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1
Li, G. D., K. R. Helyar, C. M. Evans, M. C. Wilson, L. J. C. Castleman, R. P. Fisher, B. R. Cullis y M. K. Conyers. "Effects of lime on the botanical composition of pasture over nine years in a field experiment on the south-western slopes of New South Wales". Australian Journal of Experimental Agriculture 43, n.º 1 (2003): 61. http://dx.doi.org/10.1071/ea01194.
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Two permanent pastures (annual pasture v. perennial pasture) were established in 1992 as part of the long-term field experiment, MASTER — Managing Acid Soils Through Efficient Rotations. The primary objective of the experiment was to develop an agricultural system that is economically viable and environmentally sustainable on the highly acidic soils in south-eastern Australia. This paper reports on the effects of lime on the botanical composition changes of annual and perennial pastures over 9 years. In general, lime increased the proportion of the desirable species, such as phalaris (Phalaris aquatica) in perennial pasture and subterranean clover (Trifolium subterraneum) in annual pastures, and decreased the proportion of the undesirable species, such as Vulpia spp., in both annual and perennial pastures, ultimately improving the quality of feed-on-offer to animals. As a result, the limed pastures carried 24% more sheep than the unlimed pastures, while maintaining individual animal performance similar for both limed and unlimed pastures. The phalaris-based perennial pasture was more stable in terms of maintaining the sown species than the annual pasture. Lime improved the persistence of phalaris and the longevity of the phalaris-based pasture should be at least 10 years. Lime changed the direction of plant succession of annual pastures. Without lime, Vulpia spp. gradually became more dominant while ryegrass and subterranean clover became less dominant in annual pastures. With lime, barley grass (Hordeum leporinum) gradually invaded the sward at the expense of ryegrass, thus reducing the benefits of lime, but this effect was less for the perennial pastures than for annual pastures. Liming perennial pastures should be more beneficial than liming annual pastures because of the beneficial effects on pasture composition. In addition, previously published work reported that liming perennial pastures improved sustainability through better use of water and nitrogen.
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White, R. E., K. R. Helyar, A. M. Ridley, D. Chen, L. K. Heng, J. Evans, R. Fisher et al. "Soil factors affecting the sustainability and productivity of perennial and annual pastures in the high rainfall zone of south-eastern Australia". Australian Journal of Experimental Agriculture 40, n.º 2 (2000): 267. http://dx.doi.org/10.1071/ea98013.
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A field study was carried out in the high rainfall zone (HRZ, >600 mm p.a.) of southern Australia from March 1994 to August 1997 to test the hypothesis that sown perennial grasses and liming could make the existing pastures more sustainable through better use of water and nitrogen. The site, on an acid duplex soil at Book Book near Wagga Wagga in southern New South Wales, was typical of much of the HRZ grazing country in southern New South Wales and north-east Victoria. The experiment consisted of 4 replicate paddocks (each 0.135 ha) of 4 treatments: annual pasture (mainly ryegrass Lolium rigidum, silver grass Vulpia spp., subterranean clover Trifolium subterraneum and broadleaf weeds) without lime, annual pasture with lime, perennial pasture (phalaris Phalaris aquatica, cocksfoot Dactylis glomerata and subterranean clover T. subterraneum) without lime, and perennial pasture with lime. Soil pH (0–10 cm) in the limed treatments was maintained at 5.5 (0.01 mol/L CaCl2), compared to 4.1 in the unlimed treatments. The pastures were rotationally grazed with Merino ewe or wether hoggets at a stocking rate which varied with the season, but was 10–25% higher on the limed pastures [14.8–17.3 dry sheep equivalent (dse)/ha] than the unlimed pastures. One replicate set of pasture treatments was intensively monitored for surface runoff, subsurface flow (at the top of the B horizon), water potential gradients and ammonium volatilisation. Other measurements of nitrogen inputs, transformations and losses were made on all paddocks. In a normal to wet year, surface runoff, subsurface flow and deep drainage (>180 cm depth) were about 40 mm less from the perennial than the annual pastures. The reduction in deep drainage under the perennials was about one-third to one-half (20–29 mm/year). The smaller loss of solution NO3– from the perennial pastures (up to 12 kg N/ha.year) suggested soil acidification under perennials was reduced by about 1 kmol H+/ha.year. Denitrification and volatilisation losses of N were small (1–12 kg N/ha.year). Nitrogen fixed by subterranean clover (above ground parts) ranged from 2–8 kg N/ha in the drought of 1994–95 to 128 kg N/ha in a normal year (1996). The soil-pasture nitrogen balance was positive for all treatments and averaged 76 kg N/ha.year over 2 years. The abundance of introduced and native earthworms increased from 85 to 250/m2 in the limed pastures between 1994 and 1997. Introduced species, such as Aporrectodea trapezoides, were especially responsive to lime. Animal production per hectare was 10–25% higher on pastures with lime. Critical gross margins per dse were lowest ($16/ha) for a long-lived perennial pasture (>15 years), and highest ($20/ha) for a short-lived perennial (5 years). Overall, there were substantial benefits in animal production, improved soil quality and water use from establishing perennial grass pastures with lime on these strongly acid soils.
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Li, G. D., K. R. Helyar, S. J. Welham, M. K. Conyers, L. J. C. Castleman, R. P. Fisher, C. M. Evans, B. R. Cullis y P. D. Cregan. "Pasture and sheep responses to lime application in a grazing experiment in a high-rainfall area, south-eastern Australia. I. Pasture production". Australian Journal of Agricultural Research 57, n.º 10 (2006): 1045. http://dx.doi.org/10.1071/ar05298.
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‘Managing Acid Soils Through Efficient Rotations (MASTER)’ is a long-term pasture–crop rotation experiment commenced in 1992. One of the objectives was to demonstrate the extent of crop, pasture, and animal responses to lime on a typical acidic soil in the 500–800 mm rainfall zone in south-eastern Australia. Two types of pastures (perennial v. annual pastures) with or without lime application were established in 1992. This paper presents the results of the pasture dry matter (DM) responses to lime application over 6 years from 1992 to 1997. Results showed that both perennial and annual pastures responded positively to lime on a highly acidic soil on the south-west slopes of New South Wales. Averaged across pasture types and 5 growing seasons, the limed pastures produced 18% more pasture DM (520 kg/ha, P < 0.05) than the unlimed pastures. Significant responses to lime were detected on perennial pastures (610 kg DM/ha, P < 0.05), but not on annual pastures, although the limed annual pastures produced more DM (420 kg/ha, P = 0.20) than the unlimed annual pastures. There was a large seasonal variation in pasture growth rate with the significant lime responses in winter and spring on both perennial pastures (P < 0.05) and annual pastures (P < 0.10 in winter and P < 0.05 in spring), but no responses in autumn and summer on either perennial or annual pastures. The extra growth in winter is of importance as winter is the period when feed is normally inadequate and limits stocking rates. It is recommended that perennial-based pastures should be promoted for the purposes of productivity, in terms of increasing pasture production and improving feed quality, and for the environmental benefits in terms of alleviating the soil acidity problem and reducing the risk of dryland salinity in the high-rainfall zone in south-eastern Australia.
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Saul, Geoffrey, Gavin Kearney y Dion Borg. "Pasture systems to improve productivity of sheep in south-western Victoria. 1. Growth, composition, nutritive value and persistence of resown pastures". Animal Production Science 49, n.º 8 (2009): 654. http://dx.doi.org/10.1071/ea06142.
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Two pasture systems were compared at five on-farm sites across south-western Victoria between 1990 and 1996. The ‘typical’ pasture treatment mimicked the pasture and grazing management common in the region, with volunteer annual-based pastures fertilised with around 5 kg/ha phosphorus (P) each year. The ‘upgraded’ pasture treatments were resown to phalaris, perennial ryegrass and subterranean clover, and higher rates of fertiliser (13–25 kg P/ha.year) plus other nutrients were applied. Both pastures were set stocked with the participating farmers breeding ewes. Stocking rate was an emergent variable on each plot. The stocking rate on the typical treatments was based on normal farm practise. Initially, the stocking rate of the upgraded pastures was 15% higher than for the typical pastures and increased over time depending if the ewes in the upgraded pastures were heavier than those in the typical pastures. Measurements included soil fertility, pasture production, nutritive value and composition, and animal production. Net annual pasture production of the upgraded pastures was 10 500 kg/ha compared with 8700 kg/ha for the typical pastures. This average difference (18%) between the treatments was greatly influenced by the large advantage (40%) of the upgraded pasture in the wet year of 1992. Upgraded pastures had higher pasture production than typical pastures in spring but the reverse occurred in autumn. In a separate small plot experiment, the response of each pasture to higher P fertiliser applications was tested. In autumn and winter, there was a significant interaction between pasture type and P rate, with higher responses on the upgraded pastures. In spring, both pastures responded to increased P applications but the upgraded pastures were more responsive at all P rates. The upgraded pastures contained significantly higher legume content (30–50%) than the typical pastures (10–20%). The proportion of sown perennial grasses in the upgraded pasture declined from around 30 to 10% after 6 years displaced by annual grasses and broad-leaf weeds. Herbage from upgraded pastures had significantly higher crude protein content (2–7 units) and digestibility (1–10 units) than the typical pastures with the difference between the treatments increasing over time. The set stocking policy used in this experiment is likely to have exacerbated the decline in sown perennial grasses and implementation of some form of strategic or rotational grazing may have improved persistence. The experiment also highlights the importance of selecting perennial grasses able to cope with the local environment and grazing conditions. Despite the decline in perennials, these results show significant potential to improve pasture productivity and quality in south-western Victoria.
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Kemp, D. R. y P. M. Dowling. "Towards sustainable temperate perennial pastures". Australian Journal of Experimental Agriculture 40, n.º 2 (2000): 125. http://dx.doi.org/10.1071/ea98003.
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Naturalised pastures across the higher rainfall (>600 mm) perennial pasture zone of south-eastern Australia are less productive than they were, while sown pastures fail to maintain their initial levels of production. Several factors have contributed to this, including lack of knowledge of suitable grazing practices, weed invasion, increasing acid soils, rising water tables and poor management practices during droughts. A key issue in each case is the decline in perennial grass species which is both a cause and effect of the decline in productivity and sustainability of these ecosystems. This paper introduces a volume devoted to the largest collaborative study done to evaluate tactics for better grazing management and to improve the sustainability of perennial pasture ecosystems. Grazing practices to manage the composition of pastures have been largely neglected in pasture research, but are an important first step in improving pasture sustainability. This paper also outlines a new, open communal grazing experimental design which was developed and used across 24 sites on farms in New South Wales, Victoria, Tasmania and South Australia, to evaluate tactics for grazing management. The general aim across these experiments was to maintain (if adequate) or enhance (if degraded), the proportion of desirable perennial grasses in the sward to achieve more sustainable pastures. The results will provide the basis for building more sustainable grazing systems.
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CHEN, G., G. D. LI, M. K. CONYERS y B. R. CULLIS. "LONG-TERM LIMING REGIME INCREASES PRIME LAMB PRODUCTION ON ACID SOILS". Experimental Agriculture 45, n.º 2 (abril de 2009): 221–34. http://dx.doi.org/10.1017/s0014479708007497.
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SUMMARYPrime lamb live weight response to lime application on pasture was measured in a grazing experiment in the high rainfall zone of the southwestern slopes of New South Wales, Australia. The pastures were limed every 6 years over 15 years. First cross South African Meat Merino lambs were used as test animals. Pre- and post-grazing pasture dry matter (DM) yield, botanical composition, feed quality and lamb live weight were monitored over 12 weeks in 2007. Results showed that liming significantly increased pasture DM yield of high quality species and improved overall pasture quality due to increased digestibility and metabolic energy content. As a result, the limed perennial and annual pastures carried 24.0% (3.6 lambs ha−1) and 29.0% (4.4 lambs ha−1) more stock than the unlimed perennial and annual pastures, respectively. Averaged across pasture types, the limed pastures produced 30.6% (131 kg ha−1) more lamb live weight gain than the unlimed pastures over 12 weeks. The live weight gain varied between grazing cycles depending on the availability of feed-on-offer and feed quality, which were closely related to the rainfall pattern. The perennial pastures did not show any advantage in animal production over annual pastures during the experimental period due to lack of moisture in the deep soil profile because of severe drought in the previous year. More seasons with normal or above average rainfall are needed to compare animal production on perennial pastures and annual pastures to investigate the advantage of perennial pastures in animal production.
