bluuebunny/crossref_metadata_2025 huggingface dataset:
Body composition and implications for heat production of Angus steer progeny of parents selected for and against residual feed intake
Authors: Richardson E. C. , Herd R. M. , Oddy V. H. , Thompson J. M. , Archer J. A. , Arthur P. F.
Published: September 2002

Yearling Angus steer progeny of parents selected for low residual feed intake
(RFI; high efficiency) or high RFI (low efficiency) were evaluated for feed
intake, growth and differences in body composition. RFI is the difference
between actual feed intake and expected feed intake based on an animal’s
size and growth over a test period. Individual intakes of a high grain content
ration and growth rates were recorded for 140 days and then the steers were
slaughtered for measurement of body composition. All internal organs and
non-carcass fat depots were removed, weighed and ground for chemical analysis.
Carcasses were kept overnight in the chiller and the left half of every
carcass physically dissected into retail cuts, and then into total fat, lean
and bone. Carcass fat and lean were then combined and ground for chemical
analysis. Steers from low RFI parents ate less
(P<0.05) than the steers from high RFI parents, for
similar rates of growth. Improvement in RFI was accompanied by small changes
in body composition towards greater lean and less fat in the progeny of low
RFI parents. Correlations of sire estimated breeding values for RFI with end
of test whole body chemical protein, chemical fat and a principal component
that condensed information on fat and lean body composition at the end of the
test, were statistically significant. These confirmed there was a genetic
association between body composition and RFI, with fatness being associated
with higher RFI (i.e. lower efficiency). However, the correlations were small
and suggested that less than 5% of the variation in sire RFI was
explained by variation in body composition of their steer progeny. There was
no evidence that a difference in the chemical composition of gain over the
test explained the greater intake of metabolisable energy (ME) by the high RFI
steers. The results suggest that the difference in ME intake following a
single generation of divergent selection for RFI was due to metabolic
processes rather than to changes in body composition.
Post-weaning growth of cattle in northern New South Wales. 1. Grazing value of temperate perennial pasture grazed by cattle
Authors: Ayres J. F. , Dicker R. W. , McPhee M. J. , Turner A. D. , Murison R. D. , Kamphorst P. G.
Published: September 2002

This paper describes the botanical components, seasonal herbage mass, and
nutritive value of pastures used for post-weaning growth of CRC cattle at Glen
Innes before their progression to subsequent finishing and meat quality
studies. The pastures under study comprised introduced temperate perennial
species (tall fescue, Festuca arundinacea; phalaris,
Phalaris aquatica; perennial ryegrass,
Lolium perenne;
cocksfoot,Dactylis glomerata; white clover,
Trifolium repens; and red clover,
Trifolium pratense) grazed by yearling cattle and
managed according to local practice to maintain herbage mass between
pre-determined limits. The study took place on 3 adjacent pasture systems (P1,
pasture only; P2, pasture plus formulated pellets fed in later
winter–early spring; P3, pasture plus forage crop grazed in later
winter–early spring) over the 3 years 1994–96 that included a
severe 20-month drought event followed by a drought-recovery phase. Results
are discussed in the context of the pasture feed year which was shown to
comprise 3 distinct phases: (i) spring primary growth phase, high availability
of green herbage mass (2500–4500 kg DM/ha) of very high
digestibility (0.80–0.85) and very high N status (about 30 g N/kg
DM); (ii) summer–autumn secondary regrowth, high availability of green
herbage mass (2500–4000 kg DM/ha) but with only moderate nutritive
value (0.65–0.70 digestibility, 15–20 g N/kg DM); and (iii)
winter dormancy, low availability of green herbage mass (750–1500 kg
DM/ha) but with high nutritive value (0.75–0.80 digestibility,
20–30 g N/kg DM). It was concluded that the limitations of the feed
year for yearling cattle in this environment include a feed gap in
winter–early spring due to low herbage mass associated with winter cold
and a feed gap in summer–autumn associated with moderate nutritive value
of secondary regrowth pasture.
Grazing effects on soil physical properties and the consequences for pastures: a review
Authors: Greenwood K. L. , McKenzie B. M.
Published: September 2002

Grazing animals exert pressure on the ground comparable to that of
agricultural machinery. As a result, soil under pasture can be compacted. In
grazing systems based on permanent pastures or rangelands, there is little
opportunity to ameliorate poor soil physical conditions through tillage.
Hence, it is important to understand the effects of grazing on soil physical
properties and the consequent effects of these properties on pasture growth
and composition.
Most soils under grazed pasture, even those managed to minimise soil physical
degradation, will be compacted to some extent. However, the magnitude of this
compaction is usually small, and limited to the upper 50–150 mm of the
soil. Compaction to greater depth, and other changes in soil physical
properties, are more likely in recently tilled or wet soils.
The response of pasture to the poorer soil conditions caused by grazing is
difficult to determine, but it is likely to be small compared with the
defoliation effects of grazing. Maintenance of a vigorous pasture should be a
major aim of grazing management and would also achieve the secondary aim of
maintaining acceptable soil physical conditions.
Nematophagous fungi in pasture: colonisation of sheep faeces and their potential for control of free-living stages of gastro-intestinal nematode parasites of sheep
Authors: Hay F. S. , Niezen J. H. , Leathwick D. , Skipp R. A.
Published: September 2002

