bluuebunny/crossref_metadata_2025 huggingface dataset:
The prediction of retail beef yield from real time ultrasound measurements on live animals at three stages through growout and finishing
Authors: Wolcott M. L. , Thompson J. M. , Perry D.
Published: September 2002

Analyses were performed to test the relationship between retail beef yield
percentage (RBY) and real time ultrasound measurements taken at weaning, entry
to finishing and preslaughter for animals finished under pasture and feedlot
conditions to meet domestic, Korean and Japanese market specifications.
The first analysis tested the power of live animal measurements (scanned P8
fat depth, scanned eye muscle area and liveweight) to predict RBY and
contrasted this with a model containing these live animal measurements plus a
term (HERD × KILL ) which accounted for all known classification
variables. This indicated that scanned P8 fat depth, measured at slaughter,
was the most useful predictor of retail beef yield, accounting for 52%
of the variation in RBY for the equation containing live animal measurements
alone. The power of live animal measurements to predict RBY decreased as the
time between scanning and slaughter increased. Models which included HERD
× KILL predicted RBY accurately (accounting for 82–86%
of the variation in RBY), but live animal measurements contributed little to
this result, accounting for only 8% of the variation in RBY for
measurements at slaughter in the presence of the HERD × KILL term.
A second analysis examined whether market category, finishing regime or breed
classifications consistently influenced the relationship between the measured
traits and RBY at the 3 scanning times. The magnitude of the variation between
significantly different coefficients (for scanned P8 fat depth, scanned eye
muscle area and liveweight) was generally small, though the results suggested
that in some instances, developing separate equations for animals of different
classifications would marginally improve the accuracy of RBY prediction.
The final analysis investigated the improvement in RBY prediction when
measurements from entry to finishing were included with those taken before
slaughter. HERD × KILL was included in the model to account for all
known classification variables. Measurements of both P8 fat depth and EMA from
the earlier measurement time were significant predictors of RBY in the
presence of the corresponding measurement at slaughter, but accounted for an
increase in R 2 of only 0.0007. It
was concluded that a single scan and liveweight measurement, close to
slaughter, would provide the best live animal measurements for RBY prediction,
and that no improvement in accuracy would be achieved by additional scans
taken earlier in an animal’s life.
Commercial cane sugar trends in the Tully sugar district
Authors: Lawes R. A. , Wegener M. K. , Basford K. E. , Lawn R. J.
Published: September 2002

Commercial cane sugar (CCS), as measured by sugar mills, is in decline in the
wet tropics of Australia. One of these mills, Tully Sugar Ltd, has measured
CCS in the factory as required by legislation and also measured whole clean
stalk CCS through a small mill, which is free of contaminants. ‘Factory
CCS’ measures the CCS of cane entering the mill, after it has been
harvested. The harvesting and transport process delivers to the mill cane that
is contaminated by extraneous matter such as leaf material and soil. Beween
1988 and 1998, 1516 blocks were sampled for ‘small mill CCS’.
These data were combined with block productivity information to determine the
trends in small mill CCS and factory CCS using a linear mixed model analysis
as the data were unbalanced. Other data, including the date of harvest for
factory CCS, date of sampling for small mill CCS, farm of origin and cane
variety were available and fitted as random effects in the mixed model. Year
was fixed to determine time related trends in the 2 measures of CCS. Small
mill CCS was higher than factory CCS and remained constant from 1988 to 1998.
Predicted factory CCS declined from 12.76 units in 1988 to 10.91 units in
1998. We conclude that the CCS levels in whole clean stalks were actually
stable, since small mill CCS remained constant over the 10-year period.
Possible reasons for the differences in the trends for the 2 CCS measures are
discussed.
Occurrence of Phytophthora clandestina in Trifolium subterraneum paddocks in Australia
Authors: Aldaoud R. , Guppy W. , Callinan L. , Flett S. F. , Wratten K. A. , Murray G. A. , Cook T. , McAllister A.
Published: September 2002

In 1995–96, a survey of soil samples from subterranean clover
(Trifolium subterraneum L.) paddocks was conducted
across Victoria, South Australia, New South Wales and Western Australia, to
determine the distribution and the prevalence of races of
Phytophthora clandestina (as determined by the
development of root rot on differential cultivars), and the association of its
occurrence with paddock variables. In all states, there was a weak but
significant association between P. clandestina detected
in soil samples and subsequent root rot susceptibility of differential
cultivars grown in these soil samples.
Phytophthora clandestina was found in 38% of the
sampled sites, with a significantly lower prevalence in South Australia
(27%). There were significant positive associations between
P. clandestina detection and increased soil salinity
(Western Australia), early growth stages of subterranean clover (Victoria),
mature subterranean clover (South Australia), recently sown subterranean
clover (South Australia), paddocks with higher subterranean clover content
(Victoria), where herbicides were not applied (South Australia), irrigation
(New South Wales and Victoria), cattle grazing (South Australia and Victoria),
early sampling dates (Victoria and New South Wales), sampling shortly after
the autumn break or first irrigation (Victoria), shorter soil storage time
(Victoria) and farmer’s perception of root rot being present (Victoria
and New South Wales). Only 29% of P. clandestina
isolates could be classified under the 5 known races. Some of the unknown
races were virulent on cv. Seaton Park LF (most resistant) and others were
avirulent on cv. Woogenellup (most susceptible). Race 1 was significantly less
prevalent in South Australia than Victoria and race 0 was significantly less
prevalent in New South Wales than in South Australia and Western Australia.
This study revealed extremely wide variation in the virulence of
P. clandestina. The potential importance of the results
on programs to breed for resistance to root rot are discussed. in South
Australia.
Inter-seasonal population dynamics and cultural management of Helicoverpa spp. in a Central Queensland cropping system
Authors: Sequeira R.
Published: September 2002

