Siga este link para ver outros tipos de publicações sobre o tema: Victorian pastures.
Artigos de revistas sobre o tema "Victorian pastures"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores artigos de revistas para estudos sobre o assunto "Victorian pastures".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja os artigos de revistas das mais diversas áreas científicas e compile uma bibliografia correta.
1
Robertson, S. M. "Mass to height relationships in annual pastures and prediction of sheep growth rates". Animal Production Science 54, n.º 9 (2014): 1305. http://dx.doi.org/10.1071/an14072.
Texto completo da fonteResumo:
The relationship between pasture height and mass influences the availability of pasture for grazing, and is important for predicting intake of pasture and liveweight change by sheep. The relationship between pasture mass and structure and sheep production is poorly defined for low-mass, clumpy pastures in low-rainfall regions. Between 2001 and 2004, 480 quadrats of pastures were measured in 23 paddocks throughout the Victorian Mallee. Pasture height was related to live mass for medic (linear; r2 = 0.70; P < 0.001) and grassy medic (asymptotic; r2 = 0.64; P < 0.001) pastures, and prediction of grassy medic pasture height was improved by inclusion of proportion live groundcover. During 2004, pasture dry matter accumulation and liveweight changes in sheep grazing annual pastures were measured and compared with predicted outputs from GrazFeed, a software model used to estimate feed intake and liveweight change in sheep. Improved predictions of liveweight gain in grazing sheep were obtained using measured height rather than the GrazFeed default height. The results show that the height to mass relationship of annual pastures in the Victorian Mallee differs between pasture types, between years, and may differ from other published relationships. This study provides information that may assist in the development of models of grazing systems.
2
Crawford, DM, TG Baker e J. Maheswaran. "Soil pH changes under Victorian pastures". Soil Research 32, n.º 1 (1994): 105. http://dx.doi.org/10.1071/sr9940105.
Texto completo da fonteResumo:
The severity and extent of surface soil acidification was assessed at 107 pasture sites across Victoria. At each site, soil samples (0.20 cm depth) were taken from the pasture area and an adjacent reference (undisturbed) area for analysis of soil pH (1:5 0.01 m CaCl2 or water). Acidification was evident in the 0.10 cm depth of sites with moderately and slightly acid (pH [water] 5.5-7) reference soils, while alkalinization was evident in the 0.20 cm depth of sites with strongly acid (pH [water] <5.5) reference soils. Causes of pH changes were not clearly evident from the relationships between site factors and changes in soil. It was evident that site factors were confounded since sites that had acidified often supported subterranean clover and had slightly to moderately acid reference soils, while sites which had alkalinized often supported white clover-based pastures under higher rainfall and had more acidic reference soils. An understanding of the causes of acidification in pasture-based agricultural ecosystems will only be gained through more fundamental studies at individual sites.
3
Reed, K. F. M., J. R. Walsh, P. A. Cross, N. M. McFarlane e M. A. Sprague. "Ryegrass endophyte (Neotyphodium lolii) alkaloids and mineral concentrations in perennial ryegrass (Lolium perenne) from southwest Victorian pasture". Australian Journal of Experimental Agriculture 44, n.º 12 (2004): 1185. http://dx.doi.org/10.1071/ea03242.
Texto completo da fonteResumo:
On all of 120 farms in south-west Victoria that were selected at random and sampled during autumn and winter over 2 years, perennial ryegrass was present in the pasture and tested positive for the presence of the naturally occurring ryegrass endophyte, Neotyphodium lolii (mean frequency 78%). Ryegrass staggers were reported on 33% (1999) and 43% (2000) of the surveyed farms. Clinically significant concentrations of lolitrem B were detected in perennial ryegrass samples with concentrations in the range 0–4.44 mg/kg. Concentration exceeded 1.8 mg/kg in 37% of pastures indicating an inherent, widespread problem for livestock farmers. Concentration was independent of endophyte frequency, pasture age, pasture height, annual rainfall and origin of sown cultivar. Ergovaline was detected in most of the perennial ryegrass samples with concentrations up to 3.90 mg/kg. In 1999, the mean concentration of ergovaline was 0.76 (± 0.70) mg/kg with 33% of pastures having a level >0.4 mg/kg, the level associated with heat stress in cattle. In 2000, sampling was carried out later in the year than for the 1999 survey and the mean concentration of ergovaline was 0.12 (± 0.10) mg/kg; 3% of samples exceeded 0.4 mg/kg. The mean concentration of peramine was 13.7 (± 6.6) mg/kg in the 1999 survey and 4.2 (± 5.1) mg/kg in the 2000 survey. Mineral analysis indicated that perennial ryegrass nutrition was inadequate with regard to phosphorous on 17% of the dairy pastures and on 37% of the sheep/beef pastures. Potassium was deficient in perennial ryegrass on 5 and 37% of dairy and sheep/beef pastures respectively. For perennial ryegrass in sheep/beef pastures, 25% were deficient in sulphur. For lactating cattle having only perennial ryegrass as a food source, phosphorous and copper concentrations in the grass were inadequate on 80% of the pastures. Calcium, zinc, magnesium, potassium and sulphur concentrations in perennial ryegrass were also inadequate on some pastures. However, with 1 exception, the ratio [K/(Ca+Mg) expressed as equivalents] was less than 2.2, the level associated with the development of hypomagnesemia. Hypomagnesemia (grass tetany) was therefore unlikely to be a major cause of the staggers syndrome. Lolitrem B was negatively correlated with grass potassium concentration (P<0.001). Ergovaline was negatively correlated with date of sampling (P<0.001). Peramine concentration was positively correlated with endophyte frequency, the potassium and sodium concentrations in perennial ryegrass and negatively correlated with date of sampling. The need for research on the economic impact and management of pasture contaminated with ryegrass endophyte toxins is discussed.
4
Trompf, J. P., e P. W. G. Sale. "The paired-paddock model as an agent for change on grazing properties across south-east Australia". Australian Journal of Experimental Agriculture 40, n.º 4 (2000): 547. http://dx.doi.org/10.1071/ea00046.
Texto completo da fonteResumo:
A detailed study was undertaken on the pasture management practices of 146 producers across south-east Australia who participated in the Grassland’s Productivity Program (GPP) for 3 years between 1993 and 1997. The GPP was an extension program to assist wool producers to develop skills and gain confidence in their ability to manage more productive pastures on their farms. The program consisted of 50 farmer groups (200 farmers participating) spread across the 4 states of South Australia, southern New South Wales, Victoria and Tasmania. Each farmer established paired-paddocks on their own property to compare productive pastures with existing pastures. Productive pastures involve increased rates of fertiliser on pastures containing productive species, with stocking rate adjusted to consume available pasture. After 3 years of involvement in the GPP, there was a whole-farm increase in P fertiliser use by 6.3 kg P/ha, stocking rates by 2.6 dse/ha and annual pasture resowing by 0.9% of the farm, when averaged across the 146 participants. The participants were applying the productive pasture technology to almost a third of their properties in 1997 and the intention was to increase this to over half of their properties by 2000. The participants also changed farm management practices as the program effectively developed management skills. There were increases in the ability to assess pasture quality and quantity, livestock by weighing or physical assessment, and the ability to calculate per hectare production and per hectare gross margins. A high proportion of GPP participants were soil testing (0.92) and spring lambing (0.72) at the completion of the program. The results indicated that the adoption of productive pastures was generally consistent across south-east Australia for pastoral producers who participated in this program, although south-west Victorian and south-east South Australian GPP participants did increase whole-farm P application by more than GPP participants from outside that region. The widespread change in farming practice was attributed to the additive and interactive effect of the paired-paddock comparison, the guidance provided by the facilitator, the group interaction and the skills training. Each of these components of the paired-paddock model combined to form an effective agent for change to increase pasture productivity on these grazing properties.
5
Harris, R. H., M. J. Unkovich e J. Humphris. "Mineral nitrogen supply from pastures to cereals in three northern Victorian environments". Australian Journal of Experimental Agriculture 46, n.º 1 (2006): 59. http://dx.doi.org/10.1071/ea04177.
Texto completo da fonteResumo:
An experiment at 3 sites (Birchip, Elmore and Speed) in the northern Victorian cropping belt compared dry matter (DM) production of short-term (2 year) pastures and their contributions to soil mineral nitrogen (N) and subsequent wheat and barley production. The pastures included different varieties of subterranean clover, annual medic and lucerne, and these were compared with ryegrass-dominant pasture, which represented the experimental control. More productive legume pastures generally resulted in greater accumulation of soil mineral N at sowing of the following cereal at both Elmore and Speed; however, at Birchip, soil mineral N remained high under all treatments. At Elmore and Speed, significant (P<0.10) positive relationships were observed between available N at sowing and subsequent wheat and barley production. Cereal grain yield at Birchip was not associated with available N at sowing. The quantities of soil mineral N available at sowing (152 kg/ha) of the cereals were in excess of crop demand at Birchip. At Elmore, the soil mineral N supply (83 kg/ha) was below that required for wheat and barley to reach their water-limited potential yield (20 kg grain/mm of growing season rainfall). However, at Speed, the supply of soil mineral N (63 kg/ha) was sufficient to achieve the water-limited potential grain yield and to produce malting-grade barley, but not sufficient to elevate wheat grain protein concentrations above 11.5%. In environments with low soil N levels, the amount of residual N following short-term pastures increased the availability of N to following cereals. Whether this is sufficient to satisfy subsequent crop demand is largely determined by water availability in the year of cropping. In cases where available N is already high, short-term pasture phases may have little effect on increasing crop production.
6
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.º 8 (2006): 1005. http://dx.doi.org/10.1071/ea04034.
Texto completo da fonteResumo:
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.
7
Elliott, D. E., e R. J. Abbott. "Nitrogen fertiliser use on rain-fed pasture in the Mt Lofty Ranges, SouthAustralia. 2. Responses of perennial grasses, Tama ryegrass, andsod-sown oats to nitrogen fertiliser and cutting frequency". Australian Journal of Experimental Agriculture 43, n.º 6 (2003): 579. http://dx.doi.org/10.1071/ea01132.
Texto completo da fonteResumo:
Two series of experiments were conducted in the Mt Lofty Ranges, South Australia, to examine, in a grass–subterranean clover pasture, the contribution of the companion grass to herbage mass and the responsiveness to the application of nitrogen (N) fertiliser. The first study examined the responsiveness, to a single rate of N, of grass–clover pastures containing either Tama ryegrass, sod-sown oats or 1 of 4 perennial grasses, viz. Victorian perennial ryegrass, Demeter fescue, Currie cocksfoot or Australian phalaris. These were compared in 2 experiments, under 3��different cutting frequencies at 3 periods during the growing season. In the other study, consisting of 12�experiments, the response to increasing rate of N fertiliser application of sod-sown oats or the existing pasture were compared over a 3-month period following N fertiliser application in autumn.In autumn and winter, all pastures responded significantly to N fertiliser, whereas in spring, the proportion of clover in each pasture and its growth determined whether or not there was a response to N fertiliser. Clover composition of pastures declined with N application, but clover was not eliminated from swards by application of 210 kg N/ha a year. In both series of experiments, pastures that established well with a high density of sod-sown oats out-yielded all other pastures in autumn and winter, whether the swards were unfertilised or received regular N fertiliser applications. In late winter, pastures sod-sown with Tama ryegrass yielded as well as the pasture sod-sown with oats, and enhanced spring growth significantly compared with perennial ryegrass. However, spring production of Tama ryegrass was poorer than that of perennial ryegrass, and overall no increase in annual production occurred. Of the perennial grasses, the highest yielding when N fertiliser was applied were Currie cocksfoot and perennial ryegrass (yielding in autumn), phalaris (winter), and perennial ryegrass and Demeter fescue (spring). Increased cutting frequency depressed the herbage mass response to N fertiliser following the initial application, but increased herbage N concentration of all pastures and also increased the final clover composition of N-fertilised pasture of 4�pasture types.
