bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of rotation and time of germinating rains on the productivity and composition of annual pastures in Western Australia
Authors: Thomson C. J. , Revell C. K. , Turner N. C. , Ewing M. A. , Le Coultre I. F.
Published: August 2004

A long-term rotation experiment located in south-western Australia was used to
measure the effect of rotation and time of germinating rains on the
productivity and botanical composition of grazed annual pastures in 2
contrasting seasons in an environment with an average annual rainfall of 325
mm.
The density of self-regenerating seedlings of subterranean clover
(Trifolium subterraneum), capeweed
(Arctotheca calendula), and grasses
(Lolium rigidum, Hordeum leporinum, Bromus diandrus) was
greatly increased (approx. 3 times the density) when there was a second year
of pasture after crop compared with the first year after crop. The lower plant
density resulted in first-year pastures having only about 33% of the
autumn biomass accumulation of second-year pastures. This difference in early
pasture growth had no effect on total pasture production in 1992, but in 1993
total pasture production was 30% greater in second-year pastures
compared with first-year pastures. Botanical composition varied between and
within seasons with the percentage of subterranean clover increasing
throughout the season and the percentage of capeweed decreasing throughout the
season. Grasses comprised <20% of the biomass in all seasons and
treatments. Production of subterranean clover seed in 1993 was higher in a 1 :
2 crop-pasture rotation than in a 1 : 1 crop-pasture rotation and direct
drilling in the cropping phase increased seed set compared with conventional
tillage in both 1 : 1 and 1 : 2 crop-pasture rotations.
Capeweed seedlings emerged in large numbers after rainfall between February
and May and subsequently showed a relative growth rate twice that of
subterranean clover and the grasses, but exclusion of rainfall until June
resulted in a significant reduction in the emergence of capeweed seedlings.
Additionally, capeweed had a lower rate of seedling survival compared with
other pasture species, and this is contrary to observations by other
researchers that capeweed is highly resistant to moisture stress during early
growth.
Estimating net annual soil sulfur mineralisation in New Zealand grazed pastures using mass balance models
Authors: Goh K. M. , Nguyen M. L.
Published: August 2004

Estimates of net soil sulfur (S) mineralisation of grazed pastures in New
Zealand were made using the New Zealand Ministry of Agriculture (MAF) S model
and a recently developed simple mass-balance S model. Quantitative estimates
of S inputs and outputs in the MAF S model were also compared with those
obtained in recent field trials. Results obtained showed that the MAF S model
was reasonably accurate in estimating S inputs and outputs and long-term
maintenance pasture S requirements but not short-term pasture S requirements,
due to the parameters used not accounting for the effects of major factors
affecting soil organic S mineralisation. Net annual soil S mineralisation
under high-producing pastures estimated by the simple mass-balance model was
substantial, ranging from 17·7 to 29·1 kg S/ha ·
year, thus showing that the mineralisation of soil organic S can be a
significant source of S for pasture plant growth. The inclusion of the MAF
soil organic S test into the MAF S model may improve short-term S
requirements, but the soil organic S test needs to be calibrated with net soil
S mineralisation potential, soil types, management practices, and pasture
production. Although some of the excreta S that has been transferred to stock
camps may be returned to the main grazing area, this excretal S and sulfate
leaching losses were found to be major S outputs of the main grazing area. The
results suggested that the mineralisation of soil organic S may not be
sufficient to replace S losses indefinitely when S fertiliser applications are
withheld.
Production practices in Western Australia for wheats suitable for white, salted noodles
Authors: Anderson W. K. , Crosbie G. B. , Lambe W. J.
Published: August 2004

Wheat cultivars acceptable for the Noodle wheat segregation in Western
Australia were compared with cultivars suitable for the Australian Standard
White (ASW) grade over the period 1989–93. Yield and grain quality
responses to sowing time, nitrogen fertiliser, soil type, and cropping history
were examined to determine management practices most likely to result in wheat
grain suitable for the production of white, salted noodles. Thirty experiments
were conducted in the 300–450 mm average annual rainfall zone between
Three Springs in the north (approx. 29° 30′S) and Newdegate in the
south (approx. 33°10′S).
The ASW cultivars, Spear, Kulin, and Reeves, outyielded the Noodle cultivars,
Gamenya and Eradu, by 8–10% on average, but the yield difference
was less at later sowings. The optimum sowing time was early May for most
cultivars. The new cultivars, Cadoux (Noodle) and Tammin (potential Noodle,
but classiffied General Purpose), tested in 1992 and 1993 in 12 experiments
showed an optimum sowing time of late May, as did other midseason cultivars.
Grain yields of May-sown crops were increased by 13 kg for every 1 kg of
nitrogen applied, compared with 3 : 1 for June-sown crops. Previous legume
history of the site and grass weed control in the crop also influenced the
grain protein percentage. It was concluded that adoption of production
guidelines that include sowing at, or near, the break of the season with about
40 kg/ha of nitrogen fertiliser, a rotation that includes 2-3 years of
legume crop or pasture in the previous 5 years, and adequate grass weed
control will result in an excellent chance (>80%) of producing grain
proteins within the receival standards for the Noodle grade.
Flour swelling volume (FSV), an indicator of noodle eating quality, was
negatively correlated (not always significantly at P
= 0·05) with grain protein percentage in 7 out of 8 experiments.
FSV values were larger from sites located in the south of the study area and
this appeared to be independent of protein and time-of-sowing effects. Small
grain sievings (<2 mm) were increased by sowing after the end of May,
especially in the longer season cultivars.
Effects of soil drought during the generative development phase on seed yield and nutrient uptake of faba bean (Vicia faba)
Authors: Xia M. Z.
Published: August 2004

