bluuebunny/crossref_metadata_2025 huggingface dataset:
Obtaining soil hydraulic properties for water balance and leaching models from survey data. 1. Water retention
Authors: Smettem K. R. J. , Bristow K. L. , Heng L. K. , Oliver Y. M. , Ford E. J.
Published: November 2005

A physico-empirical 2-parameter power law model of the draining water
retention curve (WRC) based solely on clay content is described and further
developed using 6 datasets obtained from Australian and New Zealand soils. The
slope of the WRC, or pore-size distribution index, is well described by the
model but the bubbling pressure, or inflection point is poorly described.
Without a good estimation of the bubbling pressure it is not possible to scale
the physico-empirical model to the WRC. To achieve the scaling, a single
measured point on the WRC in the unsaturated range is required. The resulting
estimated water contents may be satisfactory for application within
broad-scale leaching risk models and for generalised extrapolation of results
from detailed experimental sites but caution is still required for
quantitative applications of nitrate leaching models at a particular site.
It is concluded that soil surveys could usefully include a single WRC
measurement in the field at each sampling location to improve their utility
for water and chemical transport modelling.
Sulfur amino acid metabolism in the whole body and mammary gland of the lactating Saanen goat
Authors: Lee J. , Knutson R. J. , Davis S. R. , Louie K. , Mackenzie D. D. S. , Harris P. M.
Published: November 2005

Five multiparous Saanen goats in late lactation were infused with
35S-cysteine into the mammary gland via the external
pudic artery. A further 2 goats were infused with
35S-methionine via the same artery and later with
35S-methionine into the jugular vein. Total uptake of
cysteine from the arterial blood supply by the mammary gland was approximately
6% of the 35S-cysteine flux past the gland,
whereas uptake of methionine was 30–40%. Total mammary uptake of
cysteine was also lower than that of methionine when expressed as a percentage
of whole body utilisation (6.5 and 14%, respectively). The uptake from
the blood did not account for output in the milk for either cysteine or
methionine. Both amino acids were highly conserved by the gland as shown by
little release of any degraded constitutive protein amino acids and no
evidence of oxidation products of either cysteine or methionine being released
into the blood. Comparison of 35S activity in the milk
from the infused and non-infused sides of the gland showed up to 10%
trans-sulfuration of methionine to cysteine within the gland, none of which
was exported in the venous drainage. Total ATP production by one side of the
gland was 12.1 mol/day or 13 mmol/min.kg mammary tissue, of which
15% was required for gland protein synthesis. The experimental
measurements from both the cysteine and methionine infusions were used to
solve a model of gland amino acid uptake and partitioning. Modelling
radioactivity of both amino acids in the blood, intracellular free pool, and
milk protein suggested that a single intracellular pool cannot be the only
source of amino acid for protein synthesis. The model also provides support
for the hypothesis that a significant proportion of the uptake of at least
some amino acids by the mammary gland is from intracellular hydrolysis of
extracellularly derived peptides.
Low input grasses useful in limiting environments (LIGULE)
Authors: Johnston W. H. , Clifton C. A. , Cole I. A. , Koen T. B. , Mitchell M. L. , Waterhouse D. B.
Published: November 2005