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Li, G. D., K. R. Helyar, M. K. Conyers, L. J. C. Castleman, R. P. Fisher, G. J. Poile, C. J. Lisle, B. R. Cullis y P. D. Cregan. "Pasture and sheep responses to lime application in a grazing experiment in a high-rainfall area, south-eastern Australia. II. Liveweight gain and wool production". Australian Journal of Agricultural Research 57, n.º 10 (2006): 1057. http://dx.doi.org/10.1071/ar05299.
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‘Managing Acid Soils Through Efficient Rotations (MASTER)’ is a long-term pasture–crop rotation experiment commenced in 1992. One of the objectives was to demonstrate the extent of crop, pasture, and animal responses to lime application on a typical acidic soil in the 500–800 mm rainfall zone of south-eastern Australia. Two types of pastures (perennial v. annual pastures) with or without lime application were established in 1992. Fifteen- to eighteen-month-old Merino hoggets were used as test animals and were changed annually. This paper reports the results of sheep responses to liming from the 4 continuous pasture treatments over 6 years from 1992 to 1997. The stocking rate was the same on all plots within a treatment during each rotation period, but was varied between treatments based on the pasture availability and sheep body condition. The most important findings from this study are that the limed treatments carried 29% and 27% more stock (up to 4 DSE/ha) than the unlimed treatments for perennial and annual pastures, respectively. As a result, the limed perennial pastures produced 27% more liveweight gain (62 kg/ha.year) and 28% more greasy wool (13 kg/ha.year) than unlimed perennial pastures, whereas the limed annual pastures produced 34% more liveweight gain (77 kg/ha.year) and 24% more greasy wool (11 kg/ha.year) than unlimed annual pastures. The significant responses to lime in liveweight and wool production were detected from the second growing season after the pastures were established. The increased sheep productivity on the limed treatment was due to a combination of increased pasture production and improved pasture quality. Perennial pastures showed a slight advantage in wool production, but not in liveweight gain. However, the seasonal variation of liveweight was greater on annual pastures than on perennial pastures. The larger variation in liveweight change could lead to more adverse effects on wool quality especially at high grazing pressures. Grazing management can be used to manipulate pasture and animal productivity to increase profits from lime use.
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Ward, G. N., S. G. Clark, G. A. Kearney, M. R. McCaskill, M. C. Raeside, A. R. Lawson y R. Behrendt. "Summer-active perennials in pasture systems improve seasonal pasture distribution without compromising winter-spring production". Crop and Pasture Science 64, n.º 7 (2013): 673. http://dx.doi.org/10.1071/cp13003.
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Improved dryland pastures for sheep and beef cattle production in south-western Victoria are typically based on summer-dormant cultivars of perennial ryegrass (Lolium perenne L.) or phalaris (Phalaris aquatica L.). These are highly productive in spring but exhibit low accumulation rates over summer–autumn. Summer-active perennial pasture species could potentially alleviate this summer–autumn feed gap. Three pasture systems that used different pastures on each of the three landscape classes (crest, slope, and valley floor) were compared over 4 years. The perennial ryegrass system (henceforth Ryegrass) had a different ryegrass cultivar on each landscape class. The Triple system used lucerne (Medicago sativa L.) (crest), perennial ryegrass (slope), and summer-active tall fescue (Lolium arundinaceum (Schreb) Darbysh.) (valley floor). The Novel system used chicory (Cichorium intybus L.) (crest), Italian ryegrass (Lolium multiflorum Lam.) or hybrid ryegrass (L. × boucheanum Kunth.) (slope), and kikuyu (Pennisetum clandestinum Hochst. ex Chiov.) (valley floor). The pastures were grazed by either one (in the case of the Novel system) or three (in the case of the Ryegrass and Triple systems) animal systems that varied over the life of the experiment. Total annual herbage accumulation of the Ryegrass and Triple systems did not differ. The Novel system consistently had lower total annual dry matter accumulation than the other two systems. Lucerne pastures generally had the highest accumulation rates over summer, followed by the chicory pastures. The kikuyu pastures responded well to summer rainfall but otherwise had similar accumulation rates to the perennial ryegrass and tall fescue pastures over summer. Tall fescue pastures grew well in autumn following wet summers. In spring the perennial ryegrass pastures based on Fitzroy or Avalon were highly productive but seldom grew faster than other pastures. The results support the hypothesis that incorporating deep-rooted, summer-active perennial species will increase pasture production over summer–autumn compared with conventional pasture systems but not at the expense of winter–spring production.
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Moore, Andrew D. "The case for and against perennial forages in the Australian sheep–wheat zone: modelling livestock production, business risk and environmental interactions". Animal Production Science 54, n.º 12 (2014): 2029. http://dx.doi.org/10.1071/an14613.
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Perennial forages have been proposed as a means of ameliorating both the summer–autumn feed gap and the risks posed by soil salinity and erosion in mixed farming areas of southern Australia. Whole-farm simulation analyses using the APSIM and GRAZPLAN models at nine locations across southern Australia have evaluated the likely trade-offs among expected profitability, financial risk, soil erosion risk, deep drainage and soil carbon change as annual pastures are converted to perennial pastures based on a C3 grass, a C4 grass or lucerne. Differences between perennial and annual feedbases in total pasture growth (median –11%, range –47% to +20%) and metabolisable energy supply from pasture (median +1%, range –48% to +52%) were diverse across locations and perennial species. At some locations, improvements in the pasture feedbase were counter-balanced by lower livestock intakes from crop stubbles. The modelled farming system with the highest profit included some perennial pasture at seven of the nine locations, but no one pasture species or land-use system predominated across all locations or producer risk attitudes. Local characteristics of the soils and farming systems are as important as broad climatic factors in determining how substituting perennial for annual pastures alters the trade-off between profitability and wind erosion risk. Further expanding permanent pastures into land currently used for crops only unequivocally reduced wind erosion risk at the four locations with Mediterranean climates. Lucerne grown in long rotations provided the best trade-off between mean gross margin and financial risk at Merriwagga and Temora. Permanent C3 or C4 perennial grass pastures separated from continuous cropping may simultaneously increase profits and reduce business and erosion risk at low-rainfall locations with Mediterranean climates, as long as they can be managed to persist. Managing pastures for greater nitrogen inputs could be considered as an erosion-abatement strategy.
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Musgrave, D. J. "Non-ryegrass pastures - the science and farmer practice". NZGA: Research and Practice Series 15 (1 de enero de 2011): 163–67. http://dx.doi.org/10.33584/rps.15.2011.3192.
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A review of recently published science demonstrates that relatively simple non-perennial ryegrass mixtures have performed well in environments as diverse as under deer grazing in Dunedin and the Manawatu, under sheep grazing in dryland mid-Canterbury, and under both irrigated and dryland dairy cow grazing in the Waikato and Northland. Animal productivity has been lifted by up to 30% in milk solids and 50% in deer liveweight gain in non-perennial ryegrass mixtures compared to perennial ryegrass-based pastures. In some cases, the ryegrass pasture has produced similar or more dry matter, yet animal performance has been greater on the non-perennial ryegrass pastures. In other cases, dry matter productivity from complex nonryegrass mixtures has been around 30% higher than from perennial ryegrass pastures. Interviews with farmers from South Canterbury to Northland have all reported positive experiences with non-ryegrass pastures and most have said they will not be planting perennial ryegrass-based pastures again.
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Vere, D. y P. Dowling. "An economic analysis of sown pasture trends on the tablelands of south-eastern New South Wales". Rangeland Journal 25, n.º 1 (2003): 56. http://dx.doi.org/10.1071/rj03005.
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The latter part of the 20th century has seen a persistent decline in the productivity of some types of sown pastures on the central and southern tablelands of New South Wales. Currently, much research effort is directed to stabilising the perennial grass component of these pastures. This paper evaluates the economic justification of that emphasis. It is argued that trends in livestock production can usefully represent increases or decreases in the stocks of three broad categories of sown pastures that are defined as being those pastures sown to introduced perennial grasses and legumes (perennial grasses), introduced legumes only (legumes), and the total of both these categories. Regression methods were used to determine the changes that have occurred in the livestock production from these pastures that could be explained by changes in a range of economic and other variables. The estimated models were then used to forecast wool, beef and lamb production from each pasture type. The results indicate that changes in prices and costs have influenced the trends in animal production from these pastures and that the structures of these influences have changed over time. Production from perennial grass-legume pastures has remained high relative to production from legume pastures despite adverse cost-price trends. The forecasts indicated a continuation of present levels of perennial grass-legume pasture areas but a decline in production from the legume pastures. The results support the concerns about the continued deterioration in the legume only pastures and the thrust of R&D programs that promote the benefits of perennial grass-legume pastures. The use and analysis of public data to improve understanding of the economic factors that influence the long-term stability of intensively grazed rangelands is highlighted.
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Lawson, A. R. y K. B. Kelly. "Responses to the renovation of an irrigated perennial pasture in northern Victoria. 1. Pasture consumption and nutritive characteristics". Australian Journal of Experimental Agriculture 47, n.º 2 (2007): 149. http://dx.doi.org/10.1071/ea05258.
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A field experiment was established in northern Victoria in the autumn of 1999 to quantify the effects of renovating a 15-year-old irrigated perennial pasture which had a high paspalum content [>40% dry matter (DM)] in summer. The treatments were: (i) control, the existing pasture; (ii) oversown, in which the existing pasture was grazed, topped and direct drilled; and (iii) resown, in which the existing pasture was sprayed, cultivated and sown with a new pasture. The grass species used in both renovation treatments were perennial ryegrass, Italian ryegrass and tall fescue. The treatments were grazed by dairy cows when the perennial ryegrass had reached the 2.5–3 leaf stage. Grazing of the resown tall fescue coincided with the resown ryegrass in years 1 and 2, but in subsequent years, resown tall fescue was grazed at a rising plate meter height of 80 mm. All treatments were grazed to a residual pasture height of 40–45 mm, as measured with a rising plate meter. Pasture consumption (measured as DM removed by dairy cows), in vitro DM digestibility (in vitro DMD) and crude protein (CP) contents were measured. Oversowing increased pasture consumption over the 4-year period, compared with the control, by an average of 1.1 t DM/ha.year when oversown once with perennial ryegrass and by 1.6 t DM/ha.year when oversown annually with Italian ryegrass. This increase occurred principally during the winter–spring period for pastures oversown with both perennial (0.7 t DM/ha) and Italian (1.6 t DM/ha) ryegrass. Oversowing with perennial or Italian ryegrass did not affect the in vitro DMD or CP content of the pasture on offer. These results show that oversowing with either perennial or Italian ryegrass is a viable means of increasing pasture availability over winter and spring from perennial pastures consisting of a mixture of perennial ryegrass, white clover and paspalum. Pasture consumption in the first 12 months after resowing was 3.5–4.1 t DM/ha lower from the resown than from the control pasture. This was because of two fewer grazings in autumn–winter and to reductions in pasture consumption of 20% in spring and of 40% in summer. These reductions would add considerably to the cost of resowing through increasing the need for supplementary feeding. Pasture consumption from the resown perennial ryegrass pasture in years 2–4 was, on average, the same as the control, although it was higher during winter and spring and lower during summer. Pasture consumption from the resown tall fescue pasture in years 2–4 was, on average, 2.5 t DM/ha.year higher than that of the resown perennial ryegrass pasture, with most of this increase occurring in summer and autumn. The resown pastures had higher in vitro DMD and CP contents than the control with little difference between the resown perennial ryegrass and tall fescue pastures. These findings show that tall fescue is a viable alternative to perennial ryegrass when resowing pastures. The use of nitrogen fertiliser did not affect the in vitro DMD or CP contents of the pasture on offer but allowed an increase in DM consumption, with this increase being greater for the control and oversown pastures than for the resown pasture.
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Elliott, D. E. y R. J. Abbott. "Nitrogen fertiliser use on rain-fed pasture in the Mt Lofty Ranges, SouthAustralia. 2. Responses of perennial grasses, Tama ryegrass, andsod-sown oats to nitrogen fertiliser and cutting frequency". Australian Journal of Experimental Agriculture 43, n.º 6 (2003): 579. http://dx.doi.org/10.1071/ea01132.
