOGICAL ZONES
Another important air circulation system – the Walker circulation – links warmer and cooler areas of the oceans in equatorial regions, producing moist south-easterly winds over eastern Australia when there is a large pool of warm water adjacent to eastern Australia, as occurs during a La Niña (wet) phase. These winds are drier and less frequent during the El Niño (dry) phase, a phase that is associated with warm water in the central Pacific Ocean and droughts in eastern Australia. Hence, there is interest in monitoring the ENSO (El Niño – Southern Oscillation) phenomenon, which is rather crudely estimated in Australia by differences in air pressure recorded at Darwin and Tahiti (Southern Oscillation Index). The Indian Ocean Dipole, which is based on a comparison of sea surface temperatures near the equator in both the western and eastern Indian Ocean, is another phenomenon that is associated with wet and dry phases on the Australian continent.
There are three significant ocean currents that influence the near-shore environment of Australia. The first is the cold WA current that swings from the southern Indian Ocean up the WA coast in summer. The second is the Leeuwin current, a warm offshore current that flows down the west coast of Australia. This current is low-salinity and nutrient deficient; it prevents the upwelling of cold, nutrient rich water as happens on the west coasts of South and North America, Africa and Europe. The third current is the warm east Australian current that brings warm water down the east coast of Australia. The interplay of the main air current systems (cyclones and anticyclones) with the ocean currents (cold, warm) determines the Australian climate from season to season and location to location. Seasonal conditions depend on the positioning of the subtropical ridge in relation to the occurrence and movement in summer of the tropical monsoons, the tropical continental winds (hot north-westerlies) and south-east trade winds, and in winter of the southern maritime and polar maritime systems.
The climate records of the past 100 years identify a general global warming.
Parts of Australia seem to be following this trend, which appears to have
accelerated in recent years. Temperatures in eastern Australia rose by
about 0.5 degrees Celsius over the period 1930 to 1988 (Bureau of Meteorology,
1995) and, across Australia, the mean temperature during 2005 was 1.1
0C higher than the mean for the 1961-90 period. The implications of climate
change for pastures and livestock are dealt with in sections 4-6.
3.2 Agro-ecological zones
Pasture adaptation/production in the temperate and tropical zones follows a similar seasonal regime to crops. In southern Australia, self-regenerating annual pastures, dryland temperate crops (wheat, barley, oats, canola, lupins, peas and chickpea) and forages (cereals for grazing and grain) are grown from May (late autumn) to November late spring); there are also significant areas of perennials including native grasses, sown temperate grasses and dryland lucerne (= alfalfa, Medicago sativa) (Section 5). Further north in the subhumid and wet zones of northern NSW and south-central Queensland, subtropical/tropical perennial grasses and legumes, dryland tropical crops (sorghum, sunflowers) and forages/green manures (forage sorghum, lablab, butterfly pea) are grown from October to April (summer); in inland southern Queensland, lucerne, annual medics and forage oats are grown and grazed in winter when sufficient soil moisture is available. Along the eastern Queensland coast, many native grasslands have been improved by the introduction of sown subtropical and tropical species. The wet/dry monsoonal tropics, where sown pastures are infrequent (Figure 8), remain dominated by native tropical grasses (Section 5) but buffel grass (Cenchrus ciliaris) is sown and has become naturalised over large areas. Of the legumes available for north of the Tropic, a range of stylos (e.g. shrubby stylo S. scabra) have a similar potential.
In southern NSW and northern Victoria, on either side of the Murray River
which receives water from annual snowmelt stored in high-country water
storages, summer crops (rice, maize, soybean), winter crops and forage
crops are grown under irrigation, as well as subtropical grass + temperate
legume pastures for dairy and fat lamb production (Figure 8). On the subhumid
subtropical plains on northern NSW and southern Queensland, limited irrigation
water is used for the flood irrigation of areas of cotton production with
some soybeans and maize, not pastures.
4.1 Australian livestock production
In temperate Australia, year-round stocking rates of about 0.5-2 dry sheep equivalents (dse) per hectare (or the equivalent in cattle) are carried on non-degraded native pastures, with about 8-10 dse on good quality improved pastures. In northern Australia, one beef animal or its equivalent in sheep (8 dse) can be carried per ha on well-improved pastures or on 3 ha of the best native pastures, compared with more than 50 hectares being needed to carry the same animal on the least productive pastures.
Domestically, Australians annually consume 37 kg beef and veal (steady trend), 13 kg of sheep meat per capita (steady), along with 25 kg pig meat (↑) and 38 kg poultry (↑) (Australian Bureau of Statistics). Livestock production is geared both to this domestic demand and to export markets for livestock products and livestock.
4.2 Dairy cattle
There are many different breeds of sheep in Australia, each having attributes that suit different conditions and circumstances. Conditions such as climate, soil type, access to markets, economic trends and a variety of social factors affect breed popularity. The Merino breed still constitutes the majority of the total Australian sheep flock, because of their adaptation to the environment, high quality wool, relatively high wool production per head and their value as a component of the fat lamb production system. Dual-purpose breeds such as the Corriedale and Polwarth are declining but meat breeds are needed for the production of sires of fat lambs. The four main types of sheep enterprises in Australia are:
Table 2. The distribution of broadacre slaughter lamb producing farms, 2001-02 to 2007-08 by number of slaughter lambs sold
The majority of sheep farms are staffed by family members, with occasional contract labour. Most farms are diversified, producing wool, beef and/or grain. In southern Australia, the biological optimum time for joining ewes with rams is from late February with lambing in late July (slopes and plains) to late September (tablelands). In practice, sheep are mated to lamb from March to September, with some flocks split for lambing in different months.
4.4 Beef production
The differentiation into various systems of beef production is due largely to the growth rate of the animal and the degree of finish or fat cover that can be achieved on a particular farm or under a particular environment. Broadly, animals may be raised on the one farm until slaughter or they may be purchased as ‘store cattle’, for finishing on pasture in a more favourable environment or in a feedlot. Adult cattle are slaughtered to produce a carcass weight of 325-350 kg at 2-2.5 years of age in southern Australia and 4-4.5 years (bullocks or culled cows, Figure 9) in northern Australia. Better livestock management and improved pastures have closed the gap between turn-off rates between beef cattle in northern and southern Australia (Figure 10).
On temperate improved pastures in southern Australia, other systems of production include:
The most popular types of beef cattle are the Angus and Hereford breeds
in southern Australia, with Brahman and Brahman-derived crossbreeds such
as the Santa Gertrudis, Braford and Droughtmaster in tropical Australia.
Other breeds include Charolais, Murray Grey and Shorthorn.
Table 3. The distribution of broadacre beef cattle farms by numbers of cattle (average between 2001/02 and 2007/08) (Mackinnon, 2009)
4.5 Other livestock production
5.1 Native grasslands
5.1.1 Native grasslands in southern Australia
Garden and Bolger (2001) and Wolfe and Dear (2001) used the state and
transition model to update the nature and timing of changes that occurred
in grasslands on the tablelands of NSW since 1950 (Figure 11). These changes
were rapid, driven by the popular practice of aerially applying legumes
and superphosphate (originally 100-125 kg/ha/year) to native pastures
to provide higher quality feed and to provide nitrogen for grasses, as
well as sowing exotic grasses and legumes into herbicide-treated or prepared
seedbeds. Other agents of change were grazing at higher stocking rates
(which enhanced the transfer of fixed nitrogen to the associated species),
invasion by nitrophilous weeds, a process of soil acidification (due to
changes in the cycling and distribution of nitrogen and carbon in the
grazed ecosystem), various good and bad management practices, bursts of
enthusiasm and apathy towards pasture improvement, and wet/dry years.