Sheep faeces placed on a pasture in New Zealand in February and April were
retrieved at intervals up to 28 days and examined for fungi that parasitise
nematodes (nematophagous fungi).
Monacrosporium haptotylum,
Harposporium bysmatosporum,
H. helicoides and a Nematoctonus
sp. were present, respectively, in 37, 22, 13 and 8% of 283 samples
retrieved in February and from 29, 14, 11 and 15% of 200 samples
retrieved in April. Fungi entered faeces rapidly, being present in 35 and
54% of samples retrieved after 3 days in February and April,
respectively. The ability of migrating soil nematodes to carry fungal
propagules from soil into faeces was assessed in 2 laboratory experiments.
Sheep faeces separated from soil by filters that allowed passage of both
nematodes and fungi was colonised by H. helicoides more
frequently than faeces on filters that excluded nematodes, indicating
nematodes were vectors. However,
Arthrobotrys oligospora,
M. haptotylum and A. brochopaga
occurred in faeces independently of filter type, indicating that these species
grew into faeces. Two laboratory experiments examined the ability of
nematophagous fungi, when inoculated into sheep faeces containing eggs of the
gastro-intestinal nematode parasite Trichostrongylus colubriformis to reduce
the number that developed to third-stage larvae.
Monacrosporium gephyropagum,
A. cladodes, A. conoides and
A. oligospora reduced the number of third-stage larvae
that emerged by 54–91% (P<0.05) in
comparison to a control; however, M. haptotylum and
H. bysmatosporum were ineffective. In a second
experiment, several species of nematophagous fungi reduced the number of
third-stage larvae that emerged by 41–96%
(P<0.05) in comparison to a control, while others had
no effect.
Effect of long-term stubble management on yield and nitrogen-uptake efficiency of wheat topdressed with urea in north-eastern Victoria
Authors: Newton Philip J.
Published: September 2002

Use of urea fertiliser for cereal cropping in south eastern Australia has
increased rapidly in recent years to arrest a general decline in grain protein
and to increase yields. In conservation cropping systems, crop stubbles
provide a source of carbon, which has the potential to retain a portion of the
fertiliser nitrogen in the soil. The impact of fertiliser nitrogen was
compared under 4 stubble management regimes for efficiency of nitrogen uptake
by a wheat crop in a long-term cereal–grain legume rotation. The
experiment was established on a duplex red-brown earth in 1985 to compare
stubble retention (standing, shredded, incorporated) with stubble burning. In
1995, wheat following a failed lupin crop was topdressed with urea fertiliser
at 50 kg nitrogen per hectare to split plots of each stubble treatment at the
third-leaf stage of growth. The urea significantly increased nitrogen uptake
by wheat grown on burnt stubbles and increased grain yield by 1 t/ha.
Nitrogen applied to wheat grown on stubbles retained above-ground increased
yield by 0.5 t/ha, whereas there was no significant yield increase from
nitrogen when stubble was incorporated due to less transfer of dry matter to
grain. Efficiency of urea-nitrogen uptake in grain was reduced under stubble
retention. The total grain nitrogen uptake in response to stubble burning
increased by 17.6 kg/ha, which was equivalent to a conversion efficiency
of 35%, compared with only 26, 24 and 16% of the applied 50 kg
nitrogen per hectare for stubble standing, shredding and incorporation
treatments, respectively. Soil organic carbon and total nitrogen levels were 1
and 0.1%, respectively, irrespective of stubble treatment. Added urea
increased microbial decomposition of cellulose in calico cloth buried beneath
stubbles retained above-ground by 30%, compared with stubble
incorporated or burnt treatments. These results suggest that where low levels
of available nitrogen exist in cropping systems that use stubble retention,
higher nitrogen inputs may be needed, due to less efficient uptake of nitrogen
from urea fertiliser.
Industrial waste ferrogypsum — a substitute for gypsum to alleviate sodicity
Authors: Jagadeeswaran R. , Singaram P. , Murugappan V.
Published: September 2002

Ferrogypsum is a waste from the effluent treatment plant of the titanium
industry located in Tuticorin in south India. It contains gypsum (526.3 g/kg)
and iron (102.4 g/kg as Fe2O3). It
does not contain any heavy metal at a detectable level. To evaluate
ferrogypsum as a soil amendment to alleviate sodicity, a field experiment was
conducted on a sodic soil (fine mixed non-calcareous isohyperthermic very deep
Vertic Ustropepts) with rice as the test crop. There were 7 treatments
consisting of ferrogypsum as well as gypsum used either alone or in
combination with farmyard manure or green manure, and a control. The grain and
straw yields of rice were significantly increased over the control.
Postharvest soil analysis revealed a significant reduction in pH (9.00 to
7.63) and ESP (37 to 14.9) due to soil reclamation with ferrogypsum or gypsum.
Thus, ferrogypsum was as effective as gypsum in alleviating sodicity.
Cotton-based rotation systems on a sodic Vertosol under irrigation: effects on soil quality and profitability
Authors: Hulugalle N. R. , Entwistle P. C. , Weaver T. B. , Scott F. , Finlay L. A.
Published: September 2002