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Two series of experiments were conducted in the Mt Lofty Ranges, South Australia, to examine, in a grass–subterranean clover pasture, the contribution of the companion grass to herbage mass and the responsiveness to the application of nitrogen (N) fertiliser. The first study examined the responsiveness, to a single rate of N, of grass–clover pastures containing either Tama ryegrass, sod-sown oats or 1 of 4 perennial grasses, viz. Victorian perennial ryegrass, Demeter fescue, Currie cocksfoot or Australian phalaris. These were compared in 2 experiments, under 3��different cutting frequencies at 3 periods during the growing season. In the other study, consisting of 12�experiments, the response to increasing rate of N fertiliser application of sod-sown oats or the existing pasture were compared over a 3-month period following N fertiliser application in autumn.In autumn and winter, all pastures responded significantly to N fertiliser, whereas in spring, the proportion of clover in each pasture and its growth determined whether or not there was a response to N fertiliser. Clover composition of pastures declined with N application, but clover was not eliminated from swards by application of 210 kg N/ha a year. In both series of experiments, pastures that established well with a high density of sod-sown oats out-yielded all other pastures in autumn and winter, whether the swards were unfertilised or received regular N fertiliser applications. In late winter, pastures sod-sown with Tama ryegrass yielded as well as the pasture sod-sown with oats, and enhanced spring growth significantly compared with perennial ryegrass. However, spring production of Tama ryegrass was poorer than that of perennial ryegrass, and overall no increase in annual production occurred. Of the perennial grasses, the highest yielding when N fertiliser was applied were Currie cocksfoot and perennial ryegrass (yielding in autumn), phalaris (winter), and perennial ryegrass and Demeter fescue (spring). Increased cutting frequency depressed the herbage mass response to N fertiliser following the initial application, but increased herbage N concentration of all pastures and also increased the final clover composition of N-fertilised pasture of 4�pasture types.
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Jones, Roger A. C. "Virus diseases of perennial pasture legumes in Australia: incidences, losses, epidemiology, and management". Crop and Pasture Science 64, n.º 3 (2013): 199. http://dx.doi.org/10.1071/cp13108.
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This article reviews current knowledge for Australia over the occurrence, losses caused, epidemiology, and management of virus diseases of perennial pasture legumes. Currently, 24 viruses have been found infecting perennial pasture legumes, and one or more viruses have been detected in 21 of these species. These viruses are transmitted by insect vectors, non-persistently or persistently, by contact or via seed. Their modes of transmission are critical factors determining their incidences within pastures in different climatic zones. Large-scale national or state surveys of lucerne (alfalfa) (Medicago sativa) and white clover (Trifolium repens) pastures revealed that some viruses reach high incidences. Infection with Alfalfa mosaic virus (AMV) was very widespread in lucerne stands, and with AMV and White clover mosaic virus (WClMV) in white clover pastures. Several other viruses are potentially important in pastures in these and other perennial temperate/Mediterranean pasture species. Data demonstrating herbage yield losses, diminished pasture persistence, and impaired nitrogen fixation/nodule function are available for AMV in lucerne, and AMV, WClMV, and Clover yellow vein virus in white clover. Integrated Disease Management approaches involving phytosanitary, cultural, chemical, and host resistance control measures are available to minimise virus infection in lucerne and white clover. Research on virus diseases of perennial tropical–subtropical pasture legumes has focussed almost entirely on virus identification, and information on their incidences in pastures, the losses they cause, and how to control them is lacking. Overall, viruses of perennial pasture legumes are least studied in South Australia and the Northern Territory. These and other critical research and development gaps that need addressing are identified.
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Thompson, A. N., A. J. Kennedy, J. Holmes y G. Kearney. "Arrowleaf clover improves lamb growth rates in late spring and early summer compared with subterranean clover pastures in south-west Victoria". Animal Production Science 50, n.º 8 (2010): 807. http://dx.doi.org/10.1071/an09100.
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The profitable production of lamb from pasture-based systems is dependent on high levels of pasture production being efficiently utilised by sheep of superior genetic merit. Pastures that can extend the pasture-growing season and provide high quality feed in late spring and summer have the potential to increase production efficiency and the proportion of lambs that meet market specifications. In this paper we tested the hypothesis that arrowleaf clover (cv. Arrotas), a cultivar selected for late maturity, would supply feed of higher nutritive value than conventional annual legumes and perennial ryegrass mixtures during December and January and this would improve lamb growth rates over this period. Two experiments were conducted to compare the nutritive value of pasture and growth rates of lambs grazing arrowleaf clover, subterranean clover (cv. Leura) or subterranean clover/perennial ryegrass mixtures at different stocking rates during late spring and early summer in south-west Victoria. In the second experiment an arrowleaf clover/perennial ryegrass treatment was also included. Lambs were removed from the plots when they could no longer maintain liveweight. Arrowleaf clover extended the growing season by 4–6 weeks and provided feed of significantly higher digestibility than subterranean clover during December and January. The digestibility of arrowleaf and perennial ryegrass was comparable, but arrowleaf had significantly higher crude protein content during this period. Lambs grazing arrowleaf clover at stocking rates up to 24 lambs/ha grew at or above 100 g/day until the end of January, whereas lambs grazing subterranean clover and perennial ryegrass mixed pastures could not maintain weight by mid-to-late December in both years and were removed from the pastures. At the highest stocking rates total lamb production from arrowleaf clover monoculture pastures in late spring and early summer was ~400 kg liveweight/ha, and was more than double that achieved from the subterranean clover and perennial ryegrass/subterranean clover mixed pastures. The perennial ryegrass/arrowleaf clover mixed pastures in the second experiment produced a similar quantity of lamb per hectare as the arrowleaf clover monoculture pastures at the same stocking rate. In this paper we demonstrated that late-maturing arrowleaf clover can be a profitable, special purpose lamb-finishing pasture. Arrowleaf clover was most suited to more elevated parts of the landscape where estimated carrying capacity was 20 to 40% greater than that from lower lying parts of the landscape that were more subject to water logging and weed infestation. The risks of including arrowleaf clover pastures into the farming system could be reduced by direct drilling arrowleaf clover, which has relatively poor winter production, into existing perennial ryegrass pastures.
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Bird, P. R., T. T. Jackson, G. A. Kearney, G. R. Saul, R. A. Waller y G. Whipp. "The effect of improved pastures and grazing management on soil water storage on a basaltic plains site in south-west Victoria". Australian Journal of Experimental Agriculture 44, n.º 6 (2004): 559. http://dx.doi.org/10.1071/ea03019.
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Soil salinity of non-irrigated farmlands in Australia has been largely attributed to tree clearing and their replacement by annual pasture and crop species. This paper deals with the effects of sowing perennial ryegrass and greater inputs of fertiliser, and the effect of grazing management, on water use and the potential to improve recharge control on a gravelly soil derived from basalt.In 1991, neutron access tubes were inserted into plots on a project established in 1989 to examine the impact of upgrading the pasture on sheep productivity. These plots were subdivided in 1996 to examine the impact of grazing management (tactical v. set-stocking) and pasture type (pastures dominated by annual species v. upgraded pastures) on productivity. Neutron probe readings were taken periodically from tubes in each plot, at depth intervals of 25 cm (December 1991–March 1995) or 20 cm (August 1995–April 1999) to 170 cm. There was no effect of treatment on soil moisture. Data for 2 wet years (1995 and 1996) indicate that the effective soil-water storage capacity to 170 cm depth for these pastures was a mean of 125 mm of water. This represents the potential buffer before winter rainfall exceeds the water use by the pasture, fills the soil profile to capacity and then either runs off or allows deep drainage to occur.We did not achieve a significant reduction in soil-water storage, and therefore potential recharge of groundwater, by re-sowing the pasture with perennial ryegrass and applying more fertiliser, or by altering the grazing management to a form of rotational grazing. Compared with set-stocked annual pasture, the impact of such treatments was to reduce soil-water storage to a depth of 170 cm in autumn by less than 20 mm/year. There was no association between total herbage production and soil-water storage, however an increased percentage of perennial ryegrass in the pasture was associated with a small reduction in soil-water storage in 1 year. Greater use of soil-water may depend upon using deeper-rooted perennials or maintaining a higher proportion of perennial species in the sward (the perennial ryegrass in the re-sown pastures declined from 53% in October 1996 to 4% in October 1998).
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Burnett, V. F., G. R. Seymour, S. Norng, J. L. Jacobs y E. N. Ponnampalam. "Lamb growth performance and carcass weight from rotationally grazed perennial pasture systems compared with annual pasture systems with supplements". Animal Production Science 52, n.º 4 (2012): 248. http://dx.doi.org/10.1071/an11053.
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Annual pastures used to finish lambs can decline in herbage nutritive value (NV) from January to April in the temperate zone. If lambs are to be finished to market specifications for carcass weight during this period, the use of summer-active perennial pastures or supplementation of annual pastures, is required. The present study investigated liveweight (LW) gain and carcass characteristics of lambs finished on perennial pastures compared with annual pastures and supplementation. Fifty-four second-cross lambs were allocated to one of the following four treatments in an asymmetric split-plot design: perennial pasture (PP), annual pasture with hay and grain (AP), AP with flaxseed (AP+FS) and AP with flaxmeal (AP+FM). Lambs were fed for 7 weeks and weighed weekly. Blood glucose and total antioxidant status were determined before, during and at the end of the experiment. Carcass weight and GR fat were measured at 24 h post-slaughter. Lambs grazing PP had significantly higher daily LW gain (P < 0.001), slaughter weight (P < 0.001), carcass weight (P < 0.01) and GR fat (total tissue depth at 12 rib, 110 mm from midline) (P < 0.001) than did lambs grazing AP, AP+FS or AP+FM. Lambs receiving AP+FS and AP+FM grew significantly faster (P < 0.001) than lambs receiving AP. It is likely that lambs grazing the perennial pasture were actively selecting the green portion of lucerne that had higher herbage NV than that indicated by the conventional feed analysis. Results show that lambs grazing a lucerne-dominant perennial pasture performed better than did lambs grazing annual pasture with supplements during the finishing period. Further work is required to determine the efficacy of other perennial species to enable economic finishing of lambs during summer and early autumn.
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Reed, K. F. M., J. R. Walsh, P. A. Cross, N. M. McFarlane y M. A. Sprague. "Ryegrass endophyte (Neotyphodium lolii) alkaloids and mineral concentrations in perennial ryegrass (Lolium perenne) from southwest Victorian pasture". Australian Journal of Experimental Agriculture 44, n.º 12 (2004): 1185. http://dx.doi.org/10.1071/ea03242.
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On all of 120 farms in south-west Victoria that were selected at random and sampled during autumn and winter over 2 years, perennial ryegrass was present in the pasture and tested positive for the presence of the naturally occurring ryegrass endophyte, Neotyphodium lolii (mean frequency 78%). Ryegrass staggers were reported on 33% (1999) and 43% (2000) of the surveyed farms. Clinically significant concentrations of lolitrem B were detected in perennial ryegrass samples with concentrations in the range 0–4.44 mg/kg. Concentration exceeded 1.8 mg/kg in 37% of pastures indicating an inherent, widespread problem for livestock farmers. Concentration was independent of endophyte frequency, pasture age, pasture height, annual rainfall and origin of sown cultivar. Ergovaline was detected in most of the perennial ryegrass samples with concentrations up to 3.90 mg/kg. In 1999, the mean concentration of ergovaline was 0.76 (± 0.70) mg/kg with 33% of pastures having a level >0.4 mg/kg, the level associated with heat stress in cattle. In 2000, sampling was carried out later in the year than for the 1999 survey and the mean concentration of ergovaline was 0.12 (± 0.10) mg/kg; 3% of samples exceeded 0.4 mg/kg. The mean concentration of peramine was 13.7 (± 6.6) mg/kg in the 1999 survey and 4.2 (± 5.1) mg/kg in the 2000 survey. Mineral analysis indicated that perennial ryegrass nutrition was inadequate with regard to phosphorous on 17% of the dairy pastures and on 37% of the sheep/beef pastures. Potassium was deficient in perennial ryegrass on 5 and 37% of dairy and sheep/beef pastures respectively. For perennial ryegrass in sheep/beef pastures, 25% were deficient in sulphur. For lactating cattle having only perennial ryegrass as a food source, phosphorous and copper concentrations in the grass were inadequate on 80% of the pastures. Calcium, zinc, magnesium, potassium and sulphur concentrations in perennial ryegrass were also inadequate on some pastures. However, with 1 exception, the ratio [K/(Ca+Mg) expressed as equivalents] was less than 2.2, the level associated with the development of hypomagnesemia. Hypomagnesemia (grass tetany) was therefore unlikely to be a major cause of the staggers syndrome. Lolitrem B was negatively correlated with grass potassium concentration (P<0.001). Ergovaline was negatively correlated with date of sampling (P<0.001). Peramine concentration was positively correlated with endophyte frequency, the potassium and sodium concentrations in perennial ryegrass and negatively correlated with date of sampling. The need for research on the economic impact and management of pasture contaminated with ryegrass endophyte toxins is discussed.
