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1
McIvor, JG, e 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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Roulière, Camille. "Herbaceous Traces: A History of Agri/cultural Sinuosities". Performance Philosophy 6, n.º 2 (1 de novembro de 2021): 39–60. http://dx.doi.org/10.21476/pp.2021.62321.
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In this piece, I follow the geo-temporal meanderings of native grasses (in particular yam daisy-Microseris lanceolate and native millet-Panicum decompositum) through the Australian colonial record and beyond to reveal co-constitutive entanglements which bear witness to a plurality of agri/cultural narratives. In particular, I draw on the concept of trace as theorised by philosophers Jacques Derrida and Édouard Glissant to explore and produce aesthetic interventions which reveal, shape, coerce and/or support these grasses’ presence and agency—their voices. Scattered through geo-temporalities and media, these interventions document—trace—native grasses’ historical experiences and the role(s) awarded to them. Their punctual nature accounts/allows for ruptures, disruptions and (dis)continuity: each intervention carries its own rhythms of the collision between past and future in its midst. This fragmentary state also supports the fluid positioning of voices—the crafting of a textual space where poetics become a tool of decoloniality. Such a juxtaposition of perspectives and representational practices aim to generate intertwining accounts of vegetal being-in-the-world. More precisely, it aims to provide new insights into how native grasses have shaped and been shaped by colonial and decolonial practices—to illuminate their sinuous trajectories with(in) the fabric of the land.
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Hendricksen, RE, MA Gilbert e LD Punter. "Effect of superphosphate application on macro-nutrient and micro-nutrient concentrations in grazed stylo-native grass pasture in tropical Australia". Australian Journal of Agricultural Research 43, n.º 8 (1992): 1725. http://dx.doi.org/10.1071/ar9921725.
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Soils of northern Australia are generally old, strongly weathered, and of low fertility status. Some knowledge of the status of nitrogen, phosphorus and sulfur and its effects on pasture productivity is available from small plot trials, but few detailed studies of macro-nutrient and micro-nutrient levels in grazed pastures have been reported. Such a study from a site near Mareeba in north Queensland has recently been completed. The major components of the pasture were kangaroo grass ( Themeda triandra), giant speargrass (Heteropogon triticeus) and the legumes, Stylosanthes scabra cv. Seca and S. hamata cv. Verano, which were oversown into the native grass pasture 6 years previously. Generally, the effects of superphosphate on nutrient concentration were minor compared with the effects of season, plant part and species. Superphosphate application increased concentrations of P and S, but decreased concentrations of Zn and Mo and the N/S ratio in both sets of legume and grass. There was no effect on the concentrations of N, K, Na, Ca, Cu and Co. Fertilizer effects did not often interact significantly (P < 0.05) with season, species and plant part (green leaf and stem). Seasonal changes in nutrient concentration were not consistent for all nutrients. As the growing season progressed from December to June, concentrations of the mobile nutrients, N, P, K, Na, Cl, S, Se and I decreased, the immobile nutrients Ca and Mo increased, but Mg, Cu and Co and the N/S ratio remained relatively constant. Both Zn and Mn concentrations remained constant with season in the legumes, but increased in the grasses. Season * species interactions were often significant for the grasses possibly due to the differing maturity patterns of kangaroo grass and giant spear grass. Cattle grazing the native pasture during the wet season are likely to be deficient in N, P, Na, S and Cu based on the nutrient concentrations in plucked pasture samples and published dietary requirements. However, cattle grazing productive stylo - native grass pasture which has received adequate single superphosphate are likely to suffer only from Na deficiency. At suboptimal levels of superphosphate, a deficiency of P in the diet is also indicated.
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Winter, WH, JJ Mott, RW McLean e D. Ratcliff. "Evaluation of management options for increasing the productivity of tropical savanna pastures. 1. Fertiliser". Australian Journal of Experimental Agriculture 29, n.º 5 (1989): 613. http://dx.doi.org/10.1071/ea9890613.
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Options for increasing pasture and animal production from native perennial pastures comprising predominantly Themeda triandra, Chrysopogon fallax, Sehima nervosum and Sorghum plumosum were studied over 5 years at Katherine in the semi-arid tropics of north-western Australia. The pastures were augmented with either Stylosanthes humilis, S. hamata or a mixture of S. scabra and S. viscosa, either without fertiliser or with low inputs of superphosphate (100 kg/ha at establishment and 25 kg/ha annually), and with the trees either killed or left undisturbed. At each fertiliser level there were 3 stocking rates. Five years after sowing, only half of the pastures persisted, due to the poor productivity of the legumes and the inability of the native perennial grasses to tolerate high grazing pressure which was about 10-fold that for non-augmented native pasture. This effect was greater in the unfertilised treatments, where the legume contributed less to pasture yield, so that the sustainable stocking rate was only half of that for pastures fertilised with small amounts of superphosphate. When fertilised, stable pastures of nearly pure legume were obtained after 3-4 years at the highest stocking rate of 1 steer/ha. Fertiliser also (i) increased the nitrogen and sulfur concentrations of S. humilis and the perennial stylos S. scabra and S. viscosa, but lowered their concentrations in S. hamata, particularly in the early wet season; (ii) decreased nitrogen concentration in Chrysopogon fallax; and (iii) increased phosphorus and sulfur concentrations of all the perennial grasses. In general, fertiliser promoted higher liveweight gains of cattle during the wet season and lower losses during the dry season. In the fertilised treatments growth tended to be poorer at the highest stocking rate, particularly during the late dry and early wet seasons. This effect was attributed to spoilage of dry legume by the early rainfall and lack of grass in these treatments. We conclude that S. hamata, S. scabra and S. viscosa grow reasonably well in soils of low fertility, but the productivity of the legumes and of the cattle can be improved by small inputs of superphosphate. The mediocre growth of the cattle in all the treatments may have been due to the low levels of some nutrients, particularly phosphorus and sulfur, in these pastures.
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Taylor, Ben, e George G. Ganf. "Comparative ecology of two co-occurring floodplain plants: the native Sporobolus mitchellii and the exotic Phyla canescens". Marine and Freshwater Research 56, n.º 4 (2005): 431. http://dx.doi.org/10.1071/mf04196.
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In the northern Murray–Darling Basin (MDB), Australia, the displacement of native floodplain grasses by Phyla canescens (Lippia), an exotic herb, coincided with a reduced frequency of floodplain inundation owing to river regulation. Although river regulation and P. canescens occur in the southern MDB, P. canescens abundance has not increased significantly since 1988. This work reports on the current distribution of P. canescens and the native grass Sporobolus mitchellii on the lower River Murray. It demonstrates that there are significant differences in the edaphic characteristics of sites occupied by the two species and co-occurrence is rare. To explain this observation, two factors were investigated: the resilience of S. mitchellii to invasion by P. canescens and the response of both species to artificial spring floods. At initial densities of >25%, S. mitchellii exhibited strong resilience to invasion by P. canescens. The growth response of both species to spring floods was similar. However, P. canescens reproduced asexually when inundated and, on exposure, exhibited a root distribution that would enhance its capacity to survive future droughts. In contrast, S. mitchellii was more tolerant of low soil moisture than P. canescens. The re-introduction of spring floods could favour the expansion of P. canescens.
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Winter, WH, JJ Mott e RW McLean. "Evaluation of management options for increasing the productivity of tropical savanna pastures. 3. Trees". Australian Journal of Experimental Agriculture 29, n.º 5 (1989): 631. http://dx.doi.org/10.1071/ea9890631.
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The effect of killing trees upon the production and quality of native perennial grasses, Themeda triandra, Chrysopogon fallax, Sehima nervosum, and Sorghum plumosum, and oversown legumes from the genus Stylosanthes, was studied over 4 years at Katherine, in the semi-arid tropics of northwestern Australia. The pastures were either unfertilised or received low inputs of superphosphate, and for each fertility level were grazed at 3 stocking rates. At no time were legume yields affected by killing the trees but, in the first 3 years, the amount of grass was approximately twice as much when the trees were killed. During this period the mean grass yields declined 4-5 fold from about 2.2 t/ha. By the fourth year the advantage from tree killing upon grass yield was apparent only at the lowest stocking rates at each fertility level. Nitrogen concentrations of the grasses and legumes, with the exception of S. hamata, were increased 7 and 10% respectively above the mean annual values of 0.89 and 1.75% where the trees were killed, while the phosphorus and sulfur concentrations were not affected. Tree killing had no effect upon wet season liveweight gains during the last 2 years of the experiment. However, there were some benefits during the dry season when weight losses were lower for most treatments during the early dry season (June-September) and also lower for the lowest stocking rate treatment without fertiliser during the late dry season (October-November).
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Winter, WH, JJ Mott e RW McLean. "Evaluation of management options for increasing the productivity of tropical savanna pastures. 2. Legume species". Australian Journal of Experimental Agriculture 29, n.º 5 (1989): 623. http://dx.doi.org/10.1071/ea9890623.
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The effect of legume species, used for augmentation of native perennial grasses, upon forage production and quality and animal production was studied over 4 vears in the semi-arid troPics of northwestern Australia. The legumes were Stylosanthes humilis cv. Paterson (Townsville stylo), S. hamata cv. Verano (Caribbean stylo) and a mixture of perennial species S. scabra cvv. Fitzroy and Seca and S. viscosa (perennial stylo). They were compared at 2 levels of fertility, unfertilised (UF) and with small inputs of superphosphate (F); and at stocking rates of 0.45,0.6 and 0.75 steers/ha for UF and 0.6, 0.8 and 1.0 steers/ha for F. By 1980 only half of the 3 x 12 treatments persisted, 3 Townsville stylo, 9 Caribbean stylo and 6 perennial stylo. Without fertiliser the perennial stylos had the highest wet season yields of 1-2 t/ha which constituted 4040% of pasture yield, compared with 2-20% for the other legumes. Caribbean stylo yields were highest with fertiliser, yielding 2-4 t/ha and 50-90% of the pasture at the end of the wet season, compared with 60-70% for perennial stylo and 5-30% for Townsville stylo. Anthracnose devastated Townsville stylo, and also reduced the productivity of Fitzroy. The perennial stylos had the highest concentrations of nitrogen (N), phosphorus (P), and sulfur (S) during the dry season while Caribbean stylo and its associated grasses had the lowest P and S concentrations during the wet season. When annual liveweight gains for each legume were compared at the same stocking rate-fertiliser level, differences were less than 15 kg, but there were considerable differences in the patterns of growth within the year; these differences were related to the seasonal availability and relative palatability of grass and legume. The overall mediocre animal growth of 30-110 kg/steer.year was attributed to the inadequate supply of nutrients for most of the year, with the possible exception of N.