The effects of periods of drought during different phases of reproductive
growth of faba bean (Vicia faba L.) cv. Xichang Dabai
were investigated in a pot experiment at Xichang Agricultural College, China.
Parameters were total dry matter; seed yield; yield components; concentrations
of nitrogen, phosphorus, and potassium; and total uptake in different organs.
All drought treatments decreased total dry matter production and seed yield
per plant. Plants subjected to drought from initiation of pod-set to full
pod-set (stage D4) produced 32% less total dry matter and 45%
less seed yield than the irrigated control. Mean seed weight was a relatively
stable yield component. Statistical analysis indicated that only plants
subjected to drought at stages D4 and D5 (drought from full pod-set to
maturity) had a significantly (P < 0·05) lower
mean seed weight than the control.
The nutrient concentration was generally high in the younger or more active
organs of faba bean, and comparing the nutrients, the N concentration in
leaves, stems, flowers, pods, and grain was greatest, followed by K
concentration, and P concentration was least. All soil drought treatments
decreased the nutrient concentration in various organs after 17–19 days
of drought. However, the decreases at maturity were less clear, except the
nutrient concentrations in stems and leaves. Water deficit significantly
decreased total grain nutrients per plant, the decreases being
34–45% for N uptake, 34–47% for P uptake, and
33–46% for K uptake. Simple linear correlations with the P and K
concentration in leaves at maturity and number of pods and seeds per plant
gave a correlation coefficient (r) of
0·804–0·874.
A root disease of Lupinus angustifolius caused by a new species of binucleate Rhizoctonia
Authors: MacLeod W. J. , Sweetingham M. W.
Published: August 2004

A new root disease of narrow-leafed lupins that is common in the northern
wheatbelt of Western Australia wa found to be caused by a slow-growing
binucleate Rhizoctonia sp. with characteristically
narrow hyphae (2–4 µm). The new root disease causes distinct
patches of poor growth superficially similar to rhizoctonia bare patch. This
root disease of lupins is widespread in the northern lupin-growing areas of
Western Australia.
The biological nature of the disorder was established by transfer of soil from
a patch to a clean area and by treating patches using a soil fumigant (methyl
bromide–chloropicrin).
The thin binucleate Rhizoctonia sp. (TBR) was isolated
directly from soil within, but not outside, patches by using a soil immersion
plate technique. Lupins grown in pots inoculated with the TBR developed
symptoms consistent with those seen on plants in patches in the field, and the
fungus was re-isolated from the diseased roots.
Field soil was inoculated with TBR, and in the following year, lupins were
sown over the inoculated area and developed patches identical to the stunted
patches occurring naturally. The fungus was re-isolated from diseased lupin
roots taken from inoculated patches but not from diseased roots from outside
patches.
Effect of age, retinol, and cholecalciferol on carcass fat and adipocyte number and size in growing lambs
Authors: Payne E. , Watkins S.
Published: August 2004

To determine whether hyperplasia occurs in young growing meat lambs when fat
is laid down we measured the changes in fat parameters with age in Coopworth
× Dorset lambs and, in parallel, ran groups treated with retinol and
cholecalciferol (reported inhibitors of adipocyte differentiation
in vitro), which were slaughtered at 33–34 weeks
of age. The lambs were fed a pelleted ration at 30 g/kg body weight from
16 weeks of age and serially slaughtered for age effects in groups of 4,
whereas the treatment groups contained 6 lambs. Some lambs developed urethral
blockage from pellet feeding so the experiment was terminated early at
33–34 weeks.
The lambs showed a steady growth rate and an increase in the proportion of fat
in the carcass, total carcass fat, and subcutaneous adipocyte diameter at
25–29 weeks of age. The total number of adipocytes in the carcass
derived from diameter measurements on subcutaneous adipocytes and the total
carcass fat showed no significant changes. Retinol and cholecalciferol caused
significant reductions in cell diameter and increases in total adipocytes but
little change in total fat.
Early vesicular-arbuscular mycorrhizal colonisation in soil collected from an annual clover-based pasture in a Mediterranean environment: soil temperature and the timing of autumn rains
Authors: Braunberger P. G. , Abbott L. K. , Robson A. D.
Published: August 2004