As a consequence, pastures along the NSW slopes and tablelands exist in
an array of states (Figure 11), some even reverting back to native species
after a history of fertilization and legumes. Several native grasses,
especially perennials like the wallaby grasses (Austrodanthonia
spp.) and redgrass (Bothriochloa macra), [see Photo 4.] are currently
regarded as useful because of their tolerance of grazing, their adaptation
and their lack of spiny awns. Poa tussock and weeping grass (Microlaena
stipoides) are persistent on wetter, more fertile sites. The main
impediments to resowing larger areas of native pastures are their relatively
low productivity in favoured areas compared with exotics and the lack
of seed, or its high cost if available.
Other important components of the degraded grasslands of southern Australia included many grasses, forbs and legumes that became naturalised after their entry to Australia. Sometimes this naturalisation followed their accidental introduction in agricultural produce from various destinations along the sea routes from Europe and the Mediterranean region to Australia (for example, silver grass Vulpia spp.), barley grass (Hordeum leporinum) and capeweed (Arctotheca calendula). In other cases, plants that were introduced deliberately as ornamentals, such as soursob (Oxalis pes-caprae), variegated thistle (Silybum marianum) and Paterson’s curse or ‘Salvation Jane’ (Echium plantagineum), colonised pastures (Michael, 1970). Most of the strains of subterranean clover (Trifolium subterraneum) found in the suburbs of Perth by Gladstones (1966) entered Australia accidentally before 1870, and some annual Medicago spp. were naturalised by the early 1900s (Crawford et al., 1989). Michael (1970) attributed the competitive success of these alien species to their adaptability to disturbed environments and/or the absence of their native pests and competitors. Why they were so successful in competition with the native perennial grasses is open to speculation. A possible reason is that the winter-growing Mediterranean annuals depleted soil water in spring such that the summer-growing perennials were unable to survive the long, dry summers. Another factor may have been selective grazing of the perennials by sheep over summer, reducing the above-ground green material and energy reserves of the perennial grasses, and encouraging invasion by serious weeds such as serrated tussock (Nassella trichotoma).
With some variations, similar patterns of clearing and botanical change occurred throughout the tablelands, slopes and plains of NSW, central and southern Victoria, Tasmania, lower SA and the south-western tip of WA. On parts of the Central and Southern Tablelands of NSW, the aggressive and indigestible serrated tussock (Nassella trichotoma, a native of South America) colonised tracts of non-arable country (Campbell, 1998). On the northern slopes of NSW and on granite soils in southern Queensland, three-awned speargrass or wiregrass (Aristida ramosa), an unpalatable C4 species, became co-dominant with redgrass on extensive areas of lightly grazed grasslands – it has subsequently been shown that A. ramosa is sensitive to defoliation and the balance can be shifted back towards more palatable C3 species by strategic seasonal grazing (Lodge and Whalley, 1985). Towards the 300-350 mm rainfall isohyets (Figure 2) in north-western Victoria, southern SA and south-western WA, extensive areas of mallee shrublands (‘mallee’ is a multi-stemmed, lignotuber form of eucalypt species, a form that occurs in sandy areas of variable rainfall) were cleared for wheat growing, with sheep pastured on the various native and naturalised, annual volunteer species that occurred in fallows. The mallee shrublands that occur along parts of the coast of SA and WA were cleared and used for crops/pastures only in the last 40-60 years, after micronutrient problems were solved and when heavy equipment was available for sowing crops and pastures.
Accurate statistics on current pasture areas in Australia are difficult
to obtain due to the nature of the questions asked in the official census
that is taken every 5 years. Dear and Ewing (2008), who extracted the
area data from the Australian Temperate Pastures database (Hill and Donald,
1998), reported an area (excluding Queensland, NT and tropical WA) of
32 M ha of unimproved native pastures and 6 M ha of improved native pastures
(fertilized or fertilized + oversown, mainly in areas with >550 mm
average annual rainfall). These values compare with an area of up to 25
M ha of sown pastures in southern Australia. The adaptation of sown species
and cultivars in southern Australia is discussed in section 5.2.
5.1.2 Native grasslands in northern Australia
In 1996 and 1997, Bortolussi et al. (2005a, 2005b, 2005c) comprehensively
surveyed 375 producers representing the northern Australian beef industry
that is based on these subtropical and tropical native grasslands. In
contrast to southern Australia, where cropping and livestock grazing for
meat and wool is conducted on properties that are of moderate size (median
2000 ha) with most beef farms having less than 400 head (Table 3), the
median size of the survey properties was 1,669 ha (Maranoa and south-west)
to 36,310 ha (north-west) in Queensland (range 324-2,133,100 ha), 304,200
ha in the Northern Territory (range 20,000-1,630,433 ha) and 286,216 in
northern WA (range 300-914,386 ha). Median herd sizes were from 1,550
head (central coastal Queensland) to 62,000 (Northern Territory). From
the survey, the most commonly used native pasture communities (Table 4)
were speargrass (high rainfall, near to the coast) and Mitchell grass
(inland plains), while improved pastures based on grasses or grasses +
legumes were sown mainly in intermediate areas formerly dominated by black
speargrass, woodland (Aristida-Bothriochloa association) or acacia
scrub (brigalow, gidgee).
Table 4. The frequency of native and sown pasture communities and the average annual liveweight gains of cattle (LWG, kg/head) on 375 surveyed beef properties in northern Australia, 1996/97 (Bortolussi et al., 2005b)
Based on a broad scale assessment of Queensland’s land resources in the late 1980s and expert opinion (Walker and Weston, 1990; J.G. McIvor personal communication), the area of native pastures grazed by livestock in northern Australia is likely to be about 110 M ha, of which an area of around 5 M ha comprises naturalised pastures (occasionally fertilized, oversown and/or naturally spreading improved species) and 4.5 M ha sown pastures. The adaptation of sown species and cultivars in northern Australia is discussed in section 5.3.
5.1.3 Native or exotic?
5.2 Sown pasture types and species, temperate Australia
5.2.1 Map of zones
5.2.2 Temperate pasture zones
5.2.3 Perennial temperate species
Phalaris, grown on 4.5 M ha, is second to perennial ryegrass in total pasture sowings and is the dominant temperate sown grass where perennial ryegrass will not persist. It characterises important sheep and cattle meat-producing areas in NSW, Victoria, SA and Tasmania. A deep-rooted, prostrate habit, dense tillering, partial summer dormancy and the presence of a large underground rhizome are features associated with the outstanding persistence of the ‘Australian Commercial’ cultivar. This cultivar possesses important deficiencies such as poor seed production due to shattering, slow seedling establishment, a susceptibility to acidic soils and several anti-nutritional components, factors that have been addressed, at least in part, by breeding (Oram and Lodge, 2003; Oram et al., 2009). However, the presence of phalaris in grazed pastures is generally prized, conferring both stable productivity and sustainability (soil protection, competitive ability with weeds, reduction in groundwater accessions).