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Vere, D. T., R. E. Jones y M. H. Campbell. "The economics of temperate pasture systems on the central and southern Tablelands of New South Wales". Rangeland Journal 23, n.º 2 (2001): 159. http://dx.doi.org/10.1071/rj01003.
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Pastures are the basis of most forms of agricultural production on the New South Wales central and southern tablelands. Pastures occupy the bulk of the region's landmass and pasture-based livestock production annually contributes more than three-quarters of the regional gross value of rural production. Throughout the region, there is substantial variation in pasture composition, ranging from high quality introduced perennial grasses and legumes to pastures comprising mainly low quality native species. This paper examines the economics of the main categories of temperate pastures over a range of soil fertility-rainfall environments on the south-eastern tablelands areas of New South Wales. Using a linear programming model and discounted development budgets, the results demonstrate the strong influence of the environment on the economics of the individual pasture systems. The highest economic returns in both the short and longer-terms were to the introduced perennial grass pastures in most of the environments. Pastures based on introduced legumes and the high quality native species also generated sound economic returns, although there are recognised problems with the persistence of the legume pastures. Over time, the returns to the better quality native pastures compare favourably with the introduced legumes and are better suited to acidic soils than the perennial grasses. Low quality native species produced relatively poor economic returns in all environments and unfortunately, are the main pasture type in the region's less favourable environments.
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McKirdy, SJ, BA Coutts y RAC Jones. "Occurrence of bean yellow mosaic virus in subterranean clover pastures and perennial native legumes". Australian Journal of Agricultural Research 45, n.º 1 (1994): 183. http://dx.doi.org/10.1071/ar9940183.
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In 1990, infection with bean yellow mosaic virus (BYMV) was widespread in subterranean clover (Trifolium subterraneum) pastures in the south-west of Western Australia. When 100 leaves were sampled at random per pasture, the virus was detected by ELISA in 23 of 87 pastures and incidences of infection ranged from 1 to 64%. BYMV was present in all seven districts surveyed, but highest incidences of infection occurred in the Busselton district. In smaller surveys in 1989 and 1992, incidences of infection in pastures were higher than in 1990, and ranged up to 90%. In 1992, when petals from 1703 samples of 59 species of perennial native legumes from 117 sites were tested by ELISA, only 1% were found infected with BYMV. The infected samples came from 5/7 districts surveyed. Species found infected were Kennedia prostrata, K. coccinea, Hovea elliptica and H. pungens. Representative isolates of BYMV from subterranean clover and native legumes did not infect white clover systemically confirming that clover yellow vein virus (CYVV) was not involved. It was concluded that BYMV infection was present in many subterranean clover pastures, but normally at low incidences, except in epidemic years such as 1992. Also, perennial native legumes are unlikely to act as major reservoirs for reinfection of annual pastures each year. In areas of Australia with Mediterranean climates where perennial pastures are absent, persistence of the virus over summer is therefore by some other method than infection of perennials.
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Michalk, D. L., P. M. Dowling, D. R. Kemp, W. McG King, I. J. Packer, P. J. Holst, R. E. Jones et al. "Sustainable grazing systems for the Central Tablelands, New South Wales". Australian Journal of Experimental Agriculture 43, n.º 8 (2003): 861. http://dx.doi.org/10.1071/ea02180.
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Pasture degradation is a major issue in the high rainfall zone (>600 mm) of temperate Australia. Characterised by a decline in the perennial grass component, this degradation is responsible for reduced livestock production and implicated in environmental problems, such as dryland salinity, through changed water-use patterns. This paper reports on a multi-disciplinary research program conducted at Carcoar in central New South Wales, one of 6 sites that comprised the Sustainable Grazing Systems National Experiment. The aim of the experiment was to develop more profitable and sustainable pasture systems by evaluating the impact of changes in the perennial grass component on animal production and water-use patterns. Tactical management strategies were evaluated on naturalised and sown perennial grass pastures and on chicory (Cichorium intybus), using a Merino ewe-based first cross lamb enterprise. Data presented showed that grazing deferment over summer, combined with reduced stocking rate, increased perenniality and reduced annual grass weeds compared with continuous grazing. Livestock performance, however, did not always follow trends in available perennial herbage mass. Naturalised and sown pastures were suitable for raising prime lambs, but only chicory had the capacity to finish lambs to market specification without supplementation. With respect to water-use patterns, sown perennial pastures were more successful than naturalised pastures in reducing leakage of water from the root zone, although this seemed to be related mostly to the abundance of the perennial grass in the pasture. From a sustainability perspective, continuously grazed pastures generated higher net cash flows, but had negative environmental impacts, whereas tactically grazed pastures had positive on- and off-farm impacts but lower net cash flows. The implications of these findings for incorporation into future management strategies for sustainable production in high rainfall environments are discussed.
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McIvor, JG y CJ Gardener. "Germinable soil seed banks in native pastures in north-eastern Australia". Australian Journal of Experimental Agriculture 34, n.º 8 (1994): 1113. http://dx.doi.org/10.1071/ea9941113.
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Germinable soil seed banks were determined in 20 native pasture communities of widely varying composition (dominated by native tussock grasses, Bothriochloa pertusa, or forbs) near Collinsville (20�34'S, 147�51'E). Samples of surface soil (0-10 cm) were taken during the late dry season, seeds were germinated in a shadehouse, and seedlings were identified and counted. Over all pastures there were seeds of 100 species in the seed banks, including 29 grasses (14 perennial), 11 legumes, 8 sedges, and 52 forbs. Total seed numbers varied among pastures from 210 to 9770/m2. Forbs were the most numerous component, followed in order by sedges, perennial grasses, annual grasses, and legumes. Of the 790 seeds/m2 of perennial grasses, the naturalised species B. pertusa contributed 620/m2. Even though the native perennial grasses were prominent in these pastures, they had few seeds in the soil, especially when the pastures had been heavily grazed. To maintain these grasses in pastures, management should aim to prevent excessive mortality of the perennial plants as seedling regeneration could be limited by the small seed numbers available.
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Jones, Roger A. C. "Virus diseases of pasture grasses in Australia: incidences, losses, epidemiology, and management". Crop and Pasture Science 64, n.º 3 (2013): 216. http://dx.doi.org/10.1071/cp13134.
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This paper reviews current knowledge for Australia over the occurrence, losses caused, epidemiology, and management of virus diseases of pasture grasses. It also reviews all records of viruses in wild grasses likely to act as alternative host reservoirs for virus spread to nearby pastures or crops. Currently, 21 viruses have been found infecting 36 pasture or forage grass species and 59 wild grass species. These viruses are transmitted by arthropod vectors (mites or insects) or, in one instance, via grass seeds. Their modes of transmission are critical factors determining their incidences within pastures in different climatic zones. Large-scale surveys of perennial grass pastures growing in regions with temperate–Mediterranean climates revealed that Barley yellow dwarf virus (BYDV), Cereal yellow dwarf virus (CYDV), and Ryegrass mosaic virus (RyMV) sometimes reach high infection incidences. The same was true for BYDV and CYDV when perennial pasture grasses and wild grasses growing outside pastures were surveyed to establish their occurrence. Smaller scale surveys of grasses growing both inside and outside annual pastures found that Wheat streak mosaic virus (WSMV) infection could also reach high incidences in some annual grass species. Herbage yield loss data are available demonstrating potentially serious impacts on pasture production under Australian conditions from BYDV infection in perennial ryegrass swards, and from RyMV infection in both perennial and Italian ryegrass swards. Also, infection with BYDV or RyMV diminished the ability of infected pasture grass plants to compete with pasture legumes or weeds. Host resistance to BYDV, CYDV, and/or RyMV has been identified within a few temperate–Mediterranean pasture grasses, and is available for use in Australian pasture breeding programs. Integrated Disease Management tactics involving phytosanitary, cultural, chemical, and host resistance measures were devised against BYDV, CYDV, and RyMV infection in mixed species pasture, but no field experiments were undertaken with pasture grasses to validate their inclusion. Several other grass viruses that occur in other countries, but have not been looked for in Australia, are potentially important, especially in temperate–Mediterranean pasture grass species. With few exceptions, research on viruses of perennial or annual tropical–subtropical pasture or wild grass species growing within or outside pastures has focussed only on virus identification and characterisation studies, and information on incidences in pastures, losses caused, epidemiology, and management is lacking. Critical research and development gaps that need addressing are identified.
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Li, Guangdi D., Richard C. Hayes, Jeff I. McCormick, Matthew J. Gardner, Graeme A. Sandral y Brian S. Dear. "Time of sowing and the presence of a cover-crop determine the productivity and persistence of perennial pastures in mixed farming systems". Crop and Pasture Science 65, n.º 10 (2014): 988. http://dx.doi.org/10.1071/cp13447.
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Incorporation of perennial pastures into cropping rotations can improve whole-farm productivity, profitability and sustainability of mixed farming systems in southern Australia. However, success in establishing perennial pastures depends on choice of species, time of sowing, method of establishment, seasonal conditions, and whether sowing is under a cover-crop. Field experiments were sown from 2008 to 2010 to determine effects of sowing time and the presence of a cover-crop on the performance of four perennial pasture species, lucerne (Medicago sativa L.), chicory (Cichorium intybus L.), phalaris (Phalaris aquatica L.) and cocksfoot (Dactylis glomerata L.), at Yerong Creek, New South Wales (NSW). Results showed that lucerne was the most productive pasture, followed by chicory and phalaris, with cocksfoot being the poorest performer. Under favourable seasonal conditions, lucerne and chicory pastures produced 29.3 and 25.0 t ha–1 of total dry matter (DM), comprising 71% and 52%, respectively, of sown perennial species in the sward in their second growing season, when sown in autumn. Spring-sown pastures produced 24.6 and 18.3 t ha–1 of total DM in the second season, with 55% and 47% of sown species in the sward being lucerne and chicory, respectively. However, spring-sown pastures contained a very low proportion of subterranean clover (Trifolium subterraneum L.) in the sward in the first 2 years, despite efforts to broadcast seeds at the break of season in the following year. It is recommended that non-legume perennial species, such as chicory and phalaris, be sown in autumn with companion annual legumes until methods are developed and tested to establish annual legumes reliably in spring. However, lucerne can be established in autumn or spring because it can fix its own nitrogen and is not reliant on a companion legume. Cocksfoot cv. Kasbah, in general, appears less suitable than the other perennial species for this medium-rainfall environment in southern NSW. Our study showed that pastures sown without a cover-crop had the most reliable establishment, whereas pastures sown with a cover-crop in a dry year had poor establishment or total failure, as well as a significant reduction of grain yield from the cover-crop. In a wet year, pastures established satisfactorily under a cover-crop; however, growth of the cover-crop still suppressed pasture DM production in subsequent years. Research is under way to model our data to determine the likely financial implications of establishing perennial pastures under cover-crops.
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Lawes, R. A. y M. J. Robertson. "Effect of subtropical perennial grass pastures on nutrients and carbon in coarse-textured soils in a Mediterranean climate". Soil Research 50, n.º 7 (2012): 551. http://dx.doi.org/10.1071/sr11320.