A strategic trap cropping program targeting Helicoverpa
spp. on cotton was developed and implemented in the Emerald irrigation area of
Central Queensland beginning in the winter of 1997. Growers were advised to
plant 1% of total cropping area to a trap crop of chickpea
(Cicer arietinum) in winter and pigeon pea
(Cajanus cajan) in summer. The population dynamics of
Helicoverpa spp. in relation to the Emerald cropping
system was studied over a 3-year period (August 1996–July 1999) to
provide a framework for testing the validity of key assumptions underlying the
trap cropping strategy and optimising the implementation of the program.
The population dynamics study showed continuous production of
Helicoverpa pupae (moths) in the crop production system
during each calendar year. The pattern of pupae production was consistent with
cycling of Helicoverpa populations between irrigation
and rainfed cropping components of the system. Spring rainfall and the
availability of host plant resources is shown to impact on the population
dynamics of Helicoverpa in the cropping system and its
pest status on early-season cotton. Performance and potential impact of the
trap crops are discussed within the context of host plant availability and
resource bottlenecks. It is shown that the impact of the trap crops on
abundance of Helicoverpa spp. early in the growing
season could not be distinguished from that of naturally occurring host plant
resource bottlenecks in spring most likely as a result of suboptimal timing of
trap crop destruction. The potential contribution of cultural control tactics
to integrated pest management of Helicoverpa spp. in
cropping systems is discussed.
Measuring the relative economic costs of legume and fertiliser nitrogen
Authors: Brennan J. P. , Evans J.
Published: September 2002

In assessing the economics of nitrogen in a farming system, there is a need to
assess the full economic costs and benefits of each potential source of
nitrogen. In this paper, the basis for measuring and comparing the full
economic costs of fertiliser and legume nitrogen is explored. The relative
costs of different forms of nitrogen for the South-West Slopes of New South
Wales are examined, to identify the least-cost forms of nitrogen. The results
indicate that legume nitrogen can be cheaper or more costly than fertiliser
nitrogen, depending on the legume used and that different outcomes can be
obtained when different time horizons are used in assessing the cost of the
nitrogen. Therefore, farmers need to make those comparisons for their
particular situation before they can make informed decisions on the farm.
Farmers need to be aware of these issues if they are to make fully informed
decisions about their nitrogen use.
Sultana fruitfulness and yield: responses to rootstock and nitrogen supply
Authors: Treeby M. T.
Published: September 2002

Nitrogen supply to irrigated Sultana grapevines on own roots or on Ramsey
rootstock was varied in a field trial conducted at Irymple, north-western
Victoria, over 3 seasons. The nitrogen treatments imposed were 0, 40 and 80 kg
N/ha.year supplied in 4 equal applications (2 pre-flowering — late
September and mid-October; 1 post-flowering — mid-November; 1
post-harvest — late February) Yields of dried vine fruit were responsive
to both nitrogen supply and rootstock. Despite lower bud fertility, Sultana on
Ramsey rootstock out-yielded Sultana on own roots due to greater numbers of
1-year-old canes suitable as bearers, more berries per bunch and larger
berries. Yield of Sultana on own roots responded in a similar manner to
increasing nitrogen supply as yield of Sultana on Ramsey rootstock. Yield
increases were due to improved bearing potential (more suitable bearers) and
more berries per bunch when nitrogen supply increased from 0 to 40 kg
N/ha.year. When nitrogen supply was raised from 40 to 80 kg N/ha.year,
a further yield increase was due to enhanced bud fertility and larger berries.
These yield components behaved differently for Sultana on own roots compared
with Sultana on Ramsey rootstock, but, overall, balanced out such that final
yield was not affected by rootstock. Consequently, rootstock was not a
significant factor in the dried vine fruit yield response of Sultana to
nitrogen supply.
Post-weaning growth of cattle in northern New South Wales. 3. Carry-over effects on finishing, carcass characteristics and intramuscular fat
Authors: Robinson D. L. , Oddy V. H. , Dicker R. W. , McPhee M. J.
Published: September 2002