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Fensham, Roderick J., Jason Halford, Chris Hansen, Boris Laffineur e Billie Williams. "Threatened species in a threatened ecosystem: the conservation status of four Solanum species in the face of ongoing habitat loss". Oryx 53, n.º 3 (20 de maio de 2019): 439–49. http://dx.doi.org/10.1017/s0030605318001266.
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AbstractPlant biodiversity is threatened by habitat loss, fragmentation and invasion by exotic species, but the effects of these disturbances on individual plant species are rarely quantified. Since the 1950s, brigalow Acacia harpophylla forests in Australia have been extensively cleared and converted to pastures dominated by exotic grasses. Here we assess the habitat requirements, population numbers and threats for four poorly known bush tomato species, Solanum adenophorum, Solanum dissectum, Solanum elachophyllum and Solanum johnsonianum. Herbarium records and surveys demonstrated a strong association of all four species with brigalow habitat, although S. elachophyllum also occurred in other habitat. We derived historical and current population estimates from plant densities at current sites and the area of mapped brigalow habitat. Density estimates are imprecise because the survey data vary greatly, but the assessment indicates the populations of all four species have declined > 93%. Solanum dissectum and S. johnsonianum did not persist in cleared brigalow habitat, whereas S. adenophorum and S. elachophyllum had some capacity to persist in clearings. None of the species occur where the exotic grass cover is > 40%. Between 27% and 57% of the records of the four species are in brigalow remnants with a high edge-to-area ratio or open canopy (< 50% cover), making them highly vulnerable to invasive grasses. We recommend the categorization of S. dissectum and S. johnsonianum as Critically Endangered, S. adenophorum as Vulnerable and S. elachophyllum as Near Threatened.
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Prober, SM. "Conservation of the Grassy White Box Woodlands: Rangewide Floristic Variation and Implications for Reserve Design". Australian Journal of Botany 44, n.º 1 (1996): 57. http://dx.doi.org/10.1071/bt9960057.
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Grassy white box (Eucalyptus albens Benth.) woodlands once covered several million hectares of the wheat-sheep belt of south-eastern Australia. The pre-European floristic composition of these woodlands is little-known, as almost all of them were rapidly cleared for cropping or modified by livestock grazing. Woodland remnants were surveyed across NSW, to describe rangewide variation in the woodland flora, and to provide a basis for reserve design. As far as could be detected from current remnants, some of the major features of the original grassy white box woodland understorey appear to have been relatively constant across NSW: on a wide variety of soils and parent materials from southern to northern NSW, the dominant native grasses in little-disturbed sites were generally Themeda australis (R.Br.) Stapf andor Poa sieberiana Sprengel, and many of the subsidiary herbs and grasses occurred across this range. There were, however, several natural patterns of variation requiring consideration in conservation planning: about half of the subsidiary herb and grass species showed a relationship with latitude, probably relating to a climatic gradient; the understorey became more shrubby, with a sparser and more varied grass component, on soils classed as being 'unsuitable for agriculture'; and on basalt parent materials of the Inverell Plateau, Dichanthium sericeum (R.Br.) A.Camus may have been a more prominent component of the understorey. Natural floristic variation was overlain by patterns resulting from European disturbance, as indicated by floristic distinctions between sites of differing landuse. While these distinctions were partly related to poorer soil resource class in State Forests and Nature Reserves, grazing by livestock and tree clearing are likely to to have contributed to them. Reserves in ine whire box woodiands are presentiy few, and are not representative of the naturai variation. ~ o s t existing reserves occur on soils unsuited to agriculture, compared with the grazing or arable land of typical grassy woodland. Cemetery remnants, rail easements, Travelling Stock Reserves and roadsides provide the best opportunities for conservation on higher-quality soils. Remnant quality declined significantly in southern NSW, indicating a need for greater conservation effort in southern areas.
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Shrestha, Sangita, Stephen W. Adkins, Glenn C. Graham e Donald S. Loch. "Phylogeny of the Sporobolus indicus complex, based on internal transcribed spacer (ITS) sequences". Australian Systematic Botany 16, n.º 2 (2003): 165. http://dx.doi.org/10.1071/sb02009.
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The entire internal transcribed spacer (ITS) region, including the 5.8S subunit of the nuclear ribosomal DNA (rDNA), was sequenced by direct double-stranded sequencing of polymerase chain reaction (PCR) amplified fragments. The study included 40 Sporobolus (Family Poaceae, subfamily Chloridoideae) seed collections from 14 putative species (all 11 species from the S. indicus complex and three Australian native species). These sequences, along with those from two out-group species [Pennisetum alopecuroides (L.) Spreng. and Heteropogon contortus (L.) P. Beauv. ex Roemer & Schultes, Poaceae, subfamily Panicoideae], were analysed by the parsimony method (PAUP; version 4.0b4a) to infer phylogenetic relationships among these species. The length of the ITS1, 5.8S subunit and ITS2 region were 222, 164 and 218 base pairs (bp), respectively, in all species of the S. indicus complex, except for the ITS2 region of S. diandrus P.Beauv. individuals, which was 217 bp long. Of the 624 characters included in the analysis, 245 (39.3%) of the 330 variable sites contained potential phylogenetic information. Differences in sequences among the members of the S. pyramidalis P.Beauv., S. natalensis (Steud.) Dur & Schinz and S. jacquemontii Kunth. collections were 0%, while differences ranged from 0 to 2% between these and other species of the complex. Similarly, differences in sequences among collections of S. laxus B.K.Simon, S. sessilis B.K.Simon, S. elongatus R.Br. and S. creber De Nardi were 0%, compared with differences of 1–2% between these four species and the rest of the complex. When comparing S. fertilis (Steud.) Clayton and S. africanus (Poir.) Robyns & Tourney, differences between collections ranged from 0 to 1%. Parsimony analysis grouped all 11 species of the S.�indicus complex together, indicating a monophyletic origin. For the entire data set, pair-wise distances among members of the S. indicus complex varied from 0.00 to 1.58%, compared with a range of 20.08–21.44% among species in the complex and the Australian native species studied. A strict consensus phylogenetic tree separated 11 species of the S. indicus complex into five major clades. The phylogeny, based on ITS sequences, was found to be congruent with an earlier study on the taxonomic relationship of the weedy Sporobolus grasses revealed from random amplified polymorphic DNA (RAPD). However, this cladistic analysis of the complex was not in agreement with that created on past morphological analyses and therefore gives a new insight into the phylogeny of the S.�indicus complex.
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Uchida, J. Y., e L. L. Loope. "A Recurrent Epiphytotic of Guava Rust on Rose Apple, Syzygium jambos, in Hawaii". Plant Disease 93, n.º 4 (abril de 2009): 429. http://dx.doi.org/10.1094/pdis-93-4-0429b.
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A Neotropical rust of the Myrtaceae, Puccinia psidii Winter, was described from Psidium guajava L., or guava, in Brazil in 1884 (1). It was first discovered in Hawaii on potted Metrosideros polymorpha Gaud. on Oahu in April 2005 (2) with pathogenicity and identity established (3). It spread quickly, and by January 2006, severe outbreaks of this rust occurred statewide on new leaves of Syzygium jambos (L.) Alston, or rose apple. Rose apple, a native to South and Southeast Asia, was introduced to Hawaii in 1825 and is locally abundant to invasive from just above sea level to as high as 1,000 m in elevation in wet sites. Healthy, reddish green immature leaves on new twigs become deformed, yellow-red, and covered with masses of yellow urediniospores following infection. As the disease progresses, infected leaves are blackened and defoliate, with no functional leaves formed. Stem tips and branches are killed and the canopy becomes progressively smaller. Repeated mortality of juvenile leaves was observed to kill 8 to12 m tall trees in the Haiku area of Maui. Wind dispersal of urediniospores resulted in heavy infection of even small groups of S. jambos isolated by 1 km or more and billions of urediniospores covered the ground under diseased trees. On Hawaii, Maui, and Oahu, trees with many dead branches are becoming common with concerns about the fire hazard of these dead trees surrounded by dry grasses. At low humidity levels, or on more mature leaves characterized by soft expanded yellow-green tissue, fewer, mostly circular spots are formed that do not expand. S. jambos is an example of a highly vulnerable host in Hawaii and represents one of approximately 3,500 species of Myrtaceae outside the Neotropics growing in Australasia, Southeast Asia, the Pacific, and tropical Africa, which have evolved unexposed to P. psidii. Severely infected S. jambos plants have been the major source of spores in the environment, exposing many Myrtaceae hosts to P. psidii. The pathogenicity of P. psidii has been consistent among and within islands with S. jambos severely infected and M. polymorpha, Melaleuca quinquenervia, Rhodomyrtus tomentosa, Myrtus communis, and Eugenia species commonly infected. Other hosts such as S. cumini, S. malaccense, and Myriciaria cauliflora are also infected, although guava and Eucalyptus spp. are rarely infected. Strain differences within P. psidii are suspected (4). In the tropics, it is rare for mature trees to be killed by a foliar pathogen, but given the devastation of new growth, death of more S. jambos trees is likely. References: (1) T. A. Coutinho et al. Plant Dis. 82:819, 1998. (2) E. M. Killgore and R. A. Heu. New Pest Advisory No. 05-04. Hawaii Department of Agriculture, 2007. (3) J. Y. Uchida et al. Plant Dis. 90:524, 2006. (4) S. Zhong et al. Mol. Ecol. Res. 8:348. 2008.
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Shivas, R. G., e A. R. McTaggart. "Three new species ofTilletiaon native grasses from northern Australia". Australasian Plant Pathology 38, n.º 2 (2009): 128. http://dx.doi.org/10.1071/ap08089.
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Whalley, R. D. B., D. A. Friend, P. Sanford e M. L. Mitchell. "Evaluation of native and introduced grasses for low-input pastures in temperate Australia: rationale and scope". Rangeland Journal 27, n.º 1 (2005): 1. http://dx.doi.org/10.1071/rj05004.