The results of 2 experiments investigating the early stages of the formation
of vesicular- arbuscular (VA) mycorrhizas in response to both soil temperature
and the timing of autumn rains are reported for a Mediterranean environment in
the south-west of Western Australia.
In Expt 1, treatments including an early break, a late break, and a false
break followed by a late break were applied to a mixed and sieved field soil
collected dry in the summer and placed in pots in a glasshouse. In each break,
pots were watered to field capacity and planted with subterranean clover
(Trifolium subterraneum) or capeweed
(Arctotheca calendula). In early and false breaks, both
initiated on the same day in early autumn, the soil temperature was maintained
at 30°C, and in the late break, initiated 50 days later in autumn, the
soil temperature was maintained at 18°C. In both early and late breaks,
pots were watered to field capacity for either 21 or 42 days when plant and
mycorrhizal variables were assessed. In a false break, pots were watered to
field capacity for 7 days after which the soil was allowed to dry and newly
emerged plants died. These pots were then rewatered and replanted at the same
time as pots receiving a late break, and subjected to the same soil
temperature (18°C). In Expt 2 performed the following year, soil
temperature was maintained at 31 or 18°C in both early and late breaks.
Pots were planted with clover and watered to field capacity for 21 or 42 days,
when plant and mycorrhizal variables were assessed.
In Expt 1, VA mycorrhizal colonisation of both clover and capeweed was
initially low in an early break compared with levels observed in a late break.
Only mycorrhizas formed by Glomus spp. were observed in
the early break, whereas mycorrhizas of Glomus,
Acaulospora, and Scutellospora
spp. and fine endophytes were observed in the late break. Colonisation was
decreased by a false break, predominantly because of a decrease in formation
of mycorrhizas of Glomus spp. In Expt 2, mycorrhizas of
Glomus spp. predominated in warm soil in both early and
late breaks and mycorrhizas of Acaulospora spp.,
Scutellospora spp., and fine endophytes were observed in
greater abundance in cool soil in early and late breaks.
These experiments indicate that soil temperature at the time of the break will
have a large impact on both the overall levels of VA mycorrhizal colonisation
of pasture plants and colonisation by different fungi. In addition, fungi that
remain quiescent in warm soil may avoid damage in a false break.
Effect of sowing date and plant density on yield and yield components in the faba bean
Authors: Adisarwanto T. , Knight R.
Published: August 2004

Faba bean cv. Fiord was sown at 3-week intervals between 24 April and 26 June
at 6 densities varying from 20 to 56 plants/m2.
Days to emergence, flowering, pod set, and maturity were determined. At
harvest, the biomass, yield, pod number, seeds per pod, and weight per seed
were evaluated per unit area and the distribution of the yield components was
evaluated for each node of the main stem.
Later sowing had little effect on the number of days to the appearance of the
first pod but it progressively reduced the duration of the pod development
period from 98 to 60 days. The biomass at maturity of the plants sown on 24
April was constant across all densities, at about 13·5 t/ha. Yield,
however, decreased linearly with density from 6·7 to 5·2
t/ha. Harvest index, therefore, also fell with density. With later sowing,
biomass and yield increased with density. The increase in yield was not as
great; so again harvest index fell with density. Later sowing resulted in much
lower yields and even at the highest density only reached 5·2 t/ha.
Variation in yield was largely determined by variation in the number of pods
per unit area. Seeds per pod was constant across the treatments but weight per
seed decreased if sowing was delayed beyond 10 June.
With later sowing, the number of pod-bearing nodes on the main stems declined
from 27 to 15. Early-sown plants at high density had fewer pods per node at
the lower nodes and more pods per node at the higher nodes than plants at low
density. This interaction was not evident at the second sowing and the number
of pods at each node was unaffected by density. For the sowings in June, all
nodes of the low density plants bore more pods
The number of seeds per pod was smaller at the lowest and highest nodes, but
as there were so few pods at these nodes, this did not affect the mean number
of seeds per pod when evaluated for all pods on a plant. Weight per seed was
more uniform for the nodes of the early-sown plants than for those of the
plants sown later, in which there was a marked decrease in weight per seed at
the upper nodes
Structural and chemical changes of cell wall types during stem development: consequences for fibre degradation by rumen microflora
Authors: Wilson J. R. , Hatfield R. D.
Published: August 2004

Legume and grass stems decrease substantially in digestibility as they mature.
This review evaluates how anatomical and chemical factors restrict digestion
of cell walls in legume and grass stems. Cells that make up legume stems fall
into 2 groups: cells with high (≅ 100%) digestibility (e.g. cortex
and pith) and cells that appear indigestible (e.g. xylem). The digestibility
of xylem cells is restricted by the highly lignified secondary walls (SW).
Although cortex and pith cells may develop SW or thickened primary walls,
digestibility is high because these cell types do not undergo lignification.
In contrast, as grass stems mature, SW thickening and lignification occur in
all main cell types. However, lignified SW in grass is readily digested when
accessible to rumen microorganisms. Analysis of tissue and cell architecture
in grasses strongly supports the hypothesis that observed poor digestion of
lignified SW in vivo is due to limits imposed by
anatomical structure. Compositional limitation to wall digestion lies in the
lignified, indigestible middle lamella–primary wall. This structure
confines SW digestion to inner (lumen) surfaces of cells with an open end. Low
sclerenchyma SW degradation in vivo can be explained by
limited movement of bacteria into sclerenchyma cells and low surface area on
interior walls. For example, the ratio of surface area to total cell wall
volume for sclerenchyma cells is 100-fold lower than for mesophyll cells.
Apparent relationships of some wall constituents–chemical structures to
wall digestibility may be the result of the increasing SW and, therefore, may
simply reflect limitations imposed by anatomical structure.
Nitrogen benefits of lupins, field pea, and chickpea to wheat production in south-eastern Australia
Authors: Armstrong E. L. , Heenan D. P. , Pate J. S. , Unkovich M. J.
Published: August 2004