8
Reed, K. F. M., W. J. Mace, L. V. Walker e L. R. Fletcher. "Endophyte metabolites associated with perennial ryegrass toxicosis". Animal Production Science 56, n.º 5 (2016): 895. http://dx.doi.org/10.1071/an14495.
Texto completo da fonteResumo:
Perennial ryegrass (PRG) was analysed for alkaloids associated with the expression of perennial ryegrass endophyte toxicosis (PRGT) in south-east Australia. Over two seasons, the PRG cultivar Samson (‘high endophyte’, viz. naturally infected with a wild-type strain of Epichloë festucae var. lolii) was sampled on five occasions during November to May at four farms in Victoria and at Lincoln, New Zealand. Endophyte frequency in the populations was 77–100%. PRG was also sampled from 20 Victorian and Tasmanian farm pastures where stock were experiencing PRGT (endophyte infection frequencies of 87–100%). The Victorian summer of 2010–11 was atypically moist; pasture remained green. Lolitrem B was consistently high at Lincoln and 2–3 times that observed in Victorian samples of isogenetic PRG, or in PRG causing PRGT; it was the dominant toxin in 2011 with concentrations commonly exceeding the tolerance level of 1.8 mg/kg. In the following year, one with a more typical summer, ergovaline was the dominant toxin. Liquid Chromatography–Mass Spectrometry/Mass Spectrometry (LC-MS/MS) was carried out to determine indole diterpene intermediates in the lolitrem B biosynthesis pathway and for ergot alkaloid intermediates in the ergovaline pathway. The values for lolitrem B determined by LC-MS/MS correlated strongly with those obtained using high pressure liquid chromatography. In both Years 1 and 2, significantly higher expression was observed in the Lincoln relative to Victorian samples of PRG for paspaline, terpendole C, lolitrem E, lolitrem B and lolitrem F. For the ergot alkaloids, significant differences were not apparent between Victorian and Lincoln samples in Year 1. In Year 2, LC-MS/MS results showed ergovaline concentrations were greater in Victorian samples. In addition to endophyte-produced toxins, ergot alkaloids produced by Claviceps purpurea (ergotamine, ergocryptine and ergocornine) were detected in grass samples on 6/27 occasions. Some unidentified metabolites were noted in both Victorian and Lincoln samples. The effects of ingested vaso-constrictive ergot alkaloids combined with that of high solar radiation on ruminants’ heat load are considered most important with respect to the occasionally severe expression of PRGT in Australia.
9
Gardner, WK, RG Fawcett, GR Steed, JE Pratley, DM Whitfield, Hvan Rees e Rees H. Van. "Crop production on duplex soils in south-eastern Australia". Australian Journal of Experimental Agriculture 32, n.º 7 (1992): 915. http://dx.doi.org/10.1071/ea9920915.
Texto completo da fonteResumo:
The environment, duplex soil types and trends in crop production in South Australia, southern New South Wales, north-eastern and north-central Victoria, the southern Wimmera and the Victorian Western District are reviewed. In the latter 2 regions, pastoral industries dominate and crop production is curtailed by regular and severe soil waterlogging, except for limited areas of lower rainfall. Subsurface drainage can eliminate waterlogging, but is feasible only for the Western District where subsoils are sufficiently stable. The other regions all have a long history of soil degradation due to cropping practices, but these effects can now be minimised with the use of direct drilling and stubble retention cropping methods. A vigorous pasture ley phase is still considered necessary to maintain nitrogen levels and to restore soil structure to adequate levels for sustainable farming. Future productivity improvements will require increased root growth in the subsoils. Deep ripping, 'slotting' of gypsum, and crop species capable of opening up subsoils are techniques which may hold promise in this regard. The inclusion of lucerne, a perennial species, in annual pastures and intercropping at intervals is a technique being pioneered in north-central and western Victoria and may provide the best opportunity to crop duplex soils successfully without associated land degradation.
10
Lorimer, MS, e LA Douglas. "Effect of management practice on properties of a Victorian red-brown earth .1. Soil physical-properties". Soil Research 33, n.º 5 (1995): 851. http://dx.doi.org/10.1071/sr9950851.
Texto completo da fonteResumo:
The effects of five management practices (native forest, native pasture, Phalaris pasture, crop-pasture rotation, continuous cropping), that had been in place for 18 years, on some soil physical properties of a red-brown earth near Bendigo, Victoria, were studied. Particle size distribution, bulk density and hydraulic conductivity of soil in the A and B horizons at different, management sites were measured. Where cultivation had occurred, soil in the A horizon contained less silt and clay, and more fine sand and coarse sand. The bulk density of the A horizon of soil that had produced at least six wheat crops since 1969 was greater than that of soil used for pasture or forest, while the hydraulic conductivity of soil cropped every year since 1969 was much less than that of soil under native forest. Particle size distributions for soil from the B horizons at the five management sites were found to be similar. Where pastures and crops had been established, the hydraulic conductivity of the upper B horizon was lower, and the bulk density was higher, than that of soil in the native forest (Eucalyptus spp).
11
Robertson, S. M., e R. K. Wimalasuriya. "Limitations to pasture and sheep enterprises and options for improvement in the Victorian Mallee". Australian Journal of Experimental Agriculture 44, n.º 9 (2004): 841. http://dx.doi.org/10.1071/ea03030.
Texto completo da fonteResumo:
A survey of 29 sheep producers was conducted to benchmark current sheep production practices and producer attitudes to sheep and pasture management in the Victorian Mallee. This report describes the farming systems, defines current sheep management practices and identifies management issues that are limiting production. It also highlights limitations of adoption, suggests potential adoption rates of specific practices by producers, and estimates increases in productivity achievable. Sheep producers could achieve small gains in farm productivity (an estimated average 0.3% annually) by adopting sheep management practices including using superior genetics, reducing ram numbers and introducing supplementary feeding. Possible reasons why recommended practices have not been adopted are discussed. The difficulty of integrating sheep into current short cropping systems was considered to be a key limitation to the adoption of management that could substantially increase productivity, such as higher stocking rates and winter–spring lambing. Important benefits to both productivity and environmental sustainability may be achieved through the replacement of fallowed land with improved pastures. However, a lack of data on the feed base and sheep production in relation to a changing feed base made it impossible to estimate the size of these benefits. It was concluded that further research is needed to collect data and benchmark pasture and livestock enterprises to allow quantification of the potential impact on farm profit of changes to pasture and sheep management in this region.
12
Latta, RA, e PE Quigley. "A comparison of the persistence of Medicago truncatula cv. Paraggio with other annual medics in the Victorian Mallee". Australian Journal of Experimental Agriculture 33, n.º 4 (1993): 443. http://dx.doi.org/10.1071/ea9930443.
Texto completo da fonteResumo:
The annual medic Medicago truncatula cv. Paraggio has been widely sown in pastures throughout the Victorian Mallee region; however, its ability to persist in cereal pasture rotations is not known. Seed permeability and production, and plant regeneration of Paraggio, were studied in the field over 4 years, and the changes in its seed reserve were examined under 3 different cereal-pasture rotations. When compared with medic cvv. Parabinga, Harbinger, and Jemalong, Paraggio had up to twice the level of permeable seed over the summer-autumn period in 2 years (7-36% v. 2.5-19%). Paraggio produced 336-928 kg/ha of seed over 3 years, and after seed production was halted, it regenerated at densities of 150-1438 plants/m2 over the next 4 years. These results were generally the same as, or better than, the other cultivars. When seed set occurred in 1 and 2 years in the pasture phase of a 2- and 3-year rotation, respectively, Paraggio seed reserves were maintained at >4000 seeds/m2. This study demonstrated that Paraggio resulted in superior plant densities when grown in a number of typical rotations. It persisted satisfactorily and is expected to improve agricultural productivity in shor-tterm cereal-pasture rotations.
13
McCallum, M. H., M. B. Peoples e D. J. Connor. "Contributions of nitrogen by field pea (Pisum sativum L.) in a continuous cropping sequence compared with a lucerne (Medicago sativa L.)-based pasture ley in the Victorian Wimmera". Australian Journal of Agricultural Research 51, n.º 1 (2000): 13. http://dx.doi.org/10.1071/ar99023.
Texto completo da fonteResumo:
The nitrogen (N) dynamics (N2 fixation inputs, changes in soil mineral N and total N, N removed in agricultural produce) of a lucerne-based phase farming system (grazed lucerne–annual medic–ryegrass pastures grown in rotation with crops) was compared with that of continuous cropping (cereal, oilseed, and legume pulse crops) in the Victorian Wimmera. The contribution of biological N2 fixation to the N economy of these different systems was strongly linked to biomass production by the legume components of pastures, or field pea in the cropping sequence. The amount of fixed N present in field pea shoots or the total amount of N2 estimated to be fixed by the whole plant (shoots and roots) (121–175 kg N/ha.crop and 181–262 kg N/ha.crop, respectively) was generally greater than the combined measured annual inputs of fixed N by lucerne and annual medic during a pasture ley (40–95 kg N/ha.year in herbage, 80–190 kg N/ha.year in total plant), although large amounts of N were removed in the field pea grain at harvest (115–151 kg N/ha.crop). Over 2 years (1995–96), the seasonal rainfall patterns had a much larger impact on the growth, dry matter production, and N2 fixation of annual medic compared with lucerne. Winter-cleaning of ryegrass from the pasture before cropping resulted in a greater legume content in the pasture and generally increased amounts of fixed N in herbage (by up to 55 kg N/ha.year). Total soil N at depth (0.5–1.0 m) was significantly greater after 2–4 years of pasture than under continuous cropping. In one year (1996), the amount of soil mineral N following a winter-cleaned pasture was greater (by 32–45 kg N/ha, 0–1 m) than after either canola or wheat, producing a yield benefit in a subsequent canola crop that was equivalent to pre-drilling 46 kg N/ha as fertiliser. However, despite some improvements in N fertility, large crop responses to N fertiliser were still observed following pasture. Grain yield was increased by 0.33–0.55 t/ha in canola and by 1.0 t/ha in wheat, grain protein raised by 0.7–2.3% in canola and by 1.3% in wheat, and oil yield in canola enhanced by 124–205 kg/ha with pre-drilled applications of fertiliser N (46 kg/ha). It is speculated that more legume-dominant pastures (>80%) could provide greater flow-on N benefits to farming systems in the Wimmera than the mixed legume–grass swards used in the present study. However, it is likely that a need will remain for supplementary fertiliser N to optimise the nutrition of subsequent non-legume crops in the region.
14
Bird, PR, MJ Watson e JWD Cayley. "Effect of stocking rate, season and pasture characteristics on liveweight gain of beef steers grazing perennial pastures". Australian Journal of Agricultural Research 40, n.º 6 (1989): 1277. http://dx.doi.org/10.1071/ar9891277.
Texto completo da fonteResumo:
In each of 4 years (1975-78) yearling steers at stocking rates (SR) of 1.1-3.6 steers/ha continuously grazed pastures sown in 1971 with Trifolium subterraneum cv. Mt. Barker, Phalaris aquatica cv. Australian and Lolium perenne cv. Victorian at Hamilton from Mar. to Jan. Data on liveweight gain (LWG), fat depth and pasture attributes were collected over the 4 years. Body composition was estimated periodically over the first 2 years, using tritiated water. Relationships between LWG and SR were established and the overall annual effect was LWG (kg)=237-39.7 SR. However, most or all of the gains made at intermediate or higher SR were achieved in the spring and summer. Compensatory gains in these 5 months were greatest at 3 steers/ha but varied from 6.5 kg (in 1976) to 34 kg (in 1978) more than achieved at the lowest SR. The heaviest steers had more subcutaneous fat and steers at higher SR were leanest, but in 1 year of prolonged spring growth (1978) there was no difference in fat depth at any SR despite a 68 kg difference in liveweight (W) between lowest and highest SR. Seasonal LWG was modelled from W and/or pasture mass (green and dead fractions). Use of green pasture mass rather than total mass substantially improved precision in all seasons. A smaller but significant further improvement was obtained using green mass, dead mass and the interaction in the regressions. Severe penalties to LWG occurred in grazed pastures with a large component of dead material.