This paper presents a case for the selection and development of a wider range
of perennial grasses for pastoral use in the higher rainfall (annual rainfall
>500 mm) zone of southern Australia, especially the southern sector of the
Murray–Darling Basin. There is also a need to reconsider the use of
‘high-input’ pastures on hill lands by developing more appropriate
recommendations for managing existing native grass pastures productively.
Past experiments which compared native grass based pastures with sown pastures
promoted the view that indigenous grasses were inferior in most respects to
exotic improved species. Even though many of the findings were confounded with
fertiliser, stocking rate, and other treatment effects, they reinforced the
general direction of cultivar development programs which in the temperate zone
have been based mainly on the 4 exotic C3 species
Phalaris aquatica L.,
Dactylis glomerata L., Lolium L.
spp., and Festuca elatior var.
arundinacea (Schreb.) Hackel (syn.
Festuca arundinacea Schreb). This has led to an
imbalance in the adaptability and range of species available to be sown in
pastures, particularly for sowing on less productive landscapes where stony,
shallow, infertile, acid soils limit the persistence of current cultivars.
The pre-European vegetation of temperate Australia comprised species with a
capacity for active growth and transpiration during summer. The water use
pattern resulted in soil moisture being near capacity in late winter and
spring, and exhausted by summer’s end. Replacement of this vegetation
with annual-growing and summer-dormant C3 species has
changed the water use pattern so that soils are drier in spring and wetter in
autumn. This has reduced the pre-winter soil moisture deficit, which in turn
has increased rates of deep drainage in winter.
Land degradation in southern Australia is a consequence of this changed water
use pattern. Deep drainage of water beyond the reach of plant roots has
mobilised salts stored in the landscape and caused watertables to rise, which
has led to large areas becoming saline. Lack of growth in summer in pastures
consisting of senescent annual-growing species and dormant
C3 perennial grasses limits utilisation of the products
of nitrogen mineralisation, which allows nitrate nitrogen to accumulate in
summer and be readily leached by rainfall in autumn. This increases rates of
soil acidification. Although there may be scope to reduce deep drainage by
increasing pasture growth in spring in areas where there is little likelihood
of summer rainfall, this is not the case in south-eastern Australia where
significant falls of rain occur during summer and autumn.
Effects of a network of mycorrhizae on capsicum (Capsicum annuum L.) grown in the field with five rates of applied phosphorus
Authors: Olsen J. K. , Schaefer J. T. , Edwards D. G. , Hunter M. N. , Galea V. J. , Muller L. M.
Published: November 2005

This field trial determined the importance of mycorrhizae[Acaulospora mellea Spain & Schenck,Gigaspora margarita Becker & Hall,Glomus clarum Nicolson & Schenck,Glomus etunicatum Becker & Gerdemann, andScutellospora pellucida (Nicol. & Schenck) Walker & Sanders], established from an existing intact network ofvesicular-arbuscular mycorrhizae (VAM) propagules, for production of capsicum(Capsicum annuum L. cv. Target) in a low phosphorus(≤14 mg NaHCO3-extractable P/kg) Typic Paleudalf. The mycorrhizalnetwork was formed previously with sweetcorn (Zea maysL. cv. Snosweet) plants grown in distinct rows. A narrow band of milledsuperphosphate was applied at 0 (P1), 5(P2), 15 (P3), 45(P4), or 135 (P5) kg P/ha toplots that were either fumigated (VAM ) or not fumigated (VAM+).The higher (P < 0.05) concentrations of P in theyoungest mature leaf (blade plus petiole) of VAM+ than those of VAMcapsicum plants at P1, P2, andP3 coincided with a greater (P< 0.05) weight of marketable fruit of VAM+ than of VAM– plants;this finding confirmed the importance of VAM to the enhanced P nutrition ofcapsicum at low P levels. In the non-fumigated soil (1061 non-dormantinfective VAM propagules/g air-dry soil), the inverse sine transformedmeans of percentage colonisation of roots were generally unaffected by Papplication, indicating that addition of P may not reduce VAM colonisation ofroots if the inoculum potential of the soil is high. An alternative hypothesisto account for the relatively undiminished mycorrhizal colonisation ofVAM+ plants at high P rates may relate to a reduction in colonisation forroots growing within the narrow band of applied P, but not for roots growingin the much larger volume of soil outside of this localised P zone. Theabsence of reduced yields and of lower starch concentrations of roots of VAM+ relative to VAM– plants suggested that photosynthateproduction was surplus to the requirements of the plant and fungus for theirradiance encountered during the trial. The gross margin for VAM plants wasmaximal at P5 ($AU3340/ha), and this amountwas similar to the margin for VAM+ plants grown at all treatments exceptP1, which had a lower gross margin. As a substitute forP, mycorrhizae have limited potential in intensive vegetable productionsystems since the cost of P is low compared with total costs. However, otherbenefits of VAM such as decreased susceptibility to disease and improvedstructure of the soil need to be fully assessed to determine the full benefitof mycorrhizae in such systems.
Differential responses of field pea (Pisum sativum L.) to ascochyta blight (Mycosphaerella pinodes): rating disease in the field
Authors: Wroth J. M. , Khan T. N.
Published: November 2005