Nitrogen balances of narrow leaf lupin
(Lupinus angustifolius L.), albus lupin
(L. albus L.), field pea
(Pisum sativum L.), chickpea
(Cicer arietinum L.), and barley
(Hordeum vulgare L.) sown over a range of dates were
examined in 1992 in a rotation study at Wagga Wagga, NSW. Each N budget
included assessment of dependence on fixed as opposed to soil N, peak
aboveground biomass N, and N removed as grain or returned as unharvested
aboveground crop residues. N balances of wheat sown across the plots in 1993
were assessed similarly in terms of biomass and grain yield. Yields,
N2 fixation, and crop residue N balances of the legumes
were markedly influenced by sowing time, and superior performance of lupins
over other species was related to higher biomass production and proportional
dependence on N2 fixation, together with a poorer
harvest index. Residual N balances in aboveground biomass after harvest of the
1992 crops were significantly correlated with soil mineral N at 1993 sowing
and with biomass and grain N yields of the resulting wheat crop. Best mean
fixation and grain N yield came from albus lupin. Wheat grain N yields
following the 2 lupins were some 20% greater than after fiield pea and
chickpea and 3 times greater than after barley. Net soil N balance based
solely on aboveground returns of N of legumes in 1992 through to harvest of
wheat in 1993 was least for narrow leaf lupin-wheat ( –20 kg N/ha),
followed by albus lupin-wheat ( –44), chickpea-wheat ( –74), and
field pea-wheat ( –96). Corresponding combined grain N yields
(legume+wheat) from the 4 rotations were 269, 361, 178, and 229 kg
N/ha, respectively. The barley-wheat rotation yielded a similarly computed
soil N deficit of 67 kg/ha. Data are discussed in relation to other
studies on legume-based rotations.
Genetic analysis of preharvest sprouting tolerance in three wheat crosses
Authors: Lawson W. R. , Godwin I. D. , Cooper M. , Brennan P. S.
Published: August 2004

Three recombinant inbred populations were assessed for tolerance to preharvest
sprouting (PHS). Genetic analysis of the PHS scores, as assessed under
artificial rain treatment, indicated that for 2 of the populations, tolerance
to sprouting was simply inherited and was controlled by 2 independent genes,
both of which are necessary for full tolerance. The data presented here show
that in these 2 populations the trait is highly heritable under controlled
environment situations. It was also demonstrated that the red seed colour
gene, derived from Aus1490 and traditionally associated with tolerance, is not
necessary for full tolerance to sprouting, although indirect selection for
preharvest sprouting tolerance can be performed very effectively by selecting
for red grain. The presence of white-seeded lines, recovered from this cross
with a red-seeded donor of PHS tolerance, that are at least as tolerant as the
most tolerant red-seeded individuals demonstrates that red-seeded donors of
PHS tolerance should not be discarded for improvement of this trait.
Effect of sowing time on barley yellow dwarf virus infection in wheat: virus incidence and grain yield losses
Authors: McKirdy S. J. , Jones R. A. C.
Published: August 2004

In 4 field experiments at 2 sites in Western Australia, wheat was sown at
different times in autumn and early winter. Within each sowing, incidence of
barley yellow dwarf luteovirus (BYDV) was monitored by ELISA tests on leaf
samples, using antiserum specific to BYDV serotype PAV. Delaying sowing
decreased BYDV incidence in all 4 experiments. At the higher rainfall site,
decreased BYDV incidence due to delayed sowing was associated with increased
grain yield and size, and in 1 experiment also with a decrease in the
proportion of shrivelled grain. In contrast, at the lower rainfall site, grain
yield penalties derived from late sowing negated the yield increases
associated with decreased BYDV levels. When imidacloprid seed-dressing
followed by foliar sprays of alpha-cypermethrin were applied to control aphids
at the lower rainfall site, within each sowing BYDV incidence and the
proportion of shrivelled grain decreased and grain yield and size increased.
Applications of pirimicarb at the higher rainfall site also decreased BYDV
incidence and the proportion of shrivelled grain within each sowing, and grain
yield and size were increased. In all experiments, the only, or predominant,
colonising aphid species was Rhopalosiphum padi. At flag
leaf emergence, delayed sowing decreased the number of aphids on plants.
In high BYDV risk zones, when an appropriate insecticide is not applied to
control aphid vectors in autumn-sown wheat, delaying sowing may be advisable
to minimise BYDV-induced grain yield losses. However, the yield benefits from
decreased BYDV infection need to be balanced against possible yield penalties
due to late sowing.
A single drench of virginiamycin to increase safety of feeding grain to sheep
Authors: Thorniley G. R. , Rowe J. B. , Cowcher P. C. , Boyce M. D.
Published: August 2004

Two experiments tested the efficacy of a single drench of virginiamycin for
protecting sheep against grain poisoning (lactic acidosis). In Expt 1, 80
penned sheep (30±0·4 kg) were drenched with 0, 40, 80, or 160 mg
of virginiamycin in 10 mL of water, then fed wheat ad
libitum. Eleven sheep that received no virginiamycin and
one receiving 40 mg virginiamycin were withdrawn from the trial due to
inappetence after eating wheat. Sheep drenched with 80 or 60 mg virginiamycin
were heavier (P < 0·05) than control sheep at
20 days after drenching, and none was withdrawn. Rumen pH was higher
(P < 0·05) in sheep drenched with
virginiamycin than in control sheep.
In Expt 2, 100 sheep (62±0·7 kg) were either gradually
introduced to a standing wheat crop by restricting the length of time they had
access to the crop, or drenched with 160 mg of virginiamycin then given
unlimited access to the crop. Sheep receiving virginiamycin lost more weight
in the first week of the experiment, but thereafter gained weight faster than
the sheep gradually introduced to wheat. There was no difference between
groups in wool strength.
These trials indicate that a single drench of virginiamycin can effectively
prevent lactic acidosis in sheep.
Environmental control of potential yield of sunflower in the subtropics
Authors: Bange M. P. , Hammer G. L. , Rickert K. G.
Published: August 2004

