The development and use of perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), phalaris (Phalaris aquatica L.) and tall fescue (Lolium arundinaceum Darbysh.) in the high-rainfall zone and the wheat–sheep zone is reviewed through the pastoral era of extensive grazing (from European settlement to ∼1930), the expansive era of pasture improvement (1930–80) and in the modern era. Their adoption, in conjunction with inoculated clover seed, rose steadily in specifically Australian systems of animal production, designed with an appreciation of the environment, and aided by technical developments such as single-disc and aerial spreaders for mineral fertiliser, chemical fallowing and direct-drilling. These species remain vital contributors to the competitive productivity of Australia’s cattle and sheep industries. Perennial ryegrass (∼6 Mha by 1994) and cocksfoot emerged as the most important after a wide range of species was introduced through the 19th Century; many of these became naturalised. Regional strains of perennial ryegrass were subsequently selected for commercialisation in Victoria, New South Wales and Tasmania. In the modern era, persistent ecotypes were harnessed to breed persistent cultivars. Vision to both improve grass persistence and extend the area of adaptation encouraged the adoption of phalaris (∼2.7 Mha by 2009) and, to a lesser extent, early-flowering types of cocksfoot and tall fescue, particularly for the marginal-rainfall, wheat–sheep zone. The sowing of grass and clover seed expanded after the wide adoption of superphosphate, which became recognised as essential for correcting the severe deficiency of soil phosphorus and nitrogen associated with ancient, intensely weathered soils. The initial and dramatic response of clover to superphosphate increased farm revenue, so fostering a phase in which perennial grasses could be successfully sown, due to having the benefit of (biologically fixed) nitrogen. The influence of European practice, agricultural societies, the Welsh Plant Breeding Station, CSIRO, universities, state Departments of Agriculture, collaborative arrangements and individuals that nurtured and managed pasture technology, plant breeding, cultivar registration and evaluation are outlined. Future considerations emerging from the review include monitoring the national pasture inventory, promotion of the great potential for increasing livestock carrying capacity, cultivar discrimination and information, relevance of models, and national coordination of collaborative research.

Persistence of pasture in grazing systems has technical and economic dimensions. Profit from investment in pasture is maximised when the profit from the pasture is maximised over cycles of investments in pasture over the life of the farm business. The economic decision-rule is that an existing pasture should be replaced when the expected extra average addition to farm profit per year over the whole of the expected life of the next cycle of pasture investment exceeds the expected addition to farm profit from one more year of the existing pasture. This profit-maximising decision-rule means that the persistence of pasture is an economic phenomenon to be accounted for over several cycles of investment—a different concept to technical views that focus on the number of years of existence (i.e. persistence) of a pasture in one investment cycle. The number of years in which a pasture performs near peak potential annual dry matter (DM) production is a useful perspective on pasture persistence. The longer a pasture persists at peak level the more profitable. An empirical example was analysed of a pasture that had declined to carrying annually 6 dry sheep equivalents/ha (DSE/ha) and reinvestment occurred. The new pasture attained a peak of 11 000 kg/dry matter/ha in years 4–7, carrying an extra 15 DSE/ha.year, and declined to 50% of peak DM production by year 11, which was maintained until year 20. The modified internal rate of return for the base model of investing in pasture improvement was 12% real. The profit-maximising life of the pasture analysed was 8 years in repeated cycles over the life of the farm business. If this pasture produced at 65% of peak kg DM/ha for years 11–20, then the pasture was equally profitable whether the life of the pasture was any length from 8 to 20 years. If the pasture maintained production >65% of peak annual kg DM/ha, then longer pasture lives were more profitable than shorter lives.

Plant–animal interactions impact on all elements of pasture and animal performance in grazing systems. The quality of pastures for animals can be described in terms of feeding value (FV), which is a combination of feed nutritive value (NV) and voluntary intake. There are numerous complex interactions between plant physiology and pasture FV and NV. This review focuses on these interactions in four key areas (plant growth strategies, phenological development, pasture regrowth, and response to environmental stress), extracting key principles and illustrating how plant breeding or management may be used to manipulate such interactions to improve FV. The FV is low in pastures with native species that have evolved in nutrient-poor environments, especially if there are greater proportions of C₄ than C₃ species in the sward. Reproductive development of grasses and long grazing intervals (which affect stage of regrowth) reduce the proportion of leaf and increase stem or dead matter content in the sward. This is exacerbated by environmental stresses such as warmer temperatures and water deficit. Management decisions provide a means of manipulating many of these interactions to improve the FV of pasture, especially by improving soil nutrient status, using irrigation where possible, introducing exotic perennial pasture species such as perennial ryegrass, phalaris and tall fescue, linking the timing of grazing to stage of regrowth, and carefully managing post-grazing residual sward state. Likewise, plant breeding has focused on altering the flowering date of grasses, reducing aftermath heading, and reducing lignification within the plant to improve the FV of pasture for livestock.