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The historical approach to pasture improvement in the high rainfall zone of temperate Australia has been to add introduced herbaceous legumes and to replace perennial native grasses with introduced species requiring high inputs of fertiliser for maintenance. The application of this high-input approach on land with low capability has lead to the loss of perennial grasses, erosion, soil acidification and increasing salinity on the lower slopes. This model of pasture improvement has not been successful on the margins of the wheat belt and in semi-arid regions. The Native and Low-input Grasses Network (NLIGN) was established in 1996 to coordinate research on grasses suitable for land with low capability and for semi-arid regions. The NLIGN multi-site evaluation project was initiated to test promising lines (accessions) of native and introduced grasses for low-input pastures at eight sites across southern Australia. The broad objective of the project was to identify native and/or introduced perennial grass lines that had possible commercial potential for low-input pastures. This objective was achieved in an initial 3-year evaluation phase, which began in 1998 and tested lines for persistence, production and palatability.
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Mitchell, M. L., M. R. McCaskill e R. D. Armstrong. "Phosphorus fertiliser management for pastures based on native grasses in south-eastern Australia". Crop and Pasture Science 70, n.º 12 (2019): 1044. http://dx.doi.org/10.1071/cp19217.
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Approximately 3.1 Mha (22%) of the agricultural area of south-eastern Australia can be classified as native pasture. There is the assumption that, owing to the widespread occurrence of low-fertility soils in Australia, native grass species do not respond to increased phosphorus (P) fertility. Currently, there are no industry recommendations of target soil-test P values for native-grass-based pastures. This paper reviews the responses of perennial native pasture species endemic to south-eastern Australia to P application in controlled environments, surveys, replicated experiments and paired-paddock trials. Eighty-seven site-years of trial data where different levels of P were applied, conducted over the last two decades, on native-based pastures in south-eastern Australia are reviewed. Data indicate that application of P fertilisers to native grass pastures can increase dry matter (DM) production and maintain pasture stability. However, minimum targets for herbage mass (800 kg DM/ha) and groundcover (80%) are required to ensure persistence of perennial native grasses. Stocking rates also need to match carrying capacity of the pasture. Based on previous research, we recommend target soil-test (Olsen; 0–10 cm) P levels for fertility-tolerant native grass pastures, based on Microlaena stipoides, Rytidosperma caespitosum, R. fulvum, R. richardsonii, R. duttonianum and R. racemosum, of 10–13 mg/kg, whereas for pastures based on fertility-intolerant species such as Themeda triandra, lower levels of <6 mg/kg are required to ensure botanical stability.
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Cavanagh, Annette M., Robert C. Godfree e John W. Morgan. "An awn typology for Australian native grasses (Poaceae)". Australian Journal of Botany 67, n.º 4 (2019): 309. http://dx.doi.org/10.1071/bt18216.
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Australia has a large diversity of native grasses. The diaspores of many species possess awns that vary considerably in their number and shape. Some variations of awn shape have been found to be effective at diaspore dispersal. Although morphological descriptions of awns exist for most native grass species, the number of species that possess awns and the extent of awn variation is unknown. This makes it difficult to determine the evolutionary importance of awns and the potential function of the various morphologies. The aim of this study was to construct an awn typology based on morphological descriptions collated from published flora databases that will quantify the awn type diversity of all native grass species in Australia, and will inform awn type relationships and help to clarify the role of differing awn morphologies in diaspore dispersal. We found that 42.1% of 1000 Australian native grasses with a single awn type were determined to have a ‘significant’ awn. These could be classified into one of 20 awn types, the most common being (1) single, apical, geniculate (once-sharply bent) awns (93 species; 28 genera, especially Iseilema), (2) three, apically-attached, straight awns (59 species, mainly Aristida) and (3) single, apical, bigeniculate (twice-sharply bent) awns (46 species, mainly Austrostipa). Among Australian grasses, slightly (though significantly) more C3 species (49.2%) had awns than C4 species (39.9%), although the most common awn types in both contained sharply bent awns (bigeniculate and geniculate respectively). Our classification system will help to improve our understanding of the amount of awn morphological variation in Australian grasses and will enable further investigation into the important ecological role of awns in species fitness.
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Garden, D. L., C. M. Waters, A. B. Smith, M. R. Norton, G. C. Auricht e E. Kobelt. "Performance of native and introduced grasses for low-input pastures. 2. Herbage production". Rangeland Journal 27, n.º 1 (2005): 41. http://dx.doi.org/10.1071/rj05003.
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A total of 62 perennial grasses were evaluated for herbage production under low-fertiliser conditions at eight sites in the temperate zone of southern Australia from 1999 to 2001. A brief assessment of relative preference ranking by sheep was also made at the end of the experimental period. Four sites were in the high rainfall areas of south-east Australia, two in the drier mixed farming areas of western NSW, and two sites in Mediterranean southern Australia. Seven standard cultivars were included in the comparisons. Plants were grown from seed in glasshouses and transplanted to the field as spaced plants at 6–8 weeks age. Plants were harvested at irregular intervals by clipping to determine herbage production. Relative preference was determined by enclosing sheep in the experimental area at high stocking rates and estimating the amount of herbage grazed after 1, 3 and 5 days. Herbage production data were analysed using a multi-environment trial approach in which the environments comprised all combinations of sites and sampling times over the 3-year period. Overall, 73.6% of the total genetic variation for herbage production was accounted for. Average seasonal comparisons revealed good herbage production from Eragrostis curvula cv. Consol in both winter and summer, but in spring, several Dactylis glomerata lines were the most productive. Consol was not generally preferred by sheep, while D. glomerata lines were. Apart from cv. Consol, C4 species, including Bothriochloa macra, Chloris truncata, Enteropogon acicularis and Dichanthium sericeum had low herbage production in winter and spring, and had low acceptability to grazing sheep. These particular grasses were also not highly ranked for production in summer, although other C4 lines, notably selections of Themeda australis, Paspalidium jubiflorum and P. constrictum were. Few native C3 grasses had superior herbage production, although selections of Elymus scaber, Austrodanthonia fulva and A. duttoniana showed good growth rates. When considering further evaluation, grasses with very high recruitment (e.g. A. caespitosa) may need to be included, and the acceptability of grasses to sheep should also be assessed.
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Morgan, J. W. "Relationship between fire frequency and nitrogen limitation on foliage production in a native grassland community in Victoria, Australia". Rangeland Journal 29, n.º 1 (2007): 101. http://dx.doi.org/10.1071/rj06046.
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The relationship between fire frequency (annual v. infrequent) and nitrogen (N) limitation to foliage production in a temperate native grassland community in western Victoria, Australia, was assessed over one growing season using a simple ammonium nitrate addition experiment. Fire history affected the magnitude of the vegetation responses to N addition. At the community level, mean live biomass in infrequently-burned grasslands declined by 20 ± 8% in response to N addition. In contrast, mean biomass increased by 60 ± 15% in annually-burned grasslands in response to N addition. Both grasses and forbs responded positively to N addition in annually-burned grasslands, with forbs responding more substantially than grasses. Foliage production in annually-burned native grasslands therefore appears to be constrained by N availability. The results of this study may have important implications for understanding species coexistence and invasion by non-native species in temperate native grasslands.
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Nie, Z. N., S. Miller, G. A. Moore, B. F. Hackney, S. P. Boschma, K. F. M. Reed, M. Mitchell et al. "Field evaluation of perennial grasses and herbs in southern Australia. 2. Persistence, root characteristics and summer activity". Australian Journal of Experimental Agriculture 48, n.º 4 (2008): 424. http://dx.doi.org/10.1071/ea07136.
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Field experiments were carried out at seven sites in southern Australia from 2002 to 2006 to measure changes in plant frequency, root characteristics and summer activity for a range of grass and herb species or cultivars. Annual rainfall during the experimental period was on average 75 mm lower than the long-term average. Plant frequency differed significantly between species and between sites. Temperate grasses generally had higher frequencies than subtropical grasses, native grasses and herbs. Cocksfoot (Dactylis glomerata cvv. Currie, Porto), tall wheat grass (Thinopyrum ponticum cv. Dundas), winter-active tall fescue (Festuca arundinacea cvv. Fraydo, Resolute MaxP) and phalaris (Phalaris aquatica cvv. Atlas PG, Australian) were the most persistent of the temperate perennial species over the experimental period. The frequency of most cultivars declined from year 2 to year 4 after establishment, but the frequency of kikuyu (Pennisetum clandestinum cv.Whittet) and wallaby grass (Austrodanthonia richardsonii cv. Taranna) increased by over 5% from year 2 to year 3, and cocksfoot (cv. Currie) increased from year 3 to year 4. At two sites where measurements were made, there were significant differences in rooting depth between species. Whittet kikuyu was the deepest among all species with a rooting depth of up to 2 m, followed by phalaris, tall fescue, grazing brome (Bromus stamineus) and tall wheat grass. Root density was affected by plant genotype and soil structure. Root density of the species varied significantly in the subsoil (0.1–1.1 m) and deeper subsoil (1.1–2 m) but not in the topsoil (0–0.1 m). Green-leafiness over summer was generally higher for subtropical grasses, native grasses, herbs and some summer-active temperate grasses, than most temperate grasses with high summer dormancy.
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Lenz, Tanja I., e José M. Facelli. "Correlations between environmental factors, the biomass of exotic annual grasses and the frequency of native perennial grasses". Australian Journal of Botany 54, n.º 7 (2006): 655. http://dx.doi.org/10.1071/bt05083.
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The species composition of temperate grasslands in the mid-north of South Australia has been radically altered from a system dominated by native perennial grasses to a system dominated by Mediterranean annual grasses. This study investigated the importance of chemical and physical soil characteristics, topographical features and climatic variables on the abundance of native and exotic grass species in nine ungrazed grasslands. Overall, climatic and other abiotic factors were highly variable. In addition, past management practices and original species composition are generally unknown, leading to further unexplained variation in the data. On a large spatial scale (among sites), the abundance of exotic annual grasses was positively correlated with mean annual rainfall, and on any scale, with finer soil textures and higher soil organic carbon levels. The most abundant annual grass, Avena barbata (Pott ex Link), was generally associated with soil factors denoting higher soil fertility. The abundance of native perennial grass species was not correlated with any environmental variables at any scale. The various native perennial grass species did not show clear associations with soil factors, although they tended to be associated with factors denoting lower soil fertility. However, at small spatial scales (within some sites) and among sites, the abundances of exotic annual and native perennial grasses were strongly negatively correlated. The results suggest that at the present time, rainfall and soil properties are important variables determining the abundance of annual grasses. The driving variables for the abundance of perennial grasses are less clear. They may be controlled by other factors or extreme rainfall events, which were not surveyed. In addition, they are likely to be controlled by competitive interactions with the annual grasses.