A simple framework was used to analyse the determinants of potential yield of
sunflower (Helianthus annuus L.) in a subtropical
environment. The aim was to investigate the stability of the determinants crop
duration, canopy light interception, radiation use efficiency (RUE), and
harvest index (HI) at 2 sowing times and with 3 genotypes differing in crop
maturity and stature. Crop growth, phenology, light interception, yield,
prevailing temperature, and radiation were recorded and measured throughout
the crop cycle. Significant differences in grain yield were found between the
2 sowings, but not among genotypes within each sowing. Mean yields (0%
moisture) were 6·02 and 2·17 t/ha for the first sowing, on
13 September (S1), and the second sowing, on 5 March (S2), respectively.
Exceptionally high yields in S1 were due to high biomass assimilation
associated with the high radiation environment, high light interception owing
to a greater leaf area index, and high RUE (1·47–1·62
g/MJ) across genotypes. It is proposed that the high RUE was caused by
high levels of available nitrogen maintained during crop growth by frequent
applications of fertiliser and sewage effluent as irrigation. In addition to
differences in the radiation environment, the assimilate partitioned to grain
was reduced in S2 associated with a reduction in the duration of
grain-filling. Harvest index was 0·40 in S1 and 0·25 in S2. It
is hypothesised that low minimum temperatures experienced in S2 reduced
assimilate production and partitioning, causing premature maturation.
Effect of defoliation frequency on an irrigated perennial pasture in northern Victoria. 1. Seasonal production and sward composition
Authors: Lawson A. R. , Sale P. W. G. , Kelly K. B.
Published: August 2004

A field experiment was carried out to investigate whether changes in winter
and post-winter defoliation frequency would increase the white clover content
of an irrigated perennial ryegrass–white clover pasture in northern
Victoria. Pastures defoliated every 4 weeks during winter had higher white
clover growing point (stolon apices with at least 2 nodes) density at the end
of winter than pastures defoliated every 8 weeks or those receiving a single
defoliation after 16 weeks, but these differences did not affect the clover
content in the spring. Reasons for this are suggested. Pastures defoliated at
8-week intervals in winter were the most productive over winter{early
spring.
Less frequent defoliation (4 v. 2 weeks) during the
post-winter, September–May period reduced white clover growing point and
perennial ryegrass tiller densities. However, the white clover growth rate
during this period was increased by less frequent defoliation, whereas the
ryegrass growth rate was reduced, resulting in an increase of 10% in
the white clover content, and a 1·9 t dry matter (DM)/ha increase
in total DM produced. This higher clover content and pasture yield during
spring–autumn with less frequent defoliation has important implications
for the management of irrigated perennial pastures for the dairy industry in
northern Victoria.
Effect of defoliation frequency on an irrigated perennial pasture in northern Victoria 2*Part 1, Aust. J. Agric. Res., 1997, 48, 811 - 17.. Individual plant morphology
Authors: Lawson A. R. , Sale P. W. G. , Kelly K. B.
Published: August 2004

The effect of 5 winter and 2 post-winter defoliation frequencies on the
morphology of medium-leafed and large-leafed white clover and perennial
ryegrass plants in an irrigated perennial pasture in northern Victoria was
investigated. Measurements included leaf appearance rates, axillary bud
development and survival, stolon elongation and survival, and tiller
production and survival.
White clover leaf appearance rate was affected little by either defoliation
frequency or cultivar, ranging from 0·4 leaves/week in July to
1·1 leaves/week in February. In contrast, perennial ryegrass leaf
appearance rate in the same period ranged from 0·35 to 0·7
leaves/week. Axillary bud production on clover stolons was highest in
winter and spring and lowest through summer, and was usually greater in the
medium-leafed than in the large-leafed cultivars. When the swards were not
defoliated through winter, the rate of bud production was reduced in late
winter; this was followed by a high rate of bud production in early spring,
resulting in little treatment difference in the number of buds per stolon by
mid spring. Bud survival was greater when initiated in winter than in summer.
The rate of stolon death in spring was higher in the swards not defoliated
during winter and higher in the large-leafed than in the medium-leafed
cultivar. These effects were associated with the stolon elongation rate in
late winter; the medium-leafed cultivar was unaffected by defoliation
frequency, whereas in the large-leafed cultivars the rate of stolon elongation
increased as the defoliation interval lengthened and canopy shading increased.
Perennial ryegrass tiller production was greater with frequent than infrequent
winter or post-winter defoliation, but never exceeded 1·2 daughter
tillers/tiller, with 44% of the reproductive tillers failing to
replace themselves. The low leaf appearance rate and tiller production of the
perennial ryegrass may contribute to its poor competitiveness and persistence
in this environment.
A molybdenum - sulfur - cadmium interaction in sheep
Authors: Smith G. M. , White C. L.
Published: August 2004