15
Crawford, DM, TG Baker e J. Maheswaran. "Changes in soil chemistry associated with changes in soil-pH in Victorian pastures". Soil Research 33, n.º 3 (1995): 491. http://dx.doi.org/10.1071/sr9950491.
Texto completo da fonteResumo:
Relationships between changes in soil pH and changes in other soil chemical properties were examined using data from a survey of 107 pasture sites from across Victoria. At each site, soil samples (0-5, 5-10, 10-15 and 15-20 cm depths) were taken from the pasture and an adjacent undisturbed (reference) area for chemical analysis. Changes in soil chemical properties were inferred from differences between pasture and reference soils. Increases in extractable Al and extractable Mn and decreases in the sum of exchangeable cations were associated with decreases in pH. Changes in soil organic C, total soil N and total soil P were not associated with changes in pH but were related to pasture composition at each site. Increases in total soil P and exchangeable Ca, and decreases in exchangeable Mg were partly attributed to the application of superphosphate. Decreases in electrical conductivity are discussed in relation to vegetation and salinization.
16
Robertson, S. M., e J. G. Smith. "Do some naturalised legumes have the potential to improve pasture production in the Victorian Mallee?" Australian Journal of Experimental Agriculture 46, n.º 5 (2006): 615. http://dx.doi.org/10.1071/ea04262.
Texto completo da fonteResumo:
Some naturalised (not commercialised or deliberately sown) annual pasture legumes may be valuable pasture components, but their production relative to commercial species is poorly defined. This study aimed to determine the relative productivity, morphology, nutritive value, ecotype variation and sulfonylurea tolerance of some naturalised species in the Victorian Mallee. A series of 3 glasshouse and 2 ungrazed field experiments compared the production of haresfoot clover (Trifolium arvense L.), little woolly burr medic (Medicago minima L.), spineless M. minima, and M. monspeliaca (L.) Trautv. with the commercial species strand medic (M. littoralis Loisel cv. Herald) and barrel medic (M. truncatula Gaertn cv. Paraggio). The crude protein and in vitro digestibility of leaf and stem components were similar among species. The proportion of leaf was associated with species maturity, with later maturing species having a greater proportion of leaf at each harvest. There was a range of 52 days among species for date of first flowering. T. arvense produced similar or more biomass than the commercial species in spring, but had lower winter production. A 38-day range in days to first flower and a 2-fold range in winter biomass production among T. arvense ecotypes indicate potential for selection within this species. T. arvense also appears to have greater tolerance of triasulfuron residues than M. littoralis. Spineless M. minima requires further evaluation for persistence in this environment, but the low production of M. monspeliaca limits its value as a component of pastures. T. arvense, spineless and spiny M. minima all have some characteristics which could enhance pasture production in low-rainfall, low-input mixed farming systems.
17
Robertson, S. M. "Crop stubbles are as important for sheep production as annual pastures in the Victorian Mallee". Australian Journal of Experimental Agriculture 46, n.º 8 (2006): 993. http://dx.doi.org/10.1071/ea04033.
Texto completo da fonteResumo:
The impact of different management strategies on production and profit can be evaluated with knowledge of how sheep production responds to changes in the available feed base and sheep or pasture management. This study aimed to quantify on-farm pasture and sheep production in mixed sheep and cropping systems in the Victorian Mallee of south-eastern Australia (325 ± 50 mm annual rainfall) as a prelude to computer simulation modelling. During 2001 (average rainfall) and 2002 (extreme drought) pasture production, the feed base and sheep production were monitored in 15 paddocks on 5 properties located across the region. Crop stubbles were the major source of feed for 6 months of the year, enabling ewes to maintain liveweight. There was more variation in pasture parameters between paddocks at the 1 location than between locations. The botanical composition, plant density, soil fertility and management were key variables associated with between-paddock variation in pasture production. Variation in pasture production between years was larger than within-year differences. In contrast, stocking rates were not much lower in the drought year of 2002 than in 2001. This study suggests there is potential for management to improve pasture production, and demonstrates the importance of feed sources other than annual pasture for sheep production in environments where the annual pasture growing season is short.
18
McCallum, M. H., D. J. Connor e G. J. O'Leary. "Water use by lucerne and effect on crops in the Victorian Wimmera". Australian Journal of Agricultural Research 52, n.º 2 (2001): 193. http://dx.doi.org/10.1071/ar99164.
Texto completo da fonteResumo:
The effect of the perennial legume lucerne on the soil water regime of a farming system in the Victorian Wimmera was investigated by a combination of direct field measurements and the use of simulation modelling. In the field, soil profiles under lucerne-based pastures (also containing annual medic and Wimmera ryegrass) remained consistently drier throughout the year compared with continuous annual cropping. The amount of plant-available soil water (0–2.0 m) after 3–4 years of lucerne pasture was on average 48 mm less than after annual crops (wheat, field pea), most of which (81%) was extracted at depth (1.0–2.0 m). A wheat simulation study evaluated yield responses post-lucerne under a range of environmental conditions likely to be experienced within the region. It was predicted that the yield penalty for the first wheat crop after lucerne would vary from 0 to 0.87 t/ha, depending upon seasonal conditions. Overall, the analysis predicted a median yield penalty of 0.4 t/ha (15%) for wheat after lucerne. The risk of a large yield penalty (>0.8 t/ha) was low (5 years in 100). In the simulation, the risk of yield loss decreased during a cropping phase with each year after lucerne as the soil profile progressively became recharged with water. The time taken to recharge the soil prof ile fully after lucerne to levels equivalent to that under continuous cropping was not resolved in the field, but simulation studies suggested that it would be within 5 years.
19
Reed, K. F. M., Z. N. Nie, L. V. Walker, W. J. Mace e S. G. Clark. "Weather and pasture characteristics associated with outbreaks of perennial ryegrass toxicosis in southern Australia". Animal Production Science 51, n.º 8 (2011): 738. http://dx.doi.org/10.1071/an11016.
Texto completo da fonteResumo:
Severe outbreaks of toxicosis caused by the natural endophyte Neotyphodium lolii in perennial ryegrass (Lolium perenne L.) have occasionally resulted in heavy loss of livestock in Victoria and Tasmania. Meteorological records were examined from locations where acute toxicosis was recorded. High rainfall (>350 mm) in spring–summer was an obvious common feature; typically, it prolonged the period of high growth rate of pasture, increasing predicted spring–summer (September–March) growth (by ~36%) and increasing the predicted digestibility of organic matter of summer pasture (1 February) by 2.7% units (up to 55.6%). In years when severe toxicosis occurred, such rainfall was accompanied by dry, warm conditions in March and April, viz. mean maximum daily temperatures on the mainland of ≥21°C (March) and ≥18°C (April). During summer–autumn 2002, pastures from 10 Victorian farms on which acute perennial ryegrass toxicosis resulted in the loss of >7000 sheep/deer, were found to be dominated by perennial ryegrass. The ryegrass endophyte-produced toxins, ergovaline and lolitrem B, were detected in 74% and 100%, respectively, of composite faecal samples collected from acutely affected animals. The populations of perennial ryegrass all tested positive for Neotyphodium lolii endophyte, with a mean infection frequency of 90.5% (s.e.m. 1.81). The mean mycelial mass in basal tillers of perennial ryegrass was estimated at 66.00 (s.e.m. 3.40) from a sample of 20 plants, each of which was assessed on a scale of 1–5. Mycelial mass accounted for 19–20% of the variation in the concentration of ergovaline and lolitrem B in perennial ryegrass. Toxin concentrations in the plants where acute toxicosis was observed exceeded the tolerance levels for sheep (ergovaline 0.8 mg/kg; lolitrem B 1.8 mg/kg) in the minor (green) fraction of the plant in all but one affected pasture for ergovaline and all but two for lolitrem B. Maximum concentrations recorded were 4.3 and 4.6 mg/kg for ergovaline and lolitrem B respectively. Ergovaline increased in an asymptotic relationship with lolitrem B, which accounted for 45% of the variation in ergovaline. The concentrations of ergovaline and lolitrem B in the whole plant (green and dead fractions combined) were not greater than those recorded from randomly sampled pastures in earlier seasons, when only occasional mild cases of toxicosis were reported. Further examination of stored grass samples collected during the 2002 outbreak recently revealed unidentified peaks on the chromatograms for both ergovaline and lolitrem B; peaks that are not seen on chromatograms for toxic perennial ryegrass from New Zealand, where the expression of perennial ryegrass toxicosis is usually milder and rarely fatal.
20
Walsh, GL, e HA Birrell. "Seasonal variations in the chemical composition and nutritive value of five pasture species in south-western Victoria". Australian Journal of Experimental Agriculture 27, n.º 6 (1987): 807. http://dx.doi.org/10.1071/ea9870807.
Texto completo da fonteResumo:
The dry matter digestibility (DMD), grinding energy, and the concentration of neutral detergent fibre, crude protein, soluble carbohydrate, calcium, magnesium, sodium, potassium, and phosphorus in 5 pasture species were monitored over 2 years from pasture which was grazed at 14.8 sheep/ha in south-western Victoria. The species were: perennial ryegrass (Lolium perenne L. cv. Victorian), phalaris (Phalaris aquatica L. cv. Australian), Yorkshire fog grass (Holcus lanatus), subterranean clover (Trifolium subterraneum cv. Mount Barker), and capeweed (Arctotheca calendula). Perennial ryegrass and subterranean clover were the dominant species and contributed 50 and 20% DM, respectively, to the sward in winter and the opposite in spring. The DMD of the 5 pasture species did not vary greatly throughout the vegetative phase of growth (autumn-mid spring). In winter, fog grass was slightly less digestible (70-74% DMD), while the other grasses were similar (76-79% DMD). Subterranean clover was not digested (72-75% DMD) as thoroughly as the other species until after late spring; then it retained its digestibility while the digestibility of the others fell. None of the species provided digestible herbage above 65% DMD in the summer. The energy required for grinding herbage was lowest in the autumn-winter, and increased with a corresponding increase in neutral detergent fibre content as pastures matured in late spring. The crude protein content of all species declined from 27-30% in autumn to 18-20% in spring, while the soluble carbohydrate contents increased from about 54% in autumn to 10-13% by spring. The implications on animal production of these seasonal changes in nutritive value are discussed. Higher soluble carbohydrate contents in spring herbage than in autumn herbage possibly explain the better performance of animals when grazing spring pasture. The levels of magnesium, sodium and potassium were adequate for the dietary requirements of ruminants; however, on grass dominant pasture, shortages of calcium (0.14-0.25% DM) and phosphorus (0.11-0.24% DM) were likely in the summer when energy and protein were also deficient. The problem of a calcium deficiency is greatly reduced by the presence of legumes. Capeweed is an accumulator of minerals, but it is only occasionally eaten and is rarely present in summer; hence its presence is of marginal benefit to stock.
21
Doyle, PW, R. Barlow e RE Darnell. "Straightbred and crossbred weaner steers bred in north-eastern New South Wales and grown on Victorian foodlots and pastures". Australian Journal of Experimental Agriculture 32, n.º 8 (1992): 999. http://dx.doi.org/10.1071/ea9920999.