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Johnston, W. H., D. L. Garden, A. Rančić, T. B. Koen, K. B. Dassanayake, C. M. Langford, N. J. S. Ellis et al. "The impact of pasture development and grazing on water-yielding catchments in the Murray - Darling Basin in south-eastern Australia". Australian Journal of Experimental Agriculture 43, n.º 8 (2003): 817. http://dx.doi.org/10.1071/ea02236.
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Experiments conducted from November 1996 to June 2002 in adjacent small catchments near Wagga Wagga, New South Wales, compared the productivity and hydrology of a heavily fertilised (about 30 kg phosphorus/ha.year) Phalaris aquatica (phalaris) pasture with that of a lightly fertilised (about 14 kg phosphorus/ha every second year) native grassland that contained a mixture of C3 and C4 perennial grasses, dominantly C4 Bothriochloa macra (redgrass).In summer, the native catchment was dominated by C4 perennial grasses while the phalaris catchment was dominated by annual C4 weedy species. During the cooler months, the phalaris pasture contained higher proportions of Vulpia spp., and other less-desirable annual grasses. Throughout the experiment, the native catchment was dominated by redgrass, whereas in the phalaris catchment the persistence of phalaris declined. Redgrass became prominent on the more arid aspects of the phalaris catchment as the experiment progressed.Pasture production in the phalaris catchment was higher in most seasons than the native catchment, which resulted in an overall stocking rate advantage of about 80%. The productivity gain per unit of P input was 0.4 for the phalaris catchment compared with 1 for the native catchment, implying that phosphorus was applied to the phalaris catchment at an excessive rate.During wet periods the native catchment produced substantially more runoff than the phalaris catchment, while in dry times it developed substantially larger soil water deficits. Runoff from the phalaris catchment was higher in suspended and dissolved nitrogen and phosphorus than for the native catchment. Higher runoff from the native catchment combined with its drier soil profile in summer indicated that its deep drainage potential was less than in the phalaris catchment.
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Bolger, T. P., A. R. Rivelli e D. L. Garden. "Drought resistance of native and introduced perennial grasses of south-eastern Australia". Australian Journal of Agricultural Research 56, n.º 11 (2005): 1261. http://dx.doi.org/10.1071/ar05075.
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Perennial grasses are the key to the economic and environmental sustainability of pastures for livestock grazing in south-eastern Australia. Mortality of perennial grasses can occur during drought periods and there is anecdotal evidence of differences in drought resistance among species, but information on the basic ecophysiological responses of these species to drought is lacking. An experiment was conducted to determine the responses of 7 native and 3 introduced perennial grass species to continuous drought. Leaf survival during severe drought varied among the species nearly 4-fold, from 11 to 40 days, and was considered a measure of their overall drought resistance. All of the species had good dehydration tolerance, so the differences in drought resistance were related more to their dehydration avoidance traits, specifically to the amount of water available to the plant at the point where plant transpiration became minimal. The native species had both the longest and shortest leaf survival periods, with the introduced species ranking intermediate. Species exhibited various morphological traits that contributed to dehydration avoidance during severe drought, including leaf folding or rolling, rapid leaf shedding, and large amounts of cuticular wax. The results are discussed in terms of their implications for perennial grass persistence in south-eastern and in south-western Australia.
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Fensham, RJ. "Native Grasslands of the Central Highlands, Queensland, Australia. Floristics, Regional Context and Conservation." Rangeland Journal 21, n.º 1 (1999): 82. http://dx.doi.org/10.1071/rj9990082.
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A floristic classification of grassland and related woodland vegetation from the Central Highlands of Queensland suggests four broad types: Mountain coolibah (Eucalyptus orgadophila) woodland on basalt, Mitchell grassland (dominated by Astrebla lappacea) on alluvia and two closely related groups dominated by Dichanthium sericeum, Blue grassland on basalt and Blue grassland on sediment. An analysis including floristic data from grassland and woodland on vertosols from throughout southern, central and western Queensland revealed that the Blue grasslands of the Central Highlands are highly dissimilar from other grasslands in Queensland. Mountain coolibah woodland on basalt is represented within four reserves, but the other more arable grassland types are either not represented or only barely represented within the reserve system. The most immediate threatening process to these communities is conversion to crops and this process is exacerbated by the difficulties of managing the grasslands as native pasture. Large areas of grasslands are degraded, having been converted from dominance by native perennial grasses to the unpalatable, annual, exotic herb Partheniunz hysterophorus. Once this shift has occurred a long period with little or no production benefits is required to recover a sward of native perennial grasses and the cropping alternative becomes particularly favourable. The long-term security of the native grasslands of the Central Highlands will require an enhanced reserve system and incentives designed to retain appropriately managed native pasture. Key words: grassland, grazing, reserves, woodland. Queensland, exotics, Parthenium
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Huxtable, C. H. A., T. B. Koen e D. Waterhouse. "Establishment of native and exotic grasses on mine overburden and topsoil in the Hunter Valley, New South Wales". Rangeland Journal 27, n.º 2 (2005): 73. http://dx.doi.org/10.1071/rj05006.
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Native grasses have an important role to play in mine rehabilitation throughout Australia, but there have been few scientifically designed studies of field establishment of native grasses from sown seed in this country. Current recommendations for rehabilitation of open-cut coal mines in the Hunter Valley involve the sowing of exotic pasture species to reinstate mined land to Class IV and V under the Rural Land Capability System. Despite the importance of native grasses in the pre-mined landscape, they are currently not widely included in mine rehabilitation. To address this issue a project was conducted between 1994 and 2000 to research the use of native grasses for rehabilitation of open-cut coal mines in the Hunter Valley. This paper reports on 2 mine site experiments that aimed to assess establishment and persistence of a broad range of native and exotic grass species from an autumn sowing in both topsoil and raw spoil over a period of 61 months. The most promising natives in terms of early establishment, persistence and spread over time, included six C3 accessions (five Austrodanthonia spp. and Austrostipa bigeniculata) and one C4 accession (Cynodon dactylon). Persistence of these accessions was better in raw spoil than topsoil, despite initial low numbers, due to a lack of weed competition and their ability to spread by self-seeding. In topsoil, and in the absence of any biomass reduction, native species were mostly out-competed by vigorous exotic perennial grasses which were sown in these experiments and from seed influx from adjacent rehabilitation areas or from the soil seed bank. The effects of climatic conditions and differences in soil physical, chemical and seed bank characteristics at the 2 mine sites are also discussed.
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Brown, Sharon L., Nick Reid, Jackie Reid, Rhiannon Smith, R. D. B. (Wal) Whalley e David Carr. "Topsoil removal and carbon addition for weed control and native grass recruitment in a temperate-derived grassland in northern New South Wales". Rangeland Journal 39, n.º 4 (2017): 355. http://dx.doi.org/10.1071/rj17029.
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Restoring the grassy understorey to temperate woodlands in south-eastern Australia is often disregarded due to a poor understanding of the techniques involved. The natural recruitment of native grasses is uncommon in the remnants of some of these woodlands, so the restoration of the grass layer is often dependent on interventions to overcome restoration barriers. Soil enrichment from agricultural fertilisers favours the invasion of exotic broadleaf weeds and grasses, and is one of the primary barriers to the successful recruitment and establishment of native grasses, which dominated before agricultural development. This study on the Northern Tablelands of New South Wales investigated the effects of different weed control treatments – scalping, glyphosate (Roundup®) herbicide, and combinations of glyphosate with carbon (sugar and sawdust) addition and a control (nil treatment) recruitment of native grasses and weed emergence after broadcast seeding. The experimental site was a mown grass lawn consisting of fescue (Festuca arundinacea Shreb.), cocksfoot (Dactylis glomerata L.) and paspalum (Paspalum dilatatum Poir). Native grass recruitment varied significantly between treatments. The maximum number of recruits in scalped plots was 29 recruits m–2 compared with an average of <2 recruits m–2 for the glyphosate and glyphosate carbon combinations. Scalping reduced soil nitrogen from 0.6% in non-scalped plots to 0.1% and phosphorus from 191.6 ppm to 40.3 ppm. Maximum weed cover occurred in the glyphosate herbicide treatment (45%), whereas combinations of glyphosate plus either sugar or sawdust maintained weed cover at 13%. The present study suggests that scalping may be a successful intervention strategy because it has the potential to significantly improve native grass recruitment compared with other restoration methods used in this study. Scalping allows more time for native grasses to germinate and establish in the absence of competitive fast-growing exotic weeds.
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Hacker, Ronald B., Ian D. Toole, Gavin J. Melville, Yohannes Alemseged e Warren J. Smith. "Managing competitive interactions to promote regeneration of native perennial grasses in semi-arid south-eastern Australia". Rangeland Journal 39, n.º 1 (2017): 59. http://dx.doi.org/10.1071/rj16048.
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Treatments to reduce available soil nitrogen and achieve specified levels of weed control were evaluated for their capacity to promote regeneration of native perennial grasses in a degraded semi-arid woodland in central-western New South Wales. Treatments were factorial combinations of nitrogen-reduction levels and weed-control levels. The four levels of nitrogen reduction were no intervention, and oversowing of an unfertilised summer crop, an unfertilised winter crop or an unfertilised perennial grass. The three weed-control levels were defined by the outcome sought rather than the chemical applied and were nil, control of annual legumes and control of all annual species (AA). Regeneration of perennial grasses, predominantly Enteropogon acicularis, was promoted most rapidly by the AA level of weed control with no introduction of sown species. Sown species negated the benefits of weed control and limited but did not prevent the regeneration of native perennials. Sown species also contributed substantially to biomass production, which was otherwise severely limited under the AA level of weed control, and they were effective in reducing soil nitrogen availability. Sown species in combination with appropriate herbicide use can therefore maintain or increase available forage in the short–medium term, permit a low rate of native perennial grass recruitment, and condition the system (by reducing soil mineral nitrogen) for more rapid regeneration of native perennials should annual sowings be discontinued or a sown grass fail to persist. Soil nitrate was reduced roughly in proportion to biomass production. High levels of soil nitrate did not inhibit native perennial grass regeneration when biomass was suppressed by AA weed control, and may be beneficial for pastoral production, but could also render sites more susceptible to future invasion of exotic annuals. The need for astute grazing management of the restored grassland is thus emphasised. This study was conducted on a site that supported a remnant population of perennial grasses. Use of the nitrogen-reduction techniques described may not be appropriate on sites where very few perennial grass plants remain.
