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1
Kemp, D. R., e P. M. Dowling. "Towards sustainable temperate perennial pastures". Australian Journal of Experimental Agriculture 40, n. 2 (2000): 125. http://dx.doi.org/10.1071/ea98003.
Testo completoAbstract (sommario):
Naturalised pastures across the higher rainfall (>600 mm) perennial pasture zone of south-eastern Australia are less productive than they were, while sown pastures fail to maintain their initial levels of production. Several factors have contributed to this, including lack of knowledge of suitable grazing practices, weed invasion, increasing acid soils, rising water tables and poor management practices during droughts. A key issue in each case is the decline in perennial grass species which is both a cause and effect of the decline in productivity and sustainability of these ecosystems. This paper introduces a volume devoted to the largest collaborative study done to evaluate tactics for better grazing management and to improve the sustainability of perennial pasture ecosystems. Grazing practices to manage the composition of pastures have been largely neglected in pasture research, but are an important first step in improving pasture sustainability. This paper also outlines a new, open communal grazing experimental design which was developed and used across 24 sites on farms in New South Wales, Victoria, Tasmania and South Australia, to evaluate tactics for grazing management. The general aim across these experiments was to maintain (if adequate) or enhance (if degraded), the proportion of desirable perennial grasses in the sward to achieve more sustainable pastures. The results will provide the basis for building more sustainable grazing systems.
2
Pearson, C. J., R. Brown, W. J. Collins, K. A. Archer, M. S. Wood, C. Petersen e B. Bootle. "An Australian temperate pastures database". Australian Journal of Agricultural Research 48, n. 4 (1997): 453. http://dx.doi.org/10.1071/a96095.
Testo completoAbstract (sommario):
A census of pasture types and their composition and attributes (e.g. purpose and carrying capacity) was carried out throughout southern Australia from June to October 1994. This paper describes the survey process and subsequent creation of an Australian temperate pastures database. Data were created for 562 local government areas (LGAs) from ‘desk estimates’ by trained agriculturists. They identified about 2500 pasture types, which were grouped into 120 standardised pasture categories. Some findings from the data are identified, namely the high relative importance on an area basis of unimproved native pastures, the importance of weedy species (e.g. Vulpia), and the marked decline with increasing rainfall in importance of annual medics compared with subterranean clover. This paper provides examples of the data and their use for assessment of the regional economic impact of increases in productivity of pasture species.
3
Eyles, Alieta, Garth Coghlan, Marcus Hardie, Mark Hovenden e Kerry Bridle. "Soil carbon sequestration in cool-temperate dryland pastures: mechanisms and management options". Soil Research 53, n. 4 (2015): 349. http://dx.doi.org/10.1071/sr14062.
Testo completoAbstract (sommario):
Permanent pastures, which include sown, native and naturalised pastures, account for 4.3 Mha (56%) of the national land use in Australia. Given their extent, pastures are of great interest with respect to their potential to influence national carbon (C) budgets and CO2 mitigation. Increasing soil organic C (SOC) mitigates greenhouse gases while providing other benefits such as pasture productivity, soil health and ecosystem services. Several management approaches have been recommended to increase C sequestration in pasture-based systems; however, results have proved variable and often contradictory between sites and years. Here, we present an overview of the processes and mechanisms responsible for C sequestration in permanent pastures. In addition, we discuss the merits of traditional and emerging pasture-management practices for increasing SOC in pastures, with a focus on dryland pasture systems of south-eastern Australia. We conclude by summarising the knowledge gaps and research priorities for soil C-sequestration research in dryland pastures. Our review confirms that soils under a range of pasture types have considerable potential for sequestration of atmospheric CO2 in Australia, and that the magnitude of this potential can be greatly modified by pasture-management practices. Although the shortage of long-term studies under Australian conditions limits our ability to predict the potential of various management approaches to sequester soil C, our review indicates that prevention of erosion through maintenance of groundcover and adoption of options that promote deep C sequestration are likely to confer broad-scale maintenance or increases in SOC in pasture soils over a decade or longer. We acknowledge that the evidence is limited; therefore, confidence in the recommended practices in different locations and climates is largely unknown.
4
Lattimore, MAE. "Pastures in temperate rice rotations of south-eastern Australia". Australian Journal of Experimental Agriculture 34, n. 7 (1994): 959. http://dx.doi.org/10.1071/ea9940959.
Testo completoAbstract (sommario):
Legume-based pastures have long been an integral part of rice growing in the southern New South Wales irrigation areas and still offer potential to improve the productivity, profitability, and sustainability of the temperate rice-cropping system.This paper reviews both historical and current aspects of pastures in temperate rice rotations in southern New South Wales and highlights the importance of pastures in sustaining this cropping system as environmental pressures increase. Topics discussed include pasture species and rotations, their role in improving soil fertility and sustainability, the value of pastures in weed control, and their management for maximum profitability.
5
Vere, D. T., R. E. Jones e M. H. Campbell. "Long-term change in the economic productivity of four major pasture categories on the south-eastern Tablelands of New South Wales". Rangeland Journal 23, n. 2 (2001): 148. http://dx.doi.org/10.1071/rj01002.
Testo completoAbstract (sommario):
The perception of change or decline in the productivity of temperate pastures in south-eastern Australia is an important concern to livestock producers and pasture scientists. Much of this concern relates to reductions in the proportions of desirable species in the composition of pasture systems as a result of increased soil and weed problems. The purpose of this paper is to investigate trends in the long-term economic productivity of four categories of temperate pastures (all introduced pastures, introduced perennial grasses, introduced legumes and all native pastures) on the central and southern tablelands of New South Wales. The results provide evidence of economic productivity decline in the all introduced pastures category in relation to sheep production, but this has been due to productivity decline in the dominant legume component of the introduced pastures. In contrast, there has been strong growth in the economic productivity of the introduced perennial grass pastures. Abnormally high beef cattle numbers in the mid-1970s appear to have created an illusion of high productivity and subsequent decline in all introduced pastures. In contrast, the economic productivity of the native pastures which are the bulk of the region's grazing areas, has fallen substantially.
6
Vere, D. T., R. E. Jones e M. H. Campbell. "The economics of temperate pasture systems on the central and southern Tablelands of New South Wales". Rangeland Journal 23, n. 2 (2001): 159. http://dx.doi.org/10.1071/rj01003.
Testo completoAbstract (sommario):
Pastures are the basis of most forms of agricultural production on the New South Wales central and southern tablelands. Pastures occupy the bulk of the region's landmass and pasture-based livestock production annually contributes more than three-quarters of the regional gross value of rural production. Throughout the region, there is substantial variation in pasture composition, ranging from high quality introduced perennial grasses and legumes to pastures comprising mainly low quality native species. This paper examines the economics of the main categories of temperate pastures over a range of soil fertility-rainfall environments on the south-eastern tablelands areas of New South Wales. Using a linear programming model and discounted development budgets, the results demonstrate the strong influence of the environment on the economics of the individual pasture systems. The highest economic returns in both the short and longer-terms were to the introduced perennial grass pastures in most of the environments. Pastures based on introduced legumes and the high quality native species also generated sound economic returns, although there are recognised problems with the persistence of the legume pastures. Over time, the returns to the better quality native pastures compare favourably with the introduced legumes and are better suited to acidic soils than the perennial grasses. Low quality native species produced relatively poor economic returns in all environments and unfortunately, are the main pasture type in the region's less favourable environments.
7
Jones, Roger A. C. "Virus diseases of pasture grasses in Australia: incidences, losses, epidemiology, and management". Crop and Pasture Science 64, n. 3 (2013): 216. http://dx.doi.org/10.1071/cp13134.
Testo completoAbstract (sommario):
This paper reviews current knowledge for Australia over the occurrence, losses caused, epidemiology, and management of virus diseases of pasture grasses. It also reviews all records of viruses in wild grasses likely to act as alternative host reservoirs for virus spread to nearby pastures or crops. Currently, 21 viruses have been found infecting 36 pasture or forage grass species and 59 wild grass species. These viruses are transmitted by arthropod vectors (mites or insects) or, in one instance, via grass seeds. Their modes of transmission are critical factors determining their incidences within pastures in different climatic zones. Large-scale surveys of perennial grass pastures growing in regions with temperate–Mediterranean climates revealed that Barley yellow dwarf virus (BYDV), Cereal yellow dwarf virus (CYDV), and Ryegrass mosaic virus (RyMV) sometimes reach high infection incidences. The same was true for BYDV and CYDV when perennial pasture grasses and wild grasses growing outside pastures were surveyed to establish their occurrence. Smaller scale surveys of grasses growing both inside and outside annual pastures found that Wheat streak mosaic virus (WSMV) infection could also reach high incidences in some annual grass species. Herbage yield loss data are available demonstrating potentially serious impacts on pasture production under Australian conditions from BYDV infection in perennial ryegrass swards, and from RyMV infection in both perennial and Italian ryegrass swards. Also, infection with BYDV or RyMV diminished the ability of infected pasture grass plants to compete with pasture legumes or weeds. Host resistance to BYDV, CYDV, and/or RyMV has been identified within a few temperate–Mediterranean pasture grasses, and is available for use in Australian pasture breeding programs. Integrated Disease Management tactics involving phytosanitary, cultural, chemical, and host resistance measures were devised against BYDV, CYDV, and RyMV infection in mixed species pasture, but no field experiments were undertaken with pasture grasses to validate their inclusion. Several other grass viruses that occur in other countries, but have not been looked for in Australia, are potentially important, especially in temperate–Mediterranean pasture grass species. With few exceptions, research on viruses of perennial or annual tropical–subtropical pasture or wild grass species growing within or outside pastures has focussed only on virus identification and characterisation studies, and information on incidences in pastures, losses caused, epidemiology, and management is lacking. Critical research and development gaps that need addressing are identified.