Lucerne, sown either alone or in mixture with other species, is currently grown on more than 3.5 M ha (Dear and Ewing, 2008), with most of this area occurring in the wheat belt. During the 1980s, after the dominant Hunter River cultivar succumbed to the spotted alfalfa aphid and the blue-green aphid, successful breeding programs were developed to produce several aphid-resistant, Australian-adapted lucerne cultivars with boosted winter activity (Williams, 1998; Humphries and Auricht, 2001). A beneficial spin-off from this effort was the improved tolerance of Australian cultivars to diseases such as phytophthora root rot (Phytophthora medicaginis) and colletotrichum crown rot (Colletotrichum trifolii) (Irwin et al., 2001). These diseases limited lucerne survival in humid summer environments found in northern NSW and Queensland, the zone where lucerne is most needed to restore soil fertility. During the 1990s and into the new millennium, a continuing investment in lucerne improvement was justified, at least in part, by the stronger focus on soil health and agricultural sustainability in the main pasturelands and croplands (Cocks, 2001). Several Australian studies (Turner and Asseng, 2005) have confirmed the value of lucerne in utilising water spared by annual crops and annual pastures, thereby reducing the potential of groundwater recharge both directly (water extraction) and indirectly (creating extra water storage capacity prior to winter).
Dear and Ewing (2008) outlined the rationale for a targeted effort to increase the available deep-rooted perennial pasture species for the control of dryland salinity in Australia. Hughes et al. (2008) described the systematic process, including the development of a database of priority species (nearly 700); their screening for weed risk; securing the needed germplasm from Australian and overseas collections or by direct collecting; quarantine; nursery and plot evaluation; and species characterisation and multiplication. A preliminary review of the results of this program was given by Dear et al. (2008) who, among other species, mentioned cullen or tall verbine (Cullen australasicum, an Australian native, leguminous shrub), lotononis (Lotononis bainseii, already available from prior work done in subtropical Australia), several available temperate and tropical perennial grasses and, for discharge (salty) environments, certain legumes (e.g. Melilotus siculus, M. sulcatus) and grasses (e.g. Puccinellia ciliata). This program, restricted somewhat by inadequate funding, is an example of what can be done when experienced, committed professionals work towards a clear objective.
Finally in this section, mention needs to be made of the potential of
subtropical and tropical perennial C4 species such as Kikuyu, Rhodes grass
(Chloris gayana), buffel grass and lotononis in temperate areas,
especially in the temperate/subtropical transition zone along the NSW-Queensland
coast (Figure 8), the border slopes/plains (Boschma et al., 2009)
and for specific purposes such as the management of groundwater accessions
in southern Australia (Nie et al., 2008).
5.2.4 New temperate annual legumes for pastures
During the 1980s, the release of cultivars of yellow serradella (Ornithopus compressus, tolerant of acidic, sandy soils), Medicago murex (tolerant of acid soils) and balansa clover (Trifolium michelianum, suitable for waterlogged, heavy–textured soils) extended annual legumes into specific niches. From 1990, the changing nature of farming systems and a recognised lack of legume biodiversity triggered a new emphasis on annual pasture legume breeding and selection (Loi et al., 2005). A national effort (Nichols et al., 2007) was directed towards producing annual legumes to deal with particular problems and opportunities, such as legume adaptation on difficult soils (acid, waterlogged or saline), weed and insect threats, longer pasture and cropping phases, deeper-rooted plants to reduce groundwater accessions, and the need for easily harvested and sown seed. As a result, a wide range of species and cultivars are now available for the wheat belt in WA and other States (Table 5).
Cultivars of pink or French serradella (Ornithopus sativus), gland
clover (Trifolium glanduliferum) and biserrula (Biserrula pelicinus)
[see Photo 6.] are the most successful outputs from this recent, well-executed
program (Loi et al., 2005; Nichols et al., 2007). Yellow
and pink serradella are the only species that are well-adapted to the
sandy soils of coastal WA. New cultivars of yellow serradella (cvs. Yelbini,
Charano, Santorini and King) and French serradella (cvs. Cadiz, Margurita
[Photo 6], Erica) were selected for the combination of pod retention and
straight (non-segmenting) pods, which allowed direct heading and reduced
the need for seed processing. Gland clover (cv. Prima) has resistance
to redlegged earth mite and aphids. Biserrula, which can be harvested
with commercial headers, is a successful alternative to subterranean clover,
which is difficult to harvest. Biserrula (cvs. Casbah, Mauro) offers a
high level of hard seeds with a delayed seed softening pattern, a deep-rooted
habit and a potential for herbicide-free weed management (Loi et al.,
2005). Another legume species that is of particular interest is eastern
star clover (Trifolium dasyurum) [Photo 6]. Following the normal
break of season (late autumn), eastern star clover germinates several
weeks after other pasture legumes and weeds (Loi et al., 2005),
a pattern that can be combined with strategic grazing or herbicide application
to control crop weeds during the pasture phase. In addition to the recent
release of cultivars of these and other new annual legume species (e.g.
T. spumosum , bladder clover), new cultivars have also revitalised
the use of traditional subterranean clover and annual medic as well as
less popular species such as rose clover (T. hirtum) and arrowleaf
clover (T. vesiculosum) (Nichols et al. 2007). This program
is a further example that illustrates Australian ingenuity in assembling
temperate germplasm, ingenuity that also applies to the domestication
of a range of genera and species for subtropical and tropical Australia
Table 5. The effects of soil type and the length of the pasture phase on the choice of legume species used in pastures in the wheat belt of southern Australia. In each zone, the areas of the legumes in parenthesis are subdominant.
There has been little recent research into annual pasture grasses for the cropping zone because of the potential of these grasses to become important crop weeds. Such is the case with Wimmera ryegrass, which has become resistant to a wide range of herbicides (Broster and Pratley, 2006). However, cereals sown for grazing and grain (Hacker et al., 2009), oats sown with vetch (Vicia sativa) or peas (Pisum sativum) (Coventry et al., 1998; Kaiser et al., 2007) and an array of annual and biennial grasses marketed by commercial companies are potentially valuable as short-term forages.
5.3 Sown pasture species, subtropical and tropical Australia
5.3.1 Pasture zones in the subtropics and tropics
Early successful introductions were Rhodes grass, Kikuyu, lucerne, white clover and various annual forages. As well, experience was gained with a range of tropical grasses and legumes, but pasture improvement was limited until the complex major and trace element deficiencies of the coastal soils were sorted out and corrected during the 1950s. Then, it was clear that certain trailing/climbing legumes, such as centro (Centrosema molle) and puero (Pueraria phaseoloides) in the north, and Desmodium spp., Macroptilium spp. and glycine (Neonotonia wightii) in the south, grew well once their rhizobiology limitations were resolved. Several grass species, belonging to genera including Digitaria, Panicum, Setaria and Paspalum, which were productive and persistent in plots, were adopted commercially.