An experiment was established in 1993 on a sodic Vertosol (Vertisol, Typic
Haplustert) at Merah North, north–western New South Wales, to evaluate
the sustainability of selected irrigated cotton
(Gossypium hirsutum L.)–rotation crop sequences.
Crop sequences were selected following discussions with local cotton growers.
The indices used to evaluate sustainability included soil quality,
microbiology, yield and profitability. This paper presents data on soil
properties [soil organic C, structure as air–filled porosity of
oven–dried soil, exchangeable Ca, Mg, K and Na, pH, electrical
conductivity (EC1:5) and
EC1:5/exchangeable Na in the 0–0.6 m depth], lint
yield and profitability (as gross margins/ha and gross margins/ML of
irrigation water). The 6 cropping systems sown after minimum tillage were:
continuous cotton (R1), long–fallow cotton (R2), cotton–green
manured faba bean (Vicia faba L.) (R3),
cotton–dolichos (Lablab purpureus L.)–green
manured faba bean in the first year followed by cotton–wheat
(Triticum aestivum L.) (R4), cotton–dolichos (R5),
cotton–fertilised dolichos (with P and K removed by cotton replaced as
fertiliser) (R6).
In 1996, air–filled porosity of oven–dried soil was highest with
R4 at the surface but lowest with R1 in the 0.15–0.30 m depth. In
subsequent years, air–filled porosity of oven–dried soil was
higher with R2 and R4 in the deeper depths, although differences between
cropping sequences were small. Air–filled porosity of oven–dried
soil increased between 1996 and 1998 in all treatments, and was probably
caused by the change from intensive to minimum tillage in 1993, irrigation
with moderately saline water and application of gypsum resulting in an
increase in EC1:5/exchangeable Na. In general,
differences in soil properties such as soil organic C, exchangeable Ca, Mg, K
and Na, pH, electrical conductivity (EC1:5) and
EC1:5/exchangeable Na between cropping sequences were
far less than those which occurred with time. The key changes were decreases
in pH, exchangeable sodium percentage, exchangeable cations and organic C
between 1994 and 1996, and increases in air–filled porosity of
oven–dried soil, EC1:5 and
EC1:5/exchangeable Na between 1996 and 1998. A decrease
in air–filled porosity of oven–dried soil occurred between 1998
and 1999 as a consequence of preparing land and sowing cotton under very wet
conditions. R1 had the highest cumulative gross margin/ha and R3 had the
lowest. R2 had the highest cumulative gross margin/ML of irrigation water and
R3 again the lowest. Among crop sequences, R2 and R4 gave the best returns
with respect to both land and water resources.
Effects of composted feedlot manure on the chemical characteristics of duplex soils in north-eastern Victoria
Authors: Slattery W. J. , Christy B. , Carmody B. M. , Gales B.
Published: September 2002

The beef feedlot industry in Australia produces a large amount of solid
organic by-product each year that is currently applied to agricultural land as
a fertiliser supplement. Manure is known to be a valuable source of organic
matter and some plant nutrients, especially nitrogen and phosphorus. In
addition, manure contains excessive quantities of cations such as sodium (Na)
and potassium (K), which may result in long-term sustainability problems for
the soil, particularly when large amounts are applied over short time periods.
The aim of this study was to determine the effects of composted beef feedlot
manure when applied to agricultural soils.
Two sites were selected, one a brown Dermosol and the other a red Kurosol,
both in north-eastern Victoria near the Rutherglen Research Institute. Both
sites received rates of manure up to 109 t/ha in 1996. In 1997 soil samples
were collected and compared with untreated control soils. The Dermosol site
was sown to an oat and clover mixture in 1996 and 1997 and the red Kurosol was
sown to lupin in 1996 and wheat in 1997. The application of composted bovine
manure resulted in a 1% increase in soil organic carbon, an increase in soil
pH by 1.5 units, increased levels of magnesium, calcium, nitrogen and K in the
surface 10 cm soil layer at both sites and an increase in extractable
phosphorus levels in the subsoil. There was no detectable increase in surface
Na, although there was a small but significant decrease in Na in the
40–80 cm soil layer. It is suggested that soluble organic compounds,
migrating down through the soil profile are able to complex with Na and
effectively remove some of this cation from the exchange sites of the clay
surfaces. In addition, the high porosity of these soils coupled with the high
degree of Na mobility ensures that most of this cation is transported deeper
into the soil profile. The beneficial effects of applying composted manure are
promising as a means of reducing sodicity although these results will require
further validation. In addition, the long-term effects of saturating
subsurface soil with Na are also a cause for concern and need to be further
investigated.
Adult learning principles embodied in the paired-paddock model
Authors: Trompf J. P. , Sale P. W. G.
Published: September 2002

A checklist was developed to determine the extent to which different adult
learning principles were embodied in the paired-paddock model used in the
Triple P Program. A total of 181 producers that were involved in the Triple P
Program between 1997 and 1999 completed the checklist at the end of the
program. This enabled the relative strengths and weaknesses of the
paired-paddock model from an adult learning perspective to be identified.
The 15 adult learning principles assessed in the checklist were all operating
in the paired-paddock model to varying degrees. The adult learning principles
relating to the learning environment and learning process received the highest
ratings from producers. In addition, the ratings given for these adult
learning experiences were significantly correlated with the change index, a
measure of the degree of on-farm adoption of productive pastures by the
program participants. The principles relating to the learning environment were
the existence of a comfortable learning environment, which allowed effective
2-way communication enabling participants to learn from each other. Principles
relating to the learning process were the active participation of producers in
activities, the use of knowledge and experience within the group, and the
provision of opportunity for reinforcement of information and practice of
skills.
The relative weaknesses identified in the paired-paddock model from an adult
learning perspective were the degree of self-directed learning done by
participants, the limited involvement of participants in planning their
learning experience, and the limited extent to which the program related to
problem issues among the group. Despite these relative weaknesses it was
concluded that the paired-paddock model embodies sound adult learning
principles that assist in the delivery of quality learning outcomes for
participants.
Pasture yield and composition changes in a Central Queensland black speargrass (Heteropogon contortus) pasture in relation to grazing management options
Authors: Orr D. M. , Burrows W. H. , Hendricksen R. E. , Clem R. L. , Rutherford M. T. , Conway M. J. , Myles D. J. , Back P. V. , Paton C. J.
Published: September 2002