8
McPhee, M. J., J. F. Ayres e M. L. Curll. "Growth periodicity of introduced pastures on the northern tablelands of New South Wales". Australian Journal of Agricultural Research 48, n. 6 (1997): 831. http://dx.doi.org/10.1071/a96176.
Testo completoAbstract (sommario):
This paper reports on the growth periodicity of introduced temperate perennial pastures in a summer-rainfall environment in the high-rainfall zone of eastern Australia. Data were derived from an experiment (1985-87) directed at evaluating pasture cultivars when sown in binary mixtures grazed by sheep. The data were also simulated by using the decision support system SheepO (Version 4·0) and validated by visual techniques, deviance measures, and statistical tests. The model simulated pasture growth rate and total biomass with acceptable accuracy. The study provided a quantification of the growth rhythm of temperate perennial pastures in this environment. The data show that growth rhythm comprises a high growth rate (>50 kg DM/ha·day) during the primary growth cycle in spring, a moderate growth rate (20-50 kg DM/ha·day) during the secondary growth cycle in summer-autumn, and low growth rate (<20 kg DM/ha·day) in winter. The growth performance of introduced pastures based on cv. Demeter tall fescue (Festuca arundinacea) exceeded that of pastures based on cv. Sirosa phalaris (Pharlaris aquatica) in all seasons, at low and high stocking rates, and in all 3 years. The results highlight the potential for pasture cultivars with enhanced seasonal growth rate to increase the pasture feed supply for grazing animals.
9
King, K. L., e K. J. Hutchinson. "Pasture and grazing land: assessment of sustainability using invertebrate bioindicators". Australian Journal of Experimental Agriculture 47, n. 4 (2007): 392. http://dx.doi.org/10.1071/ea05270.
Testo completoAbstract (sommario):
Impacts of practices frequently used to manage Australian pastures are reviewed with the aim of determining which groups are responsive to changes in grazing regime, fertiliser use, pasture types, tree clearing, pesticide use, liming and irrigation. Invertebrate groups sensitive to pasture management regimes may be potential candidates for use as bioindicators of ecological sustainability of these pasture types. This review concentrates on the more intensively utilised temperate pastures of southern Australia, as very little work has been done on the impact of the grazing animal and pasture management on invertebrate fauna on the extensive rangelands of the arid and semiarid zones. Background to the relative importance of invertebrates in the functioning of the pasture ecosystem is given. This has culminated in the construction of food webs for two temperate perennial pastures (an unfertilised, native and a fertilised, sown pasture) at Armidale, NSW, for which there is comprehensive data available. Invertebrate bioindicators of pasture sustainability emerged from the consideration of grazing lands and invertebrate responses. Currently, only four groups would seem to be likely candidates as bioindicators of sustainability of pastures. These are soil nematodes, earthworms, protozoa and Collembola. The main difficulty in monitoring these groups is that it requires specialist expertise, and services provided by commercial laboratories for routine biological soil tests are still in their infancy. There are gaps in our knowledge of how invertebrate fauna react to the pressing issues of soil acidity and salinity.
10
Fulkerson, WJ, e K. Slack. "Estimating mass of temperate and tropical pastures in the subtropics". Australian Journal of Experimental Agriculture 33, n. 7 (1993): 865. http://dx.doi.org/10.1071/ea9930865.
Testo completoAbstract (sommario):
The feasibility of estimating, with acceptable precision, temperate and tropical pasture mass in a subtropical environment was evaluated. For the tropical grasses kikuyu (Pennisetum clandestinum) and setaria (Setaria ancepts), 3 different pasture meters were calibrated against 1 of 3 dry matter (DM) estimates. Temperate pastures (predominantly Lolium perenne and Trifolium repens) were evaluated using the Ellinbank rising plate meter (RPMl) calibrated against DM to ground level. A single regression equation was developed for syegrass-white clover pasture from data pooled within season over first- and second-year swards. The s.e. of estimate (s.e.e.) for assessing tropical grass pasture mass using RPMl was similar to that for a heavier Ellinbank meter and substantially lower than that for the electronic pasture probe. Using RPMl, separate regression equations were required for early (November-February) and late (March-May) season determinations for both kikuyu and setaria. The regression equations were based on calibrations against shoot DM (>5 cm stubble height for kikuyu and 6 cm for setaria) and are only applicable to well-managed and highly utilised pastures. Calibrations of all pasture meters over all months to green DM (senescent leaf and stem removed) gave a lower s.e.e. than total DM (kikuyu 138 v. 177 kg DM/ha, n = 171; setaria 211 v. 224 kg DM/ha, n = 177) whilst shoot DM gave a more substantial reduction in s.e.e. (kikuyu 95 v. 147 kg DM/ha; setaria 140 v. 193 kg DM/ha).
11
Axelsen, A., PJ Waller, AD Donald, RJ Dobson e JB Nadin. "Grazing management and nematode parasite control in cattle in the temperate climatic zone of Australia". Australian Journal of Experimental Agriculture 26, n. 3 (1986): 267. http://dx.doi.org/10.1071/ea9860267.
Testo completoAbstract (sommario):
Over 2 years, 1979 and 1981, yearling cattle were grazed from July to December/January on phalaris- or annual ryegrass-based pastures that had been previously grazed by either weaners, cows or cattle drenched every 2 weeks. All yearlings had previously been drenched at weaning in autumn, and from July were either set-stocked, or moved once or twice on to pastures previously grazed by cows. The experiment was conducted at Ginninderra. near Canberra. If a portion of the pasture was saved in winter for grazing in early spring, increased liveweight gains were observed while yearlings grazed the saved area. However, the greater gains during this period were not enough to compensate for previous weight losses or lower gains, so that saving pasture was no better than set-stocking over the total period. In 1979, a year of low rainfall and pasture growth, yearlings drenched 2-weekly gained no more weight than undrenched yearlings, despite much lower worm burdens. In 1981, with average pasture growth, yearlings drenched in July before moving on to pastures previously grazed by cows, and drenched again in September, gained as much weight as those drenched every 2 weeks and significantly more than those undrenched and set-stocked. It is recommended that weaners or yearlings should be moved in July on to improved pastures of low infectivity (obtained by previous grazing with cows or sheep). If combined with one or two drenches, this single move would be as effective for optimising weight gains as more complicated management schemes.
12
Garden, D. L., G. M. Lodge, D. A. Friend, P. M. Dowling e B. A. Orchard. "Effects of grazing management on botanical composition of native grass-based pastures in temperate south-east Australia". Australian Journal of Experimental Agriculture 40, n. 2 (2000): 225. http://dx.doi.org/10.1071/ea98010.
Testo completoAbstract (sommario):
Grazing management strategies to alter botanical composition of native pastures were investigated at 4 locations in the high rainfall zone of south-east Australia, including Tasmania. These studies were conducted as part of the Temperate Pasture Sustainability Key Program, which evaluated the effects of grazing management on a wide range of pasture types between 1993 and 1996. Pastures in this study were based on Aristida ramosa/Bothriochloa macra, Microlaena stipoides–Austrodanthonia spp. or Themeda triandra–Austrodanthonia spp. Seasonal rests, increased grazing pressure in spring, mob stocking and cutting for hay were compared to continuous grazing at all sites. In addition, specific local treatments were tested at individual sites. Changes in composition resulting from the treatments were minimal at most sites. This may have been due to a combination of the inherent stability of the pastures, the relatively short duration of the experiments, and the drought conditions experienced, which minimised differences between treatments. Some strategies to alter composition of natural pastures are suggested. In the Aristida–Bothriochloa pasture there was a general decrease in Aristida and an increase in Bothriochloa, which was largely unaffected by the type of grazing management applied. The combination of drought conditions and increasing grazing pressure was sufficient to alter composition without specific management strategies being necessary. In the Themeda–Austrodanthonia pasture, resting in spring, 12-month rests or cutting for hay (which involved a spring rest) allowed Themeda to increase in the pasture. The Microlaena–Austrodanthonia pastures were very stable, especially where annual grass content was low. However, certain treatments allowed Microlaena to increase, a result which is regarded as being favourable. The major effects in these latter pastures were on undesirable species. Vulpia spp. were reduced by resting in autumn and increased spring grazing pressure, while Holcus lanatus was increased dramatically by resting in spring and was also increased by resting in autumn or winter, but only when conditions were suitable for growth of this species. In many cases, treatment differences were only expressed following recovery from drought, showing that timing of grazing management to achieve change is critical.
13
Vere, D. T., P. M. Dowling, R. E. Jones e D. R. Kemp. "Economic impact of Vulpia in temperate pasture systems in south-eastern Australia". Australian Journal of Experimental Agriculture 42, n. 4 (2002): 465. http://dx.doi.org/10.1071/ea01100.