The effects of prior growth on subsequent growth and body composition of
cattle potentially affect the profitability of growing cattle to meet
specifications based on weight and fatness. The effects of different growth
rates and patterns of growth between weaning (about 230 kg) and entry to
finishing (average 400 kg) on growth rate, carcass characteristics and
intramuscular fat content of steers finished on pasture and in a feedlot on a
predominantly grain ration to 2 liveweights (520 kg, Korean and >600 kg,
Japanese) are reported here. Over a period of 4 years (1994–1997), 1095
Bos taurus steers of 4 breeds (Angus, Hereford, Murray
Grey and Shorthorn), were allocated to 1 of 3 grow-out pathways from weaning
until entry into finishing. The pathways were based on introduced pasture
(P1), with different animal growth rates induced by strategic supplementation
with a pelleted concentrate feed (P2), or a forage crop (P3) (Ayres
et al. 2001; Dicker et al. 2001).
In general, the mean growth rate of steers from the different growth pathways
during finishing was inversely related to mean growth rate during grow-out.
However, where the difference in liveweight at the end of grow-out was greater
than 15 kg, increased growth rate during finishing was insufficient to permit
complete catch up of liveweight by the end of finishing. There was no further
compensation beyond 520 kg liveweight. Steers with better nutrition during
grow-out tended to have more intramuscular fat at Japanese market weights, but
lower retail meat yield. Steers finished on pasture had less fat thickness and
intramuscular fat content than those finished on the grain based ration.
Compared with P3 steers, there was a tendency for steers from pathways P1 and
P2 to have lower intramuscular fat content in their
M. longissimus at Japanesese market weights.
Significance of gaseous nitrogen loss from a tropical dairy pasture fertilised with urea
Authors: Prasertsak P. , Freney J. R. , Denmead O. T. , Saffigna P. G. , Prove B. G.
Published: September 2002

This paper reports a study in the wet tropics of Queensland on the fate of
urea applied to a dairy pasture in the absence of grazing animals. A nitrogen
balance was conducted in cylindrical plots with
15N-labelled urea, and ammonia volatilisation was
determined using a mass balance micrometeorological method. The pasture plants
took up 42% of the applied nitrogen in the 98 days between fertiliser
application and harvest. At harvest 18% of the applied nitrogen was
found in the soil, and 40% was lost from the plant–soil system.
The micrometeorological study showed that 20% of the unrecovered
nitrogen was lost by ammonia volatilisation. As there was no evidence for
leaching or runoff losses it was concluded that the remaining 20% of
the applied nitrogen was lost by denitrification. It is evident from these
results that fertiliser nitrogen is not being used efficiently on dairy
pastures, and that practices need to be changed to conserve fertiliser
nitrogen and reduce contamination of the environment.
Impact on soil hydraulic properties resulting from irrigating salinesodic soils with low salinity water
Authors: Bethune M. G. , Batey T. J.
Published: September 2002

Irrigation-induced salinity is a serious problem facing irrigated areas in the
Murray–Darling Basin of Australia. Groundwater pumping with farm re-use
for irrigation is a key strategy for controlling salinity in these irrigation
areas. However, the re-use of highly saline–sodic groundwater for
irrigation leads to accumulation of sodium in the soil profile and can result
in sodic soils. Leaching of saline–sodic soils by winter rainfall and
low salinity irrigation waters are 2 management scenarios likely to exacerbate
sodicity problems. Characteristic to sodic soils is poor soil structure and
potentially reduced soil permeability. Two indicators of soil permeability are
infiltration rate and hydraulic conductivity.
A replicated plot experiment was conducted to examine the long-term impact of
irrigation with saline–sodic water on soil permeability. High levels of
soil sodicity (ESP up to 45%) resulted from 10 years of saline irrigation.
Over this period, leaching by winter rainfall did not result in long-term
impacts on soil hydraulic properties. Measured soil hydraulic properties
increased linearly with the salinity of the applied irrigation water. Leaching
by irrigating with low salinity water for 13 months decreased soil salinity
and sodicity in the topsoil. The resulting reduction in steady-state
infiltration indicates soil structural decline of the topsoil.
This trial shows that groundwater re-use on pasture will result in high sodium
levels in the soil. Sodicity-related soil structural problems are unlikely to
develop where there is consistent groundwater irrigation of pasture. However,
structural decline of these soils is likely following the cessation of
groundwater re-use.
Response of grapevines to irrigation-induced salinesodic soil conditions
Authors: Stevens R. M. , Walker R. R.
Published: September 2002