At this time (1960s-70s), constraints to research funding and the declining importance of dairying relative to beef production shifted the emphasis to tropical pastures further north and west of south-eastern Queensland. Concurrently, the emphasis in the main program shifted from species agronomy to pasture utilisation by cattle. It was realised that the impressive growth of tropical species that were tall (grasses) and/or climbing/twining (e.g. legumes such as siratro, Macroptilium atropurpureum) did not necessarily translate well into cattle production. The poorer production from pastures based on tall or climbing species versus shorter, denser pastures occurred both at low stocking rates, where the open sward structure resulted in cattle grazing for relatively long periods to harvest sufficient forage to meet their requirements (Stobbs, 1973), and at moderate to high stocking rates, where twining species persisted poorly under heavy cattle grazing (Jones and Jones, 1978).
Hence, subsequent emphasis was on expanding the list of shorter, denser species that were likely to be tolerant of heavy grazing (Cameron et al., 1989), on improving disease and insect tolerance in proven species (Cameron et al., 1993 quoted by ‘t Mannetje, 2003), and overcoming anti-nutritional constraints to cattle production (Jones and Megarrity, 1986). Some of the persistent legumes released were lotononis, jointvetch (Aeschynomene americana, A. falcata and A. villosa) and creeping vigna (Vigna parkeri). The highly persistent and productive, rhizomatous legume Arachis glabrata was released as an option for intensively grazed dairy pastures, but it proved commercially unacceptable since it required vegetative propagation. Pinto peanut (A. pintoi) is now recommended widely.
Relatively recently, forage resources in the form of a forage selection tool (SoFT) supplemented with fact sheets in CD-ROM (world database) and online (Australian database) versions have been made available (Cook et al., 2005 – see www.tropicalforages.info). Examples of the output of potentially suitable tropical species from the CD-ROM database are given in Table 6, for perennial grasses and legumes that tolerate heavy grazing on relatively dry sites (500-750 mm annual rainfall) and wet sites (1800-2500 mm). The species that are suitable for intermediate rainfall (800-1500 mm) areas can be inferred from this table. [Details of grass and legume species, with photographs, are also available in the FAO Grassland Species database < /www.fao.org/ag/AGP/AGPC/doc/GBASE/Default.htm >].
In Figure 12 are shown five pasture zones that occur in subtropical and
tropical Australia – the subtropical transition zone, the humid
coastal perennial pasture zone that is primarily confined to Queensland,
the tropical (speargrass) pasture zone in Queensland that was originally
colonised by Townsville stylo (Stylosanthes humulis), the wet/dry
tropics of northern Australia and an inland, low-moderate rainfall zone
(here termed tropical sub-humid/semi-arid perennial pasture zone) in which
species must tolerate a long (6+ months) winter drought. These zones,
described below, are a convenient simplification of reality. For greater
detail concerning tropical pasture species recommended for regions in
northern Australia, the reader is referred to the following on-line pasture
5.3.2 Subtropical transition zone
Table 6. Sown pasture plants suitable for long-term pastures and heavy grazing in Australia’s subtropics and tropics (Cook et al., 2005).
5.3.3 Humid coastal perennial pasture zone
If the soil fertility is relatively low and the grazing system is intensive, Indian bluegrass (Bothriochloa pertusa), creeping bluegrass (Bothriochloa insculpta), Caribbean stylo (Stylosanthes hamata) and shrubby stylo (Stylosanthes scabra) are preferred. Several grasses are suitable for seasonally wet areas in this zone, such as para grass (Brachiaria mutica = Urochloa mutica), aleman grass (Echinochloa polystachya) and humidicola (Brachiaria humidicola = Urochloa humidicola).
5.3.4 Tropical (speargrass) pasture zone
Walker and Weston (1990) mentioned the replacement of black speargrass
with volunteer Indian bluegrass on 0.8 M ha in parts of coastal and sub-coastal
north Queensland, as a result of heavy grazing that followed the anthracnose-induced
collapse of the Townsville stylo component. When the stylo population
“crashed”, leading to near denudation of catchments, the already
naturalised Indian bluegrass was fortuitously able to revegetate the bare
landscapes, thereby minimising the potentially catastrophic erosion problems
that would have otherwise occurred.
The current species that are suitable for sowing on sites in this zone include:
When grown in pure stands, many grasses experience N rundown, requiring legumes such as leucaena, caatinga stylo and desmanthus (D. virgatus). Creeping bluegrass, which is often sown on the better forest soils, tends to be too competitive with the legume component.
5.3.5 Wet/dry tropics
Some potentially useful species for permanent pastures in seasonally
flooded areas in the monsoonal Northern Territory include Brazilian centro
(Centrosema brasilianum), aleman grass (which can only be established
from cuttings), green/Gatton panic and perennial forage sorghum (sorghum
hybrid). Shrubby stylo is worth introducing into grassy pastures in inland,
drier areas. Centrosema pascuorum is an important legume on the
floodplain country and Digitaria milanjiana is also finding application.
Andropogon gayanus and the water grass, Hymenachne amplexicaulis,
which are very useful forages in their respective habitats, have both
become environmental weeds in the region.
5.3.6 Tropical sub-humid/semi-arid zone
On the plains of this zone, there are each year 1-2 M ha of winter and
summer crops in northern NSW and southern/central Queensland, principally
wheat and sorghum. The cropped areas are grazed after harvest. There has
been work done to develop legumes that may be used either in short pasture
phases of tropical cropping systems or as a component of a perennial pasture
for areas where grazing intensity can be controlled (Cameron, 1996). This
legume research was a response to declining grain yields and grain protein
levels of cereal crops. Butterfly pea (Clitoria ternatea), burgundy
bean (Macroptilium bracteatum) and lab lab (Lablab purpureus)
are recommended as ley legumes in central Queensland, and burgundy bean
has potential in southern Queensland also (Pengelly and Conway, 2000).
Currently, about 1.2 M ha of lucerne pastures are grown to restore soil
fertility after several years of cereal crops. These lucerne pastures
also are grazed or cut for hay. According to Walker and Weston (1990),
annual medics are naturalised on about 1.7 M ha of inland pastures and
dry watercourses in southern Queensland. The interface between the temperate
and subtropical areas that are either side of the inland NSW-Queensland
border poses particular problems for pasture systems, requiring the selection
and utilisation of temperate grasses that are either deep-rooted or summer
dormant, or subtropical species that are frost tolerant (Boschma et
6.1 Research outcomes
Some of the past highlights from animal production research have included the adoption by the sheep industry of the system of crossing Merino x Border Leicester ewes to Dorset Horn sires (and alternatives) for prime lamb production, the introduction of Bos indicus bloodlines into tropical cattle, the exploitation of novel exotic pasture legumes, successful strategies to substantially reduce the impact of rabbits on Australian pastures, the eradication of tuberculosis and brucellosis in Australian cattle, and the recognition and management of soil acidity in southern Australia (Scott et al., 2000). The last-mentioned topic (Box 1) exemplifies win-win benefits for both production agriculture and the environment. Current Australian research priorities reflect the production-environmental approach, such as the management of agricultural systems and catchments to avoid soil erosion, species losses and salinisation, the abatement of greenhouse gas emissions from agriculture, the ongoing need to achieve improvements in water efficiency and conservation, and the adjustment of local agriculture to climate change.