In temperate regions of Australasia, feed-base management is the key determinant of the economic viability of dairy enterprises. However, conjecture exists regarding agreed grazing management practices for pasture-based dairy systems, because of the combined effects of variable seasonal conditions and input management (irrigation and nitrogen (N) usage). To address this conjecture a 2-year defoliation study was undertaken in the high-rainfall zone of north-western Tasmania, to examine the effect of these interactions on the yield of perennial ryegrass (Lolium perenne L.) dominated pasture. Treatments were imposed in a split-split-plot design with moisture availability the main plot treatment (irrigated or dryland), defoliation intervals (full emergence of 1, 2, or 3 new leaves/tiller) assigned to subplots, and both defoliation intensity (30, 55 and 80 mm) and N application rate (0.0, 1.5 and 3.0 kg N/ha.day) treatments crossed within sub-subplots. Although the independent effects of each treatment on total yield were significant (P < 0.05), the effect of N application was found to diminish with time (P < 0.05). Furthermore, under periods of high pasture growth resulting from the absence of moisture stress (irrigation), shortening the grazing rotation via defoliating at the second leaf stage had no detrimental impact on growth rates. However, to optimise growth rates during periods of either soil moisture deficits or low temperatures, longer rotation lengths (to the 3-leaf stage) were required. High response rates to N fertiliser were found during the initial (first 6 month) period of this 2-year study; however, these responses diminished with time, with plots receiving zero N fertiliser achieving growth rates comparable to those plots that received rates as high as 3 kg N/ha.day.

Perennial ryegrass and tall fescue are key grasses of sown pastures in the high-rainfall zone of south-eastern Australia. Ryegrass in naturalised pastures, and in sown seed, is widely infected with Neotyphodium fungal endophytes, with toxic endophyte strains occasionally causing toxicosis in livestock. Endophyte infection is also beneficial in sown grasslands, assisting ryegrass hosts to overcome biotic stresses, and tall fescue hosts to overcome biotic and abiotic stresses. We review the literature for Australia and present new data, to examine the agronomic effects of endophyte. Frequency of endophyte infection in old, perennial ryegrass pastures and ecotype-based cultivars is high and, in all pastures, increases with time, providing evidence for endophyte-infected plants having an agronomic advantage over endophyte-free plants. Within a cultivar, agronomic field experiments have compared endophyte-infected with endophyte-free swards. Endophyte significantly improved ryegrass establishment in seven of 19 measurements taken from 12 trials. In mature ryegrass pastures, over half of the experiments found advantages to endophyte infection. Tall fescues infected with a selected endophyte (‘AR542’) had improved agronomic performance relative to endophyte-free in a majority of experiments, and on occasions, the endophyte was essential for tall fescue persistence. Cultivar × endophyte interactions occurred but were inconsistent. In high-stress environments, endophyte was more important for agronomic performance than difference between cultivars. The relative importance of cultivar and endophyte is discussed, with elite cultivars that are adapted to the region and are infected with elite endophytes being the best avenue to capture the benefits and minimise detrimental endophyte effects on livestock. The major drivers are likely to be insect pests and drought, but evidence is limited.