Lotus glaber Mill. is a herbaceous legume, tolerant to
flooding, that in a few decades has colonised the Flooding Pampa grasslands,
an extensive wetland of 90 000 km in central-east Argentina. In this study,
the growth and nodulation of flooded plants in 5 local populations were
evaluated. Thirty-day-old seedlings, grown in pots, were flooded outdoors
during 4 months. Stem, leaf, and root biomass, as well as the number of
nodules per plant, were lower in flooded plants than in non-flooded ones. In
flooded plants, the submerged portions of stems were hypertrophied and
populations differed in the proportion of plants with adventitious roots.
Flood tolerance was significantly related to the proportion of plants with
adventitious roots in stems of each population. A positive relationship was
shown between the proportion of plants with adventitious root and number of
nodules per plant. The plants were also tolerant of low temperatures and
ice-sheeting of water. These results underline the importance of morphological
adaptations related to the maintenance of plant functionality under flooding
conditions. The results provide evidence of the existence of characters
related to flooding tolerance, which should be taken into account in
ecological studies and agronomic selection programs.
Interaction of pH amendment and potassium fertiliser on soil chemistry and banana plant growth
Authors: Vimpany I. A. , Johns G. G.
Published: November 2005

Two glasshouse trials were conducted at Alstonville, NSW, to investigate the
effects of rates of potassium (K) fertiliser and pH amendment on soil
chemistry, plant nutrient content, and growth of tissue-cultured banana
plants. The first trial used 5 rates of lime combined with 5 rates of KCl with
plants in 1.5-L pots, and the subsequent trial used 4 rates of pH amendment
(CaCO3 + MgO) combined with 4 rates of
K2SO4 with plants in 140-L
troughs. The soil used in both trials was the A horizon of a Yellow Kurosol.
In the pot trial, very high rates of KCl caused a reduction in plant weight,
and heaviest plants were produced at pH 4.5 5 (pHCa,
measured with CaCl2). Analysis of exchangeable and
soluble cations indicated that increasing rates of added KCl displaced both Ca
and Mg off cation exchange surfaces into the soil solution, from where they
could be lost by leaching. Liming caused a marked decrease in plant Zn and Mn
concentrations to levels that may have limited growth when soil
pHCa exceeded about 5.0.
In the trough trial, plant weight was greatest at pHCa
4.3. Plant weight responded negatively to increasing
K2SO4 at
pHCa 3.5, positively at pHCa 4.3,
and was generally unresponsive at the higher pHCa values
of 5.0 and 5.8. A multiplicative Mitscherlich model was used to relate plant
weight to leaf nutrient concentrations and indicated that plant weight was
most limited by Mg deficiency at pHCa 3.5 and Mn
deficiency at pHCa 5.8, with K availability having a
moderate effect on growth at intermediate pHCa levels.
Mg deficiency occurred at low pH despite regular foliar applications of this
element, indicating the inefficacy of the foliar pathway for fertilising
bananas with macro-nutrients. The study indicated that attempting to raise the
pHCa of this soil above 5.0 for banana growing may not
be appropriate, and due attention should be paid to Mg requirements and
possible effects of liming on trace element availability.
Grain nitrogen concentration differences among three sorghum hybrids with similar grain yield
Authors: Kamoshita A. , Cooper M. , Muchow R. C. , Fukai S.
Published: November 2005