A grazing study commenced in 1988 at Calliope, Central Queensland, measured
the effects of stocking rate, legume over-sowing and animal diet
supplements/burning on pasture and animal production in a native black
speargrass (Heteropogon contortus) pasture. This paper
reflects on changes in yield and pasture composition between 1988 and 1996,
during which time the seasonal rainfall was below average. At the pasture
community scale, the highest stocking rate of 1 steer/2 ha reduced pasture
yield but had little impact on pasture composition. The frequency of
H. contortus showed no clear differences due to stocking
rate although there was a slight overall trend for it to decline with time.
The frequency of increaser species such
asChloris divaricata was highest at the highest stocking
rate. At the individual plant scale, the density of
H. contortus plants declined at high stocking rate.
The proportion of the sown legume Stylosanthes scabra
cv. Seca increased with time reaching a density of 15 plants/m
2 and contributing 33% to the total yield in the
legume treatments. Burning has reduced the occurrence of
H. contortus compared with that in unburnt native
pasture and this may be due to the stocking rates being too high following the
fire. These results indicate the stability of pasture composition across a
4-fold range of stocking rates from 1988 to 1996. This study needs to
continue, at least through a period of above average rainfall, to determine
further effects of stocking rate and pasture type on pasture composition.
Some soil-related issues in the disposal of effluent on land
Authors: Tillman R. W. , Surapaneni A.
Published: September 2002

There is increasing environmental pressure to dispose of waste effluents on
land, rather than discharging them directly into surface waterways. In
addition to reducing impacts on water quality, land disposal of effluents
offers the possibility of beneficial recycling of water and essential plant
nutrients.
Frequently, however, waste water contains high concentrations of dissolved
salts, particularly sodium, that can affect the levels of salinity and
sodicity in soils. This, in turn, can diminish the utility of soils for
productive agriculture. Astute soil management can often ameliorate these
adverse affects but this may require land-use practices that reduce the
commercial return from farming activities. It is therefore important to
identify the main purpose of effluent disposal areas and to compensate land
users appropriately when the operation of the effluent disposal scheme affects
farm profitability. If farmers are forced by commercial pressures to adopt
inappropriate land use practices on areas used for effluent disposal, the
operation of the scheme will be compromised, and there may even be the risk of
complete failure.
The results of a limited number of experiments investigating the application
of effluents to land in northern Victoria are used to demonstrate these risks.
The effects on soil chemical properties of applying saline–sodic waste
water to land are now well understood. Considerably less certain are the
effects of these changes on soil chemical properties, on the physical
properties of soils and the way soils behave under various land uses —
such as cultivation or grazing by heavy animals.
Various approaches to modelling and predicting the impacts on soil of
irrigation with saline–sodic waste water are discussed. A number of
simple, classification models, based on practical experience and empirical
equations, currently provide valuable assistance for land managers. More
complex, mechanistic models have been developed that describe successfully the
movement of water and salts through soils, given appropriate soil measurements
as input parameters. The major limitations now are the availability of soil
data at an appropriate scale and an understanding of the ways changes in soil
chemical properties affect soil physical properties and subsequent soil
behaviour. In particular there is a need to investigate those critical zones
at the soil surface or the top of the B horizon where water movement is
impeded in sodic soils.
Band incorporation of fluazinam (Shirlan) into soil to control clubroot of vegetable brassica crops
Authors: Donald E. C. , Porter I. J. , Lancaster R. A.
Published: September 2002

Commercially suitable methods for application of fluazinam were evaluated in
field trials conducted in Victoria and Western Australia. Incorporation of
fluazinam into the soil in bands 23 cm wide along the transplant row (to a
depth of about 15–20 cm) immediately before transplanting was the most
effective method of application. Plants grown in soil treated in this way
developed significantly less clubroot than when fluazinam was applied using
either a spot drench (100 mL/plant) or a continuous spray over the plants
immediately after transplanting. The banded soil incorporation treatment
consistently increased the marketable yield of broccoli and cauliflower. In
one trial, banded soil incorporation increased the marketable yield of both
crops by at least 80% compared with the other commercial methods of
application currently in use. The banded soil incorporation treatment was more
reliable and effective in a range of soil types than the high volume drenches
currently used. This method of application remained effective, significantly
reducing clubroot severity, when the volume of water used to apply fluazinam
was reduced by 80% from 2500 to 500 L/ha.
Establishment of the peanut bruchid (Caryedon serratus) in Australia and two new host species, Cassia brewsteri and C. tomentella
Authors: Cunningham D. C. , Walsh K. B.
Published: September 2002