Texto completo da fonteResumo:
Weaner steers of 6 breed types were procured from 82 herds from the North Coast of New South Wales and grown in feedlots and on pastures in Victoria over a 3-year period. Growth and carcass traits were compared when adjusted to a common initial liveweight (204 kg), and breed type effects were tested using the between-herd (of origin) mean square as error. Steers comprised Hereford; first-cross Angus x Hereford (A x H); first-cross Brahman x Hereford (B X H); Braford; an outcross A x (B x H); and a backcross H x (B x H). Initial liveweight was significantly and positively correlated with final liveweight, carcass weight, dressing percentage, muscle score, subcutaneous fat depth [except for B x H and A x (B x H)], and eye muscle area [except for H x (B x H)]. There was no significant relationship between initial liveweight and daily gain. Feedlot steers grew faster than pasture steers (1159 v. 741 g/day) and were slaughtered earlier (after 144 v. 268 days) at similar carcass weights (202 kg) and subcutaneous fat depths at the 12-13th rib (6.6 mm). Muscle colour was significantly lighter for the younger feedlot steers, but all other fat and muscle measurements were unaffected by feed type. The A x H and B x H steers had the highest carcass weights (204 and 206 kg, respectively), while Braford and H x (B x H) steers had the lowest (both 199 kg). The A x H steers had the highest muscle score and greatest subcutaneous fat depth (5.6 units and 8.2 mm), while Braford steers ranked lowest for these measures (4.9 units and 5.5 mm) when adjusted to the same initial liveweight. Underlying these differences were significant breed effects on daily gain (range 71 g/day), final liveweight (range 10.8 kg), and dressing percentage (range 1.6%). There was a significant breed type x feed type interaction for muscle colour: on feedlot, A x (B x H) were significantly lighter than Hereford; and on pasture, H x (B x H) and A x H were lighter than B x H and A x (B x H), and Hereford were lighter than B x H. The range in producer effects (origin) on daily gain was 80-124% of the overall mean, with a repeatability of 0.47. Except for fat depth, breed differences were small, but first-cross steers were generally superior to progeny of first-cross cows. This indicates a conflict in the choice of breed type between that which performs best for rowers (first-cross cattle) and that which performs best for North Coast store weaner producers (calves from first-cross dams). There were large differences in growth rate between steers from different producers that could not be attributed to any 1 factor.
22
Heard, J. W., S. A. Francis e P. T. Doyle. "Nutritive characteristics of annual species in irrigated pasture in northern Victoria". Australian Journal of Experimental Agriculture 46, n.º 8 (2006): 1015. http://dx.doi.org/10.1071/ea04268.
Texto completo da fonteResumo:
We examined changes in estimated metabolisable energy (ME), crude protein (CP) and neutral detergent fibre (NDF) concentrations of irrigated annual pastures through winter and spring in 2002. The types of pastures sampled were ‘high’ subterranean clover (HS, at least 800 g/kg DM clover), ‘low’ subterranean clover (LS, about 400 g/kg DM clover) and ‘low’ Persian clover (LP, about 500 g/kg DM clover). Estimates were also made of selection differentials, namely the nutrient concentration in the pasture fraction likely to be consumed expressed as a proportion of the nutrient concentration in the whole sward to ground level. The ME concentrations in all pasture types increased from May to August, after which concentrations in LS and LP declined, while the ME concentrations in HS declined after September. Low Persian pasture was significantly (P<0.001) higher in ME than the subterranean clover pastures except in September. There was a significant quadratic relationship between ME and time in months and this relationship differed significantly between the 3 pasture treatments. There was a significant (P<0.001) linear decline in CP concentration through the sampling period. The rate of decline in CP concentration was greatest for HS and lowest for LP pastures. Neutral detergent fibre concentrations declined gradually until August and then increased in all pastures. High subterranean clover pastures were lower (P<0.05) than LS pastures in all months. Low Persian clover pastures were higher in NDF than HS pastures, but lower than LS pastures in most months.There were small but significant differences in selection differentials for estimated ME between months when pastures were cut to 4 cm. Selection differentials for ME were between 1.01 and 1.13 across pasture types. Crude protein selection differentials were higher than for ME and varied between 1.11 and 1.46. There were small significant differences in selection differentials between months for NDF (0.74–0.96). Calculated selection differentials at different cut heights indicated that a nutrient gradient existed throughout the annual pasture sward. Pastures cut at high (>8 cm) cut heights had higher ME and CP and lower NDF, than pastures cut to 4 cm. Differences in selection differentials at different cut heights were apparent between pasture types.
23
Dove, H., RW Mayes e M. Freer. "Effects of species, plant part, and plant age on the n-alkane concentrations in the cuticular wax of pasture plants." Australian Journal of Agricultural Research 47, n.º 8 (1996): 1333. http://dx.doi.org/10.1071/ar9961333.
Texto completo da fonteResumo:
Plants of the pasture species Phalaris aquatica cv. Sirosa, Lolium perenne cv. Victorian, Trifolium repens cv. Irrigation White, T. subterraneum ssp. subterraneum cv. Mt Barker, T. subterraneum ssp. yanninicum cv. Trikkala, and Medicago sativa cv. Siriver were grown under controlled glasshouse conditions. At weekly intervals, 6 plants of each species were harvested and dissected into their component plant parts. The concentrations of n-alkanes in plant parts from all species were then estimated using gas chromatography. Results confirmed earlier studies that alkanes with odd-numbered carbon chains were predominant in cuticular wax, especially C27, C29, C31, and C33 alkanes. For the individual alkanes (225433, differences between species accounted for 85% of the total variance in alkane concentration. Calculation of similarity coefficients indicated that the greatest similarities in the pattern of alkane concentrations occurred either between plant parts within a species or between the same plant part in closely related species. Multivariate statistical analysis using canonical variates analyses indicated that despite these similarities, it would still be possible to distinguish both plant species and plant parts in mixtures of these components. In particular, an examination of hypothetical perennial ryegrass-white clover or phalaris-subterranean clover pastures demonstrated that all fractions of all species would be likely to be distinguishable. The results are discussed in relation to the use of herbage and faecal alkane concentrations in least-squares estimates of the composition of the diet of the grazing animal.
24
Saul, Geoffrey, Gavin Kearney e Dion Borg. "Pasture systems to improve productivity of sheep in south-western Victoria. 1. Growth, composition, nutritive value and persistence of resown pastures". Animal Production Science 49, n.º 8 (2009): 654. http://dx.doi.org/10.1071/ea06142.
Texto completo da fonteResumo:
Two pasture systems were compared at five on-farm sites across south-western Victoria between 1990 and 1996. The ‘typical’ pasture treatment mimicked the pasture and grazing management common in the region, with volunteer annual-based pastures fertilised with around 5 kg/ha phosphorus (P) each year. The ‘upgraded’ pasture treatments were resown to phalaris, perennial ryegrass and subterranean clover, and higher rates of fertiliser (13–25 kg P/ha.year) plus other nutrients were applied. Both pastures were set stocked with the participating farmers breeding ewes. Stocking rate was an emergent variable on each plot. The stocking rate on the typical treatments was based on normal farm practise. Initially, the stocking rate of the upgraded pastures was 15% higher than for the typical pastures and increased over time depending if the ewes in the upgraded pastures were heavier than those in the typical pastures. Measurements included soil fertility, pasture production, nutritive value and composition, and animal production. Net annual pasture production of the upgraded pastures was 10 500 kg/ha compared with 8700 kg/ha for the typical pastures. This average difference (18%) between the treatments was greatly influenced by the large advantage (40%) of the upgraded pasture in the wet year of 1992. Upgraded pastures had higher pasture production than typical pastures in spring but the reverse occurred in autumn. In a separate small plot experiment, the response of each pasture to higher P fertiliser applications was tested. In autumn and winter, there was a significant interaction between pasture type and P rate, with higher responses on the upgraded pastures. In spring, both pastures responded to increased P applications but the upgraded pastures were more responsive at all P rates. The upgraded pastures contained significantly higher legume content (30–50%) than the typical pastures (10–20%). The proportion of sown perennial grasses in the upgraded pasture declined from around 30 to 10% after 6 years displaced by annual grasses and broad-leaf weeds. Herbage from upgraded pastures had significantly higher crude protein content (2–7 units) and digestibility (1–10 units) than the typical pastures with the difference between the treatments increasing over time. The set stocking policy used in this experiment is likely to have exacerbated the decline in sown perennial grasses and implementation of some form of strategic or rotational grazing may have improved persistence. The experiment also highlights the importance of selecting perennial grasses able to cope with the local environment and grazing conditions. Despite the decline in perennials, these results show significant potential to improve pasture productivity and quality in south-western Victoria.
25
Stockdale, C. R. "Effects of season and time since defoliation on the nutritive characteristics of three irrigated perennial pasture species in northern Victoria 2. Macro-minerals". Australian Journal of Experimental Agriculture 39, n.º 5 (1999): 567. http://dx.doi.org/10.1071/ea98052.
Texto completo da fonteResumo:
During 1993–94, the nutritive characteristics of white clover (Trifolium repens cv. Haifa), ryegrass (Lolium perenne cv. Ellet) and paspalum (Paspalum dilatatum) were examined at weekly intervals on 4 occasions. On each occasion, they were initially defoliated with a drum mower and allowed to regrow for up to 9 weeks; dates of the 4 initial harvests were 24 September, 26 November, 28 January and 25 March. The objective of the part of a larger study that is reported here was to examine changes in macro-minerals of the 3 species as they regrew after defoliation, in order to start providing information for informed decisions on the need for supplemental minerals in northern Victorian dairy systems. The ranges in mineral elements recorded in this study were 0.16–0.43% for phosphorus, 1.18–3.41% for potassium, 0.26–1.49% for calcium, 0.20–0.54% for magnesium, 0.05–0.44% for sodium, 0.79–2.02% for chlorine and 0.15–0.37% for sulfur. A major reason for the large ranges was due to variations between the 3 species. White clover was richer in a number of minerals than were the grasses, particularly calcium, potassium and magnesium, although phosphorus was also generally higher. Perennial ryegrass had high sodium concentrations, which were probably related to high watertables, with the associated propensity for salinity problems, that are endemic in irrigated northern Victoria. It is suggested that, on the basis of the pasture on offer, phosphorus is the major mineral that can potentially limit milk production by grazing dairy cows in this environment, although possible deficiencies were also demonstrated for calcium, sodium and sulfur. Where a mineral has its highest concentration in the leaves, lax grazing management or the use of short pastures should result in higher concentrations in the pasture eaten than that on offer. Leaves were not always the richest source of a mineral although this was almost always the case for all minerals in ryegrass leaves. In white clover, phosphorus, calcium, magnesium and sulfur were more concentrated in the leaves than in the stem. In paspalum, calcium, magnesium and sulfur were more concentrated in the leaves. White clover stems had higher concentrations of potassium and chlorine than leaves, while with paspalum this applied to sodium and chlorine. It was concluded that the species composition of a pasture will have a large impact on the supply of minerals for grazing dairy cows, although the leaf : stem ratio, as determined by time since the last defoliation, will also have a role in determining whole plant composition.
26
Ridley, AM, e DR Coventry. "Yield responses to lime of phalaris, cocksfoot, and annual pastures in north-eastern Victoria". Australian Journal of Experimental Agriculture 32, n.º 8 (1992): 1061. http://dx.doi.org/10.1071/ea9921061.
Texto completo da fonteResumo:
Yield responses of 3 mixed grass-clover pastures [Phalaris aquatica L. cv. Sirosa (phalaris), Dactylis glomerata cv. Porto (cocksfoot), and annual grass based Trifolium subterraneum L. cv. Trikkala (subterranean clover) pastures] were measured over 5 soil pH treatments at 2 sites in Victoria. One site (Beechworth) was strongly acidic [pH(CaCl2) < 4.21 to a depth of 40 cm and contained high concentrations of soil aluminium (Al). At the other site (Lake Rowan), yield responses to lime application had been measured previously, but only in Al-sensitive wheat cultivars. At Beechworth, pasture yield responses to lime were not consistent but. when observed. occurred in autumn and winter in all 3 pasture types. Phalaris pastures showed yield increases more often than cocksfoot and annual pastures. Low magnesium and calcium concentrations may have limited dry matter production, although yields were reasonable on all treatments. Where lime was applied, growth responses may have been due to alleviation of Al toxicity. At Beechworth, pasture yield was increased where lime increased pH from 4.2 to 4.6 and decreased soil Al (measured in 10 mmol CaCl2/L) from 11 to <3 �g/g soil. Herbage manganese concentrations were not high in phalaris and subterranean clover, and cocksfoot manganese standards were not available. At Lake Rowan (pH 4.7, Al <1 �g/g), no growth responses to lime were seen in any pasture treatment, and annual grass based pastures sometimes had higher yields than phalaris and cocksfoot pastures. On strongly acidic soils such as at Beechworth, incorporation of lime prior to pasture establishment should be considered. Perennial grasses may reduce further soil degradation through acidification. Soil A1 concentrations are commonly lower in ley-cropping areas, and the inclusion of perennial grasses in ley pastures requires further evaluation.