Testo completoAbstract (sommario):
An increasing incidence of annual grasses is considered to be a primary cause of decline in the productivity of Australia's temperate pasture systems. In particular, Vulpia (silver grass) comprises a significant proportion of the biomass of many temperate pastures and can seriously affect livestock productivity. The main economic effects of Vulpia include reducing pasture carrying capacities, contaminating produce and competing with more desirable pasture species. This paper presents the results of an economic evaluation of the costs of Vulpia and the long-term benefits of improving Vulpia management in the high-rainfall areas of south-eastern Australia. The evaluation used an integrated economic modelling system that determined the grazing system and livestock industry impacts of Vulpia and translated these into measures of economic welfare change that enabled the benefit-cost analysis of various levels of Vulpia management to be undertaken. With a focus on wool, the analysis established the high annual costs of Vulpia to wool producers and consumers, together with substantial long-term economic benefits that could potentially result from reducing the incidence of Vulpia in pastures. Total annual costs to the wool industry in the temperate pasture zone of New South Wales and Victoria ranged between A$7 and $30 million, while the potential discounted net benefits to the Australian and international wool industries were between $32 and $287�million over a 15-year period at a real discount rate of 5%. These estimates provide a strong economic basis for promoting improved management strategies for reducing Vulpia incidence in pastures.
14
McGregor, B. A. "Influence of stocking rate and mixed grazing of Angora goats and Merino sheep on animal and pasture production in southern Australia. 1. Botanical composition, sward characteristics and availability of components of annual temperate pastures". Animal Production Science 50, n. 2 (2010): 138. http://dx.doi.org/10.1071/an09128.
Testo completoAbstract (sommario):
The effects of animal species (AS; Angora goats, Merino sheep or goats and sheep mixed grazed together at ratio 1 : 1) and stocking rate (SR; 7.5, 10 and 12.5 animals/ha) on the availability, botanical composition and sward characteristics of annual temperate pastures under continuous grazing were determined in a replicated experiment from 1981 to 1984. AS and SR had significant effects on pasture availability and composition and many AS × SR interactions were detected. The pastures grazed by sheep had significantly reduced content and proportion of subterranean clover and more undesirable grasses compared with those grazed by goats. There were no differences in dry matter availabilities between goat- and sheep-grazed pastures at 7.5/ha, but at 10 and 12.5/ha goat pastures had significantly increased availabilities of green grass, dead and green clover and less weeds compared with sheep pastures. There was a significant AS × SR interaction for the density of seedlings in May following pasture germination. Between July and January, the height of pastures was greater under goats than sheep but from January to March pasture height declined more on goat-grazed than on sheep-grazed pastures. There was an AS × SR interaction for incidence of bare ground. Increasing the SR increased bare ground in pastures grazed by sheep but no change occurred on pastures grazed by goats. Changes in pasture characteristics due to increased SR were minimised on pastures grazed by goats but the grazing of sheep caused larger and faster changes and the pastures were damaged at the highest SR. Goats did not always select the same herbage material as sheep, changed their selection between seasons and were not less selective than sheep. Angora goats were flexible grazers and continually adapted their grazing behaviour to changing herbage conditions. Goat grazing led to an increase in subterranean clover, an accumulation of dead herbage at the base of the sward, reduced bare ground, taller pastures in spring and a more stable botanical composition. Mixed-grazed pasture characteristics were altered with SR. With careful management Angora goats on sheep farms may be used to manipulate pasture composition, to speed up establishment of subterranean clover, to decrease soil erosion and to reduce weed invasion.
15
Stockdale, C. R. "Effects of the composition of irrigated perennial pasture on the milk production of dairy cows and their responses to supplementation with cereal grain-based concentrates". Australian Journal of Experimental Agriculture 48, n. 7 (2008): 866. http://dx.doi.org/10.1071/ea07418.
Testo completoAbstract (sommario):
The objective of the research described here was to compare the milk production from paspalum (Paspalum dilatatum Poir.)-dominant swards with milk production from perennial ryegrass (Lolium perenne L.)–white clover (Trifolium repens L.)-dominant swards. Eight experiments were conducted over a 2-year period, during which half the cows grazed pastures that had been established for more than 15 years (old pasture) and were dominated by paspalum in summer, while the remaining cows grazed pastures sown within the previous 2–3 years (new pasture), which were dominated by temperate species. Groups of four to five lactating Friesian cows grazed either old or new pasture and were either unsupplemented or were offered ~5 kg DM/cow.day of a high energy supplement (75% barley and 25% wheat). The hypothesis was that milk production would be greater from cows grazing new pastures than old pastures (at common pasture allowances), but that marginal milk responses when cereal grain-based supplements were fed would be greater when cows grazed old pastures; this was only partially supported. Milk yields were generally greater when cows grazed new pastures, but in six out of eight experiments, the advantage was only ~1 kg milk (100 g fat plus protein)/cow or less. In these six experiments, the difference in metabolisable energy density between the pastures was 0.7 MJ/kg DM or less. When concentrates were fed to supplement grazed pasture, there were seasonal variations, but similar marginal responses in milk production were recorded on both pastures throughout the study.
16
Fernandez-Turren, Gonzalo, José L. Repetto, José M. Arroyo, Analía Pérez-Ruchel e Cecilia Cajarville. "Lamb Fattening Under Intensive Pasture-Based Systems: A Review". Animals 10, n. 3 (27 febbraio 2020): 382. http://dx.doi.org/10.3390/ani10030382.
Testo completoAbstract (sommario):
The benefits of pasture-based systems on the fatty acid composition of sheep meat appear to be achievable despite variability in the quality of the pastures. Lambs fed high levels of temperate pastures have an excess of N-ammonia derived from protein degradation. Furthermore, animal performance is highly variable depending on the quality of the pasture at the time of grazing, and high animal performance in these systems appears to be linked to the use of high-quality pastures with high availability, and is possibly added to by the inclusion of concentrates that allow increasing energy intake and a better use of the N in the pasture. The combination of high-quality pastures and total mixed ration offers a good alternative to the inclusion of concentrates in the diet, improving the use of N, and avoiding acidosis problems. However, information to determine the effect of a number of nutritional strategies on meat quality, and the minimum level of pasture intake necessary to achieve the benefits of pastoral systems is still lacking.
17
Pyle, Lysandra, Linda M. Hall e Edward W. Bork. "Linking management practices with range health in northern temperate pastures". Canadian Journal of Plant Science 98, n. 3 (1 giugno 2018): 657–71. http://dx.doi.org/10.1139/cjps-2017-0223.
Testo completoAbstract (sommario):
Little information exists on the management and range health (RH) of northern temperate pastures, where health is defined as the ability to sustain ecosystem function. We surveyed 102 pastures for RH and their associated managers during 2012–2013 across central Alberta, Canada. Pastures were generally diverse mixes of introduced grasses and contained few legumes, despite most (55%) being seeded to legumes. The majority of pastures were healthy (mean RH score = 78.8% ± 1.3%), with 2.9% having scores <50%. Criteria reducing scores were noxious weeds, bare soil, and evidence of erosion. Most pastures had a reported history of cultivation (75.5%), with those previously cultivated and seeded to introduced forage having greater stocking rates [6.18 ± 0.91 animal-unit-months (AUM) ha−1] compared with those lacking cultivation (2.14 ± 2.91 AUM ha−1). Farms with horses or mixed livestock tended to practice year-round continuous grazing and supplemental hay feeding. Stocking rates on continuous and rotationally grazed pastures were similar regardless of grazing season, with the highest stocking on pastures used year-round (19.54 ± 2.03 AUM ha−1) or throughout the dormant season (20.29 ± 3.10 AUM ha−1). Use of management inputs was variable, with manuring and harrowing common and fertilizing, over-seeding, and aerating infrequent. Herbicide use was reported on 15.7% of pastures, despite 83.3% containing noxious weeds. Use of prescribed fire was rare, although 36.3% of pastures had evidence of fire. Industrial disturbances were reported on 48.3% of pastures. Overall, these results indicate that these pastures experience complex management and the limited decline in RH is due to high stocking under year-long grazing.
18
Mason, W. K., e G. Kay. "Temperate Pasture Sustainability Key Program: an overview". Australian Journal of Experimental Agriculture 40, n. 2 (2000): 121. http://dx.doi.org/10.1071/ea98002.
Testo completoAbstract (sommario):
This special edition of the Australian Journal of Experimental Agriculture presents papers from work undertaken as part of the Temperate Pasture Sustainability Key Program (TPSKP; see Fig. 1), and presented at a workshop in Sydney in November 1997. TPSKP was initiated by Meat and Livestock Australia (MLA). The Land and Water Resources Research and Development Corporation, the International Wool Secretariat and the Murray Darling Basin Commission were joint funders of some of the individual projects. Most projects were carried out on private properties, and many had producer groups associated with the sites to provide input into treatment selections as well as management guidance and support. This substantial producer input was provided free to the program. The success of TPSKP relied heavily on physical and financial support from State departments of agriculture and conservation, CSIRO and universities, and also on the enthusiasm of these groups to work collaboratively across the 4 south-eastern states. One of the key results of this cooperation was the development of a set of experimental protocols so that measurements taken anywhere in TPSKP could be directly compared. TPSKP aimed to develop the principles for manipulating pasture composition to make grazing systems more productive and sustainable. The program priorities were to: (i) determine by survey the attitudes of producers to grazing management and identify the characteristics of those producers most likely to adopt the program results; (ii) demonstrate by June 1996 that potentially responsive perennial grass-based pastures could be upgraded using grazing management to become a ‘desirable’ pasture for animal production and sustainability; (iii) demonstrate by June 1996 that newly sown perennial grass-based pastures could be maintained in a desirable condition using grazing management; (iv) determine the critical factors responsible for the capacity of perennial grasses to persist, respond to drought, and ameliorate land degradation; (v) develop producers’ skills in pasture species identification, pasture and animal assessment, and feed budgeting, both to enhance their existing management, and to ‘prime’ them for the outputs from TPSKP; (vi) to demonstrate (in phase 2) that improvements in pasture composition and grazing management can have both economic and environmental benefits.