We determined the effects of increased dietary concentrations of molybdenum
and sulfur on the accumulation and tissue concentrations of cadmium in sheep,
and compared them with effects on copper. Forty sheep, each weighing
approximately 40 kg, were adjusted for 3 weeks to a basal diet of 80%
wheaten chaff and 20% lupin seed containing (per kg dry weight)
0·016 mg Cd, 0·45 mg Mo, 3·4 mg Cu, and 1·9 g S.
On Day 0 of treatment, 8 sheep were killed and the tissues analysed for trace
minerals to provide a baseline value. The remaining sheep were divided into 4
dietary treatment groups: control (basal diet plus 4 mg Cd/kg), +Mo
(control diet plus 15 mg Mo/kg), +S (control diet plus 4 g S/kg),
+Mo+S (control diet+15 mg Mo+4 g S/kg).
The treatment period lasted 80 days, after which sheep were killed for tissue
samples. Sulfur alone reduced the accumulation of Cd in liver, kidney, and
muscle by 60% compared with control sheep (P <
0·05). Molybdenum alone reduced Cd accumulation by 40% in liver
and muscle (P < 0·05) and 30% in kidney
(P = 0·09). When provided together
(+Mo+S), the effect was equivalent to feeding with Mo alone, showing
that Mo blocked the effect of S. Cadmium concentrations in whole kidneys for
the 4 respective treatments were 6·40 ± 0· 7, 2·8
± 0·3, 4·5 ± 0·8, and 5·0 ±
0·5 mg/kg fresh weight. The pre-treatment concentration was
0·7 ± 0·2 mg/kg.
For Cu in blood and tissues, the effects of Mo and S treatment were consistent
with the thiomolybdate hypothesis, and were quite different from those seen
for Cd. Copper concentrations in whole kidney for the 4 treatments were
4·1 ± 0·1, 3·5 ± 0·2, 4·7
± 0·3, and 22·4 ± 3·9 mg/kg fresh
weight. The pre-treatment concentration was 4·1 ± 0·3
mg/kg. The results show that increased dietary levels of Mo and S reduce
the accumulation of Cd in tissues, and the mechanisms of action differ from
those involving Cu.
Biology and control of Reseda lutea L. 1. Seed biology and seedling growth
Authors: Heap J. W.
Published: August 2004

Reseda lutea L. is a major perennial weed of alkaline
cropping soils in South Australia. Seed biology and early seedling growth of
R. lutea were studied in field and laboratory
experiments to gain information needed for effective control strategies.
Recovery of intact seeds buried for 4 years in the field at 50 and 150 mm was
77–96%. Germination of this seed was 33–63% (50 mm)
and 0% (150 mm). Germination patterns differed markedly between seed
collected from 2 populations. Seed germinated at all constant and fluctuating
temperatures between 10 and 35° C with the maximum (88%) at
25°C constant. Mean temperature, rather than constancy or fluctuation,
determined the germination rate. Light strongly inhibited germination.
Seedling shoot growth was slow but tap root growth was rapid, reaching 350 mm
within 28 days of emergence. Secondary roots arose 3–7 days after
emergence and shoot buds formed on the roots within 28 days.
R. lutea was found to be well adapted for persistence in
cultivated fields with a temperate climate.
Biology and control of Reseda lutea L. 2. Life cycle: seedling emergence, recruitment, and vegetative reproduction
Authors: Heap J. W.
Published: August 2004

The reproductive biology of Reseda lutea L. was studied
in the laboratory and field in southern Australia. Seedling emergence was
greatest from 5 mm depth (57%) to 10 mm (53%) but also occurred
from 80 mm. Seeds on the soil surface did not germinate. Following cultivation
of a field population, seedling emergence was high
(144/m2) in the first winter and recruitment to the
perennial population was estimated at 10·2%. Seedling emergence
in subsequent winters was low. Perennial shoot numbers increased gradually in
the first year after cultivation, from seedling recruitment and daughter
shoots, and then stabilised at around 28/m2. Shoots
formed on root fragments at a range of constant and fluctuating temperatures
between 10° and 35°C, with a maximum of 17·3 shoots per 50-mm
fragment at 15°C. Shoot production increased with root fragment length and
diameter. Shoots were produced on root fragments as short as 10 mm and as thin
as 1 mm. Fragments from the upper tap root produced more shoots than those
from further down the tap root, or from laterals. An illustrated model of the
life cycle of R. lutea in Australia is presented.
Soil moisture levels and their relation to water potentials of cotton leaves
Authors: Heuer Arie Nadler and Bruria
Published: August 2004

Simultaneous measurements of volumetric water content (θ) in the soil
profile by neutron scattering (NP), time domain refiectometry (TDR), and
tensiometers (TENS), and leaf water potential (LWP) were carried out in a
commercial cotton field under semi-arid conditions. The good correlation
between averaged θ values by TENS and TDR suggests that the preferred TDR
technique can replace the more commonly used TENS. Slopes of the linear
relations between LWP and θ increase in the order NP<TDR<TENS This
order may be explained by the combination of the
‘sphere-of-influence’ soil volume and the specific property of the
water molecules sensed by the particular measuring technique.
Analysis of sequential reproductive development in white lupin cv. Lublanc
Authors: Munier-Jolain N. M. , Ney B. , Duthion C.
Published: August 2004

As for other legume crops with sequential flowering, the time-lags between the
development of the different pods of white lupin affect the progress of
intra-plant competition for assimilates, the pattern of seed yield
distribution within the canopy, and the whole cycle duration. The objective of
this study was to define a convenient indicator describing pod development,
and to investigate the relationship between the plant vegetative architecture
and the progression of the reproductive stages along the different
inflorescence types. ‘Lublanc’ spring white lupin was grown in the
glasshouse during 1 year and in the field during 4 years, with various sowing
dates and plant densities. Current management techniques, including
irrigation, were applied. The progress of seed water content allowed
distinction of the period when seed abortion occurs from the seed filling
phase. The progression rate of flowering up the racemes was related to the
growth rate of the considered axes at the beginning of their flowering. The
flowering delay between 2 successive orders of axes depended on both the leaf
number on the branches and the individual branch growth rate during their
elongation. The time of the reproductive stages at a pod position depended
only on the time of flowering at that position. The duration of the seed
filling phase did not vary among pod positions.
Rainfall-yield relationships across the Australian wheatbelt
Authors: Stephens D. J. , Lyons T. J.
Published: August 2004