27
Lawson, A. R., e K. B. Kelly. "Responses to the renovation of an irrigated perennial pasture in northern Victoria. 1. Pasture consumption and nutritive characteristics". Australian Journal of Experimental Agriculture 47, n.º 2 (2007): 149. http://dx.doi.org/10.1071/ea05258.
Texto completo da fonteResumo:
A field experiment was established in northern Victoria in the autumn of 1999 to quantify the effects of renovating a 15-year-old irrigated perennial pasture which had a high paspalum content [>40% dry matter (DM)] in summer. The treatments were: (i) control, the existing pasture; (ii) oversown, in which the existing pasture was grazed, topped and direct drilled; and (iii) resown, in which the existing pasture was sprayed, cultivated and sown with a new pasture. The grass species used in both renovation treatments were perennial ryegrass, Italian ryegrass and tall fescue. The treatments were grazed by dairy cows when the perennial ryegrass had reached the 2.5–3 leaf stage. Grazing of the resown tall fescue coincided with the resown ryegrass in years 1 and 2, but in subsequent years, resown tall fescue was grazed at a rising plate meter height of 80 mm. All treatments were grazed to a residual pasture height of 40–45 mm, as measured with a rising plate meter. Pasture consumption (measured as DM removed by dairy cows), in vitro DM digestibility (in vitro DMD) and crude protein (CP) contents were measured. Oversowing increased pasture consumption over the 4-year period, compared with the control, by an average of 1.1 t DM/ha.year when oversown once with perennial ryegrass and by 1.6 t DM/ha.year when oversown annually with Italian ryegrass. This increase occurred principally during the winter–spring period for pastures oversown with both perennial (0.7 t DM/ha) and Italian (1.6 t DM/ha) ryegrass. Oversowing with perennial or Italian ryegrass did not affect the in vitro DMD or CP content of the pasture on offer. These results show that oversowing with either perennial or Italian ryegrass is a viable means of increasing pasture availability over winter and spring from perennial pastures consisting of a mixture of perennial ryegrass, white clover and paspalum. Pasture consumption in the first 12 months after resowing was 3.5–4.1 t DM/ha lower from the resown than from the control pasture. This was because of two fewer grazings in autumn–winter and to reductions in pasture consumption of 20% in spring and of 40% in summer. These reductions would add considerably to the cost of resowing through increasing the need for supplementary feeding. Pasture consumption from the resown perennial ryegrass pasture in years 2–4 was, on average, the same as the control, although it was higher during winter and spring and lower during summer. Pasture consumption from the resown tall fescue pasture in years 2–4 was, on average, 2.5 t DM/ha.year higher than that of the resown perennial ryegrass pasture, with most of this increase occurring in summer and autumn. The resown pastures had higher in vitro DMD and CP contents than the control with little difference between the resown perennial ryegrass and tall fescue pastures. These findings show that tall fescue is a viable alternative to perennial ryegrass when resowing pastures. The use of nitrogen fertiliser did not affect the in vitro DMD or CP contents of the pasture on offer but allowed an increase in DM consumption, with this increase being greater for the control and oversown pastures than for the resown pasture.
28
Saul, Geoffrey, Gavin Kearney e Dion Borg. "Pasture systems to improve productivity of sheep in south-western Victoria 2. Animal production from ewes and lambs". Animal Production Science 51, n.º 11 (2011): 982. http://dx.doi.org/10.1071/an11010.
Texto completo da fonteResumo:
Two pasture systems (Typical, Upgraded) were compared at five on-farm sites across south-western Victoria between 1990 and 1996. The Typical pasture treatment mimicked the pastures common in the region, with volunteer annual-based species fertilised with ~5 kg/ha.year phosphorus (P). The Upgraded pasture treatment was sown to phalaris, perennial ryegrass and subterranean clover using cultivars recommended for the particular area. Higher rates of fertiliser (13–25 kg/ha.year P) plus other nutrients were applied. Both pastures were set-stocked with breeding ewes. The stocking rate on the Typical treatments was based on normal farm practice. Initially, the stocking rate of the Upgraded pastures was 15% higher than the Typical pastures and increased over time depending if the ewes in the Upgraded pastures were heavier than those in the Typical pastures. Measurements included pasture growth, composition and persistence, ewe stocking rates, ewe and lamb liveweights and condition scores, lambing, marking and weaning percentages, fleece characteristics and supplementary feeding. Over the 6 years, the average carrying capacity of the Upgraded pastures was 18.0 DSE (Dry Sheep Equivalents)/ha compared with 10.2 DSE/ha on the Typical pastures (P < 0.001). As well, the ewes on the Upgraded pastures were 2–3 kg heavier (P < 0.001) and 0.3 condition score higher (P < 0.001) than those on the Typical pastures. Ewes grazing the Upgraded pastures cut significantly more wool per head (4.8 versus 4.5 kg) of higher micron wool (23.1 versus 22.6 um, P < 0.001) but with similar yield and strength. There was no difference in the supplementary feeding required on the treatments. Ewes grazing Upgraded pastures had significantly higher lambing (116 versus 102%), marking (86 versus 81%) and weaning percentages (84 versus 79%) and weaned significantly heavier lambs (23.6 versus 22.6 kg) than those on Typical pastures. There was less feed on offer (P < 0.05) in the Upgraded pastures compared with the Typical pastures in autumn–winter but similar or higher levels in spring and summer. Gross margins using current costs and prices were $20 and $24/DSE for the Typical and Upgraded pastures, respectively. These values were used in a discounted cash flow analysis to determine the long-term benefits of the treatments. Assuming a 12-year life for the pasture, the internal rate of return was 27% with the breakeven point in Year 7. Treatment and ewe condition score significantly influenced lambing percentage with ewes in condition score 3.0 at joining having a lambing percentage of 111% compared with 95% if at condition score 2.3. Irrespective of condition score, ewes grazing Upgraded pastures had a 7% higher lambing percentage than those grazing the Typical pastures. Ewe condition score and lambing time significantly affected weaning weight. Lambs born to ewes in condition score 2.3 during pregnancy and lambing in autumn, reached only 32% of mature ewe liveweight at weaning whereas lambs from ewes at condition score 3.0 achieved 51% of mature weight by weaning.
29
reardon, joan. "Simple Meals with M.F.K. Fisher". Gastronomica 8, n.º 2 (2008): 26–30. http://dx.doi.org/10.1525/gfc.2008.8.2.26.
Texto completo da fonteResumo:
During the early 70s, M.F.K. Fisher moved from her large Victorian home in St. Helena to a unique three-room palazzino, designed by David Bouverie on his Glen Ellen ranch. Mary Frances named her new home Last House and slowly adjusted to life among the natural waterfalls, streams, vineyards, and pastures. But she was also careful to balance living the Valley of the Moon with living in older, familiar landscapes. Provence drew her like a magnet, and in 1973, 1976, and 1978, with her sister Norah as a companion, she lived for extended periods of time Marseille and Aix, This article focuses on the changes that occurred in Fisher's life when she left the Napa Valley and took up residence in the Sonoma Valley and the different direction her writing took at this time. Of importance also so is her account of the changes that had occurred in Provence since she lived there in the early 60s, and the re-telling of her adventures in living and preparing meals in the various impromptu kitchens that she and her sister lived in while they each pursued their various projects in Aix and Marseille.
30
Trapnell, L. N., A. M. Ridley, B. P. Christy e R. E. White. "Sustainable grazing systems: economic and financial implications of adopting different grazing systems in north-eastern Victoria". Australian Journal of Experimental Agriculture 46, n.º 8 (2006): 981. http://dx.doi.org/10.1071/ea03022.
Texto completo da fonteResumo:
Data from experimental sites at Maindample and Ruffy, on which different grazing systems were implemented, was extrapolated to a 100-ha paddock on a commercial property to determine their economic and financial implications. Included into the analyses were risk assessments to allow for sowing failures due to adverse seasonal conditions and price variability of meat and wool during the life of the pasture. Where graziers carried out pasture improvement, the results indicated that changing from control (low-input pasture stocked at a low intensity) to high-input (high stocking rates and fertiliser addition) rather than medium-input pasture was the more profitable option. In changing to high-input pasture at Maindample, a cattle activity using nominal discount rates of 10%/year required success rates in pasture establishment of ≥80% for profitability. For cattle at Ruffy, using the same discount rate, the change was profitable for success rates in pasture establishment of ≥70%, but lamb and wool activities were only profitable for success rates in pasture establishment of ≥90%. Over both sites, cattle at Ruffy was the only activity in which the change was profitable for nominal discount rates of 15%/year, but success rates for pasture establishment also had to be ≥90%. Financial analyses performed on these increases in profitability confirmed that they were feasible because the payback periods for deficits incurred during the development and management of the improved pasture were less than the 13-year life of the investments. However, using a contractor to improve the pastures was not feasible because the deficits could not be repaid within the period of the investment. These results support the current low adoption of perennial pastures and have significant implications for catchment management bodies in Victoria and New South Wales where heavy reliance is placed on perennial pastures to improve catchment outcomes.
31
Lawson, A. R., P. W. G. Sale e K. B. Kelly. "Effect of defoliation frequency on an irrigated perennial pasture in northern Victoria. 1. Seasonal production and sward composition". Australian Journal of Agricultural Research 48, n.º 6 (1997): 811. http://dx.doi.org/10.1071/a96088.
Texto completo da fonteResumo:
A field experiment was carried out to investigate whether changes in winter and post-winter defoliation frequency would increase the white clover content of an irrigated perennial ryegrass–white clover pasture in northern Victoria. Pastures defoliated every 4 weeks during winter had higher white clover growing point (stolon apices with at least 2 nodes) density at the end of winter than pastures defoliated every 8 weeks or those receiving a single defoliation after 16 weeks, but these differences did not affect the clover content in the spring. Reasons for this are suggested. Pastures defoliated at 8-week intervals in winter were the most productive over winter{early spring. Less frequent defoliation (4 v. 2 weeks) during the post-winter, September–May period reduced white clover growing point and perennial ryegrass tiller densities. However, the white clover growth rate during this period was increased by less frequent defoliation, whereas the ryegrass growth rate was reduced, resulting in an increase of 10% in the white clover content, and a 1·9 t dry matter (DM)/ha increase in total DM produced. This higher clover content and pasture yield during spring–autumn with less frequent defoliation has important implications for the management of irrigated perennial pastures for the dairy industry in northern Victoria.
32
Crawford, MC, e MR Macfarlane. "Lucerne reduces soil moisture and increases livestock production in an area of high groundwater recharge potential". Australian Journal of Experimental Agriculture 35, n.º 2 (1995): 171. http://dx.doi.org/10.1071/ea9950171.