19
Moletto-Lobos, Italo, Cristian Mattar e Jonathan Barichivich. "Performance of Satellite-Based Evapotranspiration Models in Temperate Pastures of Southern Chile". Water 12, n. 12 (21 dicembre 2020): 3587. http://dx.doi.org/10.3390/w12123587.
Testo completoAbstract (sommario):
Farmers in the temperate zone of southern Chile have started to irrigate historically rainfed pastures during recent years to reduce dairy productivity losses against increasingly severe summer droughts. The lack of information on pasture water requirements (i.e., evapotranspiration), however, hampers the implementation of efficient irrigation programs. Here, we use in-situ observations to evaluate the skill of four remote sensing Surface Energy Balance (SEB) models and two satellite-based global evapotranspiration products (PML_V2 and GLEAM) to estimate actual evapotranspiration (ETa) of pastures in southern Chile during 2014–2017. Daily ETa measured at an evaluation site over the period ranges between 1.2 mm and 6.2 mm day−1 during the growing season (October–March), with an annual maximum of about 4.8 mm day−1 in January and a minimum 0.6 mm day−1 in June. Only the Simplified SEB (SEBS) model and its operational variant (SSEBop) and the PML_V2 global evapotranspiration product perform well, capturing 63–79% of the variance of in-situ evapotranspiration with an error between 0.75 mm day−1 and 1.1 mm day−1. The readily available PML_V2 product can be used as a convenient way to determine average water footprint of pastures and the two SEBs models can be implemented to monitor irrigation requirements in near-real time from field to regional scales. These results demonstrated a high potential of satellite observations for monitoring evapotranspiration and quantify the water footprint of pastures in southern Chile for a sustainable irrigation practice.
20
Jones, Roger A. C. "Virus diseases of perennial pasture legumes in Australia: incidences, losses, epidemiology, and management". Crop and Pasture Science 64, n. 3 (2013): 199. http://dx.doi.org/10.1071/cp13108.
Testo completoAbstract (sommario):
This article reviews current knowledge for Australia over the occurrence, losses caused, epidemiology, and management of virus diseases of perennial pasture legumes. Currently, 24 viruses have been found infecting perennial pasture legumes, and one or more viruses have been detected in 21 of these species. These viruses are transmitted by insect vectors, non-persistently or persistently, by contact or via seed. Their modes of transmission are critical factors determining their incidences within pastures in different climatic zones. Large-scale national or state surveys of lucerne (alfalfa) (Medicago sativa) and white clover (Trifolium repens) pastures revealed that some viruses reach high incidences. Infection with Alfalfa mosaic virus (AMV) was very widespread in lucerne stands, and with AMV and White clover mosaic virus (WClMV) in white clover pastures. Several other viruses are potentially important in pastures in these and other perennial temperate/Mediterranean pasture species. Data demonstrating herbage yield losses, diminished pasture persistence, and impaired nitrogen fixation/nodule function are available for AMV in lucerne, and AMV, WClMV, and Clover yellow vein virus in white clover. Integrated Disease Management approaches involving phytosanitary, cultural, chemical, and host resistance control measures are available to minimise virus infection in lucerne and white clover. Research on virus diseases of perennial tropical–subtropical pasture legumes has focussed almost entirely on virus identification, and information on their incidences in pastures, the losses they cause, and how to control them is lacking. Overall, viruses of perennial pasture legumes are least studied in South Australia and the Northern Territory. These and other critical research and development gaps that need addressing are identified.
21
Pyle, Lysandra A., Linda M. Hall e Edward W. Bork. "Soil properties in northern temperate pastures do not vary with management practices and are independent of rangeland health". Canadian Journal of Soil Science 99, n. 4 (1 dicembre 2019): 495–507. http://dx.doi.org/10.1139/cjss-2019-0076.
Testo completoAbstract (sommario):
Studies examining the influence of disturbance and management history on pasture soils across a large sampling area are uncommon. We report on the soil properties found in 102 northern temperate pastures sampled in central Alberta, Canada, and relate these attributes to ongoing pasture management practices compiled from producer surveys and aboveground measures of rangeland health (RH). Tame pastures, typically seeded to introduced forages, were associated with higher soil fertility (total carbon, nitrogen, and organic matter) than semi-native grasslands, which were associated with coarse-textured soils. Soil properties remained independent of most grazing and pasture management practices, including the grazing systems, class of livestock, fertilization, and stocking rate. However, manure application, often combined with harrowing, was associated with improved soil fertility and increased electrical conductivity (salinity). Soils with a fire history reported by land managers, largely in the Boreal natural region, were characterized by a greater soil C:N ratio. Soil surface properties (litter cover, litter depth, and bare soil) were responsive to grazing management, with growing season and year-round grazing associated with a thinner litter layer having less cover, and bare ground twice as high under continuous grazing compared with pastures rotationally grazed. Further, variation in soil surface cover was associated with contrasting RH classes (healthy, healthy with problems, and unhealthy), whereas soil attributes remained unrelated to RH. This study demonstrates that soils within these northern temperate grasslands are relatively insensitive to many pasture management practices, and highlights that existing RH assessments may provide limited insight into differences in mineral soil properties.
22
Smetham, Michael L. "The Management of Pastures for Grazing". Outlook on Agriculture 24, n. 3 (settembre 1995): 167–77. http://dx.doi.org/10.1177/003072709502400307.
Testo completoAbstract (sommario):
This article examines pasture management in moist temperate climates, and looks at the reasons why putting the findings into practice has been so difficult. Many factors affect the behaviour of the animal-pasture system, including whether continuous or rotational grazing is practised, the intensity of grazing, and seasonal differences in climate and grass reproduction. Pasture quality is defined in terms of green leaf and dead material: the amount of green leaf present in a pasture is of prime importance in determining the productivity of the canopy and its value for animal feeding, while the presence of dead material can interfere with herbage productivity and also reduce the quality of the sward for animals. Pastures and grazing animals interact strongly with each other, and maximum productivity depends on achieving a balance.
23
Pent, Gabriel J. "Over-yielding in temperate silvopastures: a meta-analysis". Agroforestry Systems 94, n. 5 (27 aprile 2020): 1741–58. http://dx.doi.org/10.1007/s10457-020-00494-6.
Testo completoAbstract (sommario):
Abstract Over-yielding in an intercropping system occurs when the productivity of the intercrop exceeds the overall productivity of the systems managed in segregation. The objective of this systematic review was to calculate the over-yielding of silvopastures compared to open pastures and forests, timber plantations, or orchards managed separately. A literature search was completed for comparisons of the productivity of these practices in temperate regions. Data collected from these studies included mean yields of timber or non-timber forest products, forages, and livestock, as well as the characteristics of the study site. Silvopasture practices improve the productivity of land typically managed separately for pasture or trees by 42–55%, depending on whether the productivity of the pastures is measured by livestock or forage output, respectively. In most cases, over-yielding occurred despite a reduction in individual forage, livestock, or tree productivity in the silvopastures. Calculating confidence intervals around these means was not feasible because standard errors were largely not reported or available. Some assumptions were made about the actual productivity of timber or non-timber forest products. This work illustrates the significant level of over-yielding that may be achieved by integrating trees, forages, and livestock into a single production system.
24
Morley, Fred. "Temperate pastures: Their production, use and management". Agricultural Systems 33, n. 4 (gennaio 1990): 377–78. http://dx.doi.org/10.1016/0308-521x(90)90062-u.
Testo completo
25
Nolan, J. V. "Temperate pastures — Their production, use and management". Animal Feed Science and Technology 31, n. 3-4 (dicembre 1990): 355–56. http://dx.doi.org/10.1016/0377-8401(90)90139-y.
Testo completo
26
Robertson, S. M. "Predicting pasture and sheep production in the Victorian Mallee with the decision support tool, GrassGro". Australian Journal of Experimental Agriculture 46, n. 8 (2006): 1005. http://dx.doi.org/10.1071/ea04034.
Testo completoAbstract (sommario):
The GrassGro decision support tool was designed to quantify sheep and pasture production in response to management and climate variability in temperate Australia, and has been tested in temperate but not low-rainfall Australian conditions. Data from field experiments and from on-farm monitoring was used to test GrassGro predictions of annual and perennial pasture production, and sheep production at 4 locations throughout the Victorian Mallee, which is a low-rainfall area (275–375 mm annually). Predictions of long-term pasture production were then made. Predictions of the herbage biomass of annual pastures closely matched observed data for both a sandy loam (1991–2002 data) and a whole paddock (combining sandy loam and loam and sand) (2001–2002 data) soil type, at several locations across the Victorian Mallee. Linear regression between observed and simulated (April to September) data produced coefficients, significance and root mean square error of r2 = 0.81, P<0.001, 217 kg DM/ha, respectively, for sandy loam soil types and r2 = 0.94, P<0.001, 72 kg DM/ha, respectively, for whole paddock soil types. A series of simulations for individual years from 1970 to 2002 quantified the large impact of climate variability and demonstrated that seedbank and location, but not soil fertility, had a large influence on annual pasture production. However, GrassGro underestimated the production of the perennial pasture, lucerne (r2 = 0.2). GrassGro was also unable to adequately predict sheep production because it failed to take into account the sparse, clumpy structure of the low biomass pastures typical of this region. Methods to improve GrassGro were identified and included: (i) the need to adjust sheep intake from low biomass, sparse pastures, (ii) the ability to predict summer growing and autumn growing plant species, (iii) the ability to graze crop stubbles and (iv) refinements to the coefficients of equations used to model lucerne growth.