In recent years, the research agenda has broadened to include environmental, financial and social issues on the farm (Mason et al., 2003). Unfortunately, past research into on-farm business management and off-farm supply chains has often not been relevant to farm profits (McCown and Parton, 2006) and, while the need for social indicators in agriculture is acknowledged, there are as yet no agreed protocols for the routine collection of indicators that define the social capital of farm families.
From the research and development pool of knowledge accumulated so far,
there are a number of aspects of pasture management that are now part
of industry best practice in Australia. An example is the widespread use
of soil and plant tissue testing services in order to plan fertilizer
applications, especially for the major nutrients P and S (soil tests)
and trace elements (tissue tests) which are needed by legumes. These aspects
are discussed further below.
6.2 Pasture management for productivity and sustainability
6.2.1 Fertilizer rates
Phosphorus (P) is widely deficient and deficiencies of sulphur (S) are common. Superphosphate (9% P, 11% S) and sulphur-fortified superphosphate (e.g. Pasture SF 5.5% P, 40 % S) are the main fertilizers applied to pastures, by aircraft in non-arable areas. Rates of P are usually 20-30 kg P/ha if the soil is deficient and new pastures are being established, with maintenance applications of 10-15 kg P/ha. These rates may be applied less frequently on land that is of lower potential productivity. On many tableland soils, molybdenum is required as a trace element (50 g/ha per application, mixed in superphosphate). In the wheat belt, rather than topdressing pastures with superphosphate, extra P- and S-containing fertilizer may be applied with the last one or two crops for the subsequent pasture phase. Soil pH is monitored routinely as a guide to the need for lime amendment every few years. On susceptible soils the common rate of lime for each application is 2.5 t/ha.
6.2.2 Grazing management
From the research evidence available, it appears that cattle and sheep
are complementary rather than competitive. A management approach that
combines sheep and cattle, grazing either together or sequentially, produces
several benefits, including a more even utilization of pasture and the
management of certain weeds that are avoided by one livestock group. For
example, Paterson’s curse, a well-known weed in south-eastern Australia,
is grazed by sheep and avoided by cattle and horses.
6.2.3 Weed management
6.3 Future opportunities
6.3.1 Research capacity (also see Section 7.)
More optimistically, the negative trends could be balanced by better
communication between scientists around the world and by improved collaboration
between production scientists and environmental scientists. Another issue,
the slow adoption of research findings, especially complex technologies
that are aligned with sustainable production, is being addressed through
the adoption by the livestock industries of participatory extension methodologies
(e.g. Pannell et al., 2006; Friend et al., 2009; Hacker
et al., 2009) rather than employing the diffusion (trickle down)
approach that is effective with simple technologies.
6.3.2 Molecular biology applications for pasture species improvement
Biotechnology is justifiable on the basis that it has the potential to
achieve what conventional plant breeding might never achieve. However,
there are two issues that are likely to ensure that most of the ideas
for projects may fail to produce an outcome. First, the pathway from the
cell to the ecosystem level is difficult (Giampietro, 1994). The scientific
understanding of the plant genome is still poor – substantial effort
will be needed to assign function to genes, particularly when protein
function is context dependent. There is a complex sequence of steps necessary
to insert a gene, alter its level of expression and utilize it (Oram and
Lodge, 2003). Biotechnologists have a track record of unrealistic optimism
in terms of achieving, on-time and on-budget, the targets that they or
their backers have set (e.g. the search for a bloat-resistant lucerne).
Second, there is the matter of unintended consequences. The experience
of Dear et al. (2003) with transgenic subterranean clover is revealing.
A gene for tolerance to bromoxynil herbicide (bxn) was isolated from a
soil bacterium and inserted successfully into a range of agricultural
plants, among them subterranean clover. Dear and his colleagues explored
some of the potential changes that a random insertion of the bxn gene
might cause. The inclusion of the bxn gene did not change the agronomic
characteristics of one of the three resultant lines, but the gene or transformation
process did have unintended effects (reduced seed production, lower levels
of hard seed, and changes to the levels of phyto-oestrogens) on the other
two transgenic lines. Third, the ongoing, unresolved conflict about GM
organisms is another negative complication. However, there are some Australian
plant breeding groups, working with a major species for the world market
(e.g. lucerne, cotton), that possess sufficient expertise and experience
for success at the genome, plant and industry levels. Such groups will
utilize molecular marker technologies that are useful in exploring plant
genomes and in building up genetic combinations for heterosis and disease
resistance (Irwin et al., 2001).
6.3.3 Pasture monitoring and decision support systems
6.3.5 The impact of global factors on pasture and livestock production
Australian agricultural producers, who receive mild benefits from government policies such as investment and research incentives, have so far adjusted to the realities of free markets. However, there are signs (increasing age of farmers, increasing indebtedness, difficulties in attracting skilled labour on farms) of market failure. One example is the plight of local dairy farmers who run large (250+ cow), multi-million dollar enterprises that do not produce a satisfactory return.
Predictions of a hotter continent, a more erratic climate and a drier south-eastern Australia (McKeon et al., 2009) may bring greater operational diversity in Australian agriculture, at least at the regional level (Harle et al., 2007). Resource limitations and other constraints may encourage many livestock producers to seek a lower input, more ecologically-focused production system rather than one that operates at a higher level of production risk. Other graziers will respond to the expanded array of useful pasture species for tropical and temperate areas (Section 5); they will make greater use of perennial species, supplemented strategically with annuals, to convert rainfall to fodder and meat and to protect the soil resource. In the wheat belt, risky crop production areas may be turned over to meat and wool production (Kopke et al., 2008), while crops may extend further into suitable high-rainfall areas (Harle et al., 2007). Before the recent improvement in prices for livestock, extension officers acknowledged the social rather than technical difficulties of improving or expanding livestock production in the wheat belt, where many crop specialists reluctantly tolerate the presence of livestock (Robertson and Wimalasuriya, 2004) as a means of capturing some of the synergies of mixed farming.
The strong demand for food may lead to a greater number of larger, specialised
farms that achieve synergy through integration with complementary businesses.
In Australia, the complexity of managing large, mixed farms may be offset
through innovative business partnerships that not only retain mixed farming
(diversification) but also encourage simultaneous specialisation, essentially
by separating the management of crops and livestock and placing each enterprise
into the hands of enthusiasts. For example, a well-organised sheep specialist
could run flocks on several farms. Greater benefits may come from innovation
in the economic and social aspects of agriculture, rather than by refining
the technology of production. During the last two decades, while the Australian
agribusiness sector has accepted a need to employ graduate agronomists
to supplement the reduced advisory services provided by government, few
agricultural specialists have been employed in commercial livestock production,
either extensive or intensive. Hence, at least in Australia, there is
an opportunity to overcome the lag in technology applied to grazing livestock
production, technology that is behind the level applied to crop management
or to intensive livestock. The need to manage greenhouse gas emissions,
with livestock farms seen as part of the solution rather than as part
of the problem (Howden and Reyenga, 1999; Howden et al., 2008),
is another factor that may lead to an exciting future.
7.1 The current landscape
The main pasture/livestock research centres are located at Perth (WA);
Katherine (NT); Townsville, Toowoomba and Brisbane (Qld); Armidale, Tamworth,
Orange and Wagga Wagga (NSW); Canberra (ACT); Hamilton and Melbourne (Vic.);
Hobart (Tas.); Adelaide (SA) (Figure 12). Pasture plant genetic resource
centres are located in Biloela (Qld, tropical species), Adelaide (Medicago
spp. and other legumes) and Perth (Trifolium spp. and other legumes).