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Sanford, P., R. D. B. Whalley, D. L. Garden, M. R. Norton, C. M. Waters, A. B. Smith, M. L. Mitchell et al. "Identification of superior native and introduced grasses for low-input pastures in temperate Australia". Rangeland Journal 27, n.º 1 (2005): 55. http://dx.doi.org/10.1071/rj05005.
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This paper is the fifth in a series describing trials evaluating native and introduced grasses at eight locations across temperate Australia. In these trials, 62 perennial grass lines were assessed for herbage production, survival and recruitment under low fertiliser conditions using spaced plants produced in glass houses and transplanted into the field. Sites were grouped into three different climatic zones: Eastern Australian permanent pasture, Eastern Australian mixed farming and Mediterranean zone. For each of these zones, superior lines were identified and their potential use in permanent pastures or mixed farming discussed. Among the C3 grasses tested, several lines of Dactylis glomerata from France on the Mediterranean coast near the Spanish border and from north-west maritime France proved to be superior lines in all zones and were better than the standard comparator cv. Currie with regard to the attributes assessed. In general, the D. glomerata lines were superior to the C3 native species except with respect to survival and recruitment. The C4 introduced standard comparator Eragrostis curvula cv. Consol was outstanding with regard to its herbage production and survival in all climatic zones, although its recruitment was generally low. Native C4 lines of Themeda australis and Paspalidium jubiflorum yielded well in all climatic zones, and even produced more herbage than Consol in one zone. Survival rates of T. australis and P. jubiflorum were also very high but recruitment was low under the conditions of the trial. In mixed pastures C4 grasses may reduce fluctuations in feed supply as well as increase water use. As a consequence mixtures of superior C3 and C4 lines identified in this study are likely to be suitable for pastures on infertile soils and in zones subjected to continuous or periodic drought. Further work on the behaviour of these superior lines under sward conditions in association with forage legumes and their responses to grazing is needed; however, for the promising native lines, sward trials are not possible until suitable technology for commercial seed production and broad acre establishment of these lines has been developed.
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Archer, KA, e GG Robinson. "Agronomic potential of native grass species on the Northern Tablelands of New South Wales. II. Nutritive value". Australian Journal of Agricultural Research 39, n.º 3 (1988): 425. http://dx.doi.org/10.1071/ar9880425.
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The quality of three year-long green and three summer-growing, frost-susceptible perennial native grasses was compared with that of two introduced temperate perennial grasses and white clover (Trifolium repens L. cv. Haifa). Digestibility of white clover generally exceeded that of all grasses, except for the green leaves of the two introduced species, Festuca arundinacea Screb. cv. Demeter and Phalaris aquatica L. cv. Sirosa, during winter. The digestibility of the green leaves of most winter-green species increased during winter and decreased in summer, the extent of this being greater for the introduced grasses.The digestibility of fescue and phalaris was generally similar throughout the study and was mostly higher than that of the native grasses, but the quality of the green leaves of two year-long green native species, Danthonra linkii Kunth and Microlaena stipoides (Labill.) R.Br., approached that of the two introduced grasses. The quality of the summer perennial species was poor during winter owing to the presence of only dead leaves, but the green leaves of Bothriochloa macra (Steud) S. T. Blake retained high levels of digestibility during summer. Considerable variation in digestibility exists between individual plants of Poaseiberana Spreng, indicating that opportunities may exist for selection of highly productive lines from some native species.In pen-feeding studies, voluntary intake of most of the year-long green native grasses was similar to that of the introduced grasses, but intake of the summer perennial species tended to be lower.Results from this study indicate that the quality of native pastures and their potential for animal production will vary considerably according to species composition, season and the presence of white clover.
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Grice, AC, e S. Mcintyre. "Speargrass (Heteropogon Contortus) in Australia : Dynamics of Species and Community." Rangeland Journal 17, n.º 1 (1995): 3. http://dx.doi.org/10.1071/rj9950003.
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The perennial tallgrass Heteropogon contortus is widespread and both ecologically and economically important. It often dominates the understorey of Eucalyptus woodlands in tropical and subtropical Australia. We present an historical overview of management and research in these important grasslands and review currently available information, particularly in relation to change at the community level. The use of H, contortus communities for extensive pastoralism led to its increase at the expense of other grasses. Ecological studies sought to explain how it came to dominate large areas but much research focussed on identifying pasture species, particularly legumes, that could replace or supplement what were seen as unproductive native grasses. Other efforts were directed at improving the generally low levels of animal production that resulted from the extreme seasonality of forage quality, and examining the animal production consequences of various management actions. There is some evidence that H. contortus has declined over large areas since the 1970s, but this process and its mechanisms are not well documented. Generally, research that has taken an empirical approach to improving animal production is poorly placed to provide a comprehensive ecological understanding. This is evident in several attempts to synthesise an ecological .understanding of H. contortus communities, notably in the form of state-and-transition models. These models contain generalities, some of which have little confirmation in experimental results. The geographic range and temporal variability of H. contortus communities make it difficult to generalise on the basis of single site, short term experiments that investigate one or a few factors in isolation. There is an increasing awareness of the need for sustainable management of native and natural pastures, including the H. contortus grasslands. Meeting this need will require the maintenance of the perennial grasses of northern Australian savannas and an ecological knowledge that can predict change in a variety of circumstances and locations.
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Truong Thi Hieu, Thao, Hoang Ho Dac Thai, Hung Le Thai e Lien Nguyen Thi Hong. "Vegetable structure in the Bay Sand Dune of Mui Ne, Phan Thiet city, Binh Thuan province". Journal of Science Natural Science 66, n.º 4F (novembro de 2021): 47–55. http://dx.doi.org/10.18173/2354-1059.2021-0067.
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There were three vegetation types in blowing sand dunes of Mui Ne, Phan Thiet city, Binh Thuan province; native sand binding grasses type, mix species of native grasses and low shrub type and evergreen trees biome in coastal sand dune type. Group of dominant typical species were identified in each vegetation type in which three significant canopy layers were confirmed with evergreen trees biome in coastal sand dune type. The similarity among different vegetation types was evaluated, Sorenson’s index (S) showed that similarity of species in the vegetation types native sand binding grasses and mix species of natuve grasses and low shrub is 0.61, Shannon index (H’) for all three types is low but the highest come from evergreen trees biome in coastal sand dune type (H’ = 0.17 for trees and 0.06 for vines and shrub species. Results and lessons learned from this study are referred to conservation and ecological restoration activities.
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Clay, Roger Edgcumbe. "Potential Effects of the Loss of Native Grasses on Grassland Invertebrate Diversity in Southeastern Australia". International Journal of Ecology 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/202056.
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Reduction in area of the southeastern temperate grasslands of Australia since European settlement has been accompanied by degradation of remaining remnants by various factors, including the replacement of native plant species by introduced ones. There are suggestions that these replacements have had deleterious effects on the invertebrate grassland community, but there is little evidence to support these suggestions. In the eastern Adelaide Hills of South Australia, four grassland invertebrate sampling areas, in close proximity, were chosen to be as similar as possible except for the visible amount of native grass they contained. Sample areas were surveyed in four periods (summer, winter, spring, and a repeat summer) using pitfall traps and sweep-netting. A vegetation cover survey was conducted in spring. Morphospecies richness and Fisher’s alpha were compared and showed significant differences between sample areas, mainly in the summer periods. Regression analyses between morphospecies richness and various features of the groundcover/surface showed a strong positive and logical association between native grass cover and morphospecies richness. Two other associations with richness were less strong and lacked a logical explanation. If the suggested direct effect of native grass cover on invertebrate diversity is true, it has serious implications for the conservation of invertebrate biodiversity.
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Ramírez, R. G., H. González-Rodríguez, R. Morales-Rodríguez, A. Cerrillo-Soto, A. Juárez-Reyes, G. J. García-Dessommes e M. Guerrero-Cervantes. "Chemical composition and dry matter digestion of some native and cultivated grasses in Mexico". Czech Journal of Animal Science 54, No. 4 (17 de abril de 2009): 150–62. http://dx.doi.org/10.17221/1741-cjas.
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The objective of the study was to quantify differences in nutritive value, over four seasons, of native grasses such as <i>Bouteloua curtipendula, Bouteloua trifida, Brachiaria fasciculata, Chloris ciliata, Digitaria insularis, Leptochloa filiformis, Panicum hallii, Panicum obtusum, Paspalum unispicatum, Setaria grisebachii, Setaria macrostachya, Tridens eragrostoides, Tridens muticu</i>s and naturalized <i>chrus ciliaris</i> and <i>Rhynchelytrum repens</i> that are used as forages for grazing beef cattle. <i>Cenchrus ciliaris</i> was included as a reference grass of good nutritional quality. Plants were collected in autumn 2001 and in winter, spring and summer 2002. The nutritive value was assessed in terms of nutrient content, effective rumen degradable dry matter (EDDM), metabolizable energy (ME) and metabolizable protein (MP). Most grasses had crude protein (CP) content comparable to the reference <i>C. ciliaris</i> grass (grand mean = 120 g/kg) and some of them had a higher content (140 g/kg). Cell wall (NDF) and lignin contents were lower in <i>C. ciliaris</i> (650 g/kg, 30, respectively) than in the other grasses (mean = 700 g/kg, 60, respectively). All grasses had less EDDM (mean = 420 g/kg) than <i>C. ciliaris</i> (470 g/kg). All grasses had the ME content (mean = 5.6 MJ/kg DM) that was lower for maintenance requirements of growing beef cattle. Conversely, mean MP values (67 g/kg DM) were sufficient. Lower content of P (annual mean = 120 g/kg DM), Na (0.3) and Cu (40 mg/kg DM) was detected in all grasses to meet the requirements of growing cattle. All grasses, in all seasons, had sufficient CP and MP content to meet the maintenance requirements of growing beef cattle. Higher levels of EDDM occurred in summer and autumn. Because of their good nutritional quality, grasses such as <i>B. fasciculata, C. ciliata, P. hallii, P. obtusum, S. grisebachii, S. macrostachy</i> and <i>T. eragrostoides</i> can be considered as good forages for ruminants.