Potential exists to select pasture species better adapted to anticipated warmer temperatures and lower rainfall, associated with increasing atmospheric carbon dioxide (CO₂) and other greenhouse gas concentrations, to maximise pasture yields and persistence. This study assessed the effect of increasing three plant traits in perennial ryegrass (Lolium perenne L.) to adapt to future climates: root depth; heat tolerance, defined as the ability of plant to grow at high temperatures; and responsiveness to elevated CO₂ concentrations. Pasture production was simulated using the Sustainable Grazing Systems Pasture model at three sites with temperate climates in south-eastern Australia: Hamilton, Victoria (medium rainfall); Ellinbank, Victoria (high rainfall); and Elliott, Tasmania (high rainfall). Two future climate scenarios were created at each site by scaling the historical climate (1971–2010) by 1°C with –10% rain (435 ppm CO₂) and 2°C with –20% rain (535 ppm CO₂). A genotype × environment interaction suggested that the plants traits most effective at increasing pasture yield differed depending on the local climate. Increased root depth was the most effective change in a single trait that increased pasture harvested at Elliott, increased heat tolerance was most effective at Ellinbank, whereas increasing all three individual traits was similarly effective at Hamilton. At each site, the most effective traits increased pasture growth during the period between late spring and mid-summer compared with the current cultivar. When all three traits were increased at the same time, the pasture production advantage was greater than the additive effects of changing single traits at Hamilton and Ellinbank. Further consideration of the feasibility of selecting multiple traits and the effects of a broader range of climate projections is required. Nonetheless, results of this study provide guidance to plant breeders for selection of traits adapted to future climates.

Microlaena (Microlaena stipoides var. stipoides (Labill.) R.Br.) is a C₃ perennial grass that is native to areas of south-eastern Australia. In this region, perennial grasses are important for the grazing industries because of their extended growing season and persistence over several years. This series of experiments focused on the population biology of Microlaena by studying the phenology (when seed was set), seed rain (how much seed was produced and where it fell), seed germination, germinable seedbank, seed predation and seedling recruitment in a pasture. Experiments were conducted at Chiltern, in north-eastern Victoria, on an existing native grass pasture dominated by Microlaena.

Seed yields were substantial (mean 800 seeds m^–2), with seed rain occurring over December–May. Microlaena has two distinct periods of high seed rain, in early summer and in early autumn. Seed predation is high. Within a 24-h period during peak seed production, up to 30% of Microlaena seed was removed from a pasture, primarily by ants. Microlaena seedlings recruited throughout an open paddock; however, seedling density was low (5 seedlings m^–2). Microlaena represented only low numbers in the seedbank (0.01–0.05% of total); hence, any seedlings of Microlaena that germinate from the seedbank would face immense competition from other species. Management strategies for Microlaena-dominant pastures need to focus on the maintenance of existing plants.

The recently completed molecular phylogenetic analysis of Dactylis germplasm has provided a clear evolutionary history of the diploid Dactylis from which modern tetraploid germplasm and cultivars have evolved. This framework will allow us to use fully a wider range of both diploid and tetraploid germplasm for a more systematic improvement of cocksfoot. Germplasm of many diploid and tetraploid forms is under serious threat from habitat degradation and climate change, and many forms are currently poorly represented in genebanks. It is critical that a wide range of these forms is collected for storage and conservation. It is also critical that core collections are developed and maintained, using molecular phylogenetic and genetic diversity information as the basic framework.

In order to apply molecular resources in an effective and balanced manner, pragmatic field breeding programs need to be continued in all major regions. This is a major concern for cocksfoot, as it is a species with limited international breeding investment. Viable, large-scale, cocksfoot breeding programs must be maintained internationally to allow adequate cultivar development, ongoing germplasm collection, introgression from wild germplasm and application of molecular resources.

The amount of pasture grown and converted to animal product is closely linked with the profitability of pasture-based systems. Kikuyu (Pennisetum clandestinum Hochst. ex Chiov.) is the predominant C₄ grass in coastal Australian beef and dairy systems. These kikuyu-based production systems face several key challenges to achieving high levels of productivity. In this review, we bring together the literature to highlight the opportunities for closing the gap between current and potential utilisation and for increasing dairy production from kikuyu-based pastures. More specifically, we highlight the significant gains that can be made on kikuyu-based commercial farms based on a conceptual model to show where the main losses originate, namely input and grazing management. The physical limitations associated with kikuyu for dairy systems are also presented, such as the relatively higher content of cell wall and lower content of water-soluble carbohydrates, together with nutrient imbalances relative to other grass species. Together, these limitations clearly indicate the need of supplying cows with supplements (particularly grain-based concentrates) to achieve moderate to high milk yield per cow. To achieve this without compromising pasture utilisation, dairy producers farming on kikuyu-based pastures need to use relatively greater stocking rates to generate enough demand of feed that can be used to align rate of pasture intake with rate of pasture growth, creating enough deficit of feed per cow to justify the addition of supplementary feed without impinging on pasture utilisation. The variability that exists between cows in kikuyu dry matter and neutral detergent fibre intake is also highlighted in this review, opening up new avenues of research that may allow significant productivity gains for kikuyu-based dairy farming in the future.