27
Burnett, V. F., G. R. Seymour, S. Norng, J. L. Jacobs e E. N. Ponnampalam. "Lamb growth performance and carcass weight from rotationally grazed perennial pasture systems compared with annual pasture systems with supplements". Animal Production Science 52, n. 4 (2012): 248. http://dx.doi.org/10.1071/an11053.
Testo completoAbstract (sommario):
Annual pastures used to finish lambs can decline in herbage nutritive value (NV) from January to April in the temperate zone. If lambs are to be finished to market specifications for carcass weight during this period, the use of summer-active perennial pastures or supplementation of annual pastures, is required. The present study investigated liveweight (LW) gain and carcass characteristics of lambs finished on perennial pastures compared with annual pastures and supplementation. Fifty-four second-cross lambs were allocated to one of the following four treatments in an asymmetric split-plot design: perennial pasture (PP), annual pasture with hay and grain (AP), AP with flaxseed (AP+FS) and AP with flaxmeal (AP+FM). Lambs were fed for 7 weeks and weighed weekly. Blood glucose and total antioxidant status were determined before, during and at the end of the experiment. Carcass weight and GR fat were measured at 24 h post-slaughter. Lambs grazing PP had significantly higher daily LW gain (P < 0.001), slaughter weight (P < 0.001), carcass weight (P < 0.01) and GR fat (total tissue depth at 12 rib, 110 mm from midline) (P < 0.001) than did lambs grazing AP, AP+FS or AP+FM. Lambs receiving AP+FS and AP+FM grew significantly faster (P < 0.001) than lambs receiving AP. It is likely that lambs grazing the perennial pasture were actively selecting the green portion of lucerne that had higher herbage NV than that indicated by the conventional feed analysis. Results show that lambs grazing a lucerne-dominant perennial pasture performed better than did lambs grazing annual pasture with supplements during the finishing period. Further work is required to determine the efficacy of other perennial species to enable economic finishing of lambs during summer and early autumn.
28
Bowdler, T. M., N. D. Casey, R. J. Moss e K. F. Lowe. "Performance of temperate perennial pastures in the Australian subtropics 2. Milk production". Australian Journal of Experimental Agriculture 39, n. 6 (1999): 677. http://dx.doi.org/10.1071/ea98022.
Testo completoAbstract (sommario):
Summary. Milk production from irrigated, pure stands of perennial ryegrass (Lolium perenne cv. Yatsyn), prairie grass (Bromus willdenodii cv. Matua) and tall fescue (Festuca arundinacea cv. AU Triumph) were compared with that achieved from Italian ryegrass (L. multiflorum cv. Concord) over 3 lactations of multiparous Holstein–Friesian cows at Mutdapilly in south-east Queensland. Pastures were fertilised with 50 kg nitrogen/ha . month as urea and annual dressings of 20 kg phosphorus/ha and 50 kg potassium/ha (as superphosphate and muriate of potash respectively). There were 4 pasture treatments grazed at 3 cows/ha in a 1-week-on, 3-weeks-off rotation with 2 replicates and 3 cows/treatment block. Cows grazed the pastures day and night from May to November. Over summer, cows grazed the pastures during the night and were fed supplements (silage in the first lactation, and lucerne hay in the second and third lactations) during the day because there was no shade available in the irrigation areas. In autumn, the animals were removed from the ryegrass and prairie grass pastures for 8 weeks to allow seedling re-establishment, either by oversowing (ryegrasses) or natural reseeding (prairie grass). Cows continued to graze the fescue pastures at night during autumn. All cows received a ration of 4 kg/cow of a grain–minerals mixture in the first lactation and 5 kg/cow in the second and third lactations. Milk production from perennial ryegrass was higher than from fescue in the first lactation and Italian ryegrass in the second and third lactations. Prairie grass gave similar milk production to perennial ryegrass in all 3 years. In the third year, perennial ryegrass, prairie grass and fescue gave similar milk production. Milk quality from the 4 grasses was similar except in the third lactation when the lactose content of milk from perennial ryegrass pastures was lowest. There were also small and inconsistent differences in milk component yields between the 4 grasses. Liveweight changes were small except in the second lactation when the cows grazing fescue lost weight relative to the other treatments. Mean liveweight at calving increased over the 3 lactations. It was concluded that all 3 temperate perennial grasses demonstrated useful traits for use in subtropical dairy pastures. Perennial ryegrass produced the most milk from the lowest amount of dry matter on offer. Prairie grass produced similar milk yields to perennial ryegrass, was well eaten by cattle and was self regenerating. Although fescue was slower to establish and needed more intensive management to control maturity, it was the most persistent and was the only grass to provide autumn grazing. In the second year this attribute resulted in a lower requirement for supplementary feeding. Fescue produced the highest gross margin in the second lactation and was only marginally less than prairie grass in the third. The performance of Italian ryegrass was as good as that of perennial ryegrass in the first lactation but fell substantially in the second and third lactations as the level of summer grass invasion increased.
29
Michalk, D. L., P. M. Dowling, D. R. Kemp, W. McG King, I. J. Packer, P. J. Holst, R. E. Jones et al. "Sustainable grazing systems for the Central Tablelands, New South Wales". Australian Journal of Experimental Agriculture 43, n. 8 (2003): 861. http://dx.doi.org/10.1071/ea02180.
Testo completoAbstract (sommario):
Pasture degradation is a major issue in the high rainfall zone (>600 mm) of temperate Australia. Characterised by a decline in the perennial grass component, this degradation is responsible for reduced livestock production and implicated in environmental problems, such as dryland salinity, through changed water-use patterns. This paper reports on a multi-disciplinary research program conducted at Carcoar in central New South Wales, one of 6 sites that comprised the Sustainable Grazing Systems National Experiment. The aim of the experiment was to develop more profitable and sustainable pasture systems by evaluating the impact of changes in the perennial grass component on animal production and water-use patterns. Tactical management strategies were evaluated on naturalised and sown perennial grass pastures and on chicory (Cichorium intybus), using a Merino ewe-based first cross lamb enterprise. Data presented showed that grazing deferment over summer, combined with reduced stocking rate, increased perenniality and reduced annual grass weeds compared with continuous grazing. Livestock performance, however, did not always follow trends in available perennial herbage mass. Naturalised and sown pastures were suitable for raising prime lambs, but only chicory had the capacity to finish lambs to market specification without supplementation. With respect to water-use patterns, sown perennial pastures were more successful than naturalised pastures in reducing leakage of water from the root zone, although this seemed to be related mostly to the abundance of the perennial grass in the pasture. From a sustainability perspective, continuously grazed pastures generated higher net cash flows, but had negative environmental impacts, whereas tactically grazed pastures had positive on- and off-farm impacts but lower net cash flows. The implications of these findings for incorporation into future management strategies for sustainable production in high rainfall environments are discussed.
30
Campbell, MH. "Extending the frontiers of aerially sown pastures in temperate Australia: a review". Australian Journal of Experimental Agriculture 32, n. 1 (1992): 137. http://dx.doi.org/10.1071/ea9920137.
Testo completoAbstract (sommario):
Over the past 40 years large areas of pastures on hill country in temperate Australia have been improved through aerial distribution of herbicides, pesticides, seed, and fertiliser, which has increased animal production and helped to control weeds. Refinements detailed in this review could extend the use of these techniques to promote sustainable systems by the establishment of perennial pasture species on unploughed land. It is argued that the most urgent requirement is ensuring that aerial spraying is not abolished by government regulation in response to demands by specialist groups, because perennial pasture species will not establish on hill country without prior aerial spraying of herbicides. The major technical refinement needed is the reduction of losses of establishing plants due to weed competition and dry periods during their first spring and summer. This could be accomplished by increasing the spectrum of weeds controlled by the most widely used herbicide, glyphosate; applying new herbicides that give longer weed control in spring than the presently used herbicides; using herbicides that can selectively remove annual grass weeds from establishing perennial grasses; or using strategic grazing with cattle or goats to reduce weed competition. Breeding, selecting or importing pasture species specifically designed for establishment from surface sowing has never been attempted. Attributes that could improve establishment include germination that occurs only under favourable conditions; seeds resistant to weathering on the soil surface; seedlings with fast radicle entry, hairs on the radicle, fast root development, and better seedling vigour; and for subtropical species sown in semi-arid New South Wales, tolerance of low winter temperatures. Improved distribution of herbicides, seeds and fertilisers, particularly in the more rugged hill country, is needed to ensure complete cover of the treated area with minimum drift. Techniques that allow establishment of aerially sown pastures on hill country with very acid soil are needed to facilitate the development of further, large areas of Australia.
31
Stirling, G. R., e G. M. Lodge. "A survey of Australian temperate pastures in summer and winter rainfall zones: soil nematodes, chemical, and biochemical properties". Soil Research 43, n. 8 (2005): 887. http://dx.doi.org/10.1071/sr05079.