7.2 List of selected personnel/organizations involved in pasture R&D
Archer, K.A., Wolfe, E.C. & Cullis, B.R. (1987) Flowering time of cultivars of subterranean clover in New South Wales. Australian Journal of Experimental Agriculture 27, 791-797.
Barr, N.F. & Cary, J.W. (1992) Greening a Brown Land, an Australian Search for Sustainable Land Use (MacMillan, Melbourne).
Bell, A.K. & Allan, C.J. (2000) PROGRAZE – an extension package in grazing and pasture management. Australian Journal of Experimental Agriculture 40, 325-330.
Blumenthal, M.J., Prakash, K., Leonforte, A., Cunningham, P.J. & Nicol, H.I. (1996) Characterization of the Kangaroo Valley ecotype of perennial ryegrass (Lolium perenne). Australian Journal of Agricultural Research, 47, 1131-1142.
Bortolussi, G., McIvor, J.G., Hodgkinson, J.J., Coffey, S.G. & Holmes, C.R. (2005a) The northern Australian beef industry, a snapshot. 1. Regional enterprise activity and structure. Australian Journal of Experimental Agriculture, 45, 1057-1073.
Bortolussi, G., McIvor, J.G., Hodgkinson, J.J., Coffey, S.G. & Holmes, C.R. (2005b) The northern Australian beef industry, a snapshot. 3. Annual liveweight gains from pasture based systems. Australian Journal of Experimental Agriculture, 45, 1093-1108.
Bortolussi, G., McIvor, J.G., Hodgkinson, J.J., Coffey, S.G. & Holmes, C.R. (2005c) The northern Australian beef industry, a snapshot. 5. Land and pasture development practices. Australian Journal of Experimental Agriculture, 45, 1121-1129.
Broster, J.C. & Pratley, J.E. (2006) A decade of monitoring herbicide resistance in Lolium rigidum in Australia. Australian Journal of Experimental Agriculture, 46, 1151-1160.
Boschma, S.P., Lodge, G.M. & Harden, S. (2009) Establishment and persistence of perennial grass and herb cultivars in a recharge area, North-West Slopes, New South Wales. Crop and Pasture Science, 60, 753-767.
Cameron, A. (1996) Evaluation of tropical pasture species as leys in the semi-arid tropics of northern Australia. Australian Journal of Experimental Agriculture, 36, 929-935.
Cameron, D.G., Jones, R.M., Wilson, G.P.M., Bishop, H.G., Cook, B.G., Lee, G.R. & Lowe, K.F. (1989) Legumes for heavy grazing on coastal subtropical Australia. Tropical Grasslands 23, 153-161.
Campbell, M.H. (1998) Biological and ecological impact of serrated tussock (Nassella trichotoma (Nees) Arech.) on pastures in Australia. Plant Protection Quarterly, 13, 80-86.
Clark, S.G., Donnelly, J.R. & Moore, A.D. (2000) The GrassGro decision support tool: its effectiveness in simulating pasture and animal production and value in determining research priorities. Australian Journal of Experimental Agriculture, 40, 247-256.
Cocks, P.S. (2001) Ecology of herbaceous perennial legumes: a review of characteristics that may provide management options for the control of salinity and waterlogging in dryland cropping environments. Australian Journal of Agricultural Research, 52, 137-151.
Conway, G.R. (1986) Agroecosystem Analysis for Research and Development (Winrock International, Bangkok).
Cook, B.G., Pengelly, B.C., Brown, S.D., Donnelly, J.L., Eagles, D.A., Franco, M.A., Hanson, J., Mullen, B.F., Partridge, I.J., Peters, M. & Schultze-Kraft, R. (2005) Tropical Forages: an interactive selection tool., (CD-ROM), (CSIRO, QDPI&F, CIAT and ILRI, Brisbane).
Coventry, D.R., Holloway, R.E. & Cummins, J.A. (1998) Farming fragile environments: low rainfall and difficult soils in South Australia. Proceedings of the 9th Australian Agronomy Conference, Wagga Wagga, www.regional.org.au/au/asa/1998/plenary/coventry.htm
Crawford, E.J., Lake, A.W.H. & Boyce, K.G. (1989) Breeding annual Medicago species for semiarid conditions in southern Australia. Advances in Agronomy, 42, 399-437.
Davis, R.D., Irwin, J.A.G., Cameron, D.F. & Shepherd, R.K. (1987)
Epidemiological studies on the anthracnose diseases caused by Colletotrichum
gloeosporoides in north Queensland and pathogenic specialization within
the natural fungal populations. Australian Journal of Agricultural
Research, 38, 1019-1032.
Dear, B.S. & Ewing, M.A. (2008) The search for new pasture plants to achieve more sustainable production systems in southern Australia. Australian Journal of Experimental Agriculture, 48, 387-396.
Dear, B.S., Reed, K.F.M. & Craig, A.D. (2008) Outcomes of the search for new perennial and salt tolerant pasture plants for southern Australia. Australian Journal of Experimental Agriculture 48, 578-588.
Donald, C.M. (1970) Temperate pasture species. (In) Moore, R.M. (ed.) Australian Grasslands (ANU Press, Canberra), pp. 303-320.
Eyles, A.G., Cameron, D.G. & Hacker, J.B. (1985) Pasture research in northern Australia – its history, achievements and future emphasis. Research Report No. 4 (CSIRO Division of Tropical Crops and Pastures, Brisbane).
Friend, M.A., Dunn, A.M. & Jennings, J. (2009) Lessons learned about effectively applying participatory action research: a case study from the New South Wales dairy industry. Animal Production Science 49, 1007-1014.
Garden, D. & Bolger, T. (2001) Interaction of competition and management in regulating composition and sustainability of native pasture. (In) Tow, P.G., Lazenby, Alec (eds) Competition and Succession in Pastures (CABI Publishing, Wallingford), pp. 213-232.
Giampietro, M. (1994) Sustainability and technological development in agriculture. BioScience, 44, 677-689.
Gillard, P. & Fisher, M.J. (1978) The ecology of Townsville stylo-based pastures in Northern Australia. (In) Wilson, J.R. (ed.) Plant Relations in Pastures (CSIRO, Melbourne), pp. 340-352.
Gladstones, J.S. (1966) Naturalised subterranean clover (Trifolium subterraneum L.) in Western Australia: the strains, their distributions, characteristics and possible origins. Australian Journal of Botany, 14, 329-354.
Hacker, R.B., Robertson, M.J., Price, R.J. & Bowman, A.M. (2009) Evolution of mixed farming systems for the delivery of triple bottom line outcomes: a synthesis of the Grain & Graze program. Animal Production Science, 49, 966-974.
Hamblin, A. (2004) The imperatives for research implementation and delivery in Australia. Proceedings of the 4th International Crop Science Congress (International Crop Science Society, Brisbane). Verified online 8th December 2009 www.cropscience.org.au/icsc2004/symposia/6/4/1324_hamblina.htm
Harle, K.J., Howden, S.M., Hunt, L.P. & Dunlop, M. (2007) The potential impact of climate change on the Australian wool industry by 2030. Agricultural Systems, 93, 61-89.