Texto completo da fonteResumo:
A grazing experiment was conducted on an area with high groundwater recharge potential in northeastern Victoria from 1988 to 1992. Merino wether weaners were grazed on either lucerne (Medicago sativa) or a pasture consisting of annual species (Trifolium spp., Lolium rigidum, Vulpia bromoides, Hordeum leporinum) at 5.0, 8.75, or 12.5 wethers/ha. Lucerne pastures were rotationally grazed and annual pastures were set-stocked. Measurements included herbage mass, lucerne plant density, sheep liveweight, wool production and fibre diameter, and soil moisture potential. Herbage mass in both pasture treatments decreased with increasing stocking rate, but at 12.5 wethers/ha, lucerne herbage mass was significantly (P<0.001) greater than annual pasture herbage mass. Sheep liveweight showed similar trends. On annual pastures, wool production per sheep decreased with increasing stocking rate, whereas on lucerne, it was maintained as stocking rate increased from 8.75 to 12.5 wethers/ha. Mean wool production per ha on lucerne pasture was 14.5, 23.5, and 32.1 kg for 5.0, 8.75, and 12.5 wethers/ha, respectively, and on annual pasture it was 13.8, 21.7, and 24.8 kg. Supplementary feeding was needed on annual pastures every year at the high stocking rate. On lucerne pastures, it was unnecessary except for 3 weeks in 1991. Soil moisture under lucerne was less than under annual pasture, indicating that lucerne used more water than the annual pasture and created a larger soil water deficit, thus leading to potentially less groundwater recharge. In this environment, lucerne could be productively stocked at 12.5 wethers/ha, whereas annual pastures were less productive and could only be stocked at 8.75 wethers/ha. Furthermore, lucerne was more effective at using soil water and reducing the potential for groundwater recharge.
33
Chan, K. Y., A. Oates, G. D. Li, M. K. Conyers, R. J. Prangnell, G. Poile, D. L. Liu e I. M. Barchia. "Soil carbon stocks under different pastures and pasture management in the higher rainfall areas of south-eastern Australia". Soil Research 48, n.º 1 (2010): 7. http://dx.doi.org/10.1071/sr09092.
Texto completo da fonteResumo:
In Australia, pastures form the basis of the extensive livestock industries and are important components of crop rotation systems. Despite recent interest in the soil carbon sequestration value of pastures in the mitigation of climate change, little information is available on the soil carbon sequestration potential of pastures in New South Wales farming systems. To quantify the soil carbon stocks under different pastures and a range of pasture management practices, a field survey of soil carbon stocks was undertaken in 2007 in central and southern NSW as well as north-eastern Victoria, using a paired-site approach. Five comparisons were included: native v. introduced perennial, perennial v. annual, continuous v. rotational grazing, pasture cropping v. control, and improved v. unimproved pastures. Results indicated a wide range of soil organic carbon (SOC) stocks over 0–0.30 m (22.4–66.3 t C/ha), with little difference when calculated based on either constant soil depth or constant soil mass. Significantly higher SOC stocks were found only as a result of pasture improvement using P application compared with unimproved pastures. In this case, rates of sequestration were estimated to range between 0.26 and 0.72 t C/ha.year, with a mean rate of 0.41 t C/ha.year. Lack of significant differences in SOC stocks for the other pastures and pasture management practice comparisons could be due to inherent problems associated with the paired-site survey approach, i.e. large variability, difficulties in obtaining accurate site history, and the occasional absence of a valid control as well as the likely lower rates of SOC sequestration for these other comparisons. There is a need for scientific long-term trials to quantify the SOC sequestration potential of these other pastures and pasture management practices.
34
Thompson, A. N., A. J. Kennedy, J. Holmes e G. Kearney. "Arrowleaf clover improves lamb growth rates in late spring and early summer compared with subterranean clover pastures in south-west Victoria". Animal Production Science 50, n.º 8 (2010): 807. http://dx.doi.org/10.1071/an09100.
Texto completo da fonteResumo:
The profitable production of lamb from pasture-based systems is dependent on high levels of pasture production being efficiently utilised by sheep of superior genetic merit. Pastures that can extend the pasture-growing season and provide high quality feed in late spring and summer have the potential to increase production efficiency and the proportion of lambs that meet market specifications. In this paper we tested the hypothesis that arrowleaf clover (cv. Arrotas), a cultivar selected for late maturity, would supply feed of higher nutritive value than conventional annual legumes and perennial ryegrass mixtures during December and January and this would improve lamb growth rates over this period. Two experiments were conducted to compare the nutritive value of pasture and growth rates of lambs grazing arrowleaf clover, subterranean clover (cv. Leura) or subterranean clover/perennial ryegrass mixtures at different stocking rates during late spring and early summer in south-west Victoria. In the second experiment an arrowleaf clover/perennial ryegrass treatment was also included. Lambs were removed from the plots when they could no longer maintain liveweight. Arrowleaf clover extended the growing season by 4–6 weeks and provided feed of significantly higher digestibility than subterranean clover during December and January. The digestibility of arrowleaf and perennial ryegrass was comparable, but arrowleaf had significantly higher crude protein content during this period. Lambs grazing arrowleaf clover at stocking rates up to 24 lambs/ha grew at or above 100 g/day until the end of January, whereas lambs grazing subterranean clover and perennial ryegrass mixed pastures could not maintain weight by mid-to-late December in both years and were removed from the pastures. At the highest stocking rates total lamb production from arrowleaf clover monoculture pastures in late spring and early summer was ~400 kg liveweight/ha, and was more than double that achieved from the subterranean clover and perennial ryegrass/subterranean clover mixed pastures. The perennial ryegrass/arrowleaf clover mixed pastures in the second experiment produced a similar quantity of lamb per hectare as the arrowleaf clover monoculture pastures at the same stocking rate. In this paper we demonstrated that late-maturing arrowleaf clover can be a profitable, special purpose lamb-finishing pasture. Arrowleaf clover was most suited to more elevated parts of the landscape where estimated carrying capacity was 20 to 40% greater than that from lower lying parts of the landscape that were more subject to water logging and weed infestation. The risks of including arrowleaf clover pastures into the farming system could be reduced by direct drilling arrowleaf clover, which has relatively poor winter production, into existing perennial ryegrass pastures.
35
Ridley, AM, WJ Slattery, KR Helyar e A. Cowling. "Acidification under grazed annual and perennial grass based pastures". Australian Journal of Experimental Agriculture 30, n.º 4 (1990): 539. http://dx.doi.org/10.1071/ea9900539.
Texto completo da fonteResumo:
Soil samples to a depth of 60 cm were collected from adjacent, 39-year-old, phalaris-based and annual pasture fields on an acid soil at Rutherglen, north-eastern Victoria. The fields had similar histories of fertiliser application and stock enterprise. Minimum net acid addition rates were determined under both pasture types, and the soil under annual pasture showed greater acidification. Carbon cycle acid addition contributed 1.3 1 and 1.36 kmol H+/ha.year to net acid addition on annual and phalaris pastures, respectively. Because slow alkaline soil reactions in the field contribute to buffering capacity on an acid soil and lead to underestimation of net acid addition rate and nitrate leaching, estimates of such reactions were made for both pasture types. If correct assumptions were used nitrate leaching was substantial under both pasture types but was reduced by 1.01 kmol H+/ha.year under phalaris pasture. This suggests that perennial grass based pastures can be used to reduce acidification on pastoral soils. Alkali addition to counteract net acidification may be necessary on acid soils to maintain management options for growing aluminium-sensitive species.
36
Kemp, D. R., e P. M. Dowling. "Towards sustainable temperate perennial pastures". Australian Journal of Experimental Agriculture 40, n.º 2 (2000): 125. http://dx.doi.org/10.1071/ea98003.
Texto completo da fonteResumo:
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.
37
Culvenor, R. A., S. P. Boschma e K. F. M. Reed. "Persistence of winter-active phalaris breeding populations, cultivars and other temperate grasses in diverse environments of south-eastern Australia". Australian Journal of Experimental Agriculture 47, n.º 2 (2007): 136. http://dx.doi.org/10.1071/ea05342.
Texto completo da fonteResumo:
Three winter-active populations of phalaris (Phalaris aquatica L.), selected over two generations for improved persistence under grazing, were evaluated with commercial cultivars of phalaris and other temperate perennial grasses from 1999–2003 in three environments of south-eastern Australia as part of a program to develop a cultivar for more sustainable pastures and to assess genotype × environment interaction. Grazed sites were located at Bulart in western Victoria, and Rye Park on the Southern Tablelands and Tamworth on the North West Slopes of New South Wales. At the conclusion of the experiment, the frequency of live plant base was highest at Rye Park despite soil acidity and drought. Significant variance among half-sib families in each population was also observed most frequently at this site. Frequency was intermediate at Bulart but lower than expected considering high soil fertility, probably because of high grazing pressure. Frequency was lowest at Tamworth where severe drought occurred from 2001 onwards. There was significant genotype × environment interaction for frequency among half-sib families. Significant common family variance for frequency across the Bulart and Rye Park sites was demonstrated, but not between Tamworth and either of the other sites in later years. The relationship between winter herbage mass potential and persistence differed with population and site, and was negative for one population at Bulart but positive for another population at Tamworth. Mean persistence of all families was 30% higher than winter-active controls at Rye Park and at least 40% higher at Bulart. Phalaris generally persisted better than cultivars of tall fescue (Festuca arundinacea Schreb.), cocksfoot (Dactylis glomerata L.) and perennial ryegrass (Lolium perenne L.) with some exceptions, particularly at Bulart. Development of a winter-active phalaris cultivar with improved persistence under grazing was considered possible for the Southern Tablelands and western Victorian environments with these populations but a separate program using additional germplasm will be needed for the North West Slopes environment.
38
Ward, G. N., S. G. Clark, G. A. Kearney, M. R. McCaskill, M. C. Raeside, A. R. Lawson e R. Behrendt. "Summer-active perennials in pasture systems improve seasonal pasture distribution without compromising winter-spring production". Crop and Pasture Science 64, n.º 7 (2013): 673. http://dx.doi.org/10.1071/cp13003.
Texto completo da fonteResumo:
Improved dryland pastures for sheep and beef cattle production in south-western Victoria are typically based on summer-dormant cultivars of perennial ryegrass (Lolium perenne L.) or phalaris (Phalaris aquatica L.). These are highly productive in spring but exhibit low accumulation rates over summer–autumn. Summer-active perennial pasture species could potentially alleviate this summer–autumn feed gap. Three pasture systems that used different pastures on each of the three landscape classes (crest, slope, and valley floor) were compared over 4 years. The perennial ryegrass system (henceforth Ryegrass) had a different ryegrass cultivar on each landscape class. The Triple system used lucerne (Medicago sativa L.) (crest), perennial ryegrass (slope), and summer-active tall fescue (Lolium arundinaceum (Schreb) Darbysh.) (valley floor). The Novel system used chicory (Cichorium intybus L.) (crest), Italian ryegrass (Lolium multiflorum Lam.) or hybrid ryegrass (L. × boucheanum Kunth.) (slope), and kikuyu (Pennisetum clandestinum Hochst. ex Chiov.) (valley floor). The pastures were grazed by either one (in the case of the Novel system) or three (in the case of the Ryegrass and Triple systems) animal systems that varied over the life of the experiment. Total annual herbage accumulation of the Ryegrass and Triple systems did not differ. The Novel system consistently had lower total annual dry matter accumulation than the other two systems. Lucerne pastures generally had the highest accumulation rates over summer, followed by the chicory pastures. The kikuyu pastures responded well to summer rainfall but otherwise had similar accumulation rates to the perennial ryegrass and tall fescue pastures over summer. Tall fescue pastures grew well in autumn following wet summers. In spring the perennial ryegrass pastures based on Fitzroy or Avalon were highly productive but seldom grew faster than other pastures. The results support the hypothesis that incorporating deep-rooted, summer-active perennial species will increase pasture production over summer–autumn compared with conventional pasture systems but not at the expense of winter–spring production.
39
Bird, P. R., T. T. Jackson, G. A. Kearney, G. R. Saul, R. A. Waller e G. Whipp. "The effect of improved pastures and grazing management on soil water storage on a basaltic plains site in south-west Victoria". Australian Journal of Experimental Agriculture 44, n.º 6 (2004): 559. http://dx.doi.org/10.1071/ea03019.