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In the northern agricultural region of Western Australia, some farmers have integrated C4 grass pastures into their farming system. This switch away from a farming system historically dominated by annual species could alter soil nutrient and carbon (C) levels. To explore this issue, 16 ‘over-the-fence’, pair-wise comparisons were conducted between a field in an annual crop–pasture rotation and a field sown to perennial pasture. The perennial pastures were 2–8 years of age, and comprised a mix of perennial species and volunteer annuals. Soils were deep yellow sand (Tenosols), and perennial root systems extended to beyond 150 cm. Averaged over all sites, organic C (OC) in the top 90 cm of the profile was 38.7 t/ha, nitrate 34.5 kg/ha, Colwell phosphorus (P) 5.9 kg/ha, and Colwell potassium (K) 518 kg/ha. In general, there were no differences between annuals and perennials for any of these attributes. For OC, greater differences were observed between sites than between annual and perennial species. Site differences in OC ranged from 18.7 to 62.7 t/ha. There were some differences between annuals and perennials at different sites for OC, P, nitrate, and K, but these differences were not systematic. For example, at three sites, more OC was found in the annual system; at another site, more OC was found in the perennial system, and differences occurred in the surface layers at two sites and at depth in the other two. Overall, clear differences between annual and perennial farming systems were not evident and were highly variable. The survey was augmented with a simulation study using the APSIM crop model, where a continuous perennial pasture was compared with a wheat–wheat–lupin rotation. After 10 years, there was only 1.27 t/ha more OC in the perennial system than the annual. The simulation study and on-farm survey suggest the differences in the accumulation of soil C under a perennial or an annual system in this landscape are small and variable, and if differences do exist, they will take considerable time to accrue. In addition, management and local site effects were more important than the perenniality of the system per se in influencing C and nutrient levels.
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Wims, C. M., C. I. Ludemann, H. Phillips y D. F. Chapman. "The economic value to dairy systems of genetic gains in the nutritive value of perennial ryegrass in grass–clover pastures". Animal Production Science 57, n.º 7 (2017): 1357. http://dx.doi.org/10.1071/an16487.
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Perennial ryegrass (Lolium perenne L.) breeding efforts have focussed on improving pasture nutritive value by altering flowering behaviour and increasing ploidy. However, the gains in farm profitability that this has delivered are not known. The flowering behaviour, botanical composition and nutritive value of pastures based on 24 perennial ryegrass cultivar–endophyte combinations released in New Zealand since 1970 were compared under grazing for 3 years in the Waikato region of New Zealand. Cultivars were grouped into the following three functional groups for data analysis: mid-season-heading diploids, late- and very late-heading diploids, and late- and very late-heading tetraploids. The first of these groups included older, ‘standard’ cultivars, while the latter two groups were dominated by cultivars released since 2002. The appearance of reproductive tillers in grazed pastures was delayed by 4–8 weeks for the late- and very late-heading cultivars, resulting in pastures that maintained a greater proportion of green leaf and had a greater metabolisable energy (ME) concentration during spring. Tetraploid pastures had a greater ME concentration than did diploid pastures, largely due to the greater ME concentration of the perennial ryegrass component of these pastures. The gains in pasture nutritive value achieved by broadening the range of perennial ryegrass functional types have the potential to deliver economic benefits in the range of NZ$54/ha.year (late-heading diploids compared with mid-heading diploids) to NZ$232/ha.year (tetraploids compared with mid-heading diploids) to New Zealand dairy farmers. Potential economic gains can be diminished by changes in pasture botanical composition both over time and between functional groups.
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Angus, J. F., T. P. Bolger, J. A. Kirkegaard y M. B. Peoples. "Nitrogen mineralisation in relation to previous crops and pastures". Soil Research 44, n.º 4 (2006): 355. http://dx.doi.org/10.1071/sr05138.
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Most of the nitrogen (N) used by Australian crops is mineralised from the residues of previous crops and pastures. Net N mineralisation was studied in 2 field experiments in southern NSW, one comparing different residue-management and tillage systems during continuous cropping and the other comparing residues of annual and perennial pastures in a pasture–crop system. After 14 years of continuous cropping, soil total N concentration had decreased by 50%. Neither stubble retention nor direct drilling affected potential N mineralisation or the decrease in total N. However, soil mineral N in the field was greater after direct drilling than cultivation and greater after stubble retention than stubble burning. There were 2 reasons for the discrepancy. One was because retained stubble conserved soil water, leading to periods of increased mineralisation. The other was that direct drilling and stubble retention reduced growth and N uptake by crops. In contrast to the similar rates of potential mineralisation under different tillage and stubble systems, there were significant differences following different pasture species. In a 5-year study of a pasture–crop system we measured net mineralisation following annual pasture based on subterranean clover and perennial pasture based on lucerne and/or the grasses phalaris and cocksfoot. Mineralisation generally decreased with number of years after pasture removal. Previous lucerne pastures led to slow net mineralisation in the first year after removal, apparently because of immobilisation by high C : N residues. Mineralisation in soil containing perennial grass residues was the highest measured. This high rate may be due to redistribution of N to the topsoil by roots of perennial grasses. The comparison of continuous crop and pasture–crop systems showed that the decline in soil N supply was not prevented by direct drilling and stubble conservation, but N mineralisation was increased by pastures, particularly those containing perennial grasses.
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Ataja, A. M., P. R. Wilson, T. N. Barry, J. Hodgson, R. M. Hoskinson, W. J. Parker y R. W. Purchas. "Early venison production from red deer (Cervus elaphus) as affected by grazing perennial or annual ryegrass pastures, pasture surface height and immunization against melatonin". Journal of Agricultural Science 118, n.º 3 (junio de 1992): 353–69. http://dx.doi.org/10.1017/s0021859600070726.
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SUMMARYTwo grazing experiments in New Zealand, using newly weaned red deer stags, assessed methods of maximizing growth over winter and spring, with the objective of attaining a slaughter weight of 92 kg liveweight (> 50 kg carcass) at the end of spring, by 12 months of age. Perennial ryegrass/white clover pastures, and the same direct-drilled with an annual ryegrass, were grazed at two surface heights (5 cm and 10 cm; Experiment 1; 1988) or at similar pasture mass (Experiment 2; 1989). Balanced groups of stags grazing each forage were immunized against melatonin, commencing at 3 months of age (Expt 1) or at birth (Expt 2). Moata annual ryegrass comprised 19–46% of the feed on offer in Expt 1 and 65–82% in Expt 2. Perennial ryegrass comprised 79–89% of control pastures and white clover generally comprised < 10% of all pastures. Organic matter digestibility of both the feed on offer and diet selected, determined with deer fistulated in the rumen or oesophagus, was 75–80%.In Expt 1, rates of body growth during winter were greater for stags grazing at 10 cm than at 5 cm pasture height, with no effect due to the inclusion of annual ryegrass. During spring, growth rates were similar for stags grazing 10 cm pastures and the 5 cm pasture containing annual ryegrass, but were lower on 5 cm pasture based on perennial ryegrass. Inclusion of annual ryegrass slightly increased winter rates of herbage dry matter accumulation, animal carrying capacity and the proportion of stags attaining target slaughter weight.In Expt 2, annual ryegrass pastures were of higher organic matter digestibility than perennial pastures during winter, and supported greater rates of liveweight gain (LWG) and voluntary feed intake (VFI) than the perennial ryegrass. During spring, LWG increased in both groups of stags although the difference between the two groups ceased to be significant. More of the animals grazing annual ryegrass pastures attained target slaughter weight than those grazing perennial pasture. Rumen acetate: propionate ratio, measured in fistulated stags, was similar for both groups of animals. Relative to perennial ryegrass, pastures containing high proportions of annual ryegrass resulted in similar animal carrying capacity during winter but substantially lower carrying capacity in spring.Antibodies binding melatonin were detected in 75% of immunized animals, with higher and more persistent titres being obtained using Freund's than using Dextran adjuvant and titre being much higher in stags immunized at birth than at 3 months of age. This was associated with a small and variable increase in plasma prolactin concentration, but had no effect upon plasma concentrations of LH or testosterone or upon LWG.It was concluded that the small increase in deer production attributable to annual ryegrass was mainly due to higher VFI, and that grazing perennial ryegrass/white clover pastures at 10 cm surface height resulted in higher levels of deer production than grazing at 5 cm surface height. These studies emphasise the feasibility of early venison production from grazed pastures in New Zealand, and show that the young deer were growing close to their genetic potential under this system.
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Keim, J. P., I. F. López y R. Berthiaume. "Nutritive value, in vitro fermentation and methane production of perennial pastures as affected by botanical composition over a growing season in the south of Chile". Animal Production Science 54, n.º 5 (2014): 598. http://dx.doi.org/10.1071/an13026.
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Permanent pastures have been shown to produce similar herbage masses and nutrient contents to perennial ryegrass pastures. To the best of our knowledge, little research has been conducted on the ruminal fermentation of permanent pastures. Our objective was to evaluate the effect of botanical composition of four perennial pastures during a growing season in the south of Chile [winter, September 2010 ‘S1’; spring, November 2010 ‘S2’; and summer, January 2011 ‘S3’]: on in vitro fermentation products using a batch culture system. The perennial pastures studied included: permanent (PP), permanent fertilised (PFP) and renovated pastures (Lolium perenne and Trifolium repens pasture ‘RGWC’; Bromus valdivianus, Dactylis glomerata, Holcus lanatus, L. perenne and T. repens ‘MIXED’). There were strong interactions between pasture type and regrowth period for true organic matter, nitrogen (N) and neutral detergent fibre digestibility; total gas and volatile fatty acid (VFA) production; ammonia and microbial N. In general, all pasture treatments showed a high true organic matter digestibility (>800 g/kg), and tended to decrease in S3. In vitro fermentation of PFP and RGWC produced the highest total VFA concentration during S1 and S2, and no differences among pastures were observed in summer. Propionate proportion of total VFA was affected by pasture type and regrowth period, being higher for RGWC and S1, respectively. In vitro microbial N was higher for MIXED in S1, and PFP in S2 and S3. No pasture and regrowth period effects were observed for methane production and its proportion of total gas production. These results indicate that the in vitro fermentation products of a permanent fertilised pasture reach similar levels to those obtained from a sown pasture, and thus may be considered as a sustainable alternative for grazing livestock systems.
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Dear, B. S., J. M. Virgona, G. A. Sandral, A. D. Swan y S. Morris. "Changes in soil mineral nitrogen, nitrogen leached, and surface pH under annual and perennial pasture species". Crop and Pasture Science 60, n.º 10 (2009): 975. http://dx.doi.org/10.1071/cp09026.
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Soil mineral nitrogen (N) profiles during the growing season and changes in total soil N and available N after 3–4 years were examined under 9 different pasture swards containing annual legumes, lucerne (Medicago sativa L.), or one of 4 perennial grasses at 2 sites representative of the low and medium rainfall belt of south-eastern Australia. The effect of the presence of phalaris (Phalaris aquatica L.) or lucerne on the spatial variation in surface pH was also measured. The 9 pastures were subterranean clover (Trifolium subterraneum L.), subterranean clover with annual weeds, yellow serradella (Ornithopus compressus L.), lucerne, phalaris, cocksfoot (Dactylis glomerata L.), lovegrass (Eragrostis curvula (Schrader) Nees), wallaby grass (Austrodanthonia richardsonii (Cashm.) H.P. Linder), and a mixture of lucerne, phalaris, and cocksfoot. All the perennial treatments were sown with subterranean clover. Available mineral N values in the surface 0.10 m of soil following summer rainfall were substantially higher in pure subterranean clover or serradella (Ornithopus compressus L.) swards (24–50 μg N/g) than those containing a mixture of subterranean clover and perennials (9–20 μg N/g). Apparent leaching of soil nitrate down the profile during winter was greatest in annual pasture treatments and least in swards containing perennials. Soil pH(CaCl2) at the 0–0.10 m depth varied with proximity to perennial plants and was significantly higher (+0.2–1.1 pH units) near the base of perennial plants than in gaps between the perennials or in annual-only swards. Available mineral N to 1.0 m before cropping at the end of the pasture phase was highest following subterranean clover (175–344 kg N/ha) and serradella (202–316 kg N/ha) at both sites. Available N was lowest (91–143 kg N/ha) following perennial grass–clover swards at the drier site where the annual legume content was lower, but perennial grass–clover swards produced larger soil N values (147–219 kg N/ha) at the higher rainfall site. Removal of the pasture in August–September compared with November in the year before cropping increased available N at the time of sowing by an average of 44% (51 kg N/ha) at the drier site and 43% (74 kg N/ha) at the wetter site. Incorporating perennial pasture species in swards was found to be advantageous in reducing nitrate leaching and preventing a decline in surface soil pH; however, available soil N to following crops could be lower if the annual legume content of perennial grass-based pastures declined due to competition from the perennial species.
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Swan, A. D., M. B. Peoples, R. C. Hayes, G. D. Li, G. R. Casburn, J. I. McCormick y B. S. Dear. "Farmer experience with perennial pastures in the mixed farming areas of southern New South Wales: on-farm participatory research investigating pasture establishment with cover-cropping". Crop and Pasture Science 65, n.º 10 (2014): 973. http://dx.doi.org/10.1071/cp13448.