The agricultural region of south-west Western Australia (WA) has a Mediterranean climate, characterised by a winter-dominant rainfall pattern. Perennial subtropical grasses are increasingly being grown to increase productivity and reduce erosion on infertile sandy soils in the northern agricultural region (NAR) of WA, an area with mild winters and dry, hot summers. However, little information exists on the persistence of different species or their expected seasonal production and feed quality. On the south coast of WA, an area with dry, warm summers and a maritime influence, kikuyu (Pennisetum clandestinum) has been widely sown, but there is little information on the potential of other subtropical grasses. To address these issues, five trials were established across the agricultural area of south-west WA to measure the seasonal production, feed quality and persistence of the main, commercially available subtropical grasses over 3–4 years.

This study demonstrates that subtropical grasses have a long-term role in the NAR in areas with mild winters and/or where the rainfall is >400 mm. The best performing subtropical grasses across a range of sites were panic grass (Megathyrsus maximus) and Rhodes grass (Chloris gayana). These species can be expected to have a water-use efficiency of ∼10 kg ha^–1 mm^–1 over a 12-month period, provided there is a good perennial grass density. On the south coast, panic grass, Rhodes grass and setaria (Setaria sphacelata) persisted well and produced significantly more biomass than kikuyu. These grasses could complement kikuyu by increasing out-of-season production. At Kojonup, a more inland site, most of the subtropical grasses died over winter from a combination of occasional frosts and cold, wet soils. However, kikuyu re-grew from rhizomes in spring and maintained >90% ground cover 4 years after sowing. The results from these experiments are likely to be applicable to other regions across the globe with Mediterranean climates and similar soil types.

Nutrient-use efficiency is a key issue for grazing systems in Australia. Spatial variability in soil pH and nutrients at the sub-paddock scale may affect the efficiency of utilisation of, and provide an opportunity for, site-specific management (SSM) of fertiliser and soil ameliorants. However, there has been little research exploring the potential for SSM in grazing systems. This study examines the spatial variability of soil test pH, phosphorus (P), potassium (K) and sulfur (S) in two typical pasture fields (a native and an improved) on the Northern Tablelands of New South Wales and evaluates the potential for SSM based on a comparison with critical values. In both fields, the overall paddock mean from a grid survey containing >80 samples for pH, P, K and S (0–10 cm) exceeded the critical values, suggesting that the addition of fertiliser or lime was not required. However, considerable sub-paddock-scale variability was observed, with CV ranging from 35% to 66% for the key nutrients (P, K and S). The Sprengel–Liebig Law of the Minimum was applied to evaluate the proportion of each field constrained by one or more soil characteristics. Up to 55% of the improved paddock and 78% of the native pasture was potentially responsive to amendments. The results of this study suggest that SSM of fertilisers and ameliorants could provide substantial improvements in productivity and possibly reductions in fertiliser use. The development and application of appropriate systems and tools to effectively quantify this spatial variability remain a challenge, coupled with management strategies that optimise the placement of amendments and account for the variability in other production limiting factors.

Cool-season grasses, both annual and perennial, typically employ the strategies of dehydration avoidance and dehydration tolerance to help them to survive extended periods of low soil moisture. Summer dormancy is an extra trait employed by perennial grasses particularly adapted to regions experiencing extended hot, dry summers. Of the three strategies, it appears that least is known about dehydration tolerance. Using and extending a methodology developed for cocksfoot (Dactylis glomerata L.), this study compared a range of cultivars of cocksfoot, tall fescue and phalaris differing in expression of summer dormancy. Both inter- and intra-specific variation in dehydration tolerance was observed, with cocksfoot expressing the trait strongly, whereas it was least evident in phalaris. The trait was more strongly evident in cultivars originating in drier environments, and the ability to express dehydration tolerance appeared to be independent of summer dormancy. It has been confirmed that dehydration tolerance is a powerful drought-survival trait, one that warrants increasing attention in plant breeding programs for drying environments.