Testo completoAbstract (sommario):
Data for soil nematode numbers, total microbial activity, microbial biomass carbon (C), and various soil chemical properties were collected from permanent and semi-permanent pastures at 108 locations in 2 contrasting environments: a summer rainfall zone in northern New South Wales (n = 60) and a winter rainfall zone in south-east South Australia and western Victoria (n = 48). Nematodes were also categorised according to their feeding habits and reproductive rates, and the abundance of various nematode groups was used to compute 3 indices that indicate the condition of the soil food web [enrichment index (EI), structure index (SI), and channel index (CI)]. At each location, pasture species herbage mass (kg DM/ha) was estimated and locations were grouped according to dominant species (lucerne, subterranean clover and phalaris in both rainfall zones; perennial ryegrass, winter rainfall zone only) as well as total soil microbial activity. The objective of the survey was to obtain a general indication of the biological status of soils used for pasture production in temperate regions of Australia, compare the soil biology in the 2 study areas, and determine whether it was influenced by pasture species composition. The most common plant-parasitic nematode was lesion nematode (Pratylenchus spp.), which was found at 67% of locations in the summer rainfall zone and 29% of those in the winter rainfall zone. Generally, there were more free-living nematodes in the soil than plant-parasitic nematodes. Numbers of free-living nematodes were highest in the winter rainfall zone, while in the summer rainfall zone there were more free-living nematodes in subterranean clover and phalaris pastures than lucerne pastures. Graphical representations of data for EI and SI indicated that the soil food webs at all sites in the summer rainfall zone were either structured or degraded. Food webs in the winter rainfall zone were more variable, with relatively high EI values indicating that more resources were available to support the soil biology. Climate had a major effect on CI values, with the mean in the winter rainfall zone being 28 (indicating a bacterial-dominant detritus food web) compared with 72 (indicating fungal dominance) in the summer rainfall zone. Mean total microbial activity was twice as high (2.6 v. 1.3 µg fluorescein diacetate/g.min) in soils from the winter than the summer rainfall zone. Mean levels of total organic C, total nitrogen, and labile C were also higher for the winter rainfall zone than the summer zone. For both rainfall zones, mean microbial biomass C was 0.09 mg/g soil, labile C was 9.05% of total organic C, and microbial biomass C was 3.5% of labile C. In the summer rainfall zone, values for all measured biochemical properties were lower in lucerne pastures than in other pasture types. We concluded that the biological status of soils in the winter rainfall zone was better than soils in the summer rainfall zone, and that the biology under lucerne pastures in the summer rainfall zone differed from pastures dominated by phalaris and subterranean clover. Soils in both study areas were generally healthy, as they had relatively high levels of total organic C and labile C, high numbers of free-living nematodes, high microbial activities, and a general lack of problems associated with plant-parasitic nematodes. However, there were exceptions, as there was considerable within-site variability for some biological and biochemical parameters at some sites.
32
Widdup, Keith, Jaime Garcia, Juan Amadeo, Roque Guillen e Daniel Real. "White clover cultivars developed for temperate regions of South America". NZGA: Research and Practice Series 12 (1 gennaio 2006): 119–22. http://dx.doi.org/10.33584/rps.12.2006.3023.
Testo completoAbstract (sommario):
White clover is an important forage legume in temperate areas of South America but the common cultivars used are winter-active, profuse flowering types and only persist for 2-3 years due to frequent moisture stress and hot summer conditions. A breeding programme was initiated to develop new types for intensive dairy and extensive cattle grazed pastures. Wide scale screening and crossing of germplasm from international and local sources revealed the potential of Ladino and ladino x local cultivar material for use in intensive pastures with good soils and grazing management. Improved persistence was a major objective for the extensive pastures and ecotype material collected from local farms together with crosses involving ladino and SE USA ecotypes were the best combinations. Experimental selections were developed for the two target environments and evaluated in 'scope' trials at three contrasting sites to determine herbage production and persistence potential. A ladino x local cultivar selection with large leaves, high herbage yields, extended winter to summer growth and ability to persist for at least 3 years was released as the cultivar 'Goliath' for intensive dairy-type pastures. A local ecotype selection with medium leaf size, slower establishment but high stolon density aiding persistence, and high seed yields was released as the cultivar 'Aquiles' for use in extensive pastures
33
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. 1 (2005): 1. http://dx.doi.org/10.1071/rj05004.
Testo completoAbstract (sommario):
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.
34
Vere, D. T., R. E. Jones e P. M. Dowling. "Increasing the economic benefits from agricultural research: the case of enhancing the diffusion of a pasture weed technology". Australian Journal of Experimental Agriculture 44, n. 8 (2004): 779. http://dx.doi.org/10.1071/ea03035.
Testo completoAbstract (sommario):
The process of enhancing the diffusion of a new technology attempts to shorten the time between the completion and adoption of an agricultural research programme, as well as to increase the overall level of adoption. The economic benefits of introducing a new technology are influenced by the technology development lag, the adoption lag and the maximum, or ceiling, level of adoption. Technology diffusion embodies these issues and concerns the uptake of a new technology across a population of potential adopters. Diffusion enhancement is now considered to be a desirable component of pasture research programmes in Australia. This paper evaluates the economic benefits of enhancing the diffusion process for new technology in the management of Vulpia, which is a prominent annual grass weed of Australian temperate pastures. Differences in economic benefits were calculated for a range of scenarios, by varying the values of the main elements of the diffusion process relative to those of a base scenario which represented the most optimistic adoption expectations for the technology. The discounted total benefits to the Australian wool industry, calculated for a 15-year period from reducing Vulpia in temperate pastures, were between A$31.9 million and A$287.3 million, according to differences in the pasture's Vulpia content. While the 2 main time components of the diffusion process both had strong effects on the potential benefits, the technology lag had a much larger influence than the adoption lag. This result emphasises the importance of agricultural research programmes that are able to quickly diffuse such technologies to the potential adopters.
35
Lodge, G. M. "Studies of soil seedbanks in native and sown pastures in northern New South Wales". Rangeland Journal 23, n. 2 (2001): 204. http://dx.doi.org/10.1071/rj01007.
Testo completoAbstract (sommario):
Total and germinable soil seedbanks (litter and soil) were studied for a native pasture and three sown pastures (dominated by Phalaris aquatica L. cv. Sirosa) in northern New South Wales from 1993 to 1996. Soil core samples were taken from continuously grazed plots for both pasture types and two oversown treatments in the native pasture and from a spring-autumn rest treatment at the sown pasture sites. At each site above ground herbage mass was also estimated regularly as part of the Temperate Pasture Sustainability Key Program. For all sites and treatments, the proportion of germinable seeds as a percentage of the total (dormant and germinable) seedbank ranged from 1–26% for the native pasture and 1–39% for the sown pastures. Germinable seed numbers ranged from 280 to 26,110 seeds per m2, while total seedbank numbers were from 6700 to 178,360 seeds per m2. Native pasture herbage mass was dominated by native perennial grasses, but seeds of these species were less than 20% of the total seed bank in all treatments in 1994 and 1995. At the sown pasture sites, most of the germinable (51–92%) and total (65–97%) seedbanks were either barnyard grass (Echinochloa crus-galli (L.) Beauv, annual ryegrass (Lolium rigidum Gaudin), subterranean clover (Trifolium subterraneum L.) or wireweed (Polygonum aviculare L.). Since seeds of annuals and other forbs generally dominated both the total and germinable seedbanks of these perennial grass-based pastures, these species were likely to increase over time. Seeds of the sown perennial grass Phalaris aquatica L, cv. Sirosa were less than 1% of the total seedbanks in pastures sown in 1990 and less than 3% of those sown in 1979. With above average summer rainfall at the native pasture site in 1996 and prolific growth of redgrass, seeds of this species were 38–63% of the total and 11–29% of the germinable seedbank in May 1996. Except at this site and time, the species composition of the total and germinable seedbanks did not generally reflect the dominance of the above ground herbage mass of these pastures by perennial grasses.
36
Ussher, G. R., e D. E. Hume. "Sustainable perennial pastures in Northland". Journal of New Zealand Grasslands 77 (1 gennaio 2015): 141–46. http://dx.doi.org/10.33584/jnzg.2015.77.489.
Testo completoAbstract (sommario):
In the northern half of Northland, perennial ryegrassbased pastures have exhibited poor persistence. Nineteen tall fescue and ryegrass pastures in the region infected with either MaxP or AR37 fungal endophytes, respectively, had high levels of endophyte-infected tillers and low levels of contamination from wild endophytes. On surveyed farms, MaxP-infected tall fescue pastures had good contents of sown grass, which were higher than sown grass contents in AR37-infected ryegrass pastures, but on two far-north monitor farms these temperate grasses failed to compete with summer active C4 grasses such as kikuyu and carpet grass. For tall fescue and perennial ryegrass to form productive pastures in this region, sown seed should have high levels of viable endophyte, soil fertility should be adequate for good grass and legume growth, and pastures should be well managed. Summer droughts may still be too severe in some years for these temperate grasses to persist in the face of C4 grass competition. Keywords: Endophyte, Epichloë, Neotyphodium, Lolium perenne, Festuca arundinacea, soil fertility
37
Skinner, R. Howard, Michael S. Corson e Tagir G. Gilmanov. "Simulating Gross Primary Productivity of Humid-Temperate Pastures". Agronomy Journal 100, n. 3 (maggio 2008): AGJ2AGRONJ20070264. http://dx.doi.org/10.2134/agronj2007.0264.
Testo completo
38
Skinner, Howard. "Winter carbon dioxide fluxes in humid-temperate pastures". Agricultural and Forest Meteorology 144, n. 1-2 (maggio 2007): 32–43. http://dx.doi.org/10.1016/j.agrformet.2007.01.010.
Testo completo
39
Barnes, Phoebe, Brian R. Wilson, Mark G. Trotter, David W. Lamb, Nick Reid, Terry Koen e Leopold Bayerlein. "The patterns of grazed pasture associated with scattered trees across an Australian temperate landscape: an investigation of pasture quantity and quality". Rangeland Journal 33, n. 2 (2011): 121. http://dx.doi.org/10.1071/rj10068.