The differences in grain nitrogen (N) concentration among 3 sorghum
(Sorghum bicolor (L.) Moench) hybrids with similar grain
yield were examined under N-limiting conditions in relation to the
availability of assimilate and N to grain. Several manipulation treatments
[N fertiliser application, lower leaves shading, thinning (reduced plant
population), whole canopy shading, canopy opening, spikelet removal] were
imposed to alter the relative N and assimilate availability to grain under
full irrigation supply.
Grain N concentration increased by either increased grain N availability or
yield reduction while maintaining N uptake. Grain N concentration, however,
did not decrease in the treatments where relative abundance of N compared with
assimilate was intended to be reduced. The minimum levels of grain N
concentration differed from 0.95% (ATx623/RTx430) to 1.14%
(DK55plus) in these treatments. Regardless of the extent of variation in
assimilate and N supply to grain, the ranking of hybrids on grain N
concentration was consistent across the manipulation treatments. For the 3
hybrids examined, higher grain N concentration was associated with higher N
uptake during grain filling and, to a lesser extent, with higher N
mobilisation. Hybrids with larger grain N accumulation had a larger number of
grains. There was no tradeoff between grain N concentration and yield,
suggesting that grain protein concentration can be improved without
sacrificing yield potential.
Annual nitrogen fixation in grazed dairy pastures in south-western Victoria
Authors: Riffkin Penny A. , Quigley Paul E. , Cameron Fiona J. , Peoples Mark B. , Thies Janice E.
Published: November 2005

Amounts of biologically fixed nitrogen (kg N/ha) were determined in grazed
dairy pastures in 3 different areas of south-western Victoria over 12 months
between October 1995 and 1996 using measurements of pasture growth, botanical
composition, and the 15N natural abundance of white
clover (Trifolium repens) and non-legume components.
Estimates of the amounts of N fixed, based on N in clover shoots, were similar
in each pasture (11, 16, and 18 kg N/ha.year), despite different
environmental and management conditions. These on-farm determinations were low
compared with experimental studies on N fixation by white clover undertaken in
New Zealand (224–291 kg N/ha.year) and elsewhere in Australia
(44–135 kg N/ha). Low fixation levels were attributed to low pasture
yields (average 8.2 t dry matter (DM)/ha.year) and poor legume content in
the swards (average 8%). Despite this, most of the white clover N was
derived from atmospheric N2 (65%), and therefore,
N fixation could potentially be playing an important role in the N economy of
milk production on these farms.
Factors associated with biological nitrogen fixation in dairy pastures in south-western Victoria
Authors: Riffkin Penny A. , Quigley Paul E. , Kearney Gavin A. , Cameron Fiona J. , Gault Robert R. , Peoples Mark B. , Thies Janice E.
Published: November 2005

A survey of 71 sites was conducted in the dairying districts of south-western
Victoria in October 1994 to determine factors associated with nitrogen (N)
fixation in white clover based pastures. Twenty-eight factors (environmental,
microbiological, management, soil, and pasture) were considered in relation to
2 indicators of N fixation by white clover, %Ndfa (percentage of total
plant N derived from the atmosphere, as determined by the
15N natural abundance method) and kg of N fixed per
tonne herbage dry matter (legume and non-legume). On light-textured soils
(sandy loams), soil potassium, rhizobia numbers, total soil N, and density of
the nematode Pratylenchus sp. accounted for 72%
of variation in %Ndfa. On medium-textured soils (clay loams), crude
protein of perennial ryegrass and plant-available phosphorus in the soil
accounted for 30% of variation in %Ndfa. The amount of N fixed
was influenced by different factors, again depending on soil texture. Soil
chemical properties accounted for 31% variation on the medium-textured
soils with nematode density, pasture quality, and soil chemical properties
accounting for 77% of variation on light-textured soils. Amounts of N
fixed per tonne herbage dry matter produced averaged 8.2 kg on the
light-textured soils and 7.3 kg on the medium-textured soils. Average
%Ndfa values were 67% and 60% on light- and
medium-textured soils, respectively. Effects of soil texture on N fixation
were attributed to the different cation exchange and water-holding capacities
of the soils and highlight the importance of considering soil type in N
fixation studies.
Changes in bicarbonate-extractable phosphorus of a basalt-derived duplex soil associated with applications of superphosphate to pasture grazed by sheep
Authors: Cayley J. W. D. , Kearney G. A.
Published: November 2005