Texto completo da fonteResumo:
Soil salinity of non-irrigated farmlands in Australia has been largely attributed to tree clearing and their replacement by annual pasture and crop species. This paper deals with the effects of sowing perennial ryegrass and greater inputs of fertiliser, and the effect of grazing management, on water use and the potential to improve recharge control on a gravelly soil derived from basalt.In 1991, neutron access tubes were inserted into plots on a project established in 1989 to examine the impact of upgrading the pasture on sheep productivity. These plots were subdivided in 1996 to examine the impact of grazing management (tactical v. set-stocking) and pasture type (pastures dominated by annual species v. upgraded pastures) on productivity. Neutron probe readings were taken periodically from tubes in each plot, at depth intervals of 25 cm (December 1991–March 1995) or 20 cm (August 1995–April 1999) to 170 cm. There was no effect of treatment on soil moisture. Data for 2 wet years (1995 and 1996) indicate that the effective soil-water storage capacity to 170 cm depth for these pastures was a mean of 125 mm of water. This represents the potential buffer before winter rainfall exceeds the water use by the pasture, fills the soil profile to capacity and then either runs off or allows deep drainage to occur.We did not achieve a significant reduction in soil-water storage, and therefore potential recharge of groundwater, by re-sowing the pasture with perennial ryegrass and applying more fertiliser, or by altering the grazing management to a form of rotational grazing. Compared with set-stocked annual pasture, the impact of such treatments was to reduce soil-water storage to a depth of 170 cm in autumn by less than 20 mm/year. There was no association between total herbage production and soil-water storage, however an increased percentage of perennial ryegrass in the pasture was associated with a small reduction in soil-water storage in 1 year. Greater use of soil-water may depend upon using deeper-rooted perennials or maintaining a higher proportion of perennial species in the sward (the perennial ryegrass in the re-sown pastures declined from 53% in October 1996 to 4% in October 1998).
40
Douglas, M. L., M. J. Auldist, J. L. Jacobs, M. C. Hannah, S. C. Garcia e W. J. Wales. "Quantifying the ruminal degradation of nutrients in three cultivars of perennial ryegrass (Lolium perenne L.) sampled during early spring and summer". Animal Production Science 60, n.º 3 (2020): 370. http://dx.doi.org/10.1071/an19002.
Texto completo da fonteResumo:
Context The Australian dairy industry is characterised by pasture-based feeding systems, where grazed pasture is commonly supplemented with cereal grain to increase milk production of dairy cows. Perennial ryegrass (PRG; Lolium perenne L.) is the most commonly used pasture species, with a wide range of cultivars available. However, the nutritive characteristics and the degradation of nutrients in individual PRG cultivars grown in different environments in Australia are unknown, and significant variation between cultivars may impact on supplementary nutrient requirements. Aims The objective of this experiment was to quantify the extent of ruminal degradation of nutrients in three contrasting PRG cultivars (Bealey NEA2, Trojan NEA2 and Victorian SE) harvested during early spring and summer from Gippsland, northern Victoria and south-west Victoria in Victoria, Australia. Methods Degradation parameters were determined by in situ incubation in the rumens of non-lactating, rumen-fistulated Holstein–Friesian cows for 72 h using a nylon bag technique. Key results During both seasons, Bealey NEA2 had the greatest effective degradability of crude protein and neutral detergent fibre compared with Trojan NEA2 and Victorian SE. Cultivars harvested during early spring had greater effective degradability of crude protein and neutral detergent fibre, and a greater amount of rumen degradable protein compared with cultivars harvested during summer. Cultivars harvested from Gippsland had greater crude protein and neutral detergent fibre effective degradability, as well as a greater amount of rumen degradable protein, whereas cultivars harvested from northern Victoria had a greater amount of undegraded dietary protein. Conclusions These results demonstrate that the ruminal degradation of PRG cultivars declines with increasing maturity, and that there are differences between cultivars and regions; however, differences between seasons are of a greater magnitude and are more important to consider when formulating optimal supplementary grain rations. Implications This research has positive implications for farmers who will be able to understand the degradation of nutrients in PRG, and the amounts of rumen degradable protein and undegraded dietary protein available from pasture during each season. Farmers will be able to use this information to formulate supplementary grain rations that complement the nutrients from pasture and optimise milk production.
41
Waller, R. A., P. W. G. Sale, G. R. Saul e G. A. Kearney. "Tactical versus continuous stocking in perennial ryegrass-subterranean clover pastures grazed by sheep in south-western Victoria. 3. Herbage nutritive characteristics and animal production". Australian Journal of Experimental Agriculture 41, n.º 8 (2001): 1121. http://dx.doi.org/10.1071/ea01019.
Texto completo da fonteResumo:
A 4-year grazing experiment was carried out in south-western Victoria to compare the effect of tactical stocking with continuous stocking on the persistence of perennial ryegrass (Lolium perenne L.) and the productivity of sheep used for prime lamb production. Tactical stocking consisted of variable length summer, autumn and winter rotations and continuous stocking in spring. The 2 grazing strategies were compared on 2 contrasting pastures: an upgraded pasture, sown with newer cultivars of perennial ryegrass and subterranean clover (Trifolium subterraneum L.) with 26 kg phosphorus/ha.year, and a naturalised perennial ryegrass pasture receiving 6 kg phosphorus/ha.year. Paddocks were grazed by Border Leicester x Merino ewes, which were mated to a terminal sire to lamb in September. In this final paper of the series, the effects of the grazing systems and pasture treatments on animal production and herbage quality are presented. The liveweights of the ewes were similar across all treatments during autumn and winter, but the tactically stocked ewes were 3–6 kg lighter than continuously stocked ewes during spring and summer. The lower liveweight was attributed to the lower (P<0.001) herbage quality on the tactically stocked pastures in spring (P<0.001). Both digestibility and crude protein concentration were about 4 percentage units lower with tactical stocking in spring. This lower quality was associated with the higher herbage mass (by 500–900 kg dry matter/ha) on the tactically stocked pastures, which presumably had a higher stem:leaf ratio and showed reproductive growth earlier than the continuously stocked pastures. Although there were differences in ewe liveweight, this did not affect individual lamb weaning weight or ewe fleece weight. There were significant increases in production per hectare from tactically stocked or upgraded pasture treatments due to the higher stocking rates that could be carried, 9 and 51%, respectively. In 1998, 544 kilograms of lamb per hectare was weaned from continuously stocked paddocks and 607 kg/ha from tactically stocked paddocks (P<0.05), and 449 and 702 kg/ha from the typical and upgraded pastures, respectively. This study reinforces the view that soil fertility and pasture improvement have a much greater impact on animal productivity than changes to grazing method with little effect on per head productivity. The negative impact of rotational stocking on herbage quality reinforces the need to use these systems strategically when benefits from increased herbage mass are expected to increase animal production or overcome sustainability or pasture persistence problems.
42
Leddin, C. M., J. L. Jacobs, K. F. Smith, K. Giri, B. Malcolm e C. K. M. Ho. "Development of a system to rank perennial ryegrass cultivars according to their economic value to dairy farm businesses in south-eastern Australia". Animal Production Science 58, n.º 8 (2018): 1552. http://dx.doi.org/10.1071/an17815.
Texto completo da fonteResumo:
Dairy production systems in south-eastern Australia are based primarily on grazed pasture. Perennial ryegrass (Lolium perenne L.) is the major grass species used in this region and farmers are faced with the challenge of choosing from more than 60 commercially available cultivars. This paper describes the development of a system termed as a forage value index that ranks the overall performance of perennial ryegrass cultivars relative to cultivar Victorian according to the summation of the estimated difference in the value of seasonal dry-matter (DM) yield of the cultivars. Average predicted seasonal DM yields were calculated by analysing the results of eight available perennial ryegrass plot trials across south-eastern Australia, using a multi-environment, multi-harvest linear mixed model. The differences in the model-predicted DM yield of each cultivar was compared with cultivar Victorian in each of five seasonal periods (autumn, winter, early spring, late spring, summer) to generate a series of performance values (1 per period) for each cultivar. Each performance value was then multiplied by an economic value (AU$/kg extra pasture grown) relating to each of four regions (Gippsland, northern Victoria, south-western Victoria, Tasmania) and seasonal period and aggregated to generate an overall forage value index rating for each cultivar. Economic values ranged from AU$0.11 to AU$0.39 per extra kilogram of DM grown, depending on the season and region, which translated into estimated benefits on dairy farms of up to AU$183 per ha per year for farmers that use high-yielding cultivars in place of cultivar Victorian perennial ryegrass.
43
Ridley, A. M., R. J. Simpson e R. E. White. "Nitrate leaching under phalaris, cocksfoot, and annual ryegrass pastures and implications for soil acidification". Australian Journal of Agricultural Research 50, n.º 1 (1999): 55. http://dx.doi.org/10.1071/a98038.
Texto completo da fonteResumo:
Nitrogen uptake and nitrate (NO-3) leaching below 1.1 m was estimated under phalaris, cocksfoot, and annual ryegrass pastures and under bare fallow in a 4-year field experiment under control and high N (500 kg N/ha) treatments in north-eastern Victoria (693 mm/year rainfall for the study period). The perennial grasses, particularly phalaris, took up more N in herbage than annual ryegrass. High concentrations of NO3-N were measured at 1 m depth below all treatments, suggesting that NO3- losses from pastures have potential to contaminate streams and/or groundwater. Perennial pastures were only able to reduce NO3- leaching compared with annuals in drier than average years. Values calculated for acid addition due to NO3-leaching resulted in a net annual input of approximately 1 kmol H +/ha.year under the phalaris pasture compared with 2 kmol H +/ha.year under annual ryegrass. Adding these figures to carbon cycle addition data of 1 kmol H+/ha.year (measured in a previous study) corresponds to a lime rate of 100 and 150 kg lime/ha.year being required to stop further acidification under these pasture types. A 1 unit pH decline to 30 cm depth was estimated to take 42 years under annual pasture or 67 years under perennial grasses. Whilst perennial pastures have a role in reducing soil acidification, lime application is the most important management option in balancing soil acidification caused by agriculture.
44
Nie, Z. N., D. F. Chapman, J. Tharmaraj e R. Clements. "Effects of pasture species mixture, management, and environment on the productivity and persistence of dairy pastures in south-west Victoria. 1. Herbage accumulation and seasonal growth pattern". Australian Journal of Agricultural Research 55, n.º 6 (2004): 625. http://dx.doi.org/10.1071/ar03174.
Texto completo da fonteResumo:
An experiment was conducted on 2 contrasting soil types for 4 years (1998–2001) to determine the effects of plant species mixture, management inputs, and environment on sown species herbage accumulation (SSHA) and seasonal growth pattern of pastures for dairy production. Five pasture types, combined with 3 management treatments, were established in south-west Victoria. Three of the pasture types were based on perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.). One pasture type included short-term, winter- or summer-active species in the perennial ryegrass–white clover mixture. The final pasture type was based on the perennial grasses cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), and phalaris (Phalaris aquatica L.). The 3 management treatments involved different levels of fertiliser input and weed/pest control. Pasture type had a significant impact on SSHA in 3 of 4 years. In the first year, the mixture based on cocksfoot, tall fescue, and phalaris had the lowest SSHA, but this pasture matched other types from 1999 onwards and yielded the highest in 2000, the year with the driest summer during the experiment. Ryegrass–white clover mixture based on old cultivars had generally lower SSHA than the other types except in the first year. Higher fertiliser inputs increased SSHA by 16–28% in 1998, 1999, and 2001. There was a significant site × pasture type interaction on SSHA in 2000. The mixture based on cocksfoot, tall fescue, and phalaris produced up to 1–2 t DM/ha.year more than the other types in summer and autumn in dry–normal years. The inclusion of short-term species, or more stoloniferous white clover cultivars, in the ryegrass–white clover mixture, had little effect on SSHA, or on the seasonal distribution of pasture growth. Pastures based on perennial grasses other than perennial ryegrass appear to have potential for altering the seasonality of pasture growth in south-west Victoria, although the benefits resulting from changing pasture type will depend on environment. Overall, increasing management inputs usually had a greater effect on SSHA than changing pasture type, but management responses were also affected by environment, particularly through the effects of a dry season on a sandy soil type.