Testo completoAbstract (sommario):
Scattered paddock trees occur across agricultural landscapes in Australia. However, in the temperate regions of Australia their numbers are rapidly declining and they may be lost across much of the landscape in 200 years. Here we examined the spatial distribution of green (GDB), senescent (SDB) and total (TDB) dry pasture biomass, and nutrient status of the GDB fraction around scattered Eucalyptus trees on three parent materials (basalt, granite and meta-sediment) in native and sown pastures across a range of grazed temperate landscapes in northern New South Wales. We used a combination of destructive harvests and a handheld active optical canopy reflectance sensor (AOS) with an integrated GPS to examine pasture biomass around scattered trees. The harvested pasture biomass data indicated that under grazed conditions the presence of scattered trees did not introduce significant radial trends in TDB or GDB out to a distance of 3.5 canopy radii regardless of tree species or parent material. The red and near-infrared reflectance-based Normalised Difference Vegetation Index (NDVI), as measured by the AOS, did indicate a consistent azimuthal trend with larger GDB on the southern side of the tree and lower GDB on the northern side in the native pasture. However, this observation must be qualified as the regression coefficient for the relationship between NDVI and GDB was significant but weak (best r2 = 0.42), and SDB reduced its predictive capacity. We also found a higher percentage of GDB under the canopy than in the open paddock. We suggest that the combination of these results may indicate higher grazing pressure under trees than in the open paddock. Pasture nutrient concentration (P, K and S) was higher in both native and sown pastures beneath the tree canopy compared with the open paddock. This study indicates that, in this temperate environment, scattered trees do not adversely affect pasture production, and that they can improve some pasture nutrients.
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King, W. McG, P. M. Dowling, D. L. Michalk, D. R. Kemp, G. D. Millar, I. J. Packer, S. M. Priest e J. A. Tarleton. "Sustainable grazing systems for the Central Tablelands of New South Wales. 1. Agronomic implications of vegetation - environment associations within a naturalised temperate perennial grassland". Australian Journal of Experimental Agriculture 46, n. 4 (2006): 439. http://dx.doi.org/10.1071/ea04039.
Testo completoAbstract (sommario):
Temperate perennial grass-based pastures dominate the high rainfall zone of south-eastern Australia and support a major livestock production industry. This area has experienced a recent change in overall pasture condition, however, typified by a reduction in the abundance of perennial grasses and an increasingly prominent winter-annual grass weed component. Improving the condition and productivity of these pastures can be achieved by improved management but this requires better knowledge of the interactions between management options and pasture species composition and of the interaction between pasture vegetation and the complex effects of a heterogeneous landscape. This paper reports the results of an intensive survey of a 60-ha paddock that was designed to identify the species present, determine their patterns of distribution and examine the relationships between pasture vegetation and the environment. The survey of species present in late summer was supplemented by the identification of seedlings that later emerged from extracted soil cores and by soil physical and chemical analyses. Data were analysed using ordination and interpreted with GIS software so that topographic features could be considered. The most frequently identified taxa were Hypochaeris radicata, Austrodanthonia spp. and Bothriochloa spp. (in late summer) and Vulpia spp., Bromus molliformis and Trifolium subterraneum (winter-annual species). Austrodanthonia spp. were commonly found on the drier ridges and more acid soils with lower phosphate levels. These were also the areas dominated in spring by Vulpia spp. and were generally lower in plant species richness overall. The most species-rich areas occurred downslope where soil fertility was higher and less moisture stress was presumably experienced. The measured environmental factors explained a substantial proportion of the variation in the vegetation dataset, which underlined the importance of considering landscape effects in the management of typical tablelands pastures.
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Ates, Serkan. "194 Sustainable Livestock Production from Phytochemically Diversified Pastures". Journal of Animal Science 100, Supplement_3 (21 settembre 2022): 88. http://dx.doi.org/10.1093/jas/skac247.172.
Testo completoAbstract (sommario):
Abstract Agricultural systems must increase productivity while conserving the natural resource base and optimizing ecosystem services to meet the converging challenges posed by a growing human population, increasing costs of production inputs, and widespread environmental degradation. Thus, sustainability concerns justify the needs for readjustment of pasture strategies and redefining the role of forages in livestock production. The function of forages in pasture-based livestock systems needs to be broaden beyond their agronomic and animal nutrition benefits. Specifically, the potential of bioactive compounds found in forb species in reducing greenhouse gas (GHG) emissions, boosting animal immune system, increasing the biochemical richness of animal products and ecosystem benefits should be considered in designing pasture systems. It is key to take full advantage of the benefits provided by the biochemicals present in diverse arrays of forages, as they can contribute to the enhancement of feed efficiency and animal health at relatively low costs to the producer. The use of phytochemically diverse pastures that include legumes and forbs with high nutritive quality together with the presence of beneficial plant secondary compounds can improve the antioxidant capacity and the immune function of livestock and reduce animal CH4 emissions and nitrate (NO3) leaching from soils. The main tenet of the invited talk will be to provide information on recent research findings on the effects of temperate forb species with high bioactive compounds on animal production, health and GHG emissions. Furthermore, how these forages can be successfully incorporated in pasture systems and animal feeding programs in temperate agro-ecologies will be discussed.
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Bowen, M. K., D. P. Poppi e S. R. McLennan. "Ruminal protein degradability of a range of tropical pastures". Australian Journal of Experimental Agriculture 48, n. 7 (2008): 806. http://dx.doi.org/10.1071/ea07414.
Testo completoAbstract (sommario):
The rumen degradability parameters of the diet selected by two to four oesophageal-fistulated Brahman steers grazing a range of tropical pastures were determined by incubation of extrusa in nylon bags suspended in the rumen of rumen-fistulated (RF) Brahman steers. The effective protein degradability (Edg) was determined by measuring the rate of disappearance of neutral detergent insoluble nitrogen (NDIN) less acid detergent insoluble nitrogen (ADIN) in the incubated extrusa. Six to eight RF steers also grazed each of the pastures along with the oesophageal-fistulated steers, to allow determination of key rumen parameters and rumen particulate matter fractional outflow rates (FOR). The seven pastures studied included: native tropical grass (C4) pasture (major species Heteropogon contortus and Bothriochloa bladhii), studied in the early wet (NPEW), the wet/dry transition (NPT) and the dry (NPD) seasons; introduced tropical grass (C4) pasture (Bothriochloa insculpta), studied in the mid wet season (BB); the introduced tropical legumes (C3), Lablab purpureus (LL) and Clitoria ternatea (BP); and the temperate grass (C3) pasture, ryegrass (Lolium multiflorum, RG). Using the measured particle FOR values in calculations, the Edg estimates were very high for both C4 and C3 species: 0.82–0.91 and 0.95–0.98 g/g crude protein (CP), respectively. Substitution of an assumed FOR (kp = 0.02/h) for the measured values for each pasture type did not markedly affect estimates of Edg. However, C4 tropical grasses had much lower effective rumen degradable protein (ERDP) fractions (23–66 g/kg DM) than the C3 pasture species RG and LL (356 and 243 g/kg DM, respectively). This was associated with a lower potential degradability and degradation rate of organic matter (OM) in sacco, lower in vitro organic matter digestibility (IVOMD) and CP concentrations in the extrusa, and lower ammonia-N and branched-chain fatty acid concentrations in rumen fluid for the tropical grasses. As tropical grass pastures senesced, there was a decline in Edg, the ERDP and rumen undegradable protein (UDP) fractions, the potential degradability and degradation rate of OM and the IVOMD. These results provide useful data for estimating protein supply to cattle grazing tropical pastures.
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Simpson, Richard J., Alan E. Richardson, Shirley N. Nichols e James R. Crush. "Pasture plants and soil fertility management to improve the efficiency of phosphorus fertiliser use in temperate grassland systems". Crop and Pasture Science 65, n. 6 (2014): 556. http://dx.doi.org/10.1071/cp13395.
Testo completoAbstract (sommario):
Phosphorus (P) fertilisers are important for productivity in many grassland systems. Phosphorus is a non-renewable and finite resource, and there are environmental and economic reasons for using P more effectively. We review the P balance of temperate pastures to identify the factors contributing to inefficient use of P fertiliser and discuss ways to improve P-balance efficiency. Immediate gains can be made by ensuring that P fertiliser inputs are managed to ensure that the plant-available P concentrations of soil do not exceed the minimum concentration associated with maximum pasture production. Unnecessarily high soil P concentrations are associated with greater potential for P loss to the wider environment, and with higher rates of P accumulation in soils that have a high P-sorption capacity. Soil microorganisms already play a crucial role in P cycling and its availability for pasture growth, but are not amenable to management. Consequently, plants with lower critical P requirements, particularly because of better root foraging, will be an important avenue for improving the P-balance efficiency of fertilised pastures. Traits such as long fine roots, branching, root hairs, and mycorrhizal associations all contribute to improved root foraging by pasture plants; some of these traits are amenable to breeding. However, progress in breeding for improved P efficiency in pasture plants has been minimal. It is likely that traditional plant breeding, augmented by marker-assisted selection and interspecific hybridisation, will be necessary for progress. There are practical limits to the gains that can be made by root foraging alone; therefore, plants that can ‘mine’ sparingly available P in soils by producing organic anions and phosphatases are also needed, as are innovations in fertiliser technology.
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Lowe, K. F., T. M. Bowdler, N. D. Casey e R. J. Moss. "Performance of temperate perennial pastures in the Australian subtropics 1. Yield, persistence and pasture quality". Australian Journal of Experimental Agriculture 39, n. 6 (1999): 663. http://dx.doi.org/10.1071/ea98021.