The distribution of Caryedon serratus, the peanut
(groundnut) bruchid, on 2 Australian native plants,
Cassia brewsteri and
C. tomentella, was documented over 2 years.
Caryedon serratus was observed across the central and
northern parts of the range of C. brewsteri (latitudes
19.258–24.140˚S) and at least part of the range of
C. tomentella (as far as 24.427˚S). Seed loss to
C. serratus in these species assessed across all
collection sites was 40 ± 8.0% (mean ± s.e.). Where the bruchid was
detected at a given site, 72 ± 8.6% of pods on 71 ± 8.5% of trees
were affected. Additional distribution points and other potential host species
from previous C. serratus collections in the Australian
National Insect Collection (ANIC) are reported. The combined data were used to
predict a potential range for the bruchid across the dry tropics of Australia.
No reports of migration to cultivated or stored peanut
(Arachis hypogaea) in Australia were located. Further
investigation of the potential impact of this bruchid on the Australian peanut
industry is recommended. A potentially beneficial aspect of C. serratus
establishment may be the biological control of
Acacia nilotica (prickly acacia) in Australia.
Residual value of ferrous sulfate for clover production on humic sandy podsols
Authors: Brennan R. F. , Highman D. D.
Published: September 2002

The residual value of ferrous sulfate, as an iron fertiliser, was measured in
3 field experiments using yield of dry herbage of clover
(Trifolium subterraneanum L.). The clover was grown on
limed acid peaty sandy soils and the iron fertiliser was spread over the soil
surface. In 1995, the effectiveness of freshly applied iron was compared with
that of iron applied 1–5 years previously. Additions of iron increased
clover herbage (DM) yield by about 0.80 t/ha in October. The longer the
period since iron was applied, the less effective was the fertiliser. Iron
applied 1 year previously was about 60% as effective as current iron
while iron applied 5 years previously was about one-third as effective as
current iron for herbage production. About 15–20 kg of freshly applied
iron/ha was required for maximum DM yield of clover. The critical
concentration of iron in the whole shoot of clover plants for 90% of
maximum DM yield was about 70 mg/kg.
Evaluation of herbage yield in a forage grass breeding program: comparison of visual rating versus measurement in single-row plots or swards
Authors: Smith K. F. , Tasneem M. , Kearney G. A. , Reed K. F. M. , Leonforte A.
Published: September 2002

To refine selection methods for a perennial ryegrass
(Lolium perenne L.) breeding program, half-sib families
and commercial cultivars were evaluated for 3 years with treatments sown as
both single-drill rows or swards. Dry matter yield of the perennial ryegrass
treatments was evaluated several times in each year as a visual score which
was subsequently calibrated against a regression determined by cutting a
subset of plots or by cutting all plots. Thus, the experiment evaluated 2
aspects of herbage-yield determination in a perennial ryegrass breeding
program: (i) the use of visual estimates of herbage yield to reduce the time
spent cutting plots, and (ii) the use of single-row plots compared with
swards. The correlation (either as Pearsons correlation coefficient, or
Spearmans rank correlation coefficient) between visual estimates of herbage
yield was always significant (P<0.01), with the
exception of the rank correlation for sward plots in the summer 1995
(r = 0.4; P<0.05).
However, the extent of the correlation varied (r
= 0.4–0.9), and at some harvests calibrated visual ratings only
explained a small proportion of the variance observed in harvested dry matter
yields. These data suggest that visual ratings of herbage yield would be
accurate enough to be used to detect large differences between families,
breeding lines, cultivars or accessions of perennial ryegrass. However, when
differences between lines are likely to be small, then harvesting all plots
would give a more accurate estimate of the yield of perennial ryegrass lines.
Likewise, the herbage yield of perennial ryegrass in single-row plots was
significantly correlated with the herbage yield of perennial ryegrass sown as
swards (P<0.01 or P<0.05).
However, the correlation was again variable leading to the conclusion that
evaluation of perennial ryegrass as single-row plots was not always an
accurate indicator of sward yield. For those 4 (of 13) harvests over 3 years
where the interaction between sward yield and row yield of the perennial
ryegrass lines was significant (P<0.05), this
interaction was shown not to be due to significant rank changes but rather to
an increase in the differences of yield in swards or yield in single-row
plots. We conclude that the harvesting of swards was the most reliable method
of estimating the dry matter yield of perennial ryegrass cultivars. However,
significant correlations between visual rating of treatments, or yield in
single-row plots and measured yield as swards illustrated that these methods
(visual ratings and single-plot yields) could be used to reduce the cost of
evaluating differences in the herbage yield potential of perennial ryegrass,
especially when these differences were likely to be large or when seed is
limited, such as during the evaluation of accessions.
Patterns of resistance to angular leaf spot, anthracnose and common bacterial blight in common bean germplasm
Authors: Islam F. M. A. , Basford K. E. , Redden R. J. , Jara C. , Beebe S.
Published: September 2002

Diseases and insect pests are major causes of low yields of common bean (Phaseolus vulgaris L.) in Latin America and Africa. Anthracnose, angular leaf spot and common bacterial blight are widespread foliar diseases of common bean that also infect pods and seeds. One thousand and eighty-two accessions from a common bean core collection from the primary centres of origin were investigated for reaction to these three diseases. Angular leaf spot and common bacterial blight were evaluated in the field at Santander de Quilichao, Colombia, and anthracnose was evaluated in a screenhouse in Popay�n, Colombia. By using the 15-group level from a hierarchical clustering procedure, it was found that 7 groups were formed with mainly Andean common bean accessions (Andean gene pool), 7 groups with mainly Middle American accessions (Middle American gene pool), while 1�group contained mixed accessions. Consistent with the theory of co-evolution, it was generally observed that accessions from the Andean gene pool were resistant to Middle American pathogen isolates causing anthracnoxe, while the Middle American accessions were resistant to pathogen isolates from the Andes. Different combinations of resistance patterns were found, and breeders can use this information to select a specific group of accessions on the basis of their need.
Environmental control of bud formation and flowering of clonal Acacia baileyana F. Muell. for ornamental horticulture
Authors: Morgan A. , Sedgley M.
Published: September 2002