The effect of 3 successive yearly applications of single superphosphate (SSP)
to pastures on bicarbonate- extractable soil phosphorus (Olsen P) was
measured. The soil was a duplex derived from basalt and the pastures, based on
perennial ryegrass and subterranean clover, were continuously stocked with
sheep. Six levels of SSP were compared at 3 stocking rates. The amount of P
applied annually varied from 0 to 100 kg/ha. These data were used to
create an empirical model which used the current value for Olsen P (Olsen
Pn), the amount of P applied as fertiliser that year
(fert Pn), and a lower limit for Olsen P for
basalt-derived duplex soils (Olsen Plow) to predict the
Olsen P for the following year (Olsen Pn+1). The
model had the form: Olsen Pn+1 = Olsen P low
+ afert Pn +
b(Olsen Pn – Olsen
Plow). Olsen P low was fixed at 3 mg P/kg soil, and
the coefficients a and b were
0.0995 and 0.8020. The model accounted for 96.6% of the variance in
Olsen Pn+1. This model was tested at the same site
at 2 other periods: when fertiliser was withheld for 3 years and again after
applications of SSP were resumed. The model was also tested against data from
another experiment conducted on a similar soil. The model can estimate the
amount of fertiliser required to maintain the P status of the soil and
predicts that to increase Olsen P by 1 unit in the following year it is
necessary to apply 10 kg P/ha in excess of soil maintenance requirement.
Nitrate leaching under phalaris, cocksfoot, and annual ryegrass pastures and implications for soil acidification
Authors: Ridley A. M. , Simpson R. J. , White R. E.
Published: November 2005

Nitrogen uptake and nitrate (NO-3)
leaching below 1.1 m was estimated under phalaris, cocksfoot, and annual
ryegrass pastures and under bare fallow in a 4-year field experiment under
control and high N (500 kg N/ha) treatments in north-eastern Victoria (693
mm/year rainfall for the study period). The perennial grasses,
particularly phalaris, took up more N in herbage than annual ryegrass. High
concentrations of NO3-N were measured at 1 m depth
below all treatments, suggesting that NO3- losses from
pastures have potential to contaminate streams and/or groundwater.
Perennial pastures were only able to reduce NO3-
leaching compared with annuals in drier than average years. Values calculated
for acid addition due to NO3-leaching resulted in a net
annual input of approximately 1 kmol H +/ha.year
under the phalaris pasture compared with 2 kmol H
+/ha.year under annual ryegrass. Adding these
figures to carbon cycle addition data of 1 kmol
H+/ha.year (measured in a previous study)
corresponds to a lime rate of 100 and 150 kg lime/ha.year being required
to stop further acidification under these pasture types. A 1 unit pH decline
to 30 cm depth was estimated to take 42 years under annual pasture or 67 years
under perennial grasses. Whilst perennial pastures have a role in reducing
soil acidification, lime application is the most important management option
in balancing soil acidification caused by agriculture.
Introduction and management of vetch/barley forage mixtures in the rainfed areas of Pakistan. 1. Forage yield
Authors: Qamar I. A. , Keatinge J. D. H. , Mohammad (dec.) Noor , Ali Asghar , Khan M. Ajmal
Published: November 2005

To investigate the introduction of vetch/barley forage mixtures with a
range of harvesting treatments in the winter season of Mediterranean-type
environments, studies were carried out during 1994–97 at the National
Agricultural Research Centre (NARC), Islamabad, which has an annual rainfall
of around 1000 mm, and at a much drier site at the Arid Zone Research Centre
(AZRC) at Quetta in Pakistan, which has an annual rainfall of around (223 mm).
Common vetch (V), barley (B), and their mixtures at seed ratios of V75B25,
V50B50, and V25B75 were sown and 3 harvest time treatments (pre-flowering,
full flowering, and maturity) were imposed. At NARC, there were significant
differences (P < 0·01) in dry matter
production between crop mixture ratios and between different harvest times.
Mixtures of vetch and barley were generally more productive than any of the
sole crops, with the yield of the best mixture V75B25 (7·6 t/ha)
being almost twice as productive as sole vetch. Productivity at the full
flowering stage was lower (5·3 t/ha) than that recorded at maturity
(7·0 t/ha) and for the dual-cut pre-flowering harvest treatment
(6·2 t/ha). At AZRC, the same trends as at NARC were observed but
with lower yields because of the substantially lower and less well distributed
rainfall and suboptimal temperatures. The highest dry matter was obtained with
the treatment V75B25 (3·3 t/ha), which was approximately 50%
higher in yield than sole vetch or sole barley (around 2 t/ha). Dry matter
was highest at the maturity stage (3·2 t/ha) and lowest at the
flowering stage (2·3 t/ha), except in the sole vetch crop which was
lowest in yield at the pre-flowering stage (2·7 t/ha), implying a
minor interaction between seed mixture and harvesting stage.
Introduction and management of vetch/barley forage mixtures in the rainfed areas of Pakistan. 2. Forage quality
Authors: Qamar I. A. , Keatinge J. D. H. , Mohammad (dec.) Noor , Ali Asghar , Khan M. Ajmal
Published: November 2005