Testo completoAbstract (sommario):
Summary. Irrigated, pure stands of perennial ryegrass (Lolium perenne cv. Yatsyn), prairie grass (Bromus willdenodii cv. Matua) and tall fescue (Festuca arundinacea cv. AU Triumph) were compared with Italian ryegrass (L. multiflorum cv. Concord) under grazing in the subtropics of south-east Queensland. Pastures were fertilised with 50 kg nitrogen/ha . month as urea and annual dressings of 20 kg phosphorus/ha and 50 kg potassium/ha (as superphosphate and muriate of potash, respectively). There were 4 pasture treatments grazed by multiparous Holstein-Friesian cows at 3 cows/ha in a 1-week-on, 3-weeks-off rotation with 2 replicates and 3 cows/treatment block. Feed on offer was measured weekly and pasture quality, at the mid point of each of the 4 seasons. Detailed measurements on plant and tiller dynamics were recorded on fixed quadrats within the grazing areas from November to May in the second and third years. Yield of pasture on offer was greatest with prairie grass and the difference was most marked in spring and early summer. Yield of fescue was generally higher than that from the other 3 grasses in the autumn. In the second and third summers, the grass weed component in the 2 ryegrass, and to a lesser extent the prairie grass, pastures was greater than the sown grass component. Fescue generally produced forage lower in quality than the other 3 grasses although the differences were small in summer. The forage quality of Italian ryegrass was higher than perennial ryegrass in most seasons and for most attributes measured. Generally prairie grass had similar quality forage to the ryegrasses but at times it was as low as fescue. Fescue was the most persistent grass; it maintained a frequency of occurrence of 88, 56 and 71% in the first, second and third autumn periods, respectively, compared with 36, 37 and 21% for perennial ryegrass. To achieve these persistence figures, perennial ryegrass needed over-sowing in each autumn. Plant density and tiller numbers per plant fell in all grasses from November to May but the fall was significantly less in fescue than in other grasses. It was concluded that all 3 temperate perennial grasses demonstrated traits which were useful for subtropical dairy pastures. Fescue was the most persistent and the only grass which could sustain grazing in autumn. The performance of Italian ryegrass was as good as that of perennial ryegrass in the first year but fell substantially in the second and third years as the level of summer grass invasion suppressed the existing population and made oversowing increasingly less effective. Prairie grass produced the highest dry matter on offer under grazing, its forage quality was generally similar to that of the ryegrasses and it regenerated from self-sown seed.
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Yates, Michelle L., Heloise Gibb e Nigel R. Andrew. "Habitat characteristics may override climatic influences on ant assemblage composition: a study using a 300-km climatic gradient". Australian Journal of Zoology 59, n. 5 (2011): 332. http://dx.doi.org/10.1071/zo11096.
Testo completoAbstract (sommario):
We assessed the relative importance of a variety of climatic and habitat variables in structuring ant communities along a 300-km climatic gradient. Sampling was conducted in semiarid, transitional and cool temperate climatic zones in New South wales, Australia. Ants were sampled at three paired sites of two habitats (pastures and conservation ‘remnants’) in each of the climatic zones (herein referred to as ‘zones’) using pitfall traps. Remnants represented original open forests, while pastures were a mix of grassland vegetation and cleared woodland. We tested the effects of habitat type, region (representing different climatic zones) and environmental variables on assemblages using distance-based similarity measures (Permanova and Permdisp) and canonical analysis of principal coordinates. Assemblage composition differed between habitats and zones, but we found no interaction effects. Assemblage dispersion (between-site heterogeneity) differed between habitats but not among zones. Pasture habitats supported more homogeneous assemblages than remnant habitats. Our findings suggest that habitat type, and structure, homogenise assemblages in pastures, thus overriding the effects of local climate apparent in remnants. As remnants are isolated within the biologically homogeneous pastures, movement of unique species between remnants in response to climate changes may be limited, thus landscape connectivity is likely to be important in reducing species loss.
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Miguel, M. F., R. Delagarde e H. M. N. Ribeiro-Filho. "Corn silage supplementation for dairy cows grazing annual ryegrass at two pasture allowances". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 71, n. 3 (giugno 2019): 1037–46. http://dx.doi.org/10.1590/1678-4162-9795.
Testo completoAbstract (sommario):
ABSTRACT Corn silage supplementation for dairy cows grazing in temperate annual pastures has rarely been investigated. The aim of this study is to compare two supplementation levels (0 and 4kg dry matter [DM]/day of a 7:1 mixture of corn silage and soybean meal) in dairy cows strip-grazing annual ryegrass (Lolium multiflorum Lam.) at two pasture allowances (PA, low= 25 and high = 40kg DM/d at ground level). The study was carried out according to an incomplete 4 × 3 Latin square design, using 12 cows and three experimental periods of 12 days. The green leaves allowances were only 4.9 and 8.5kg DM/d at the low and high PA, respectively. The total DM intake and milk production increased in supplemented cows compared to un-supplemented cows at the low PA, but were similar between supplementation levels at the high PA. The PI was unaffected by the PA, whereas the substitution rate was 0.68 in cows at the low PA and 1.35 in cows at the high PA. Corn silage supplementation may improve the total DM intake and milk production of dairy cows grazing in temperate annual pastures, but only at a low PA.
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Ayres, J. F., R. W. Dicker, M. J. McPhee, A. D. Turner, R. D. Murison e P. G. Kamphorst. "Post-weaning growth of cattle in northern New South Wales. 1. Grazing value of temperate perennial pasture grazed by cattle". Australian Journal of Experimental Agriculture 41, n. 7 (2001): 959. http://dx.doi.org/10.1071/ea00096.
Testo completoAbstract (sommario):
This paper describes the botanical components, seasonal herbage mass, and nutritive value of pastures used for post-weaning growth of CRC cattle at Glen Innes before their progression to subsequent finishing and meat quality studies. The pastures under study comprised introduced temperate perennial species (tall fescue, Festuca arundinacea; phalaris, Phalaris aquatica; perennial ryegrass, Lolium perenne; cocksfoot,Dactylis glomerata; white clover, Trifolium repens; and red clover, Trifolium pratense) grazed by yearling cattle and managed according to local practice to maintain herbage mass between pre-determined limits. The study took place on 3 adjacent pasture systems (P1, pasture only; P2, pasture plus formulated pellets fed in later winter–early spring; P3, pasture plus forage crop grazed in later winter–early spring) over the 3 years 1994–96 that included a severe 20-month drought event followed by a drought-recovery phase. Results are discussed in the context of the pasture feed year which was shown to comprise 3 distinct phases: (i) spring primary growth phase, high availability of green herbage mass (2500–4500 kg DM/ha) of very high digestibility (0.80–0.85) and very high N status (about 30 g N/kg DM); (ii) summer–autumn secondary regrowth, high availability of green herbage mass (2500–4000 kg DM/ha) but with only moderate nutritive value (0.65–0.70 digestibility, 15–20 g N/kg DM); and (iii) winter dormancy, low availability of green herbage mass (750–1500 kg DM/ha) but with high nutritive value (0.75–0.80 digestibility, 20–30 g N/kg DM). It was concluded that the limitations of the feed year for yearling cattle in this environment include a feed gap in winter–early spring due to low herbage mass associated with winter cold and a feed gap in summer–autumn associated with moderate nutritive value of secondary regrowth pasture.
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Descalzi, Constanza A., Ignacio F. López, Peter D. Kemp, José Dörner e Iván Ordóñez. "Pasture restoration improvement methods for temperate degraded pastures and consequences of the climatic seasonality on soil–pasture complex". Journal of Agronomy and Crop Science 206, n. 1 (8 ottobre 2019): 130–47. http://dx.doi.org/10.1111/jac.12368.
Testo completo
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Vickery, P. J., M. J. Hill e G. E. Donald. "Satellite derived maps of pasture growth status: association of classification with botanical composition". Australian Journal of Experimental Agriculture 37, n. 5 (1997): 547. http://dx.doi.org/10.1071/ea97014.
Testo completoAbstract (sommario):
Summary. Spectral data from the green, red and near-infrared bands of Landsat MSS and Landsat TM satellite imagery acquired in mid-spring were classified into 3 and 6 pasture growth classes respectively. The classifications were compared with a site database of botanical composition for the Northern Tablelands of New South Wales to examine the association between spectral growth class and pasture composition. Pastures ranged in composition from unimproved native perennial grasses through semi-improved mixtures of native and naturalised grasses and legumes to highly improved temperate perennial grasses and legumes. For 3 years of MSS data, the fast growth class had a mean botanical composition of about 80% improved perennial grass and 0% native; medium growth class averaged 46% improved perennial grass and 14% native; while the slow growth class had about 60% native and 1% improved perennial grass when averaged over 3 years of MSS data. For the 6 class TM data from a single year, a predictive logistic regression of cumulative probability was developed for percentage of ‘very fast’ growth pixels and ordered 10 percentile categories of improved perennial grass or native grass. Differences in patch characteristics between classes with MSS disappeared with TM reclassified to the same 3 class level. Most probable pasture type was inferred from 3 class MSS and TM data using Bayesian probability analysis. The resulting maps were similar in general appearance but detail was better with the TM data. The pasture growth classification identified highly improved perennial grass pastures and native pastures but sensitivity to intermediate pasture types was poor. Future improvement will come from direct measurement of biophysical characteristics using vegetation indices or inversion of reflectance models.
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Johnston, W. H. "The place of C4grasses in temperate pastures in Australia". New Zealand Journal of Agricultural Research 39, n. 4 (dicembre 1996): 527–40. http://dx.doi.org/10.1080/00288233.1996.9513213.
Testo completo