To study the temperature requirements for flowering, cuttings of
A. baileyana were either transferred between different
temperatures in controlled-environment growth cabinets, kept outside or in a
shadehouse. Plants in the growth cabinets were transferred from a low
(13/9˚C) to high (23/19˚C) temperature, from a high to low
temperature, or kept at a constant intermediate (18/13˚C)
temperature, and then transferred outside.
Acacia baileyana required temperatures at or above a
mean maximum of 18˚C and a minimum of 13˚C for bud formation, and at
or below a mean maximum of 16˚C and a minimum of 9˚C for flowering.
Nearly twice the number of plants transferred from high to low temperature
flowered compared with outside plants. Bud formation was inhibited at a
temperature of 13˚C maximum and 9˚C minimum. Large buds dropped when
the temperature was above 18˚C maximum and 13˚C minimum, indicating
that the timing of plant transfer between the warm and cool conditions should
be when the buds are at a medium size. Light intensity also affected
flowering, with less than half the number of plants flowering in the
shadehouse compared with outside. Plants transferred from high to low
temperature were induced to flower 4 months earlier than outside plants by
manipulating the temperature. Flowering cut stems or pot plants of
A. baileyana could be produced for Mother’s Day in
May and for other key markets.
Annual ryegrass (Lolium rigidum) seed survival and digestibility in cattle and sheep
Authors: Stanton R. , Piltz J. , Pratley J. , Kaiser A. , Hudson D. , Dill G.
Published: September 2002

A trial was conducted to investigate the survival and digestibility of annual
ryegrass (ARG) seed (Lolium rigidum L.) eaten by sheep
and cattle. Sheep (n= 8) and cattle
(n = 8) were fed a basal diet containing 1:1
lucerne chaff:oaten chaff with (ARG) or without (control) the inclusion of
20% total dry matter of annual ryegrass seed in a changeover design.
Intake was restricted to 17 g/kg liveweight. Digestibility of the control
diet was lower (P<0.01) for sheep than cattle. Annual
ryegrass seed was present (P<0.01) in the faeces of
both sheep and cattle within 24 h of first ingestion. Some 10.8 and
32.8% of seed ingested was excreted by sheep and cattle respectively,
with 3.9% (sheep) and 11.9% (cattle) remaining germinable.
Annual ryegrass seed continued to be excreted by both sheep and cattle up to 5
days after removal from the diet. Dry matter digestibility of the annual
ryegrass diet was 53% in cattle.
Prospects for biological control of cutleaf mignonette, Reseda lutea (Resedaceae), by Cercospora resedae and other pathogens
Authors: Giles I. , Bailey P. T. , Fox R. , Coles R. , Wicks T. J.
Published: September 2002

Four leaf pathogens were screened as biological control agents for the weed
Reseda lutea (Resedaceae) in South Australia.
Cercospora resedae isolated from
Reseda luteola growing in south-eastern Australia
produced a maximum damage to R. lutea seedlings of
54% of leaf area damaged at 22°C and 96% of leaf area
damaged at 27°C under laboratory test conditions. By contrast, European
isolates of C. resedae from both
R. lutea and R. luteola produced a
maximum of 10% leaf area damage to R. lutea
seedlings. Field releases of Australian C. resedae
failed to establish in dense populations of R. lutea on
Yorke Peninsula and the mid-north of South Australia, perhaps because the
climate was hotter and drier than the source locations. Attempts to enhance
the effectiveness of the pathogen by passaging it through
R. lutea, leaf abrasion, inundation, or the addition of
surfactant or sublethal doses of metsulfuron-methyl failed to increase damage
beyond that caused by the pathogen alone. The leaf
pathogensAlternaria tenuissima,
Cladosporium sp. and
Peronospora crispula did not produce damage levels that
could be useful in biological control. It is concluded that in the areas of
South Australia where R. lutea is a significant weed,
the prospects for control by any of these leaf pathogens are not good.
Influence of foliar-applied calcium nitrate on strawberry plants grown under salt-stressed conditions
Authors: Kaya C. , Ak B. E. , Higgs D. , Murillo-Amador B.
Published: September 2002

A pot experiment was carried out with strawberry (Fragaria × ananassa Duch) cultivars Oso Grande and Camarosa in sand culture to investigate the effects of foliar-applied calcium nitrate [Ca(NO3)2] to plants grown at high salinity (NaCl, 35 mmol/L). Treatments were (i) nutrient solution alone (C), (ii) nutrient solution + Ca(NO3)2 (9 mmol/L) as a foliar application (C+Fo), (iii) nutrient solution + NaCl (35 mmol/L) (C+S) and (iv)�nutrient solution + NaCl (35 mmol/L) + Ca(NO3)2 (9 mmol/L) as a foliar application twice weekly (C+S+Fo). The plants grown at high NaCl had less dry matter and lower fruit yield and chlorophyll content than those grown in normal nutrient solution for both cultivars. Foliar Ca(NO3)2 sprays ameliorated the negative effects of salinity on plant growth, chlorophyll content and fruit yield. Membrane permeability increased with high NaCl and was reduced by Ca(NO3)2 sprays. Sodium concentration in plant tissues increased in both cultivars in the high NaCl treatment. Concentrations of calcium and nitrogen were much lower in plants grown in high NaCl than in unstressed plants and foliar Ca(NO3)2 sprays increased concentrations of both nutrients.
Reaction of a range of Brassica species under Australian conditions to the fungus, Leptosphaeria maculans, the causal agent of blackleg
Authors: Marcroft S. J. , Wratten N. , Purwantara A. , Salisbury P. A. , Potter T. D. , Barbetti M. J. , Khangura R. , Howlett B. J.
Published: September 2002