The effects of a range of harvesting times and vetch/barley mixture ratios
on forage quality were investigated in Mediterranean-type environments at the
National Agricultural Research Centre (NARC), Islamabad, which has an annual
rainfall of around 1000 mm, and at a much drier site at the Arid Zone Research
Centre (AZRC) at Quetta in Pakistan, during 1994–97. Common vetch (V),
barley (B), and their mixtures at seed ratios of V75B25, V50B50, and V25B75
were sown, and 3 harvest time treatments (pre-flowering, full flowering, and
maturity) were imposed. At NARC, there were significant differences
(P < 0·01) in crude protein content,
digestible dry matter (DDM), and metabolisable energy (ME) between crop
mixture ratios and between different harvest times. Crude protein content in
mixtures declined substantially as vetch in the mixtures was replaced with
barley. The treatment V75B25 had the highest crude protein content (>1
t/ha), pure barley was least productive (<300 kg/ha), with pure
vetch being intermediate in protein yield (700–800 kg/ha). All 3
mixtures of vetch and barley had higher DDM (4-5 t/ha) and ME values of
5–6·5 104 MJ/ha (highest for treatment
V75B25) compared with both of the sole crops. DDM and ME in mixtures declined
as the proportion of barley in the seed ratio in the mixtures increased, but
pure barley had still somewhat more DDM (3·6 t/ha) and ME (43 344
MJ/ha) than pure vetch (3·2 t DDM/ha and 42 035 MJ ME/ha).
At AZRC, the same trends as at NARC were observed but with lower yields
because of the substantially lower and less well distributed rainfall and
suboptimal temperatures.
Predicting leaf area development in response to temperature in three tropical annual forage legumes
Authors: Pengelly B. C. , Muchow R. C. , Blamey F. P. C.
Published: November 2005

Ley legumes are an important option in nitrogen (N) management in
cropping–livestock systems in Australia’s northern cropping
region. The complexity of managing N and water in these systems is
increasingly being aided by the use of crop models which require quantitative
estimates of the various components of growth. A study to predict plant leaf
area (PLA) of 3 tropical forage legumes as a function of temperature under
irrigated conditions was conducted at Gatton, south-eastern Queensland. The
legumes were phasey bean [Macroptilium lathyroides
(L.) Urban.], vigna [Vigna trilobata (L.)
Verdc.], and sesbania (Sesbania cannabina Retz.).
The PLA was to be predicted by establishing a relationship between plastochron
index (PI) and accumulated thermal time, and then between PLA and PI.
Daily rate of increase in PI (DIPI) was strongly related to accumulated
thermal time in all species, with DIPI higher for phasey bean (0.51
degree-days) and sesbania (0.54 degree-days) than for vigna (0.14
degree-days). At a plant density of 50 plants/m2,
the relationship between PI and PLA was largely dependent upon the proportion
of PLA originating from branches rather than from the main stem. In sesbania,
<20% of the PLA was contributed from leaves originating from
branches, compared with about 40% in phasey bean and about 75%
in vigna. The slope of the linear component of the relationship between PLA
and PI in sesbania (85 cm2) was slightly less than the
maximum leaf area per node recorded. The comparable slope for phasey bean was
57 cm2, being greater than the area of any individual
leaf (40–50 cm2) because of the greater
contribution of leaves originating from branches. In vigna, the very large
contribution of leaves originating from branches to PLA, together with the
slower DIPI for that species, resulted in the relationship between PI and PLA
being much steeper than in either of the other species. The parameters
developed for each species were successfully validated using independent data
from other experiments in south-eastern Queensland. Increase in PLA in
response to accumulated thermal time can be successfully predicted for these 3
tropical legumes at the set plant density. The successful prediction of PLA
for legumes with a high degree of branching is of special significance, as it
indicates that these methods may have application in predicting leaf growth in
legumes which are being grazed and which have a number of active growing
points. Nevertheless, the stability of the derived parameters needs to be
assessed under a range of plant densities before they can be widely used to
predict leaf area development in ley legumes.
Genetic variation in populations of two Mediterranean annual pasture legumes (Biserrula pelecinus L. and Ornithopus compressus L.) and associated rhizobia
Authors: Loi A. , Howieson J. G. , Cocks P. S. , Carr S. J.
Published: November 2005