A network of rainfall stations was selected across the Australian wheatbelt
and monthly rainfall regressed with wheat yields from the surrounding shires
for the period 1976-87. Yields were found to be strongly related to
fluctuations in total rainfall amount and the seasonal distribution of
rainfall through the year. These temporal relationships vary spatially and
appear to be regulated by the water-holding capacity of regional soils.
Sixteen agrometeorological zones were defined with similar rainfall-yield
relationships. In all these, autumn rains that permit an early sowing, and
finishing rains after July, are most important for higher yields. As the
rainfall distribution becomes more winter-dominant, both crop yield
variability and the usefulness of high winter rainfall decreases. Heavy
rainfall in the month after sowing can have a negative effect in southern
Australia, as plants are more prone to suffer potential yield losses from a
wet soil profile. Waterlogging has a large negative effect in the south-west
of Western Australia, such that the rainfall distribution can be more
important than the rainfall amount. Rainfall-yield correlations are generally
more positive in drier regions, and are enhanced by persistent rainfall
anomalies between April and November during El Niño Southern
Oscillation years.
Influence of selected environmental factors on glyphosate efficacy when applied to awnless barnyard grass (Echinochloa colona (L.) Link)
Authors: Tanpipat Songyod , Adkins Steve W. , Swarbrick John T. , Boersma Mark
Published: August 2004

Glasshouse experiments were conducted to determine the effects of various
environmental factors on glyphosate efficacy when applied to
Echinochloa colona (L.) Link (awnless barnyard grass)
plants. The variables examined were 4 soil moisture conditions (29, 42, 55,
and 100% of field capacity), 2 levels of irradiance (400 and 800
µmol/m2· s), 3 temperature regimes
(20/15, 30/25, and 35/30°C; day/night), and 2 levels of
relative humidity (92 and 65%). The efficacy of 360 g acid equivalent
glyphosate/ha was greatest when applied to well-watered (field capacity)
plants that were placed under cool (20/25°C) and humid (92%
relative humidity) conditions. The efficacy was least when applied to plants
under severe water stress (29% of field capacity) that were placed
under hot (35/30°C) and less humid (65% relative humidity)
conditions. In all experiments, efficacy was not altered by the level of
irradiance.
Differential disease reactions on lucerne genotypes inoculated with Phytophthora medicaginis isolates from lucerne and chickpea
Authors: Liew E. C. Y. , Irwin J. A. G.
Published: August 2004

Stem inoculation of clonally propagated lucerne genotypes was used to assess
levels of host species and genotype specialisation in
Phytophthora medicaginis. A quantitative assessment of
pathogenic aggressiveness of 29 P. medicaginis isolates
(from lucerne and chickpea) on 9 different clonally propagated lucerne
genotypes revealed no significant difference in aggressiveness between
isolates from lucerne and those from chickpea on all of the lucerne genotypes.
This supported previous studies which showed that
P. medicaginis isolates from lucerne and chickpea were
indistinguishable using random amplified polymorphic DNA (RAPD) analysis.
Analysis of pathogenic aggressiveness towards individual lucerne genotypes
revealed, for the first time, specificity of individual
P. medicaginis isolates. This has implications for
breeding for resistance to P. medicaginis in lucerne,
where screening should be done using the widest range of pathogen specificity
obtainable.
Variation in growth, development, and yield of durum wheat in response to high soil boron. I. Average effects
Authors: Yau S. K. , Saxena M. C.
Published: August 2004

A greenhouse study was conducted to examine how the performance of a group of
durum wheat (Triticum turgidum L. var.
durum Desf, syn. T. Durum) lines
was affected by high soil boron (B) levels in terms of growth, phenological
development, and grain yield components. Three soil B levels (hot-water
extractable B concentrations of 0·3, 7·1, and 17·4
mg/kg) were set up by mixing soil with boric acid. Foliar symptom scores
of B toxicity were taken at the beginning of tillering. Six seedlings were
then harvested from each pot for measurement of dry weight and shoot B
concentration. Days to heading, numbers of tillers and heads, plant height,
flag-leaf area, grain and straw yield, and number of grains were also
measured.
The high soil B level (17·4 mg/kg) caused symptoms of B toxicity on
the foliage, increased shoot B concentrations, retarded growth, and reduced
grain yield. Other effects included delayed heading; greater reduction in
grain yield than straw yield; severely reduced grain yield per tiller due to
an increase in aborted tillers; and decreased 1000-grain weight and number of
heads per plant. The moderately high soil B level (7·1 mg/kg) also
severely depressed the grain yield of these durum lines.
An evaluation of the use of ultrasound scanning to predict carcass traits in steers grain fed for the Japanese market
Authors: Baud S. , Wade C. M. , Goddard M. E.
Published: August 2004