The responses of grapevines (Vitis vinifera L.),
ungrafted and grafted to Ramsey rootstock, to saline irrigation have been
investigated in drip-irrigated trials at Loxton, Dareton and Merbein in the
Riverland–Sunraysia region of the southern Murray–Darling Basin.
Soil type and climate were similar across the sites and the characteristics of
the soils were monitored in relation to salinity treatment. The treatments
involved application of defined irrigation water salinities throughout the
season at Merbein and Dareton, while at Loxton, a high salinity treatment was
applied between flowering and veraison with low salinity being applied in the
remainder of the season. Between-site comparisons of the same rootstock or
same cultivar in the fifth season of irrigation show that for water of similar
salinity (volume weighted electrical conductivity of 1.4–1.6 dS/m), the
ion accumulation patterns were not equivalent.
Leaf petiole sodium ion (Na+) and chloride ion
(Cl–) concentrations in ungrafted Sultana vines at
Dareton were 2-fold those at Merbein, which aligned with differences in
electrical conductivity of the soil saturation paste extract. Differences
between salinity of soil and ion content of leaves at the 2 sites were
attributed to different irrigation management with the estimated leaching
fraction at Merbein nearly double that at Dareton. The average
ECe at Loxton was equivalent to that at Merbein.
However, the leaf lamina Cl– in vines grafted to
Ramsey rootstock at Loxton was 2-fold that at Merbein and leaf lamina
Na+ was 10-fold.
Cultivar differences between the 2 sites — Sultana at Merbein and
Colombard at Loxton — may explain a small part of the increase in leaf
Na+ and most of that in leaf
Cl–. However, a far more plausible explanation is
that vines at Loxton experienced transient waterlogging which increased their
uptake of both Na+ and Cl–,
and increased the rate of Na+ uptake relative to that of
Cl–. Transient waterlogging was probably caused by
a combination of soil sodicity, small excesses in irrigation, and the
combination for part of the season of low electrolyte concentration and high
sodium adsorption ratio in the soil solution. Under waterlogged conditions,
the uptake of Na+ relative to
Cl– at Loxton would have been further enhanced by
the inherent differences between Loxton and Merbein in the properties of the
soil solution. The soil solution at Loxton had a higher Na:Cl ratio.
Germination response to temperature in tropical and subtropical pasture legumes. 2. Alternating temperature
Authors: McDonald C. K.
Published: September 2002

The germination response of 8 promising and commonly used tropical and subtropical legumes in northern Australia was tested at a range of alternating temperatures. Except at temperatures <20°C or >36°C, total germination was largely unaffected by different alternating temperatures. Although there were statistically significant differences between constant and alternating temperatures, overall, these differences were <2% and hence of no biological importance. Increasing amplitude of fluctuation in temperature decreased the rate of germination for some species. At 8°C amplitude Glycine latifolia, Macroptilium atropurpureum and Lablab purpureus showed no difference in the time taken to reach 50% of germination while Chamaecrista rotundifolia, Stylosanthes scabra and Desmanthus virgatus took 1.5-2 times as long as at constant temperature. Predicted germination against real time, using 2 different models, fitted the observed data poorly. In particular, prediction of the commencement of germination was poor for C. rotundifolia and S. scabra. This failure at more extreme or highly fluctuating temperatures indicates that further development is required before the models would be sufficiently reliable for inclusion in simulation models of legume persistence. In particular, the rate of death of seeds at temperatures distant from the optimum range needs to be included. The ability to germinate at a broad range of temperatures indicates that the species are well adapted to northern Australia. Some species may be susceptible to large fluctuations in temperature during germination, and this should be considered in criteria for selecting future species.
Survey of fungi and nematodes associated with root and stolon diseases of white clover in the subtropical dairy region of Australia
Authors: Zahid M. I. , Gurr G. M. , Nikandrow A. , Hodda M. , Fulkerson W. J. , Nicol H. I.
Published: September 2002

A survey of 12 white clover-based dairy pastures on the north coast of New
South Wales and south-eastern Queensland, Australia, detected 65 species of
fungi and 6 nematode species. The fungi included species of
Fusarium, Gliocladium,
Codinaea, Alternaria,
Colletotrichum, Drechslera,
Rhizoctonia, Phoma,
Pythium, Phytophthora,
Penicillium, Rhizopus and
Trichoderma from roots and stolons of white clover.
Fungal rots of roots and stolons were most severe during the summer months
(November and January samples), while root-knot symptoms caused by plant
parasitic nematodes were more severe in June. Sedentary endoparasitic
nematodes Meloidogyne trifoliophila,
Heterodera trifolii and the ectoparasitic nematode
Helicotylenchus dihystera were the numerically dominant
nematodes in the region. Other nematode species, including
Pratylenchus, Xiphinema and
Tylenchorhynchus, were present at lower frequencies and
principal component analysis indicated that these were less important as white
clover pathogens. Meloidogyne trifoliophila was detected
for the first time in Australia and was present at all sites. Many of the
fungi and nematodes found are common pathogens of white clover. These
pathogens are likely to be contributing to the poor seedling performance,
growth and persistence of white clover typical in dairy pastures of the
subtropical east coast of Australia.
Improvement of postharvest vase life and flower bud opening in Polianthes tuberosa using gibberellic acid and sucrose
Authors: Su Wei-Ren , Huang Kuang-Liang , Chang Ping-Shun , Chen Wen-Shaw
Published: September 2002