45
Henskens, F. L. F. "The biology and management of Axonopus affinis (Chase) in Australian pastures". Australian Journal of Agricultural Research 48, n.º 8 (1997): 1219. http://dx.doi.org/10.1071/a97023.
Texto completo da fonteResumo:
Carpetgrass (Axonopus affinis Chase) was described in terms of its botany, origin, distribution, seasonal growth, habitat, and dispersal. Factors that determine its agronomic importance were examined. Emphasis was given to management and ecological factors which influence competition between carpetgrass and sown pasture species. It is concluded that the management strategies that have been developed and successfully adopted in Queensland and New South Wales need to be tested for use in irrigated pastures in northern Victoria
46
Waller, R. A., P. W. G. Sale, G. R. Saul e G. A. Kearney. "Tactical versus continuous stocking in perennial ryegrass-subterranean clover pastures grazed by sheep in south-western Victoria. 2. Ryegrass persistence and botanical composition". Australian Journal of Experimental Agriculture 41, n.º 8 (2001): 1109. http://dx.doi.org/10.1071/ea01018.
Texto completo da fonteResumo:
A 4-year field experiment was carried out in south-western Victoria to determine whether tactical stocking might improve perennial ryegrass (Lolium perenne L.) persistence and prime lamb production, compared with the more common practice of continuous stocking. Tactical stocking consisted of variable-length summer, autumn and winter rotations and continuous stocking in spring. The 2 grazing strategies were compared on 2 contrasting pastures: an upgraded pasture, sown with newer cultivars of perennial ryegrass and subterranean clover (Trifolium subterraneum L.) with 26 kg phosphorus/ha.year, and a more typical naturalised perennial ryegrass pasture receiving 6 kg phosphorus/ha.year. Paddocks were grazed by Border Leicester x Merino ewes, which were mated to a terminal sire to lamb in September. The effects of the grazing systems and pasture treatments on ryegrass persistence and pasture botanical composition are presented in this paper. The perennial ryegrass component of the sward decreased from an average mass of 1000 kg dry matter/ha on the upgraded pasture and 400 kg dry matter/ha on the typical pasture in spring 1996 to 100 kg dry matter/ha and <50 kg/ha for the 2 pasture types, respectively, in spring 1998. This occurred irrespective of the grazing system imposed. The decline of ryegrass was attributed to several factors including the very dry 3-year period, summer rainfall events that caused ryegrass buds to break dormancy then die when dry conditions resumed, the gravelly soil type where the experiment was located, and the high grazing pressure used. A number of species became more prevalent in the pastures as the ryegrass disappeared. Silver grass (Vulpia spp.) increased 4–5-fold on all treatments. By the fourth year, barley grass (Hordeum leporinum) and Bromus spp. had increased significantly with tactical stocking compared with continuous stocking. Capeweed (Arctotheca calendula L.) and Erodium spp. increased on both the continuously stocked and upgraded pastures. The subterranean clover component was maintained across all treatments over the 4 years, indicating that tactical stocking did not adversely affect clover persistence. Since ryegrass declined irrespective of treatment, the tactical stocking system used in this study cannot be recommended for improving ryegrass persistence.
47
Ford, GW, JJ Martin, P. Rengasamy, SC Boucher e A. Ellington. "Soil sodicity in Victoria". Soil Research 31, n.º 6 (1993): 869. http://dx.doi.org/10.1071/sr9930869.
Texto completo da fonteResumo:
This paper gives a broad overview of the distribution and agricultural importance of sodic soils in Victoria. Sodic soils are estimated to occupy at least 13.4 Mha, representing at least 73% of Victoria's agricultural land. Most of this land is used for dryland farming; about 85% of the cropped land and 66% of the land sown to dryland pastures occurs on sodic soils. The largest sodicity class is 'alkaline sodic', dominated by a diverse range of soils (red duplex, yellow duplex, calcareous earths and self-mulching cracking clays). Alkaline sodic soils comprise half of the total agricultural land area, or about 24% of the area of land currently used for dryland cropping and 21% of the land under sown pasture. Land degradation problems are recognized as affecting most agricultural land in Victoria, and to be substantially limiting its productivity. The nature, extent and severity of the various forms of land degradation are a consequence of both intrinsic soil properties and of management practices. There is an urgent need to improve current farming practices to prevent further deterioration of the soil resource. Existing knowledge of the behaviour of sodic soils under both dryland and irrigated agriculture is reviewed. It is concluded that substantial gains in productivity are possible, but will require effective collaboration between soil scientists, agronomists, and land managers. Collation and integration of current knowledge on the properties and management of sodic soils in Victoria, and the acquisition of additional relevant information by targeted long-term research is required. Key issues for future research are identified.
48
Ridley, A. M., B. P. Christy, R. E. White, T. McLean e R. Green. "North-east Victoria SGS National Experiment site: water and nutrient losses from grazing systems on contrasting soil types and levels of inputs". Australian Journal of Experimental Agriculture 43, n.º 8 (2003): 799. http://dx.doi.org/10.1071/ea02090.
Texto completo da fonteResumo:
Water and nutrient losses, pasture and animal production were measured for a prime lamb enterprise at Maindample (rainfall 750 mm/year) and a wool enterprise at Ruffy (rainfall 671 mm/year) in north-east Victoria from 1998 to 2000. Each site comprised 3 paddock-scale treatments: control, unsown pasture receiving about 5�kg�phosphorus (P)/ha.year; medium input, sown pasture (about 10 kg P/ha.year); and high input, sown pasture (≥22 kg P/ha.year). Sown pastures were based on phalaris (Phalaris aquatica L.) at Maindample and cocksfoot (Dactylis glomerata L.) at Ruffy, and sheep were set stocked. Pastures at Maindample created a larger soil water deficit (commonly about 120 mm) compared with Ruffy (about 70 mm) in summer. Maximum soil water deficit at Maindample occurred under the high input pasture and was about 30 mm greater than the medium or control treatments. Phalaris content ranged between about 200 and 1300 kg DM/ha, between 10 and 70% of total composition (commonly about 20%). In contrast, at Ruffy the control, which had 20–40% native grasses (Austrodanthonia and Microlaena) achieved the greatest soil water deficit, about 25 mm greater than for sown pastures. Cocksfoot persisted poorly at the acid soil at Ruffy. Small differences in green leaf area over summer (about 200 kg DM/ha) between treatments could generate the soil water deficit differences over the summer.The most striking result was the markedly different pathways of water loss between surface losses and deep drainage at the 2 sites, which was of greater consequence than the effect of pasture type. At Maindample, on average, 166 mm of water was lost annually (22% of rainfall) with 110 mm of this as surface runoff. At Ruffy, annual water loss was 128 mm (19% of rainfall) with 110 mm of this total water loss estimated as loss through deep drainage.Phosphorus losses were low in all treatments (≤1 kg P/ha.year), and nitrate-N (NO3-N) losses (7–12 kg N/ha.year) were comparable with previous work. Concentrations of P in water were highest from the high treatments at both sites, averaging 0.91 and 0.83 mg P/L in surface runoff from Maindample high and Ruffy high treatments, respectively. Average soil water NO3-N concentrations ranged from 3 to 26 mg N/L. Both P and N concentrations were higher than acceptable for aquatic health.Environmental risks in terms of water and nutrient losses could be either higher or lower for sown than unsown pastures, depending upon soil type, botanical stability, persistence and the soil water extracting ability of the pasture. Results indicated that better environmental outcomes could be achieved if soil types were targeted for particular land uses. High management skills are needed if grazing enterprises are to be both profitable and have lower off-site impacts.
49
Riffkin, Penny A., Paul E. Quigley, Fiona J. Cameron, Mark B. Peoples e Janice E. Thies. "Annual nitrogen fixation in grazed dairy pastures in south-western Victoria". Australian Journal of Agricultural Research 50, n.º 2 (1999): 273. http://dx.doi.org/10.1071/a98034.
Texto completo da fonteResumo:
Amounts of biologically fixed nitrogen (kg N/ha) were determined in grazed dairy pastures in 3 different areas of south-western Victoria over 12 months between October 1995 and 1996 using measurements of pasture growth, botanical composition, and the 15N natural abundance of white clover (Trifolium repens) and non-legume components. Estimates of the amounts of N fixed, based on N in clover shoots, were similar in each pasture (11, 16, and 18 kg N/ha.year), despite different environmental and management conditions. These on-farm determinations were low compared with experimental studies on N fixation by white clover undertaken in New Zealand (224–291 kg N/ha.year) and elsewhere in Australia (44–135 kg N/ha). Low fixation levels were attributed to low pasture yields (average 8.2 t dry matter (DM)/ha.year) and poor legume content in the swards (average 8%). Despite this, most of the white clover N was derived from atmospheric N2 (65%), and therefore, N fixation could potentially be playing an important role in the N economy of milk production on these farms.
50
White, R. E., K. R. Helyar, A. M. Ridley, D. Chen, L. K. Heng, J. Evans, R. Fisher et al. "Soil factors affecting the sustainability and productivity of perennial and annual pastures in the high rainfall zone of south-eastern Australia". Australian Journal of Experimental Agriculture 40, n.º 2 (2000): 267. http://dx.doi.org/10.1071/ea98013.
Texto completo da fonteResumo:
A field study was carried out in the high rainfall zone (HRZ, >600 mm p.a.) of southern Australia from March 1994 to August 1997 to test the hypothesis that sown perennial grasses and liming could make the existing pastures more sustainable through better use of water and nitrogen. The site, on an acid duplex soil at Book Book near Wagga Wagga in southern New South Wales, was typical of much of the HRZ grazing country in southern New South Wales and north-east Victoria. The experiment consisted of 4 replicate paddocks (each 0.135 ha) of 4 treatments: annual pasture (mainly ryegrass Lolium rigidum, silver grass Vulpia spp., subterranean clover Trifolium subterraneum and broadleaf weeds) without lime, annual pasture with lime, perennial pasture (phalaris Phalaris aquatica, cocksfoot Dactylis glomerata and subterranean clover T. subterraneum) without lime, and perennial pasture with lime. Soil pH (0–10 cm) in the limed treatments was maintained at 5.5 (0.01 mol/L CaCl2), compared to 4.1 in the unlimed treatments. The pastures were rotationally grazed with Merino ewe or wether hoggets at a stocking rate which varied with the season, but was 10–25% higher on the limed pastures [14.8–17.3 dry sheep equivalent (dse)/ha] than the unlimed pastures. One replicate set of pasture treatments was intensively monitored for surface runoff, subsurface flow (at the top of the B horizon), water potential gradients and ammonium volatilisation. Other measurements of nitrogen inputs, transformations and losses were made on all paddocks. In a normal to wet year, surface runoff, subsurface flow and deep drainage (>180 cm depth) were about 40 mm less from the perennial than the annual pastures. The reduction in deep drainage under the perennials was about one-third to one-half (20–29 mm/year). The smaller loss of solution NO3– from the perennial pastures (up to 12 kg N/ha.year) suggested soil acidification under perennials was reduced by about 1 kmol H+/ha.year. Denitrification and volatilisation losses of N were small (1–12 kg N/ha.year). Nitrogen fixed by subterranean clover (above ground parts) ranged from 2–8 kg N/ha in the drought of 1994–95 to 128 kg N/ha in a normal year (1996). The soil-pasture nitrogen balance was positive for all treatments and averaged 76 kg N/ha.year over 2 years. The abundance of introduced and native earthworms increased from 85 to 250/m2 in the limed pastures between 1994 and 1997. Introduced species, such as Aporrectodea trapezoides, were especially responsive to lime. Animal production per hectare was 10–25% higher on pastures with lime. Critical gross margins per dse were lowest ($16/ha) for a long-lived perennial pasture (>15 years), and highest ($20/ha) for a short-lived perennial (5 years). Overall, there were substantial benefits in animal production, improved soil quality and water use from establishing perennial grass pastures with lime on these strongly acid soils.