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Hacker, R. B., I. D. Toole e G. J. Melville. "Effects of nitrogen and phosphorus on vegetation dynamics of a degraded native grassland in semi-arid south-eastern Australia". Rangeland Journal 33, n.º 1 (2011): 87. http://dx.doi.org/10.1071/rj10030.
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The roles of nitrogen (N) and phosphorus (P) in controlling vegetation transitions in a degraded semi-arid grassland were investigated in a factorial experiment that combined two initial levels of perennial plant density (low and high), three levels of N (N+, N0 and N–) and two levels of P (P+ and P0). Increased levels of both N and P were achieved by fertiliser addition while sucrose was used to reduce the level of N. Vegetation dynamics were driven primarily by soil N rather than P. Addition of sucrose, which was inferred to result in the immobilisation of mineral N, reduced the growth of annual species and facilitated the establishment and growth of native perennial grasses. Addition of P generally had no significant effect on dry matter production, either in total or for species grouped as forbs, annual grasses and perennial grasses, or on recruitment and mortality of perennial grasses. However, at some times of observation addition of P increased ground cover and/or the basal circumference of some perennial grass species. Basal circumference for Enteropogon acicularis was also increased by addition of N. Soil biological activity, measured by decomposition of cotton strips, was increased by addition of N, which maintained vegetation in an annual-dominated condition, and was not affected by addition of P. Carbon addition has the potential to assist restoration of this grassland. However, the capacity of some native grass species to respond to increased fertility suggests that once restoration is achieved some increase in fertility may be beneficial for pastoral production.
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Thorn, Vanessa C. "Phytolith evidence for C4-dominated grassland since the early Holocene at Long Pocket, northeast Queensland, Australia". Quaternary Research 61, n.º 2 (março de 2004): 168–80. http://dx.doi.org/10.1016/j.yqres.2003.12.002.
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Preliminary phytolith analysis of ephemeral lake fill sediment at Long Pocket, near Toomba, northeast Queensland, Australia, indicates that a C4-dominated grassland with a minor woody component has been present in the region since ca. 8000 cal yr B.P. Based on the modern distribution of C4 and C3 native grasses in Australia, this suggests that mean summer temperatures of at least 14°C (ca. 10°C cooler than present) were maintained since the early Holocene. This interpretation is comparable with previous studies, which together imply that the establishment of C4-dominated grasses in central and northeast Australia occurred between the last glacial maximum (most likely after ca. 16,000 14C yr B.P.) and ca. 7200 14C yr B.P. (ca. 8000 cal yr B.P.). Taxonomic composition of the grassland appears relatively consistent since the early Holocene at Long Pocket and includes phytoliths comparable with those from modern Arundinoideae, Panicoideae, and Chloridoideae. Rare non-grass phytoliths are also present. A gradual decrease in abundance of saddle phytolith forms (attributed to Chloridoideae grasses) from the base of the record at ca. 6500–7000 cal yr B.P. suggests decreasing aridity throughout the Holocene. This trend could reflect a locally drawn out effect of the end of the postglacial arid period due to the well-drained basalt flow catchment maintaining a local arid habitat for the Chloridoideae grasses.
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Kocsis, Erika N., Ronald F. Hooks e James N. McCrimmon. "Comparison of Nine Native Grasses Grown on Sludge Applied Soil". HortScience 30, n.º 4 (julho de 1995): 862C—862. http://dx.doi.org/10.21273/hortsci.30.4.862c.
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The use of grasses native to New Mexico are preferred for revegetating Albuquerque's sewage sludge disposal site. A greenhouse study was conducted to determine the most appropriate grass species that could be used in revegetation. Nine grasses grown in soil collected at Albuquerque's sludge disposal site were compared based on germination measurements, including plant height and density. Final shoot and root weights also were taken for comparison. Plant tissue was analyzed for the accumulation of metals and salts. With 200 ml of water applied weekly, plant height was greatest in spike dropseed (Sporobolus contractus A. S. Hitchc.) at 33.86 cm; plant density was greatest in alkali sacaton (Sporobolus airoides Torr.). Results indicate the grasses that have the best potential for use in revegetation are blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Griffiths], sideoats grama [Bouteloua curtipendula (Michx.) Torr.], and alkali sacaton.
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Johnston, W. H., C. A. Clifton, I. A. Cole, T. B. Koen, M. L. Mitchell e D. B. Waterhouse. "Low input grasses useful in limiting environments (LIGULE)". Australian Journal of Agricultural Research 50, n.º 1 (1999): 29. http://dx.doi.org/10.1071/a97159.
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This paper presents a case for the selection and development of a wider range of perennial grasses for pastoral use in the higher rainfall (annual rainfall >500 mm) zone of southern Australia, especially the southern sector of the Murray–Darling Basin. There is also a need to reconsider the use of ‘high-input’ pastures on hill lands by developing more appropriate recommendations for managing existing native grass pastures productively. Past experiments which compared native grass based pastures with sown pastures promoted the view that indigenous grasses were inferior in most respects to exotic improved species. Even though many of the findings were confounded with fertiliser, stocking rate, and other treatment effects, they reinforced the general direction of cultivar development programs which in the temperate zone have been based mainly on the 4 exotic C3 species Phalaris aquatica L., Dactylis glomerata L., Lolium L. spp., and Festuca elatior var. arundinacea (Schreb.) Hackel (syn. Festuca arundinacea Schreb). This has led to an imbalance in the adaptability and range of species available to be sown in pastures, particularly for sowing on less productive landscapes where stony, shallow, infertile, acid soils limit the persistence of current cultivars. The pre-European vegetation of temperate Australia comprised species with a capacity for active growth and transpiration during summer. The water use pattern resulted in soil moisture being near capacity in late winter and spring, and exhausted by summer’s end. Replacement of this vegetation with annual-growing and summer-dormant C3 species has changed the water use pattern so that soils are drier in spring and wetter in autumn. This has reduced the pre-winter soil moisture deficit, which in turn has increased rates of deep drainage in winter. Land degradation in southern Australia is a consequence of this changed water use pattern. Deep drainage of water beyond the reach of plant roots has mobilised salts stored in the landscape and caused watertables to rise, which has led to large areas becoming saline. Lack of growth in summer in pastures consisting of senescent annual-growing species and dormant C3 perennial grasses limits utilisation of the products of nitrogen mineralisation, which allows nitrate nitrogen to accumulate in summer and be readily leached by rainfall in autumn. This increases rates of soil acidification. Although there may be scope to reduce deep drainage by increasing pasture growth in spring in areas where there is little likelihood of summer rainfall, this is not the case in south-eastern Australia where significant falls of rain occur during summer and autumn.
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Reed, K. F. M., Z. N. Nie, S. Miller, B. F. Hackney, S. P. Boschma, M. L. Mitchell, T. O. Albertsen et al. "Field evaluation of perennial grasses and herbs in southern Australia. 1. Establishment and herbage production". Australian Journal of Experimental Agriculture 48, n.º 4 (2008): 409. http://dx.doi.org/10.1071/ea07135.
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To review pasture species for regions with 465–680 mm average annual rainfall, 22 perennial grasses and herbs were evaluated for pasture establishment and productivity in four states at seven locations where the arrest of groundwater recharge is considered necessary to ameliorate dryland salinity. Species represented introduced and native, temperate and subtropical grasses, chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.). This report describes establishment and yield; the following paper describes persistence and root characteristics. Yields were measured over 2–3 years except at one site, which suffered severe drought. Perennial ryegrass (Lolium perenne L., cv. Avalon) and tall fescue (Festuca arundinacea Schreb. = syn. Lolium arundinaceum. (Schreb.) Darbysh., cvv. AU Triumph and Resolute MaxP), cocksfoot (Dactylis glomerata L., cv. Porto) and phalaris (Phalaris aquatica L., cv. Holdfast and Australian) were the most productive species, with dry matter (DM) yields of 13.6–15.1 t/ha. For summer growth, Porto and Rhodes grass (Chloris gayana Kunth, cv. Katambora) were the most productive species; relative to Australian in summer, Porto and Katambora produced 41% and 26% more DM, respectively (95% confidence). Perennial ryegrass (cv. Avalon), tall fescue (cv. Resolute MaxP) and chicory (cv. Grouse) were particularly valuable for autumn growth; Avalon was 30% more productive than Australian. Tall fescue (cv. Resolute MaxP) was 32% more productive than Australian in winter. Avalon and AU Triumph were the most productive grasses and herbs in spring. Based on natural rainfall over the 2–3 years of measurement, the mean water use productivity, ignoring any runoff, was 10.5 kg DM/ha.mm for the three most productive species. Apart from kangaroo grass (Themeda triandra Forssk), native grasses gradually established, but over a prolonged period weeping grass (Microlaena stipoides (Labill.) R.Br., cv. Wakefield) was the most rapid. Perennial ryegrass, tall fescue, cocksfoot and phalaris maintained productive yields across a diverse range of soils and climates. Exploration of the diversity within these species in a nationally coordinated program of genetic improvement appears warranted for improving reliability and expanding the zone of adaptation.
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Lodge, G. M. "The role and future use of perennial native grasses for temperate pastures in Australia". New Zealand Journal of Agricultural Research 37, n.º 3 (setembro de 1994): 419–26. http://dx.doi.org/10.1080/00288233.1994.9513079.
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Instone, Lesley. "Unruly grasses: Affective attunements in the ecological restoration of urban native grasslands in Australia". Emotion, Space and Society 10 (fevereiro de 2014): 79–86. http://dx.doi.org/10.1016/j.emospa.2013.12.013.
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Mitchell, M. L., H. C. Norman e R. D. B. Whalley. "Use of functional traits to identify Australian forage grasses, legumes and shrubs for domestication and use in pastoral areas under a changing climate". Crop and Pasture Science 66, n.º 1 (2015): 71. http://dx.doi.org/10.1071/cp13406.