Pulsing with gibberellic acid followed by continuous sucrose treatment
enhanced flower longevity and flower bud opening in cut
Polianthes tuberosa L. cv. Double. Pulsing with
gibberellic acid at 10 or 20 mg/L plus 8-hydroxyquinoline sulfate (200
mg/L) for 24 h followed by continuous sucrose treatments (4 or 8%)
plus 8-hydroxyquinoline sulfate extended the vase life and significantly
promoted flower bud opening as compared with the 8-hydroxyquinoline sulfate
controls. A pulse with a higher concentration of gibberellic acid (50
mg/L) followed by sucrose solutions did not increase vase life or enhance
flower bud opening greater than those pulsed with gibberellic acid at 10 or 20
mg/L followed by 8-hydroxyquinoline sulfate. A gibberellic acid (10, 20 or
50 mg/L) pulse followed by 8-hydroxyquinoline sulfate holding solution had
little effect on longevity and flower bud opening in comparison to
8-hydroxyquinoline sulfate controls. Similarly, continuous sucrose treatment
at 4 or 8% without a gibberellic acid-pulsed treatment also showed
little effect on vase life and flower bud opening. Cut
P. tuberosa treated with a gibberellic acid pulse
followed by 8-hydroxyquinoline sulfate produced more ethylene than those
treated with 8-hydroxyquinoline sulfate alone. Ethylene production from
flowers pulsed with gibberellic acid followed by sucrose was low when compared
with controls or those pulsed with gibberellic acid alone. Cut stems
continuously placed in solutions containing sucrose produced less ethylene
than those without sucrose. It is suggested that a gibberellic acid pulse at
10 mg/L followed by continuous sucrose treatment at 4% be
recommended to growers for extending the vase life and enhancing flower bud
opening in cut P. tuberosa.
Tactical versus continuous stocking in perennial ryegrass-subterranean clover pastures grazed by sheep in south-western Victoria. 2. Ryegrass persistence and botanical composition
Authors: Waller R. A. , Sale P. W. G. , Saul G. R. , Kearney G. A.
Published: September 2002

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.
A survey of farmers' attitudes, management strategies and use of weather and seasonal climate forecasts for coping with climate variability in the perennial pasture zone of south-east Australia
Authors: Austen E. A. , Sale P. W. G. , Clark S. G. , Graetz B.
Published: September 2002

A survey of 62 producers in the perennial pasture zone of south-eastern
Australia was undertaken to gain an understanding of farmer attitudes toward
climate variability, the use of weather and seasonal climate forecasts on
farms and how climatic variability affects farm management. The 3 localities
surveyed were Hamilton and surrounding districts in south-western Victoria,
Lucindale and Naracoorte districts of south-eastern South Australia, and
Campbell Town, Ross and Bothwell districts of North Central and upper Derwent
Valley regions of Tasmania. Farmers in all districts considered winter
rainfall to be the most reliable in terms of consistency, while autumn
rainfall was the least reliable but had the greatest impact on production.
Perceptions of seasonal rainfall variability and its impact were influenced by
stocking rates; farmers with more heavily stocked properties considered
rainfall in the growing season to be less reliable than did farmers with lower
stocking rates and that autumn and winter rainfall had a greater impact on
production.
All farmers had strategies to manage their grazing enterprises in response to
the prevailing season’s climate conditions, but not all available
strategies were used. All participants fed supplements in poorer seasons while
Tasmanian farmers tended to reduce stock numbers more in poorer seasons than
did Victorian farmers. All the farmers used short-term weather forecasts to
help make decisions about farm management, with 100% of farmers in all
3 states using radio and television forecasts and sheep graziers’
warnings. However, farmers felt that many other forecasts were unreliable and
they were often were unwilling to incorporate them into decision making. Less
than 50% of farmers had read or heard about the 3-month seasonal
climate outlook and they were not willing to base management decisions on
these outlooks.
The uptake of information technology and the use of the Internet amongst
farmers in the perennial pasture zone have increased rapidly, with an average
of 76% of farmers using a computer and 30% connected to the
Internet. Computers were mainly used for financial and farm management, while
the Internet was mainly used for farm information. The education level
attained by the farmer was the main factor that influenced the uptake and use
of information technology.
Soil properties, root responses and production of irrigated pasture on a red-brown earth after subsoil modification
Authors: Blaikie S. J. , Hirth J. R. , Greenwood K. L. , Olsson K. A. , Dellow K. E. , Kelly K. B.
Published: September 2002

Soils used for growing irrigated pasture in northern Victoria have shallow (0.10-0.15 m) topsoils and dense, clay subsoils. Reducing soil limitations to root growth and function has the potential to increase pasture production. Therefore, subsoil modification treatments, comprising loosening and fragmentation of the B horizon to depths of 0.2, 0.4 and 0.6 m, the incorporation of calcium ameliorants, superphosphate and application of organic matter to the soil surface, were compared with unmodified soils and a 0.4 m deep topsoil, in a red-brown earth over a 2-year period (1994-96).