A range of Brassica species was screened for resistance to Leptosphaeria maculans, the causal agent of blackleg. The lines were assessed in 8 disease nurseries in 4 canola growing regions of Australia and in 1�glasshouse trial, with a view to identifying alternative sources of resistance to L. maculans for Australian breeding programs. Lines were screened for degree of internal and external blackleg symptoms during both the seedling and adult plant growth stages. Correlation for resistance with ranking between disease nurseries was very strong (0.41-0.98). Brassica carinata and B. nigra were the most resistant species in the disease nurseries, being even more resistant than B. juncea. The 7 European winter B. napus lines tested were significantly more resistant than the 7�Australian spring B. napus lines, with another crucifer, Sinapis alba, being intermediate in resistance between the European and Australian B. napus lines. The same ranking of lines from most to least resistant was also seen when cotyledons and stems were inoculated in the glasshouse with 2 well-characterised Australian isolates. With the exception of the B. napus susceptible control Westar, all lines had similar frequencies of seedling survival in the nurseries. However, mature plants of these lines varied significantly in their degree of resistance. This indicates that screening for seedling survival is not useful in selecting L. maculans resistant lines in Australia. The Brassica lines with the B genome, especially B. carinata, and the winter B. napus types are now being used as sources of resistance in Australian breeding programs.
A review of the flower characteristics of Geraldton waxflower and factors influencing their abscission from harvested stems
Authors: Joyce D. C. , Beasley D. R.
Published: September 2002

Geraldton waxflower (Chamelaucium uncinatum Schauer) is Australia's most economically important cut-flower export. Its small, attractive flowers make it particularly suitable as a filler in floral arrangements. However, postharvest bud and flower abscission is a major problem during transport, handling and marketing. Abscission may be caused by wound-induced endogenous ethylene production brought about by flower tissue infection with fungal pathogens such as Botrytis cinerea. Botany and postharvest characteristics are discussed in relation to flower abscission and how resultant postharvest losses may be minimised.
The GrassGro decision support tool: its effectiveness in simulating pasture and animal production and value in determining research priorities
Authors: Clark S. G. , Donnelly J. R. , Moore A. D.
Published: September 2002

The GrassGro decision support tool combines
animal intake and nutrition models, soil moisture and pasture growth models
with management rules. GrassGro simulates pasture and animal production using
a wide range of pasture species and sheep and cattle enterprises. Data from
the Temperate Pasture Sustainability Key Program grazing management sites were
used to validate the predictions of GrassGro.
The pasture and animal production from a diverse range of sites were
successfully simulated. Limitations of GrassGro were identified (parameter
sets not available for some pasture species, inability to simulate clumpy
swards, rudimentary interspecies competition model) and some improvements were
made to its performance (improved species parameter sets and improved modeling
of rooting depth). Recommendations are made on priority areas of research to
improve GrassGro and on improvements in methodology which could be adopted by
future programs like Temperate Pasture Sustainability Key Program.
Feral olives ( Olea europaea) as future woody weeds in Australia: a review
Authors: Spennemann D. H. R. , Allen L. R.
Published: September 2002

Olives (Olea europaea ssp.
europaea), dispersed from 19th century orchards in the
Adelaide area, have become established in remnant bushland as a major
environmental weed. Recent expansion of the Australian olive industry has
resulted in the widespread planting of olive orchards in South Australia,
Victoria, New South Wales, Western Australia, Queensland and parts of
Tasmania. This paper reviews the literature on the activity of vertebrate
(principally avian) olive predators and their potential as vectors for
spreading this plant into Australian remnant bushland. The effects of
feralisation on the olive plant, which enhances its capacity for dispersal as
a weed, place wider areas of south-eastern Australia at risk. A number of
approaches for the control of olives as woody weeds are addressed. Proponents
of new agricultural crops have moral and environmental obligations to assess
the weed potential of these crops.
Yield responses of mulla mulla (Ptilotus exaltatus Nees.) seedlings to additions of nitrogen, potassium and phosphorus fertiliser
Authors: Brennan R. F. , Webb M. G. , Crowhurst A. M.
Published: September 2002