Henzell, Ted (2007) Australian Agriculture. Its History and Challenges (CSIRO, Melbourne).
Hill, M.J. (1996) Potential adaptation zones for temperate pasture species as constrained by climate: a knowledge-based logical modelling approach. Australian Journal of Agricultural Research, 47, 1095-1107.
Hill, M.J. & Donald, G.E. (1998) ‘Australian temperate pasture database’. (CD-ROM) (CSIRO Division of Animal Production, Sydney).
Hooper, S. (2009) Australian lamb 09.1 – Financial performance of slaughter lamb producing farms 2006-07 to 2008-09 (Australian Bureau of Agricultural Resource Economics, Canberra). Verified on-line 10th September 2009 www.abare.gov.au/publications_html/livestock/livestock_09/9_1_lamb.pdf
Howden, S.M. & Reyenga, P.J. (1999) Methane emissions from Australian livestock. Australian Journal of Agricultural Research, 50, 1285-1291.
Howden, S.M., Crimp, S.J. & Stokes, C.J. (2008) Climate change and Australian livestock systems. Australian Journal of Experimental Agriculture, 48, 780-788.
Humphreys, L.R. (1997) The Evolving Science of Grassland Improvement (Cambridge University Press, UK).
Humphries, A.W. & Auricht, G.C. (2001) Breeding lucernes for Australia’s dryland cropping environments. Australian Journal of Agricultural Research, 52, 153-169.
Hughes, S.J., Snowball, R., Reed, K.F.M., Cohen, B., Gajda, K., Williams, A.R. & Groeneweg, S.L. (2008) The systematic collection and characterisation of herbaceous forage species for recharge and discharge environments in southern Australia. Australian Journal of Experimental Agriculture, 48, 397-408.
Irwin, J.A.G., Lloyd, D.L. & Lowe, K.F. (2001) Lucerne biology and genetic improvement – an analysis of past activities and future goals in Australia. Australian Journal of Agricultural Research, 52, 699-712.
Isbell, R.F. (1992) A brief history of national soil classification in Australia since the 1920s. Australian Journal of Soil Research, 30, 825-842.
Jahufer, M.Z.Z., Cooper, M., Ayres, J.F. & Bray, R.A. (2002) Identification
of strategies to improve the efficiency of breeding strategies for white
clover in Australia – a review. Australian Journal of Agricultural
Research, 53, 239-257.
Johnston, W.H. (1996) The place of C4 grasses in temperate pastures in Australia. New Zealand Journal of Agricultural Research, 39, 527-540.
Johnson, I.R., Chapman, D.F., Snow, V.O., Eckard, R.J., Parsons, A.J., Lambert, M.G. & Cullen, B.R. (2007) DairyMod and EcoMod: biophysical pasture-simulation models for Australia and New Zealand. Australian Journal of Experimental Agriculture, 48, 621-631.
Johnston, W.H., Clifton, C.A., Cole, I.A., Koen, T.B., Mitchell, M.L. & Waterhouse, D.B. (1999) Low input grasses useful in limiting environments (LIGULE). Australian Journal of Agricultural Research, 50, 29-53.
Jones, R.J. & Jones, R.M. (1978) The ecology of Siratro pastures. (In) Wilson, J.R. (ed.) Plant Relations in Pastures (CSIRO, Melbourne), pp. 353-367.
Jones, R.J. & Megarrity, R.G. (1986) Successful transfer of DHP-degrading bacteria from Hawaiian goats to Australian ruminants to overcome the toxicity of Leucaena. Australian Veterinary Journal, 63, 259-262.
Kaiser, A.G., Dear, B.S. & Morris, S.G. (2007) An evaluation of the yield and quality of oat-legume and ryegrass-legume mixtures and legume monocultures harvested at three stages of growth for silage. Australian Journal of Experimental Agriculture, 47, 25-38.
Kemp, D.R., Michalk, D.L. & Virgona, J.M. (2000) Towards more sustainable pastures: lessons learnt. Australian Journal of Experimental Agriculture 40, 343-356.
Kemp, D.R. & Michalk, D.L. (2007) Towards sustainable grassland and livestock management. Journal of Agricultural Science, Cambridge 145, 543-564.
Kopke, E., Young, J. & Kingwell, R. (2008) The relative profitability and environmental impacts of different sheep systems in a Mediterranean environment. Agricultural Systems, 96, 85-94.
Lane, L.A., Ayres, J.F. & Lovett, J.V. (2000) The pastoral significance, adaptive characteristics, and grazing value of white clover (Trifolium repens L.) in dryland environments in Australia: a review. Australian Journal of Experimental Agriculture 40, 1033-1046.
Liu, G.D., Michalk, D.L., Bai, C.J., Yu, D.G. & Chen, Z.Q. (2009) Grassland development in tropical and subtropical southern China. The Rangeland Journal 30, 255-270.
Lodge, G.M. & Whalley, R.D.B. (1985) The manipulation of species composition of natural pastures by grazing management on the northern slopes of New South Wales. The Australian Rangeland Journal, 7, 6-16.
Loi, A., Howieson, J.G., Nutt, B.J. & Carr, S.J. (2005) A second generation of annual pasture legumes and their potential for inclusion in Mediterranean-type farming systems. Australian Journal of Experimental Agriculture 45, 289-299.
‘t Mannetje, L. (2003) Advances in grassland science. NJAS – Wageningen Journal of Life Sciences, 50, 195-221.
Mason, W.K., Lodge, G.M., Allan, C.J., Andrew, M.H., Johnson, T., Russell, B. & Simpson, I.H. (2003) An appraisal of sustainable grazing systems: the program, the triple bottom line impacts and the sustainability of grazing systems. Australian Journal of Experimental Agriculture 43, 1061-1082.
Masters, D., Edwards, N., Sillence, M., Avery, A., Revell, D., Friend, M., Sanford, P., Saul, G., Beverly, C. & Young, J. (2006) The role of livestock in the management of dryland salinity. Australian Journal of Experimental Agriculture 46, 733-741.
Mackinnon, D. (2009) Australian beef 09.1 – Financial performance of beef farms 2006-07 to 2008-09 (Australian Bureau of Agricultural and Resource Economics, Canberra). Verified on-line 10th September 2009 www.abare.gov.au/publications_html/livestock/livestock_09/9_1_beef.pdf
McCown, R.L. & Parton, K.A. (2006) Learning from the historical failure of farm management models to aid management practice. Part 2. Three systems approaches. Australian Journal of Agricultural Research, 57, 157-172.
McKeon, G.M., Stone, G.S., Syktus, J.I., Carter, J.O., Flood, N.R., Ahrens, D.G., Bruget, D.N., Chilcott, C.R., Cobon, D.H., Cowley, R.A., Crimp, S.J., Fraser, G.W., Howden, S.M., Johnston, P.W., Ryan, J.G., Stokes, C.J. & Day, K.A. (2009) Climate change impacts on northern Australian rangeland livestock carrying capacity: a review of issues. The Rangeland Journal, 31, 1-29.