Subsoil modification improved the physical condition of the soil. Air-filled porosity of the deep-modified soils (0.4 and 0.6 m deep), 24 h after irrigation, exceeded 15% at 0.1 and 0.3 m depths in both years, and was always higher than in the unmodified soils. Penetrometer resistance was markedly lower in the deep-modified subsoils in both years. Greater earthworm activity was associated with these improved soil physical conditions. However, the soil treatments did not result in greater root length or root mass beneath the pasture.

In the first year, pasture yield was greater on the deep-modified soils (25-31 t DM/ha) than on the unmodified soils (19 t DM/ha). In the second year, the yield advantage of the deep-modified treatments decreased to 11%, despite the maintenance of improved soil physical conditions. In both years, pasture yields were highest where there was an initial surface application of 20 t DM/ha organic matter to a modified soil. We conclude that structural modification of the B horizon can increase pasture yields on this soil. However, further research is necessary to maintain these yield increases beyond the initial year and to develop more practical systems of soil modification.
Productivity, carcass and meat quality of lot-fed Bos indicus cross steers grouped according to temperament
Authors: Petherick J. C. , Holroyd R. G. , Doogan V. J. , Venus B. K.
Published: September 2002

One hundred and twenty Bos indicus cross steers were allocated to 3 treatments (good, mixed and poor) on the basis of flight speed, as a measure of cattle temperament. The cattle were lot-fed for 100 days and data collected at intervals on their temperament (flight speeds) and productivity (liveweight changes, body condition, pen feed intakes) during this time. After slaughter, data were collected on carcass traits and meat quality. Eating-quality attributes were measured in meat samples from 22 carcasses from each treatment.

Flight speeds were highly correlated across animals and within treatments, showed little change in variability over time and were highly repeatable. Flight speed indicated a slight deterioration in temperament with time in the feedlot until day 70, suggesting an increasing fearfulness in the steers. Differences in flight speeds between treatments were maintained throughout the feedlotting period; poor-temperament animals retained poor temperaments and good retained good.
Flight speed was correlated with measures of production, and flight speed measured at feedlot induction was a predictor of performance. Correlations and treatment effects showed that cattle with poor temperaments had poorer average daily gains, feed conversion efficiencies, body conditions and dressing percentages compared with those with good temperaments. Reduced performance in the poor-temperament animals may have resulted from their fearfulness and state of high arousal.
Treatment (temperament grouping) did not influence carcass traits, but there was evidence of lower initial pH levels and indicators of 'heat-shortening' in the meat of steers with poor temperament compared with those with good temperament. These findings suggest that the poor temperament steers were more susceptible to pre-slaughter stressors than the good temperament animals. However, the meat quality differences were not detected in eating-quality measurements.
Nitrogen fertiliser effects on nutritive characteristics of perennial ryegrass during late autumn, and mid- and late winter in western Victoria
Authors: Jacobs J. L. , McKenzie F. R. , Kearney G. A.
Published: September 2002

A study determined the effects of differing rates of nitrogen fertiliser [0 (N0), 25 (N1), 50 (N2) and 75�kg N/ha (N3)] during late autumn (T1) and mid- (T2) and late (T3) winter on the nutritive characteristics of perennial ryegrass over a 28-day period after each application. All nitrogen applications were made to pastures with a post-grazed residual mass (dry matter) of 1400 kg/ha. Changes in metabolisable energy followed similar patterns for all treatments within a given period. Metabolisable energy was highest in T1, ranging from 11.8 to 13.1 MJ/kg dry matter, followed by T2 (11.5-12.3 MJ/kg dry matter) and T3 (10.6-11.5 MJ/kg dry matter). Changes in crude protein for all treatments at each application time were similar, irrespective of rate of nitrogen application. At the commencement of treatment application times, the existing crude protein content (%DM) was highest in N3 (T1�19, T2 23, T3 22), followed by N2 (T1 18, T2 21, T3 21), N1 (T1 17, T2 20, T3 20) and N0 (T1 16, T2 17, T3 18). During both T1 and T2, neutral detergent fibre content decreased by 4 percentage units and increased by a similar amount during T3. Generally, neutral detergent fibre content (%DM) was highest during T3 (53-58%), followed by T2 (45-54%) and T1 (43-49%). Water-soluble carbohydrate content (%DM) increased during all treatment periods with the highest level observed during T1 (18-31%) followed by T2 (3-14%) and T3 (1-6%). Nitrate content (measured as nitrate-nitrogen) decreased throughout T1, primarily due to dry conditions, while during T2, levels for N3 and N2 were significantly (P<0.05) higher than for N1 and N0 following nitrogen fertiliser application. During T3, nitrate content increased for all treatments throughout the 28-day period, with highest nitrate levels being observed during T3. The effect of applied nitrogen on mineral content was variable within and across treatment periods. The study indicates that nitrogen fertiliser did not affect metabolisable (apart from N3 elevating metabolisable energy during T3), neutral detergent fibre or water-soluble carbohydrate contents of perennial ryegrass during the 28 days after nitrogen application, but increased crude protein content. Also, nitrogen fertiliser elevated nitrate content in perennial ryegrass. While the elevated nitrate content observed may result in subclinical effects, these levels are not considered fatal for dairy cows. Crude protein content was generally above 20% of dry matter throughout the study and close to 30% of dry matter for short periods during T2. Minimising the effect of excess nitrogen ingested by the grazing animal may require appropriate supplementation of low crude protein containing feeds such as cereal grains. It is argued that the effects of rain and temperature, which impact on soil nitrogen mineralisation, may have a greater influence on perennial ryegrass nitrate content than nitrogen fertiliser.
Tatura Sodicity Conference: knowledge gaps in sodicity research for major agricultural industries
Authors: Surapaneni A. , Olsson K. A. , Burrow D. P. , Beecher H. G. , Ham G. J. , Stevens R. M. , Hulugalle N. R. , McKenzie D. C. , Rengasamy P.
Published: September 2002