Native plants are increasingly being grown in Western Australia to produce
flowers for export and the nutritional requirement of some of these species is
not known. The nitrogen, phosphorus and potassium requirements for optimum
growth of seedlings of one such species,
Ptilotus exaltatus Nees., were measured in the
glasshouse experiment reported here.
There was a significant (P<0.05) growth response to
nitrogen fertilisers over the range 20–80 mg N/kg soil. At all
amounts of phosphorus and potassium, except for the nil-phosphorus treatments,
the largest amount of applied nitrogen (80 mg N/kg soil) gave the maximum
dry weight of shoots. The dry weight of shoots increased with the addition of
phosphorus fertiliser up to 40 mg P/kg soil, particularly with 60 mg
potassium and 80 mg N/kg soil. The addition of 160 mg P/kg soil and
120 mg K/kg soil depressed shoot growth at 80 mg N/kg soil. Potassium
fertiliser increased plant growth at amounts up to about 60 mg K/kg soil.
At the seedling stage of growth, critical concentration in shoots for
deficiency was about 1.5% for potassium, and 0.9% for
phosphorus. Adequate concentrations in shoots were about 1.7–2.7%
for potassium, and 1.0–1.6% for phosphorus.
Management of rhizoctonia bare patch in the South Australian mallee using a modified direct drilling system, deep-banded urea, and sowing time in relation to the break in the season
Authors: Kelly D. J. , Dubé A. J.
Published: September 2002

Tillage experiments in the South Australian
mallee, over 8 years (1990–97), have demonstrated that cultivation
directly below the seed at sowing controls rhizoctonia bare patch as
effectively as 1 or 2 cultivations prior to sowing. When combined with a short
chemical fallow and the use of press-wheels, this modified direct drilling
technique can yield as well as, or better than, conventional farming systems.
The combination of modified direct drilling and deep-banded urea increases the
control of the disease in the first 2 weeks after the break in the season. In
the first 2 weeks after the break, deep banding urea at sowing is more likely
to increase yield, than modified direct drilling with urea broadcast at
tillering, when both treatments are compared with standard direct drilling. In
a reduced tillage system, a cultivation 6–11 days after the break in the
season may be more effective in reducing bare patch than a cultivation at
other times after the break.
Grazing management of reproducing ewes affects staple strength
Authors: Robertson S. M. , Robards G. E. , Wolfe E. C.
Published: September 2002

A grazing study was conducted on irrigated pastures to assess the influence of
manipulating the availability of green pasture at different stages of
pregnancy and lactation on the staple strength of broad-wool Merino ewes
lambing in July. Sheep subjected to different treatments produced wool ranging
between 14 and 48 N/ktex for single-rearing and 22 and 53 N/ktex for
non-lambing ewes. Single-bearing/rearing ewes produced wool of strength
+4.7 (P>0.05) to –23 N/ktex
(P<0.001) in comparison with non-lambing ewes.
Reproduction was associated with a reduction in staple strength of 51, 24 and
9% for ewes grazed throughout the experiment at low, medium and high
pasture levels, respectively. A staple strength greater than 40 N/ktex was
achieved in single-rearing ewes which grazed high pasture mass throughout
pregnancy and lactation, during late pregnancy and early lactation, or during
mid-pregnancy. Single-rearing ewes, which grazed low pasture biomass
throughout either mid, late or all of pregnancy, or during lactation, produced
wool with staple strength less than 30 N/ktex. In comparison to grazing
the medium pasture allowance throughout the experiment, manipulation of
pasture availability had relatively small effects on lamb growth and average
fleece measurements, compared with the effects on staple strength. The
exception was ewes grazing only the low pasture allowance.
The interaction between reproduction and nutritional management influenced
staple strength by altering the minimum fibre diameter and the uniformity of
along-staple fibre diameter and rate of wool growth. It was concluded that
managing pasture availability to promote a uniform along-staple fibre diameter
or rate of wool growth can prevent reductions in staple strength associated
with reproduction.
The influence of seed pre-treatments and soil conditions on the emergence of sesame seedlings
Authors: Day J. S.
Published: September 2002

Poor and uneven emergence of seedlings decreases the efficiency of sesame
(Sesamum indicum) seed production. In a glasshouse
study, seedling emergence was reduced by low soil moisture content (less than
20%, w/v) and by waterlogging (common in soils with small soil
particles). Watering events that failed to raise soil moisture content above
20% caused most seeds to germinate (more than than 80%), but
only some of these seeds emerged from the soil (less than 50%).
Gibberellic acid pre-treatment of seeds (50 or 1000 mg/L) failed to
improve emergence of seeds from soils with an initial soil moisture content
less than 20%. This result supports previous reports suggesting that
gibberellic acid treatment does not influence seedling emergence, and may only
be useful to overcome seed dormancy in those sesame varieties where dormancy
is a problem. For maximum emergence it is recommended that sesame seeds be
sown in non-waterlogged soils and that soil moisture content be maintained
above 20% for a number of days after sowing.
Calibration of gypsum blocks and data loggers and their evaluation for monitoring soil water status
Authors: Johnston W. H.
Published: September 2002

The use of commercial data loggers and gypsum blocks to monitor the matric
potential of water in soil was evaluated in the laboratory and at 2 field
sites. A set of calibration resistors that simulated a matric potential range
of —20 to —2120 kPa was developed that showed close
agreement with data that was originally used to develop algorithms for the
loggers. Data loggers used in experiments were calibrated against the
resistors so output values could be re-scaled to that of the resistor set.
Close agreement was found between the matric potential of soil, which was
estimated from filter papers, and re-scaled logged matric potential values for
gypsum blocks embedded in containers of soil maintained at a range of water
contents in the laboratory. Re-scaled logged soil matric potential recorded at
2 field sites also compared favorably with filter paper estimates for soil
sampled adjacent to where gypsum blocks were buried. It was concluded that,
provided individual data loggers were standardised to the same matric
potential scale using either calibrated resistors or soil of known matric
potential, the gypsum block technique provided an economical and accurate
measure of soil water status.