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In 2009, 95 farmers in the mixed farming zone of southern New South Wales (NSW), average annual rainfall 450–700 mm, were surveyed about their use of perennial pasture species. Survey responses indicated that, on average, 52% of land was under crop, 29% contained perennial pasture and 19% annual pastures. The proportion of land sown to perennial pastures and the species used differed with rainfall. Farmers identified concerns about the cost of establishment and poor survival of perennial pasture species as constraints to wider adoption. The survey also revealed that cover-cropping (sowing pasture species under the final grain crop in a cropping phase) was the dominant method of pasture establishment. Large-scale, on-farm participatory experiments were sown with the farm machinery, three at Ariah Park and one at Brocklesby in southern NSW in 2009 (annual rainfall 100 mm less than long-term average), and a further two experiments (one at each location) commenced in 2010 (annual rainfall >200 mm above average). These experiments compared the effect of cereal cover-crop sowing rate (standard rates used by the collaborating farmer and half of the standard rate) on the establishment of the perennials lucerne (Medicago sativa), phalaris (Phalaris aquatica), cocksfoot (Dactylis glomerata), and chicory (Cichorium intybus) sown in different mixes and rates with various annual legume species. The persistence and productivity of individual species were monitored for 2 years after sowing. Results indicated little or no effect of the presence of a cover-crop on the initial establishment of any of the perennials, but pasture species survival were severely affected by cover-crop sowing rates as low as half of the farmer practice (10 kg barley or 12 kg wheat ha–1) in 2009. Despite higher than average annual rainfall in 2010 and 2011, the residual effect of establishing pastures under a cover-crop in 2009 was poorer persistence and lower productivity by lucerne at the standard cover-cropping rate, and by phalaris, cocksfoot and chicory at all cover-crop rates, and an increased incidence of weeds. Similar responses to cover-cropping occurred between 2010 and 2012, even with the wetter establishment conditions in 2010, for phalaris, chicory and weeds, despite demonstration at Ariah Park that higher populations of individual perennial species could be achieved by doubling the sowing rate of pasture seed in 2010. Lucerne compensated for lower plant numbers by increasing herbage growth in response to rainfall, but phalaris could not and total pasture productivity over the first 2 years after establishment was greatly reduced by the use of cover-crops in both 2009 and 2010. Cover-cropping also reduced annual legume seedset, which could have implications for future pasture performance. Lucerne was the most consistently productive perennial pasture species evaluated regardless of establishment technique or climatic conditions.
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Chan, K. Y., A. M. Bowman, W. Smith y R. Ashley. "Restoring soil fertility of degraded hardsetting soils in semi-arid areas with different pastures". Australian Journal of Experimental Agriculture 41, n.º 4 (2001): 507. http://dx.doi.org/10.1071/ea00052.
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To evaluate the effectiveness of a pasture phase in restoring soil fertility, changes in concentration of organic carbon, physical and chemical properties of degraded hardsetting red soils (Alfisols) were assessed at 3 sites in the semi-arid central western region of New South Wales 3–4 years after conversion to different pastures. The pasture species included an annual grass, ryegrass (Lolium rigidum cv. Wimmera), an annual legume, barrel medic (Medicago truncatulata cv. Sephi) as well as a perennial grass, Consol lovegrass (Eragrostis curvula), and a perennial legume, lucerne (Medicago sativa cv. Trifecta). Significant differences in concentration of organic carbon in soils were found only in the top 0–2.5 cm even after 3–4 years under perennial pastures. The concentration of organic carbon under annual grass pasture did not differ from that in the fallow. Corresponding to the organic carbon concentrations, significant changes in water-stable aggregation (detectable to 20 cm depth) and hydraulic properties (up to a 5-fold difference in sorptivity, namely 0.29 mm/h 0.5 under fallow to 1.42 mm/h 0.5 under lucerne) were observed under perennial pastures when compared with that of the fallow. Of the 2 perennial pastures, Consol lovegrass and lucerne were both effective in promoting soil friability as well as water-stable aggregation. However, lucerne increased mineralisable nitrogen more than Consol lovegrass (by up to 4.6 times more, equivalent to 11.6 mg/kg in the 0–10-cm layer). Our results highlight the potential benefits of perennial pastures in maintaining the quality of the fragile hardsetting soils in the low rainfall areas. However, due to the slow rate and the restricted depth of improvement (0–2.5 cm), apart from incorporation of a pasture phase in the cropping system, soil management that maintains soil organic matter level and soil structure, namely reduced tillage and stubble retention, should also be adopted. These findings should be relevant to the management of the hardsetting soils that occupy 12% of the land area of Australia, particularly those in the lower rainfall areas.
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Johnston, W. H., P. S. Cornish y V. F. Shoemark. "Eragrostis curvula (Schrad.) Nees. complex pastures in southern New South Wales, Australia: a comparison with Medicago sativa L. and Phalaris aquatica L. pastures under rotational grazing". Australian Journal of Experimental Agriculture 45, n.º 4 (2005): 401. http://dx.doi.org/10.1071/ea03117.
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A grazing experiment conducted in Wagga Wagga (New South Wales) from September 1993 to September 1998 compared the productivity of pastures containing 3 palatable types of summer-active Eragrostis curvula complex, with pastures containing either Medicago sativa or Phalaris aquatica. Issues relating to the management of E. curvula pastures were also investigated. Herbage growth rates of the P. aquatica and M. sativa pastures were highest in winter and spring; E. curvula pastures were most productive in summer and autumn. Stocking rates equivalent to 30–40 dry sheep were carried by the pastures during their growing seasons. Throughout the study, the pastures were dominated by their respective sown perennial species, however, a suite of desirable and undesirable annual grasses and annual legumes usually contributed >20% of total herbage mass in spring. The P. aquatica pasture contained a higher proportion of weedy species than the other pastures, especially C4 grasses and broadleafed species, and towards the end of the experiment it was also invaded by several native perennial grasses. Overall, the wool yield from the M. sativa pasture was 0.5–1.0 kg/animal.year higher than the other pastures. Management to minimise herbage accumulation on the E. curvula pastures was a key issue, and provided that pastures were grazed heavily, this was achieved by the rotational grazing strategy used in the experiment. It was concluded that palatable varieties of E. curvula have a useful and complementary role as perennial pastures in southern Australia. By increasing herbage availability in summer and autumn, E. curvula may improve management flexibility for a wide range of pastures that are commonly grown on farms.
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Vickery, P. J., M. J. Hill y G. E. Donald. "Satellite derived maps of pasture growth status: association of classification with botanical composition". Australian Journal of Experimental Agriculture 37, n.º 5 (1997): 547. http://dx.doi.org/10.1071/ea97014.
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Summary. Spectral data from the green, red and near-infrared bands of Landsat MSS and Landsat TM satellite imagery acquired in mid-spring were classified into 3 and 6 pasture growth classes respectively. The classifications were compared with a site database of botanical composition for the Northern Tablelands of New South Wales to examine the association between spectral growth class and pasture composition. Pastures ranged in composition from unimproved native perennial grasses through semi-improved mixtures of native and naturalised grasses and legumes to highly improved temperate perennial grasses and legumes. For 3 years of MSS data, the fast growth class had a mean botanical composition of about 80% improved perennial grass and 0% native; medium growth class averaged 46% improved perennial grass and 14% native; while the slow growth class had about 60% native and 1% improved perennial grass when averaged over 3 years of MSS data. For the 6 class TM data from a single year, a predictive logistic regression of cumulative probability was developed for percentage of ‘very fast’ growth pixels and ordered 10 percentile categories of improved perennial grass or native grass. Differences in patch characteristics between classes with MSS disappeared with TM reclassified to the same 3 class level. Most probable pasture type was inferred from 3 class MSS and TM data using Bayesian probability analysis. The resulting maps were similar in general appearance but detail was better with the TM data. The pasture growth classification identified highly improved perennial grass pastures and native pastures but sensitivity to intermediate pasture types was poor. Future improvement will come from direct measurement of biophysical characteristics using vegetation indices or inversion of reflectance models.
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Pembleton, Keith G., Katherine N. Tozer, Grant R. Edwards, Joe L. Jacobs y Lydia R. Turner. "Simple versus diverse pastures: opportunities and challenges in dairy systems". Animal Production Science 55, n.º 7 (2015): 893. http://dx.doi.org/10.1071/an14816.
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For Australian and New Zealand dairy farms, the primary source of home-grown feed comes from grazed perennial pastures. The high utilisation of perennial pasture is a key factor in the low cost of production of Australian and New Zealand dairy systems and, hence, in their ability to maintain international competiveness. The major pasture species used are perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), normally grown in a simple binary mixture. As pasture production has been further driven by increasing use of nitrogen fertiliser and irrigation, farms are getting closer to their economic optimum level of pasture utilisation. Increasing inputs and intensification have also increased scrutiny on the environmental footprint of dairy production. Increasing the diversity of pasture species within dairy swards presents opportunities to further increase pasture utilisation through additional forage production, extending the growing season, improving forage nutritive characteristics and, ultimately, increasing milk production per cow and/or per hectare. Diverse pastures also present an opportunity to mitigate some of the environmental consequences associated with intensive pasture-based dairy systems. A consistent finding of experiments investigating diverse pastures is that their benefits are due to the attributes of the additional species, rather than increasing the number of species per se. Therefore, the species that are best suited for inclusion into dairy pastures will be situation specific. Furthermore, the presence of additional species will generally require modification to the management of dairy pastures, particularly around nitrogen fertiliser and grazing, to ensure that the additional species remain productive and persistent.
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Vere, D. T., R. E. Jones y M. H. Campbell. "Long-term change in the economic productivity of four major pasture categories on the south-eastern Tablelands of New South Wales". Rangeland Journal 23, n.º 2 (2001): 148. http://dx.doi.org/10.1071/rj01002.
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The perception of change or decline in the productivity of temperate pastures in south-eastern Australia is an important concern to livestock producers and pasture scientists. Much of this concern relates to reductions in the proportions of desirable species in the composition of pasture systems as a result of increased soil and weed problems. The purpose of this paper is to investigate trends in the long-term economic productivity of four categories of temperate pastures (all introduced pastures, introduced perennial grasses, introduced legumes and all native pastures) on the central and southern tablelands of New South Wales. The results provide evidence of economic productivity decline in the all introduced pastures category in relation to sheep production, but this has been due to productivity decline in the dominant legume component of the introduced pastures. In contrast, there has been strong growth in the economic productivity of the introduced perennial grass pastures. Abnormally high beef cattle numbers in the mid-1970s appear to have created an illusion of high productivity and subsequent decline in all introduced pastures. In contrast, the economic productivity of the native pastures which are the bulk of the region's grazing areas, has fallen substantially.
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Ridley, AM, WJ Slattery, KR Helyar y A. Cowling. "Acidification under grazed annual and perennial grass based pastures". Australian Journal of Experimental Agriculture 30, n.º 4 (1990): 539. http://dx.doi.org/10.1071/ea9900539.
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Soil samples to a depth of 60 cm were collected from adjacent, 39-year-old, phalaris-based and annual pasture fields on an acid soil at Rutherglen, north-eastern Victoria. The fields had similar histories of fertiliser application and stock enterprise. Minimum net acid addition rates were determined under both pasture types, and the soil under annual pasture showed greater acidification. Carbon cycle acid addition contributed 1.3 1 and 1.36 kmol H+/ha.year to net acid addition on annual and phalaris pastures, respectively. Because slow alkaline soil reactions in the field contribute to buffering capacity on an acid soil and lead to underestimation of net acid addition rate and nitrate leaching, estimates of such reactions were made for both pasture types. If correct assumptions were used nitrate leaching was substantial under both pasture types but was reduced by 1.01 kmol H+/ha.year under phalaris pasture. This suggests that perennial grass based pastures can be used to reduce acidification on pastoral soils. Alkali addition to counteract net acidification may be necessary on acid soils to maintain management options for growing aluminium-sensitive species.
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McCallum, M. H., J. A. Kirkegaard, T. W. Green, H. P. Cresswell, S. L. Davies, J. F. Angus y M. B. Peoples. "Improved subsoil macroporosity following perennial pastures". Australian Journal of Experimental Agriculture 44, n.º 3 (2004): 299. http://dx.doi.org/10.1071/ea03076.