The value of live-animal ultrasound scanning was assessed for steers grain-fed
according to Japanese market specifications. Ultrasound scanning of the live
animal for rump fat depth at the P8 site and for
longissimus muscle area at feedlot entry did not
accurately predict the ranking of individual steers on subcutaneous fat depth
andlongissimus muscle area measured on the carcass at
slaughter. When scanning was performed at the time of feedlot exit, up to 9
months later, the prediction of post-slaughter subcutaneous fat depth using
scanned measurements made at the P8 site was of higher precision. Ultrasonic
scanning to determine longissimus muscle area on feedlot
exit was no better as a predictor of carcass longissimus
muscle area than was that scanned at feedlot entry. The low correlations were
probably due to differences in the sites of the scan (12th/13th rib
interface) and longissimus muscle-area measurement
(10th/11th rib interface) and to measurement errors in both the ultrasonic
scan and the direct carcass measurements. Ultrasonic scan measurements may
have been afiected by interference from deep fat cover on the steers. Genetic
correlations were high but imprecisely estimated. Correlations between
live-animal scanned measurements and the corresponding carcass measurements
were high for steers from the same vendor property. Heritability estimates for
the scanned measurements were in agreement with those from other studies.
Water use and drainage under phalaris, cocksfoot, and annual ryegrass pastures
Authors: Ridley A. M. , White R. E. , Simpson R. J. , Callinan L.
Published: August 2004

The water balance equation was used to calculate plant water use and drainage
below a depth of 1·1 m for phalaris, cocksfoot, and annual ryegrass
pastures and bare fallow at Rutherglen in north-eastern Victoria. Rainfall
from 1990 to 1993 averaged 693 mm/year. Soil water use was greater under
perennials over the summer{autumn period and the soil profile was
approximately 50 mm drier at the beginning of each drainage season. Following
autumn rains, soil water profiles under all treatments converged, usually
reaching similar water contents within 4{6 weeks. Over 4 years, soil
under phalaris became 33 mm drier, and cocksfoot 24 mm drier
(P < 0· 001), than under annual ryegrass or
bare fallow. Phalaris had higher actual evapotranspiration
(P < 0·05; average, 642 mm/year) than
cocksfoot (619 mm/year) and annual ryegrass (606 mm/year), the latter
two not differing significantly.
Drainage occurred during winter and early spring, ranging from 2 to 12 mm in
1991 (515 mm rainfall) to >100 mm/year in 1990 and 1992 (671 mm and 901
mm rainfall, respectively). The variation between years was greater than the
differences between pastures in any one year. Averaged over the 4 years,
drainage losses below 1 .1 m decreased in the order bare fallow > annual
ryegrass > cocksfoot > phalaris, although differences between the 3
pasture types were not statistically significant. Drainage under phalaris and
cocksfoot may have been overestimated relative to annual ryegrass and fallow
because of subsurface flow, at the top of the B horizon, between the wetter
and drier plots. The drainage under phalaris may also have been overestimated
because this pasture extracted water below the depth of soil water
measurement. Allowing for these effects, the estimated drainage under phalaris
may have been 49-56 mm/year compared with 80-87 mm/year under annual
ryegrass, an overall reduction of more than one-third.
Although perennial pasture grasses are unlikely to stop all recharge to
groundwater in high rainfall areas (>600 mm/year) of south-eastern
Australia, they offer a practical way to combine profitable agriculture with
reduced land degradation.
Phosphorus nutrition of spring wheat (Triticum aestivum L.). 3. Part 2, Aust. J. Agric. Res., 1997, 48, 869-81.. Effects of plant nitrogen status and genotype on the calibration of plant tests for diagnosing phosphorus d
Authors: Elliott D. E. , Reuter D. J. , Reddy G. D. , Abbott R. J.
Published: August 2004

The influence of plant nitrogen (N) status and plant genotype on plant test
criteria for diagnosing phosphorus (P) deficiency in wheat was examined in 2
glasshouse experiments.
Criteria for both total and labile P in leaf blades of standard physiological
age are, to only a minor extent, affected by variations in N supply and by
genotypic diversity
Interactions between N and P supply had marked and complex effects on shoot
and root yield, P and N uptake in shoots and concentrations in leaf blades,
and on the distribution of P and P fractions within wheat shoots. Thus, whilst
the external P requirement (i.e. P level required for
90% maximum shoot yield) more than doubled as N supply was raised,
variations in N supply had only minor effects on
internalP requirement (i.e. the tissue P concentration
required for 90% maximum shoot yield). On the other hand, the external
P requirement for root yield varied markedly with plant age and N supply.
N deficiency increased total P concentrations in leaf blades at all P levels,
primarily by increasing the concentration of the labile P fraction. Also, N
concentrations increased to adequate levels in the shoots of P-deficient
plants but only at the 2 lower levels of applied N.
Plant N status also affected the shape of diagnostic relationships between
relative shoot yield and P concentrations in young and mature leaf blades by
constricting P concentration in the adequate-luxury zone and increasing the
slope of the relationship in the zone of deficiency.
Whilst the asymptotic grain yield and external requirement for P for the tall
cultivar (Halberd) was substantially less than for the semi-dwarf cultivars
(Condor and Durati), consistent P cultivar interactions on shoot yield and P
uptake during vegetative growth, were largely absent. For leaf blade classes
examined, the shape of the diagnostic relationship for total and labile P was
essentially similar for each cultivar. As a result, differences in estimated
critical P concentrations for total and labile P between the cultivars for
leaf blades during vegetative growth, or criteria for grain, glumes, and straw
at maturity, were relatively small.