Genetic variation between and within populations of
Biserrula pelecinus L. (biserrula) and
Ornithopus compressus L. (yellow serradella) and
associated rhizobia was studied using germplasm collected from sites in
central-eastern and south-eastern Sardinia (Italy). Pods and root-nodule
bacteria were collected on diagonal transects at each site. Plants were
characterised in nursery rows and the rhizobia were isolated and tested for
their effectiveness. Thirteen morphological traits were recorded and the
results were analysed using cluster analysis.
Genetic and phenotypic variation of rhizobia were assessed using DNA analysis
(PCR, RAPDs) and effectiveness indices, respectively. Genetic variation based
on morphological traits was found between and within sites for both species.
Pod characteristics and flowering time were the most important traits
assisting in discriminating between accessions. Flowering time varied more in
serradella than in biserrula, particularly at Cantoniera Cannas. Although all
rhizobial strains nodulated all accessions of biserrula, great variability in
capacity to fix nitrogen was evident between and within sites. Distinct PCR
amplification profiles were generated for individual rhizobial strains, which
confirmed the phenotypic variability (effectiveness indices) of the strains.
No relationship was found between host and rhizobia variation.
The results are discussed in terms of (a) genetic
differences for each species within and between sites;
(b) differences in behaviour in respect to genetic
variation between biserrula, serradella, and other Mediterranean annual
legumes; and (c) spatial variability and symbiotic
effectiveness of rhizobia.
Effect of mixing boars during lairage and pre-slaughter handling on pork quality
Authors: D'Souza D. N. , Dunshea F. R. , Leury B. J. , Warner R. D.
Published: November 2005

Forty-eight crossbred (Large White × Landrace) boars were used in a 2
× 2 factorial design to determine the effects of mixing unfamiliar pigs
during lairage and the use of electric goads just prior to slaughter on muscle
glycogenolysis and subsequent pork quality. The treatments included 2 mixing
treatments (familiar pigs kept together during lairage and unfamiliar pigs
mixed during lairage) and 2 handling treatments [minimal handling and
negative (electric goad) handling pre-slaughter]. Pigs mixed during
lairage had lower muscle glycogen and lactic acid at 5 min, 40 min, and 24 h
post-slaughter than familiar pigs kept together during lairage. Mixing of
unfamiliar boars also resulted in higher ultimate muscle pH, a higher
incidence of dark, firm, dry (DFD) pork, and a lower incidence of pale, soft,
exudative (PSE) pork compared with familiar pigs kept together during lairage.
The use of an electric goad prior to slaughter did not affect muscle glycogen
in mixed pigs, but in unmixed pigs there were large numerical diffferences in
glycogen concentrations. The negatively handled unmixed pigs had a trend for
lower glycogen concentrations which did not reach significance. This was
probably due to the small sample size. However, pigs negatively handled
pre-slaughter had higher lactic acid concentration at 5 min post-slaughter
compared with minimally handled pigs. This experiment has demonstrated that
mixing of unfamiliar boars can have a major impact on pork quality, resulting
in a high incidence of DFD pork and a reduced incidence of PSE.
Nitrogen and sulfur mobilised from body tissue can be used for wool growth
Authors: Revell Dean K. , Baker Suzanne K. , Purser D. Barrie
Published: November 2005