This paper summarises the outcomes of the International Sodicity Conference,
‘Sodicity Issues in Agricultural Industries — Current Research and Future Directions’,
held at Tatura, Victoria, 28 February–1 March 2000. In this paper we
present (i) sodicity issues generic across agricultural industries, (ii)
results of the interactive workshop, and (iii) knowledge gaps identified
specifically for individual agricultural industries by experienced
researchers. A priority ranking was given to the key issues raised within
industry groups at the interactive workshop. Knowledge gaps for major
agricultural industries were specifically listed to enable researchers and
funding bodies alike to set future directions in sodicity research.
Grazing management studies in the Temperate Pasture Sustainability Key Program: site descriptions, treatments and data collection
Authors: Lodge G. M. , Garden D. L.
Published: September 2002

This paper outlines the site locations,
experimental layout, treatments and the site characterisation and experimental
data collection procedures for the Temperate Pasture Sustainability Key
Program (TPSKP) grazing management sites in south-east Australia. Methods for
the collection of herbage mass, botanical composition, plant frequency and
basal cover data, collected from September 1993 to September 1996, are
described in detail since these data were the main focus of the studies. Also
reported are the methods used for site characterisation (soil physical and
chemical properties and weather), pasture growth rate, and animal liveweight
and condition score. Tables of summary data are presented for each site. Data
include latitude and longitude, elevation, average annual rainfall, soil type,
initial soil pH and phosphorus levels (0–10 cm), the major perennial
grasses present at each site, fertiliser application, stock, type and stocking
rates used.
Grazing management studies within the Temperate Pasture Sustainability Key Program: experimental design and statistical analysis
Authors: Orchard B. A. , Cullis B. R. , Coombes N. E. , Virgona J. M. , Klein T.
Published: September 2002

Long-term agricultural experiments such as the
Temperate Pastures Sustainability Key Program (TPSKP) present significant
challenges in the areas of planning and design, conduct, analysis and
reporting. This paper concentrates on 2 aspects, namely, the experimental
design and the statistical analysis.
For long-term agricultural experiments which examine the effects of management
strategies over time, an enumeration of the initial biodiversity is essential
and permits the allocation of treatments to plots in such a way that potential
bias in the estimation of treatment effects due to lack of uniformity in
experimental units (plots) is reduced in the covariate analysis. Spatial
replication is considered essential and the design should include at least 2
starting dates for management strategies so that the possible interaction
between the year of start and the management strategy can be described.
The data resulting from repeated measurement of herbage mass of major
individual species or species groups represent a longitudinal data set with
complexity due to the staggered commencement of treatments and also in part
due to the nature of some of the strategies (closure and cuts). The analysis
presented is the cubic smoothing spline approach of Verbyla
et al. (1999) which integrates cubic splines, random
coefficients, covariance modelling and estimation of systematic deviation.
This approach, based on linear mixed models and using residual maximum
likelihood (REML) has the flexibility to cope with the staggered imposition of
management strategies and permits the partitioning of trends into smooth and
non-smooth components, thereby quantifying species persistence and seasonal
influence under each management strategy.
Effects of grazing management on Sirosa phalaris herbage mass and persistence in a predominantly summer rainfall environment
Authors: Lodge G. M. , Orchard B. A.
Published: September 2002