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Biopores left in the soil by perennial and annual pastures and their effects on macroporosity, water infiltration and the water use and productivity of subsequent wheat and canola crops were investigated in a field experiment on a Sodosol in southern New South Wales. Phases of both lucerne (4 years) and phalaris (10 years) improved the macroporosity and water infiltration into the dense B horizon compared with continuous annual crops and pastures. After removal of lucerne and phalaris, the subsoil (> 12 cm depth) contained similar numbers of pores > 2 mm diameter (228 and 190/m2, respectively) compared with a mean of 68/m2 after annual crops. However water infiltration rate after lucerne was greater than after phalaris, apparently because of more numerous pores > 4 mm, rather than a change in total porosity. The subsoil after phalaris on the other hand contained more pores 0.3 mm in diameter and a higher total porosity, possibly because of more roots around this diameter, and a longer period without traffic or cultivation. The number of lucerne biopores in the subsoil remained unchanged (170–180/m2) for at least 2 crops after the lucerne was removed although the average size decreased. The volume of water extracted from the subsoil by crops following lucerne was similar to that following annual crop/pasture for 10 of the 12 crop comparisons made. For 2 of the crops, more subsoil water (22 and 24 mm) was used after lucerne than after annuals, and in 1 season this was associated with higher yield of canola. During the 3-year study there was no winter waterlogging or post-anthesis water stress, so there was little opportunity for yield responses to improved subsoil structure. The results confirm speculation that the unfavourable structure of dense subsoils can be improved by the biological action of perennial pasture roots, although reduced wheel traffic and cultivation during the pasture phases may also play a role. Further studies will be necessary to demonstrate associated yield improvements.
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Lodge, G. M., M. A. Brennan, S. Harden y S. P. Boschma. "Changes in soil water content under annual, perennial, and shrub-based pastures in an intermittently dry, summer-rainfall environment". Crop and Pasture Science 61, n.º 4 (2010): 331. http://dx.doi.org/10.1071/cp09258.
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Soil water content (SWC) was monitored in an intermittently dry environment in 2003–08, for the following pasture types: perennial ryegrass (Lolium perenne cv. Skippy), lucerne (Medicago sativa cv. Venus), phalaris (Phalaris aquatica cv. Atlas PG), a lucerne/phalaris mixture, digit grass (Digitaria eriantha ssp. eriantha cv. Premier), and old man saltbush (Atriplex nummalaria). Perennial ryegrass and phalaris pastures persisted until late winter–early spring 2005 and, after that time, were maintained as degraded annual grass pastures and bare fallows, respectively. For all pasture types, mean SWC was generally higher for the 0–0.9 m soil depth than the 0.9–2.1 m (63 v. 51 mm of water per 0.2 m soil layer). At a soil depth of 0–0.9 m, few significant differences in SWC occurred among pasture types. However, significant differences among pasture types were recorded in SWC at depths of 0.9–2.1 m for these perennial-based pastures with low herbaceous plant densities. At this depth the SWC of lucerne/phalaris was lower (P < 0.05) than that of perennial ryegrass and phalaris pasture types in March 2005 (Day 500), and that of the degraded annual grass pasture in August 2006 (Day 1000) and December 2007 (Day 1500). Overall, maximum extractable water was highest (P < 0.05) for digit grass and old man saltbush pasture types (~180 mm) and lowest for the bare fallow (99 mm). Estimates of root depth were highest (2.0 m) for the lucerne/phalaris pasture type.
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Hughes, J. D., I. J. Packer, D. L. Michalk, P. M. Dowling, W. McG King, S. Brisbane, G. D. Millar, S. M. Priest, D. R. Kemp y T. B. Koen. "Sustainable grazing systems for the Central Tablelands of New South Wales. 4. Soil water dynamics and runoff events for differently-managed pasture types". Australian Journal of Experimental Agriculture 46, n.º 4 (2006): 483. http://dx.doi.org/10.1071/ea04269.
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Soil water, runoff amount and quality, pasture production and environmental data were measured for a pastoral prime lamb enterprise in the Central Tablelands of New South Wales from 1998 to 2002. There were 4 pasture treatments: fertilised and sown chicory (CH), fertilised and sown introduced pastures (SP), fertilised naturalised pastures (FN) and unfertilised naturalised pastures (UN). Two grazing management regimes, tactically grazed (TG) and continuously grazed (CG) were imposed on the SP, FN and UN treatments. The CH treatment was rotationally grazed. To compare pasture and grazing system water use, maximum soil water deficit values (SWDMax) were calculated from neutron moisture meter data. SWDMax was influenced by both environmental and management factors. Management factors that influenced SWDMax were herbage mass of perennials, degree of perenniality, and the perennial species present. Environmental factors accounted for >50% of the variation in SWDMax. Inclusion of management factors (perennial herbage mass of C3 and C4 species and percentage perennial herbage mass), accounted for an additional 16% of variation. While the influence of pasture management appears to be relatively small, importantly, management is the only avenue available to land managers for influencing SWDMax. The UNTG and all sown treatments, with greater perennial herbage mass or greater C4 herbage mass consistently produced the highest SWDMax. Runoff amount and quality data are presented for ground cover percentages which generally exceeded 80% for the experimental period. Runoff as a proportion of rain received during the experiment was <3%. Environmental factors explained 47% of variation in runoff, while pasture herbage mass and ground cover percentage explained an additional 2% of variation. Water quality was monitored on 3 treatments (SPTG, FNTG and UNCG) for total nitrogen (N), total phosphorus (P) and total suspended solids (TST) over a 6-month period. The mean values for total N and P were below the acceptable contaminant concentration for agricultural irrigation water. An important outcome of this research is the concept of a practical Targeted Water Management Plan (TWMP) which devises a framework for optimum water usage and productivity at a landscape scale.
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Ridley, A. M., R. J. Simpson y R. E. White. "Nitrate leaching under phalaris, cocksfoot, and annual ryegrass pastures and implications for soil acidification". Australian Journal of Agricultural Research 50, n.º 1 (1999): 55. http://dx.doi.org/10.1071/a98038.
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Nitrogen uptake and nitrate (NO-3) leaching below 1.1 m was estimated under phalaris, cocksfoot, and annual ryegrass pastures and under bare fallow in a 4-year field experiment under control and high N (500 kg N/ha) treatments in north-eastern Victoria (693 mm/year rainfall for the study period). The perennial grasses, particularly phalaris, took up more N in herbage than annual ryegrass. High concentrations of NO3-N were measured at 1 m depth below all treatments, suggesting that NO3- losses from pastures have potential to contaminate streams and/or groundwater. Perennial pastures were only able to reduce NO3- leaching compared with annuals in drier than average years. Values calculated for acid addition due to NO3-leaching resulted in a net annual input of approximately 1 kmol H +/ha.year under the phalaris pasture compared with 2 kmol H +/ha.year under annual ryegrass. Adding these figures to carbon cycle addition data of 1 kmol H+/ha.year (measured in a previous study) corresponds to a lime rate of 100 and 150 kg lime/ha.year being required to stop further acidification under these pasture types. A 1 unit pH decline to 30 cm depth was estimated to take 42 years under annual pasture or 67 years under perennial grasses. Whilst perennial pastures have a role in reducing soil acidification, lime application is the most important management option in balancing soil acidification caused by agriculture.
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Fillery, I. R. P. y R. E. Poulter. "Use of long-season annual legumes and herbaceous perennials in pastures to manage deep drainage in acidic sandy soils in Western Australia". Australian Journal of Agricultural Research 57, n.º 3 (2006): 297. http://dx.doi.org/10.1071/ar04278.
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The effect of including phases of long-growing-season annuals and herbaceous perennial pastures on water use was examined at 2 sites (deep sand and duplex soil) in Western Australia. Herbaceous perennials used were lucerne (Medicago sativa), and a mix of C3 grasses comprising phalaris (Phalaris aquatica), tall wheat grass (Thinopryum ponticum), and tall fescue (Festuca arundinacea) (perennial grass treatment). The long-season annual treatment was a mix of yellow and pink serradella (Ornithopus sp.) and Casbah biserrula (Biserrula pelecinus). These treatments were compared with annual-based pasture that was a mixture of subterranean clover with capeweed and Brassica species, and annual crops. Pasture treatments were first sown in 1998. High senescence of C3 grasses over the 1998–99 summer and poor germination of serradella/Casbah biserrula in the autumn of 1999 necessitated the re-seeding of the long-season annual and the perennial grass treatment in 1999. Wheat was sown in 1998, lupin in 1999, and barley in 2000 in an annual crop treatment. Soil water content to 1.5 m was measured hourly using frequency domain reflectometer probes, and a neutron probe was used monthly to measure changes in soil water to 5 m. Herbage production and species composition were determined. In each year of the study, annual pasture species senesced by November. About 20 lucerne plants/m2 persisted through the first summer–autumn in deep loamy sand and 40 lucerne plants/m2 in a duplex soil. Perennial C3 grass species did not survive the summer–autumn in sufficient density and distribution to evaluate their effect on soil water. Annual dry matter (DM) production in lucerne-based and subterranean clover-based pasture was not significantly different. Dry matter production in lucerne between 1 December and the following May–June, when germination of annual-based pastures occurred, was 1.2–1.9 t/ha at one site and 0.2–1.6 t/ha at another site. Long-season annual pastures produced significantly more DM than either lucerne or subterranean clover-based pastures in one season at one site but produced significantly less DM than either lucerne or subterranean clover-based pasture at another site in another season. Long-season annual-based pastures extracted amounts of soil water to a depth of 5 m similar to subterranean clover-based pasture when these were grown on deep sand and a duplex soil. In contrast, lucerne removed an additional 128 mm of water to 5 m, with 70 mm of this water being drawn from 2.5–5 m, compared with subterranean clover-based pasture. Lucerne was comparatively less effective in extracting water from a duplex soil where rooting depth was restricted to 2 m by a saline watertable. Early germination of annual pastures appeared to reduce drainage compared with a crop treatment where weeds were killed in autumn and early winter ahead of seeding. The need for studies at landscape scales that include concurrent measurements of groundwater levels and changes in soil water content to a depth of at least 5–6 m under perennial-based production systems is highlighted.
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Kemp, DR y PM Dowling. "Species distribution within improved pastures over central N.S.W. in relation to rainfall and altitude". Australian Journal of Agricultural Research 42, n.º 4 (1991): 647. http://dx.doi.org/10.1071/ar9910647.
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Botanical composition has a large influence on pasture productivity, but little information is available about the botanical composition of pastures on farms, the interactions of species or reasons for their distribution. A survey was done, during two successive springs and using a point quadrat method, of the botanical composition of improved pastures in central New South Wales and maps prepared of the proportion of species or groups of species in pastures. The survey area covered a wide range in rainfall (600-1000 mm), altitude (300-1400 m) and the boundary where perennial and annual pasture species overlap. Subterranean clover was the most common legume and occurred in all parts of the region. Above 700 mm rainfall, white clover replaced subterranean clover in a linear relationship, though the proportion of the pasture occupied by both species never exceeded 30%. Annual grasses were found throughout the survey area, and they were also replaced by perennial species at higher rainfall, higher altitude sites, in a linear relationship. The total proportion of the pasture from both perennial and annual grasses did not exceed a mean of 55%. The high proportion of annual species was attributed in part to continuous grazing practices. Perennial species were found down to 600 mm rainfall but only exceeded the proportion of annual species when the rainfall exceeded 800 mm for legumes or 900 mm for grasses or where the altitude was above 900 m (<12�C mean annual temperature) for both groups. It was concluded that among perennial or annual groups, legumes and grasses occupied slightly different niches in the pasture, and they would not always replace one another exclusively. The legume content of pastures, especially in the higher rainfall areas, was considered to be less than satisfactory for animal production. Pasture recommendations need to consider the climatic limits where species are able to make a major contribution to production as well as the climatic limits for persistence.
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Ussher, G. R. y D. E. Hume. "Sustainable perennial pastures in Northland". Journal of New Zealand Grasslands 77 (1 de enero de 2015): 141–46. http://dx.doi.org/10.33584/jnzg.2015.77.489.