McKinney, G.T. (1974) Management of lucerne for sheep grazing on the Southern tablelands of New South Wales. Australian Journal of Experimental Agriculture 14, 726-734.
McKenzie, N.J., Jacquier, D.W., Ashton, L.J. & Cresswell, H.P. (2000) Estimation of soil properties using the atlas of Australian soils. CSIRO Land and Water, Technical Report No. 11 – see McKenzie et al. (2004).
McKenzie, N., Jacquier, D., Isbell, R. & Brown, K. (2004) Australian Soils and Landscapes. An Illustrated Compendium. (CSIRO Publishing, Melbourne). URL: www.publish.csiro.au/pid/3821.htm
Michael, P.W. (1970) Weeds of grasslands. (In) Australian Grasslands. R.M. Moore (ed.) (ANU Press, Canberra) pp. 349-60.
Moore, R.M. (1970) (ed.) Australian Grasslands (ANU Press, Canberra).
Nichols, P.G.H., Loi, A., Nutt, B.J., Evans, P.M., Craig, A.D., Pengelly, B.C., Dear, B.S., Lloyd, D.L., Revell, C.K., Nair, R.M., Ewing, M.A., Howieson, J., Auricht, G.A., Howie, J.H., Sandral, G.A., Carr, S.J., de Koning, C.T., Hackney, B.F., Crocker, G.J., Snowball, R., Hughes, S.J., Hall, E.J., Foster, K.J., Skinner, P.W., Barbetti, M.J. & You, M.P. (2007) New annual and short-lived perennial pasture legumes for Australian agriculture – 15 years of revolution. Field Crops Research 104, 10-23.
Nie, Z.N., Miller, S., Moore, G.A., Hackney, B.F., Boschma, S.P., Reed, K.F.M., Mitchell, M., Albertsen, T.O., Clark, S., Craig, A.D., Kearney, G., Li, G.D. & Dear, B.S. (2008) Field evaluation of perennial grasses and herbs in southern Australia. 2. Persistence, root characteristics and summer activity. Australian Journal of Experimental Agriculture 48, 424-435.
Oram, R. & Lodge, G. (2003) Trends in temperate Australian grass breeding and selection. Australian Journal of Agricultural Research, 54, 211-241.
Oram, R.N., Ferreira, V., Culvenor, R.A., Hopkins, A.A. & Stewart, A. (2009) The first century of Phalaris aquatica L. cultivation and genetic improvement: a review. Crop and Pasture Science 60, 1-15.
Pannell, D.J., Marshall, G.R., Barr, N., Curtis, A., Vanclay, F. & Wilkinson, R. (2006) Understanding and promoting adoption of conservation practices by rural landholders. Australian Journal of Experimental Agriculture 46, 1407-1424.
Pengelly, B.C. & Conway, M.J. (2000) Pastures on cropping soils: which tropical pasture legumes to use? Tropical Grasslands, 34, 162-168.
Pretty, J.N., Brett, C., Gee, G., Hine, R.E., Mason, C.F., Morison, J.I.L., Raven, H., Rayment, M.D. & van der Bijl, G. (2000) An assessment of the total external costs of UK agriculture. Agricultural Systems, 65, 113-136.
Real, D., Labandera, C.A. & Howieson, J.G. (2005) Performance of temperate and subtropical forage legumes when over-seeding native pastures in the basaltic region of Uruguay. Australian Journal of Experimental Agriculture, 45, 279-287.
Robertson, S.M. & Wimalasuriya, R.K. (2004) Limitations to pasture and sheep enterprise options for improvement in the Victorian Mallee. Australian Journal of Experimental Agriculture, 44, 841-849.
Rossiter, R.C. (1966) Ecology of the Mediterranean annual-type pasture. Advances in Agronomy, 18, 1-56.
Schiere, J.B., Baumhardt, R.L., Van Keulen, H., Whitbread, A.M., Bruinsma, A.S., Goodchild, A.V., Gregorini, P., Slingerland, M.A. & Wiedemann-Hartwell, B. (2006) Mixed crop-livestock systems in semi-arid regions. (In) Dryland Agriculture (eds) G.A. Peterson, P.W. Unger, W.A. Payne. American Society of Agronomy Inc., Crop Science Society of America Inc., Soil Science Society of America Inc.: Madison WI, pp. 227-291.
Scott, B.J., Ridley, A.M. & Conyers, M.K. (2000) Management of soil acidity in long-term pastures of south-eastern Australia: a review. Australian Journal of Experimental Agriculture, 40, 1173-1198.
Shaw, A.G.L. (1990) Colonial settlement 1788-1945. (In) Williams, D.B. (ed.) Agriculture and the Australian Economy, 3rd edn (Sydney University Press, Sydney), pp. 1-8.
Sindell, B.M. (2000) (ed.) Australian Weed Management Systems (R.G. & F.J. Richardson, Melbourne).
Smith, D.F. (2000) Natural Gain: In the Grazing Lands of Southern Australia (UNSW Press, Sydney).
Spangenburg, G., Kalla, R., Lidgett, A., Sawbridge, T., Ong, E.K. & John, U. (2001) Transgenesis and genomics in molecular breeding of forage plants. Proceedings of the 10th Australian Agronomy Conference, Hobart. Verified on-line 5 November 2009 www.regional.org.au/au/asa/2001/plenary/6/spangenbergh.htm#TopOfPage
Stobbs, T.H. (1973) The effect of plant structure on the intake of tropical pastures. II. Differences in sward structure, nutritive value, and bite size of animals grazing Setaria anceps and Chloris gayana at various stages of growth. Australian Journal of Agricultural Research, 24, 821-829.
Turner, N.C. & Asseng, S. (2005) Productivity, sustainability, and rainfall-use efficiency in Australian rainfed Mediterranean agricultural systems. Australian Journal of Agricultural Research, 56, 1123-1136.
Walker, B. & Weston, E.J. (1990) Pasture development in Queensland – A success story. Tropical Grasslands, 24, 257-268.
Williams, C.H. & Andrew, C.S. (1970) Mineral nutrition of pastures. (In) Moore, R.M. (ed.) Australian Grasslands (ANU Press, Canberra), pp. 303-320.
Williams, J., Hook, R. & Hamblin, A. (2002) Agro-ecological regions of Australia. Methodology for their derivation and key issues in resource management (CSIRO Land and Water, Canberra. Verified on-line 9th September 2009 www.clw.csiro.au/publications/general2002/Agro-eco_report_nomap.pdf
Williams, R.W. (1998) Breeding better lucernes for the cropping zone of eastern Australia. Proceedings of the 9th Australian Agronomy Conference, Wagga Wagga, pp. 243-246.
Wolfe, E.C. & Dear, B.S. (2001) The population dynamics of pastures, with particular reference to southern Australia. (In) Tow, P.G., Lazenby, Alec (eds) Competition and Succession in Pastures (CABI Publishing, Wallingford), pp. 119-148.
Wolfe, E.C., Paul, J.A. & Cregan, P.D. (2006) Monitoring ley pastures
and their response to winter cleaning. Australian Journal of Experimental
Agriculture, 46, 1023-1033.
|9. CONTACTS AND ACKNOWLEDGMENTS
[The profile was drafted in the period September to December 2009 and edited by S.G Reynolds and J.M. Suttie in December 2009].