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Considerable uncertainty exists about future climatic predictions but there is little doubt among experts that the future will be warmer. Climate change and the associated elevation in atmospheric CO2 level and temperatures will provide novel challenges and potential opportunities for cultivated plant species. Plant breeding and domestication can contribute to improvements in both yield and quality of native grasses, legumes and forage shrubs. This review explores the use of functional traits to identify native Australian grasses, legumes and forage shrubs suitable for domestication, to meet the challenges and opportunities under a changing climate in pastoral areas in Australia. The potential of these species in terms of life history, regenerative traits, forage quality and quantity, drought tolerance and invasiveness is examined. The paper focuses on three Australian pastoral regions (high-rainfall temperate south, tropical and subtropical grasslands, low-rainfall semi-arid shrublands), in terms of future climate predictions and potential of selected native species to meet these requirements. Selection for adaptation to new climatic environments is challenging but many native species already possess the traits required to cope with the environment under future climate scenarios.
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Clark, Cameron E. F., Meredith L. Mitchell, Mohammed R. Islam e Brent Jacobs. "Phosphorus content of the soil influences the growth and productivity of Themeda triandra Forssk. and Microlaena stipoides (Labill.) R.Br." Rangeland Journal 36, n.º 3 (2014): 233. http://dx.doi.org/10.1071/rj13108.
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Despite native grasses occupying a large area of land in Australia, there has been limited work on the responses of these species to the addition of phosphorus (P). The main objective of this study was to investigate the effect of the addition of P to create a range of P contents in the soil on the productivity and morphology of two native grasses at two times of harvests. Two contrasting perennial native grasses, namely kangaroo grass (Themeda triandra Forssk. syn. T. australis R. Br. Stapf) and weeping grass [Microlaena stipoides var. stipoides (Labill.) R. Br.] were grown in a glasshouse with the addition of P to create five contents of P in the soil (7, 17, 32, 107 and 307 mg kg–1 soil) using a completely randomised design with four replicates per treatment. Grasses were harvested to 5 cm above the substrate surface, and the number of tillers and leaf area were recorded on Day 84 (harvest 1) and Day 112 (harvest 2) of the experiment. Dry matter production for kangaroo and weeping grass increased with P contents of the soil of 32 mg and ≥107 mg P kg–1 soil, respectively. Increased dry matter production for both species was the result of increased leaf area, tiller number and root growth. These results provide data that help to understand the disappearance sequence of kangaroo grass from more fertile soils and an increase in weeping grass, particularly in soils with greater fertility. Further research is required to determine if these results hold for other grass ecotypes.
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Waters, C. M., D. L. Garden, A. B. Smith, D. A. Friend, P. Sanford e G. C. Auricht. "Performance of native and introduced grasses for low-input pastures. 1. Survival and recruitment". Rangeland Journal 27, n.º 1 (2005): 23. http://dx.doi.org/10.1071/rj05001.
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Differential survival and recruitment patterns are commonly ignored within plant selection and breeding programs, where attention is focused largely on selection of cultivars with high biomass and seed yields. However, in low-input situations, where fertiliser application is limited, the use of pasture species with superior survival and recruitment characteristics can offer the potential of cost-effective pasture establishment. We investigated the comparative survival and seedling recruitment of 62 native and introduced perennial grasses under low-fertility conditions within three agro-ecological zones of temperate Australia: the temperate high-rainfall pasture zone; drier mixed-farming areas and Mediterranean southern Australia. Plants were grown from seed in glasshouses and transplanted to the field as spaced plants within 6–8 weeks. At regular intervals, survival of transplanted plants and recruitment of new plants were recorded. We found high mortality over a relatively short (24-month) period among both native and introduced grasses, despite good establishment. Frost damage at the cooler sites resulted in death of some C4 plants early in the experiment. Survival of some lines declined following the dry summer of 2000–01, and lines with best survival after this time were Eragrostis curvula cv. Consol, Austrodanthonia fulva (from Dalgety and Wagga, NSW) and Paspalidium jubiflorum (from Warren, NSW). C3 grasses, which generally had poor survival were a Microlaena stipoides selection from Nile, Tasmania, and two lines of Elymus scaber (Boorowa and Tumut, NSW). The C4 grasses Chloris truncata (Girilambone, NSW) and Dichanthium sericeum (Trangie, NSW) also exhibited poor survival, although there were exceptions at some sites. The native lines A. caespitosa Tas2407, M. stipoides cv. Shannon and A. racemosa were the most successful recruiters. Introduced lines generally had lower recruitment, although two lines of D. glomerata from Spain recruited well at some sites. C4 lines generally had poor recruitment, including E. curvula cv. Consol, Bothriochloa macra, Themeda australis, Enteropogon acicularis, D. sericeum, P. jubiflorum and P. constrictum. The role of plants adapted to low-input situations is discussed, as well as the implications of the attributes of survival and recruitment for selection of new cultivars for these situations.
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Mavromihalis, J. A., J. Dorrough, S. G. Clark, V. Turner e C. Moxham. "Manipulating livestock grazing to enhance native plant diversity and cover in native grasslands". Rangeland Journal 35, n.º 1 (2013): 95. http://dx.doi.org/10.1071/rj12074.
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Temperate perennial grasslands globally have been subject to extensive biodiversity loss. Identifying livestock grazing regimes that maintain and enhance the diversity and cover of native plant species in these ecosystems remains a key challenge. The responses of vegetation to different sheep grazing regimes were assessed over 3 years in grasslands of south-eastern Australia. An open communal experimental design was used to assess the effects of varying season and duration of exclusion of grazing by sheep, replicated at three locations. Manipulation of season and duration of exclusion of grazing led to few major changes in the cover of native perennial grasses or forbs, although seasonal variation was considerable. Exclusion of grazing in the spring did increase the likelihood of occurrence of grazing-sensitive native forb species but also lead to an increase in the cover of exotic annual species. However, cover of exotic annual species tended to decline with increasing duration of exclusion, while the abundance of native, grazing-sensitive forbs and the cover of perennial grasses increased. Small-scale richness of native perennial forb species increased with a 3-month period of exclusion of grazing, but declined with year-round exclusion of sheep. Total species richness also declined in response to year-round exclusion of sheep and rates of decline were correlated with the rate at which herbage mass accumulated. While strategic grazing did not result in major vegetation changes in the short term, it is suggested that some grazing exclusion may enhance the survival of infrequent species most sensitive to sheep grazing. Caution, however, should be taken when grazing regimes implemented benefit both desirable (native forbs) and undesirable (exotic annuals) species. Having a mosaic of flexible grazing management regimes across the landscape is likely to be beneficial for native plant diversity.
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Robinson, GG, e KA Archer. "Agronomic potential of native grass species on the Northern Tablelands of New South Wales. I. Growth and herbage production". Australian Journal of Agricultural Research 39, n.º 3 (1988): 415. http://dx.doi.org/10.1071/ar9880415.
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The herbage mass and relative growth rate of six perennial native grasses were compared with two introduced temperate perennial grasses (Phalaris aquatica L. cv. Sirosa, Festuca arundinacea Schreb. cv. Demeter and the temperate legume, white clover (Trifolium repens L. cv. Haifa). Of the native grasses three were year-long green species (Danthonia linkii Kunth, Microlaena stipoides (Labill) R.Br., Poa seiberana Spreng), and three were summer-growing frost susceptible species (Themeda australia (R.Br.) Stapf, Sporobolus elongatus R. Br., Bothriochloa macra (Steud) S.T. Blake). The summer perennial species, in particular Bothriochloa, were highly productive. However, in addition to inability to produce or retain green herbage during the winter, the summer-growing perennials produced a lower proportion of leaf material, a feature likely to render them less acceptable for grazing. Themeda was an exception, and produced a high proportion of leaf throughout the growing season and retained green material longer into the winter. Among the yearlong green species, both native and introduced, Poa proved a most productive species with significantly higher green leaf production than any other species, both in terms of herbage mass and relative growth rate. Although Danthonia produced as much herbage as phalaris on an annual basis, it has a higher stem component overall, and its relative growth rate was higher in the warmer months and lower during the winter months. Only Poa, white clover and phalaris produced signficant amounts of herbage during the winter months. These data suggest that native species have valuable agronomic features which could be exploited by selection and plant breeding programmes to advantage by the grazing industry.
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Norton, M. R., M. L. Mitchell, E. Kobelt e E. Hall. "Evaluation of native and introduced grasses for low-input pastures in temperate Australia: experimental approach, site and genotype descriptions". Rangeland Journal 27, n.º 1 (2005): 11. http://dx.doi.org/10.1071/rj05002.
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This paper describes the experimental methodology, sites, seasonal conditions and germplasm used in the Australian Native and Low Input Grass Network (NLIGN). In 1998, eight sites were established across the temperate pastoral zone of southern Australia. These were located at Armidale, Binya, Sutton and Trangie in NSW; Springhurst in Victoria; Jericho in Tasmania; Flaxley in South Australie and Kendenup in Western Australia. A total of 62 lines were evaluated, of which, 29 were Australian native grasses and 33 were introduced. With differences in seed size among species and a lack of information on dormancy and germination characteristics of the native plants, seedlings were transplanted into the field on weed-mat as spaced plants. Lines were compared over a 3-year period from 1998 to 2001. Methods used for determination of forage production, persistence and palatability are described. Information detailing the original collection sites of the germplasm, a list of NLIGN sites where each genotype was evaluated, as well as a detailed description of sites and seasonal conditions is also presented.
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Oram, Rex, e Greg Lodge. "Trends in temperate Australian grass breeding and selection". Australian Journal of Agricultural Research 54, n.º 3 (2003): 211. http://dx.doi.org/10.1071/ar02137.