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In the northern half of Northland, perennial ryegrassbased pastures have exhibited poor persistence. Nineteen tall fescue and ryegrass pastures in the region infected with either MaxP or AR37 fungal endophytes, respectively, had high levels of endophyte-infected tillers and low levels of contamination from wild endophytes. On surveyed farms, MaxP-infected tall fescue pastures had good contents of sown grass, which were higher than sown grass contents in AR37-infected ryegrass pastures, but on two far-north monitor farms these temperate grasses failed to compete with summer active C4 grasses such as kikuyu and carpet grass. For tall fescue and perennial ryegrass to form productive pastures in this region, sown seed should have high levels of viable endophyte, soil fertility should be adequate for good grass and legume growth, and pastures should be well managed. Summer droughts may still be too severe in some years for these temperate grasses to persist in the face of C4 grass competition. Keywords: Endophyte, Epichloë, Neotyphodium, Lolium perenne, Festuca arundinacea, soil fertility
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Grekul, Chad W. y Edward W. Bork. "Herbage Yield Losses in Perennial Pasture Due to Canada Thistle (Cirsium arvense)". Weed Technology 18, n.º 3 (septiembre de 2004): 784–94. http://dx.doi.org/10.1614/wt-03-196r.
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Although the impact of Canada thistle (CT) on annual crop production is relatively well established, few investigations report on this weed's impact within perennial pastures. This field study assessed herbage yield losses within eight central Alberta pastures from 1999 to 2001. Each pasture was sampled in 1999 to quantify thistle and herbage biomass within 25 permanent plots. CT was controlled in 2000 and the response of vegetation measured in 2000 and 2001. Before removal, significant negative relationships (P < 0.05) between thistle abundance and herbage were noted at six sites. After thistle removal, herbage at several sites displayed positive responses. Both thistle density and biomass adequately predicted herbage yield loss. Yield losses due to CT can be substantial, peaking at 2 kg/ha for each kilogram of standing thistle biomass and 4.3 kg/ha with each additional thistle stem per square meter. Demonstrated yield losses were variable among sites however, likely due to factors such as heterogeneity in soils, available moisture, and variation in disturbance history or pasture vegetation composition. CT management in perennial pastures of western Canada may enhance pasture production, but further research is required to reliably predict the ability of pastures to respond.
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Lodge, G. M. "Studies of soil seedbanks in native and sown pastures in northern New South Wales". Rangeland Journal 23, n.º 2 (2001): 204. http://dx.doi.org/10.1071/rj01007.
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Total and germinable soil seedbanks (litter and soil) were studied for a native pasture and three sown pastures (dominated by Phalaris aquatica L. cv. Sirosa) in northern New South Wales from 1993 to 1996. Soil core samples were taken from continuously grazed plots for both pasture types and two oversown treatments in the native pasture and from a spring-autumn rest treatment at the sown pasture sites. At each site above ground herbage mass was also estimated regularly as part of the Temperate Pasture Sustainability Key Program. For all sites and treatments, the proportion of germinable seeds as a percentage of the total (dormant and germinable) seedbank ranged from 1–26% for the native pasture and 1–39% for the sown pastures. Germinable seed numbers ranged from 280 to 26,110 seeds per m2, while total seedbank numbers were from 6700 to 178,360 seeds per m2. Native pasture herbage mass was dominated by native perennial grasses, but seeds of these species were less than 20% of the total seed bank in all treatments in 1994 and 1995. At the sown pasture sites, most of the germinable (51–92%) and total (65–97%) seedbanks were either barnyard grass (Echinochloa crus-galli (L.) Beauv, annual ryegrass (Lolium rigidum Gaudin), subterranean clover (Trifolium subterraneum L.) or wireweed (Polygonum aviculare L.). Since seeds of annuals and other forbs generally dominated both the total and germinable seedbanks of these perennial grass-based pastures, these species were likely to increase over time. Seeds of the sown perennial grass Phalaris aquatica L, cv. Sirosa were less than 1% of the total seedbanks in pastures sown in 1990 and less than 3% of those sown in 1979. With above average summer rainfall at the native pasture site in 1996 and prolific growth of redgrass, seeds of this species were 38–63% of the total and 11–29% of the germinable seedbank in May 1996. Except at this site and time, the species composition of the total and germinable seedbanks did not generally reflect the dominance of the above ground herbage mass of these pastures by perennial grasses.
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Mitchell, GJ, RJ Carter y SR Chinner. "Studies on the control of water-dropwort (Oenanthe pimpinelloides) in South Australia". Australian Journal of Experimental Agriculture 35, n.º 4 (1995): 483. http://dx.doi.org/10.1071/ea9950483.
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Water-dropwort (Oenanthe pimpinelloides L.), a tuberous perennial herb, is currently known in South Australia from only a single locality in the Mount Lofty Ranges. There is little information on water-dropwort control, and 2 experiments were conducted to assess the effects of sowing pasture, with or without presowing herbicides, on the control of this weed. Phalaris (Phalaris aquatica L.) and perennial clovers were successfully introduced into infested pastures by direct drilling in autumn. Water-dropwort regenerated from seed more densely in unsown plots than plots of established perennial pasture, suggesting that upgrading pastures may be a strategy to reduce the rate of spread by seed of this weed. A range of herbicide treatments applied to waterdropwort at the stem elongation stage in spring before autumn sowing of pastures provided effective shortterm control. The best short-term control was provided by glyphosate at 1440 g a.i./ha; metsulfuron methyl at 6, 12, and 36 g a.i./ha; and metsulfuron methyl at 12 g a.i./ha tank-mixed with glyphosate or 2,4-D amine at 720 or 1000 g a.i./ha, respectively. These treatments, and chlorsulfuron at 21 g a.i./ha, also significantly (P<0.05) reduced water-dropwort abundance (relative to untreated areas) for up to 18 months after sowing and initially improved the density of sown pasture species, but these improvements were not evident 14 months after resowing. Although prior season herbicide treatments controlled water-dropwort in newly sown pastures, 2 separate applications of herbicides, in May and October, gave no better control of water-dropwort than a single herbicide application in spring. Water-dropwort infestations do not appear to prevent successful direct drilling of phalaris and perennial clovers. Although pasture renovation did not provide long-term suppression of water-dropwort, the maintenance of vigorous pastures may reduce the rate of population growth from seedlings of this weed. Recropping restrictions may limit the role of chlorsulfuron for water-dropwort control in pasture renovation situations.
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Kemp, D. R., D. L. Michalk y J. M. Virgona. "Towards more sustainable pastures: lessons learnt". Australian Journal of Experimental Agriculture 40, n.º 2 (2000): 343. http://dx.doi.org/10.1071/ea99001.
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The Temperate Pasture Sustainability Key Program (TPSKP) was established across south-eastern Australia to test the hypotheses that an improved perennial grass content in pastures would result in fewer weeds, better water use (and hence lesser impacts on soil salinity), and lower soil acidification rates. Grazing tactics were seen as a means to enhance or maintain the perennial grass content. Soil and water sustainability experiments in summer and winter dominant rainfall environments showed fewer weeds, improvements in water use and less acidity under perennial versus annual grass pastures. Further work is needed to determine if these gains are sufficient to make perennial grass pastures sustainable in the long-term as some nitrate leakage still occurred at the winter rainfall site. Indicators were developed to rate the sustainability of treatments within experiments. A subset of these indicators was common across experiments and could readily be used by farmers to provide an initial assessment of the soil and water sustainability of their pasture systems. These are: the mineral nitrogen at the bottom of the root zone (40–60 cm); soil pH at the surface and bottom of the root zone and perennial grass content by species. Managing pastures through droughts is a critical aspect of grazing management in Australia. Experiments within the TPSKP demonstrated that perennial grasses survived during drought when maintained above critical lower biomass values. These values ranged from 0.5 to 1.5 t DM/ha depending upon species. Over all experiments, there was general support for the view that maintaining a higher level of biomass in pastures resulted in more sustainable systems. Twenty-three grazing experiments using an open communal grazing design showed that most perennial grasses were sensitive to grazing at some stage in their seasonal growth cycles. The exceptions were inconclusive for several reasons e.g. the grazing pressure may not have been high enough at those sites to elucidate any effects; they occurred where the perennial grass content was less than 10% or exceeded 70%, of the sward; or were confounded by interactions between species where the species under study was not dominant. After taking these exceptions into account, it was then possible to determine where grazing tactics could be expected to work. Species differed in their response to grazing. Some perennial grasses were more sensitive to grazing during periods of stress (e.g. dry summers) than when actively growing (e.g. cocksfoot), while the reverse applied with others (e.g. phalaris). Of the grasses sensitive to grazing when actively growing, sensitivity of some was largely confined to the reproductive period (e.g. perennial ryegrass). Across most experiments, continuous grazing resulted in either a decline in or no net benefit to, the perennial grass content. Microlaena stipoides was the only species to respond to increased grazing pressure — this only applied in spring. The experiments clearly showed that tactical rests were an important tool for grassland management. The effects recorded were predominantly expressed through impacts on vegetative growth and survival of existing plants. Short-term experiments and dry seasons did not enable recruitment processes to be studied. Within pastures, grazing tactics can influence many species. The challenge is to use the TPSKP outcomes to develop strategies that optimise the composition of these swards. Due to the short-term nature of these experiments the results were evaluated within a conservative framework and often simply on the absolute level of parameters. Techniques need to be developed to more effectively monitor the process (i.e. rates of change), rather than the consequences (i.e. ends). The information gained in this program needs to be incorporated into practical strategies for better management of pastures and tested at a commercial scale. The TPSKP was one of the largest, coordinated pasture programs ever attempted. Some major outcomes were the experience gained by a large number of grassland scientists in running such programs, the development and acceptance of standardised measurement protocols and a much stronger network among grazing systems scientists committed to achieving improved management systems.
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Lawson, A. R., P. W. G. Sale y K. B. Kelly. "Effect of defoliation frequency on an irrigated perennial pasture in northern Victoria. 1. Seasonal production and sward composition". Australian Journal of Agricultural Research 48, n.º 6 (1997): 811. http://dx.doi.org/10.1071/a96088.
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A field experiment was carried out to investigate whether changes in winter and post-winter defoliation frequency would increase the white clover content of an irrigated perennial ryegrass–white clover pasture in northern Victoria. Pastures defoliated every 4 weeks during winter had higher white clover growing point (stolon apices with at least 2 nodes) density at the end of winter than pastures defoliated every 8 weeks or those receiving a single defoliation after 16 weeks, but these differences did not affect the clover content in the spring. Reasons for this are suggested. Pastures defoliated at 8-week intervals in winter were the most productive over winter{early spring. Less frequent defoliation (4 v. 2 weeks) during the post-winter, September–May period reduced white clover growing point and perennial ryegrass tiller densities. However, the white clover growth rate during this period was increased by less frequent defoliation, whereas the ryegrass growth rate was reduced, resulting in an increase of 10% in the white clover content, and a 1·9 t dry matter (DM)/ha increase in total DM produced. This higher clover content and pasture yield during spring–autumn with less frequent defoliation has important implications for the management of irrigated perennial pastures for the dairy industry in northern Victoria.
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Bowen, M. K., F. Chudleigh, S. Buck y K. Hopkins. "Productivity and profitability of forage options for beef production in the subtropics of northern Australia". Animal Production Science 58, n.º 2 (2018): 332. http://dx.doi.org/10.1071/an16180.
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This study measured forage biomass production, diet quality, cattle liveweight gain, and economic performance of six forage types at 21 sites across 12 commercial beef cattle properties in the Fitzroy River catchment of Queensland during 2011–2014 (28 annual datasets in total). The forages were annual forage crops (oats (Avena sativa), sorghum (Sorghum spp.) and lablab (Lablab purpureus)), sown perennial legume-grass pastures (leucaena-grass (Leucaena leucocephala spp. glabrata + perennial, tropical grass (C4) species) and butterfly pea-grass (Clitoria ternatea + perennial, C4, grass species)), and perennial, C4, grass pastures. The sown forages resulted in 1.2–2.6 times the annual cattle liveweight gain per ha than perennial grass pastures. Annual cattle liveweight gain per ha, forage establishment and management costs, and cattle price margin (sale price less purchase price, $/kg liveweight) all influenced gross margin, however, none was an overriding factor. The average gross margins ($/ha.annum) calculated using contractor rates, ranked from highest to lowest, were: leucaena-grass pastures, 181; butterfly pea-grass pastures, 140; oats, 102; perennial grass, 96; sorghum, 24; and lablab, 18. It was concluded that the tendency towards greater average gross margins for perennial legume-grass pastures than for annual forage crops or perennial grass pastures was the result of the combined effects of lower average forage costs and high cattle productivity.