Herbage mass, plant frequency and basal cover
data collected from September 1993 to August 1996 were used to compare the
effects of various seasonal closures with continuous grazing on the
persistence of Sirosa phalaris (Phalaris aquatica cv.
Sirosa) at 3 sites on the North West Slopes of New South Wales. Sites were
on-farm and consisted of up to 10 treatments with 2 replicates and treatments
were initially imposed in 2 different years. Pastures were either newly sown
(3 years old) and grazed by either sheep or cattle, or degraded (14 years old)
and grazed by sheep.
Drought conditions prevailed in 1994–95, confounding the interpretation
of the importance of treatments that involved long periods of closure, since
significant effects could be attributed to both grazing exclusion and the
timing of the closure in relation to plant phenology. However, across all
sites and years, fitted values for phalaris herbage mass were generally
significantly higher than the continuously grazed control in only 2
treatments: spring closure (at 1 site) and an extended spring closure combined
with an autumn closure (at all sites). At the end of these studies phalaris
herbage mass in spring–autumn closures was 4–32 times higher than
the control plots. These results were confirmed by analysis of initial and
final plant frequency data. At all sites, no recruitment of Sirosa seedlings
occurred in any treatment.
These data support the hypothesis that for increased persistence in a summer
rainfall environment Sirosa phalaris requires some form of grazing management
that involves the exclusion of grazing in the critical periods of spring and
autumn.
The effects of grazing management on perennial ryegrass (Lolium perenne L.) herbage mass and persistence in south-eastern Australia
Authors: Graham J. F. , Prance T. , Thompson R. P. , Borg D. , Ball P. , Filsell P.
Published: September 2002

The effect of various grazing management
treatments on newly sown and degraded perennial ryegrass pastures was studied
at 6 different locations in the temperate high rainfall zone of southern
Australia, as part of the Temperate Pasture Sustainability Key Program. The
sites were located at Hamilton (2 sites, 1 grazed by cattle, 1 grazed by
sheep) and Cavendish, western Victoria, Victor Harbor (Delamere), South
Australia, and Ross and Parattah in Tasmania. Grazing management treatments
significantly influenced the ryegrass mass and persistence of the pasture, but
effects were not always consistent across sites. Autumn closure increased the
perennial ryegrass content at Cavendish and Ross, as did the winter and summer
closures at Ross. Spring closure increased the perennialryegrass content at
Hamilton, Cavendish and Ross, but decreased it at Parattah, as did the summer
closures at Parattah and Delamere. Fodder conservation decreased the ryegrass
only at Parattah. At the Hamilton sheep site, and at Ross, mob stocking
increased the ryegrass content, as did increased superphosphate treatments at
Hamilton. Rotational grazing at Cavendish and Delamere increased the ryegrass
content, as did the late spring or a late summer closure with a short autumn
deferment at Cavendish and Ross, but both these treatments decreased ryegrass
at Parattah. The treatments that had a negative effect at Parattah may have
had a positive effect on cocksfoot at that site, creating competition for, and
decreasing the ryegrass content. At most sites, treatments that included some
spelling during spring to foster seed shedding, and spelling again in the
following autumn to encourage germination seem to have been of benefit to the
perennial ryegrass.
Effects of grazing management on botanical composition of native grass-based pastures in temperate south-east Australia
Authors: Garden D. L. , Lodge G. M. , Friend D. A. , Dowling P. M. , Orchard B. A.
Published: September 2002

Grazing management strategies to alter
botanical composition of native pastures were investigated at 4 locations in
the high rainfall zone of south-east Australia, including Tasmania. These
studies were conducted as part of the Temperate Pasture Sustainability Key
Program, which evaluated the effects of grazing management on a wide range of
pasture types between 1993 and 1996. Pastures in this study were based on
Aristida ramosa/Bothriochloa macra,
Microlaena stipoides–Austrodanthonia spp. or
Themeda triandra–Austrodanthonia spp. Seasonal
rests, increased grazing pressure in spring, mob stocking and cutting for hay
were compared to continuous grazing at all sites. In addition, specific local
treatments were tested at individual sites. Changes in composition resulting
from the treatments were minimal at most sites. This may have been due to a
combination of the inherent stability of the pastures, the relatively short
duration of the experiments, and the drought conditions experienced, which
minimised differences between treatments. Some strategies to alter composition
of natural pastures are suggested. In the
Aristida–Bothriochloa pasture there was a general
decrease in Aristida and an increase in
Bothriochloa, which was largely unaffected by the type
of grazing management applied. The combination of drought conditions and
increasing grazing pressure was sufficient to alter composition without
specific management strategies being necessary. In the
Themeda–Austrodanthonia pasture, resting in
spring, 12-month rests or cutting for hay (which involved a spring rest)
allowed Themeda to increase in the pasture. The
Microlaena–Austrodanthonia pastures were very
stable, especially where annual grass content was low. However, certain
treatments allowed Microlaena to increase, a result
which is regarded as being favourable. The major effects in these latter
pastures were on undesirable species. Vulpia spp. were
reduced by resting in autumn and increased spring grazing pressure, while
Holcus lanatus was increased dramatically by resting in
spring and was also increased by resting in autumn or winter, but only when
conditions were suitable for growth of this species. In many cases, treatment
differences were only expressed following recovery from drought, showing that
timing of grazing management to achieve change is critical.