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Current trends in grass cultivar development are reviewed, with respect to the range of species involved, and the objectives and methodology within each species. Extrapolations and predictions are made about future directions and methodologies. It is assumed that selection will necessarily cater for the following environmental changes: (1) higher year-round temperatures, higher variability of rainfall incidence, and lower total winter and spring rainfall along the south of the continent; (2) higher nutrient and lime inputs as land utilisation intensifies; and (3) the grazing management requirements of the important pasture components will be increasingly defined and met in practice.The 'big four' species, perennial ryegrass, phalaris, cocksfoot and tall fescue, will continue to be the most widely sown species in temperate regions for many decades, with the latter 3 increasing most in area and genetic differentiation. However, species diversification will continue, especially with native grasses, legumes, and shrubs from fertile regions of Australia and exotics from little-explored parts of the world, such as South Africa, western North and South America, coastal Caucasus, and Iraq–Iran. By contrast, the recent high rate of species diversification in the tropics and subtropics will probably give way to a much lower rate of cultivar development by refinement and diversification within the established species. Domestication of native grasses will continue for amenity, recreational, land protection, and grazing purposes. As seed harvesting technologies and ecological knowledge improve, natural stands will become increasingly important as local sources of seed. It is suggested that many native grasses have been greatly changed by natural selection so as to withstand strong competition from introduced species under conditions of higher soil fertility and grazing pressure. Conversely, some introduced species are being selected consciously and naturally to persist in regions with irregular rainfall and less fertile soils. Therefore, the distinction between native and introduced grasses may be disappearing, and many populations of native species could now be as foreign to the habitats of pre-European settlement as are populations of introduced species that have been evolving here for 50–200 years. Methods used for genetic improvement will continue to be selection among both overseas accessions and the many native and introduced populations that have responded to natural selection in Australia. As well, there will be deliberate recurrent crossing and selection programs in both native and introduced species for specific purposes and environments. Increasingly, molecular biology methods will complement traditional ones, at first by the provision of DNA markers to assist the selection of complex traits, and for proving distinctness to obtain Plant Breeders' Rights for new cultivars. Later, genetic engineering will be used to manipulate nutritive value, resistance to fungal and viral diseases, and breeding systems, especially cytoplasmic male sterility and apomixis, to utilise heterosis in hybrid cultivars of grasses, particularly for dairying and intensive meat production.Areas where the practice and management of grass breeding and selection programs could be improved are highlighted throughout the review, and reiterated in a concluding statement. Most problems appear to stem from inadequate training in population ecology, population genetics, evolution, and quantitative inheritance.
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Garden, D. L., N. J. S. Ellis, M. A. Rab, C. M. Langford, W. H. Johnston, C. Shields, T. Murphy, M. Holmberg, K. B. Dassanayake e S. Harden. "Fertiliser and grazing effects on production and botanical composition ofnative grasslands in south-east Australia". Australian Journal of Experimental Agriculture 43, n.º 8 (2003): 843. http://dx.doi.org/10.1071/ea02216.
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The effects of application of superphosphate and grazing on production and botanical composition of native grasslands were investigated at 3 locations in the high rainfall zone of south-east Australia. These studies were conducted as part of the Sustainable Grazing Systems Key Program, which investigated various aspects of grassland productivity and sustainability between 1996 and 2001. Grasslands in this study either had high contents of Themeda australis or Austrodanthonia spp., or were based on a degraded Austrodanthonia spp. grassland with a high content of annual and weedy species. All sites used increasing levels of superphosphate application (nil, low, medium and high) as treatments, with clover being added in some treatments at 1 site, and herbicide in 1 treatment at another site. Grazing (sheep) was continuous at 1 site (with stocking rates matched to pasture productivity) and intermittent at other sites, with grazing being dictated by available herbage between defined trigger points. Climate was monitored and changes in soil P, herbage mass, botanical composition, ground cover and sheep production recorded. Changes in composition resulting from the treatments varied between sites. At the continuously grazed Austrodanthonia spp. site, there was a decline in native perennial grasses throughout the experiment and an increase in exotic annual grasses in spring where superphosphate was applied. The grassland at the T. australis site remained relatively stable, which may have been due to the limited amount of grazing applied. The degraded Austrodanthonia�spp. grassland showed wide seasonal fluctuations in annual species. There were no clear effects of treatments at the latter 2 sites. Sheep production increased with increased superphosphate application at the continuously grazed Austrodanthonia spp. site, but there was little effect at the other 2 sites. Recommendations are made for sustainable management of native grasslands depending on their current botanical state.
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Barnes, Phoebe, Brian R. Wilson, Chris Nadolny e Ivor Growns. "The influence of individual native trees and grazing regime on soil properties and groundcover patterns in a temperate landscape of New South Wales, Australia". Rangeland Journal 31, n.º 4 (2009): 405. http://dx.doi.org/10.1071/rj09017.
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Scattered native trees are a significant ecological resource across the agricultural landscape, yet their numbers are declining due to factors such as dieback, senescence and agricultural activity. This study examined the interactions among Eucalyptus melliodora (Cunn. ex Schauer) trees, vegetation composition and selected surface soil chemical properties in grazed and ungrazed paddocks on the Northern Tablelands of New South Wales, Australia. Four farms on granite soils were examined in grazed and ungrazed treatments. Vegetation composition was assessed, and soil samples were collected in plots beneath the canopy and in adjacent open areas in both north and south directions of the tree canopy. Native grasses dominated the vegetation in both beneath the canopy and open areas, at both grazed and ungrazed sites. However, their composition varied between farms. Several C3 and C4 grasses contributed to the groundcover of the canopy and open sites, but C3 grasses were generally more common under the canopy. Significant differences occurred in soil C, N, P and pH, and vegetation composition between canopy and open areas, and between grazed and ungrazed treatments. Soil P, C and N contents in grazed sites were typically similar to or higher than those in ungrazed sites, and soils were less acid in the ungrazed compared with grazed sites. All soil parameters measured were significantly higher under tree canopies, except P. The tree, soil and vegetation factors were strongly related. This study confirms that individual scattered trees create a distinct mosaic of localised soil improvement, and influence vegetation composition so that paddocks with trees are floristically more diverse than paddocks without trees. The results illustrate the potential benefits of retaining trees for both biodiversity values and livestock production in Australia.
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Islam, M., D. W. Turner e M. A. Adams. "Phosphorus availability and the growth, mineral composition and nutritive value of ephemeral forbs and associated perennials from the Pilbara, Western Australia". Australian Journal of Experimental Agriculture 39, n.º 2 (1999): 149. http://dx.doi.org/10.1071/ea98133.
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The effect of phosphorus fertiliser on plant growth and the quality of leaf tissues for herbivores were investigated in field and glasshouse experiments. In the field, the relative abundance of ephemeral forb species was strongly affected by the seasonal variation in rainfall. In winter, C3 ephemeral forbs were abundant, whilst in summer, C4 ephemeral grasses dominated. During the dry months, growth of all species was poor. After rain, grasses to which phosphorus had been added increased growth significantly. Nutrient concentrations in ephemeral forbs were significantly greater than those in perennial or ephemeral grasses. Phosphorus concentrations were low in perennial and ephemeral grasses and declined during the dry months. The nitrogen : phosphorus ratio of ephemeral forbs and perennial shrubs suggested a deficiency of phosphorus, whilst that of ephemeral grasses suggested a deficiency of nitrogen. A glasshouse experiment investigated the response to phosphorus of 2 common and abundant ephemeral forbs – Ptilotus macrocephalus which responded to all treatments up to a maximum rate of 200 kg P/ha, and Ptilotus exaltatus which increased in growth up to a maximum rate of 100 kg P/ha. In both species, the concentration of phosphorus increased significantly with phosphorus supply, while that of nitrogen did not vary significantly among phosphorus treatments. Generalisations about growth and nitrogen and phosphorus nutrition of native species based on more mesic plant communities are not readily applied in the arid and chronically phosphorus-poor Pilbara environment. Instead, plant life-cycle and life form play major roles in determining nitrogen or phosphorus limitations and plant responses to added nutrients.
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Read, Tamara R., e Sean M. Bellairs. "Smoke affects the Germination of Native Grasses of New South Wales". Australian Journal of Botany 47, n.º 4 (1999): 563. http://dx.doi.org/10.1071/bt97124.
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The germination responses to plant-derived smoke of seeds of 20 native grass species from New South Wales, Australia, were tested under laboratory conditions. The species belonged to 14 genera including Bothriochloa, Chloris, Cymbopogon, Danthonia, Dichanthium, Digitaria, Eragrostis, Eriochloa, Microlaena, Panicum, Paspalidium, Poa, Stipa and Themeda. The interaction between smoke and husk-imposed dormancy was examined by removing the floral structures surrounding the seeds, when sufficient seeds were available. Smoke was shown to be an important environmental stimulus for breaking the dormancy of native grasses; however, the response differed considerably between different genera and between species of the same genus. For almost half of the species, smoke significantly increased the germination percentage. Panicum decompositum showed the greatest response, with germination increasing from 7.7 to 63.1% when smoke was applied. Panicum effusum had no germination in the absence of smoke, but 16.7% germination when smoke was applied. Stipa scabra subsp. scabra had germination significantly reduced by smoke from 30.2 to 19.9%. Five species had their germination rate, but not the final germination percentage, affected by smoke, and a third of the species were unaffected by smoke. For five of the species, Chloris ventricosa, Dichanthium sericeum, Panicum decompositum, Poa labillardieri and Stipa scabra subsp. falcata, this is the first report of a smoke-stimulated germination response. For those species with germination promoted by smoke, retention of the covering structures did not prevent smoke stimulation of germination. Sowing smoke-treated husked seeds is likely to be preferable as it would still promote greater germination, whereas dehusking seeds can result in the seeds being more susceptible to desiccation and fungal attack in the field. It is suggested that other grassland communities that respond to pyric conditions may also contain species that respond to smoke.
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Bean, Judith M., Gavin J. Melville, Ronald B. Hacker, Sharon Anderson, Alicia Whittington e Stephen P. Clipperton. "Effects of fenced seed production areas and restoration treatments on the size and composition of the native grass seedbanks in moderately degraded rangelands in semiarid Australia". Rangeland Journal 38, n.º 1 (2016): 47. http://dx.doi.org/10.1071/rj15065.
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Seed production areas containing populations of native grasses were fenced on topographically high areas at two study sites in the semiarid rangelands of north-west New South Wales, Australia. The surrounding slopes were initially almost bare of pastorally preferred grasses. Three restoration treatments (control, mechanical pitting, and contour-aligned branch piles) were established on these surrounding slopes and the size and composition of the native grass seedbanks determined. A positive influence of the seed production areas mostly occurred within 15 m of the fence and was probably insignificant beyond 33 m at both sites. On a hard-setting red earth site, the size of the native grass seedbank in all three treatments increased over 2 years with the greatest increase under the piles of branches and smaller increases in the pitting and control treatments. The piles of branches preferentially incorporated seed of the pastorally preferred species Monachather paradoxus Steud into the seedbank whereas pits preferentially incorporated seed of the pastorally unpreferred species Aristida jerichoensis (Domin) Henrad. Evidence generally pointed to incoming seed rain rather than the seedbank as the main source of new seedlings. On a medium-textured lithosol site neither the pits nor the branches treatment was effective in enhancing either the size or composition of the seedbank; in fact the piles of branches resulted in a decrease in its size.