The hypothesis was tested that when nitrogen (N) and sulfur (S) are mobilised
from body tissue the rate of wool growth is determined both by the amount of N
and S apparently digested and by the amount of N and S mobilised from body
tissue. The experiment consisted of seven 5-day periods (Periods 1–7)
and N and S retention were measured during each period in 12 mature Merino
wethers. During Periods 2 and 3, casein and methionine were infused into the
abomasum of all sheep to increase the amount of N and S absorbed in the small
intestine. Three nutritional regimes were used in order to manipulate the
amount of N and S mobilised from body tissues after the cessation of the
abomasal infusion: one group of sheep (n = 4) was
fed ad libitum throughout the experiment (Group A),
another group (n = 4) was fed at a level
calculated to maintain liveweight throughout the experiment (Group M), and the
third group (n = 4) was fed
ad libitum pre-infusion and during the infusion but was
then fed at a level calculated to maintain liveweight after the infusion
ceased (Group AM). The infusion of the supplement increased wool growth, and
when the infusion ceased, it took 10 days for wool growth to return to a
steady rate of growth. Wool growth per unit of apparently digested N or S
increased markedly when N or S was mobilised from body tissue, indicating that
mobilised protein was used for wool growth. Based on the relationship between
the apparent retention of N and S in body tissues excluding wool, and changes
in plasma amino acid concentrations, it appeared that the supply of
S-containing amino acids from body tissue limited the use of mobilised protein
for wool growth.
Identification in Australia of the quarantine pathogen of sunflower Phoma macdonaldii (Teleomorph: Leptosphaeria lindquistii)
Authors: Miric E. , Aitken E. A. B. , Goulter K. C.
Published: November 2005

Isolations from black stem lesions of sunflower growing in south-eastern
Queensland yielded fungi putatively identified as species of
Phoma. Pathogenicity assays showed that these isolates
were capable of killing sunflower plants under glasshouse conditions. The
isolates were compared with authentic cultures of
Phoma macdonaldii and other isolates of Phoma taken from
sunflower from around the world. Random amplified polymorphic DNA analysis
showed that all the Australian isolates examined were very similar to the
holotype culture of Phoma macdonaldii from Canada.
Sequencing of the internal transcribed spacer regions also revealed the
relatedness of the Australian isolates to the holotype. This is the first
official record of P. macdonaldii in Australia.
Potential for selection to improve efficiency of feed use in beef cattle: a review
Authors: Archer J. A. , Richardson E. C. , Herd R. M. , Arthur P. F.
Published: November 2005

Evidence for genetic variation in feed efficiency of beef cattle is reviewed
in this paper, and ways in which this variation might be used in selection
programs to improve beef cattle in Australia are discussed. Efficiency of beef
production systems is determined by feed and other inputs of all classes of
animals in the production system as well as outputs in terms of slaughter
progeny and cull cows. Different indices have been used to express aspects of
efficiency on cattle over certain periods of the production cycle. Use of
these indices is discussed, and then evidence for genetic variation in both
growing animals and mature animals is reviewed. Genetic variation in feed
efficiency exists in both growing and mature cattle, although information is
lacking to determine whether variation in total production system efficiency
exists. The physiological basis for observed variation in feed efficiency is
discussed, with differences in requirements for maintenance, body composition,
proportions of visceral organs, level of physical activity, and digestion
efficiency identified as possible sources of variation.
Selection to improve efficiency might be achieved by measuring feed intake of
growing animals and utilising genetic correlations that are likely to exist
between efficiency of growing animals and mature animals. Measurement of feed
intake might occur in central test stations, or methods may be developed to
measure feed intake on-farm. Ways of utilising information generated in
genetic evaluations are discussed, and it is concluded that estimated breeding
values for feed intake after a phenotypic adjustment for growth performance
would be most practical, although not theoretically optimal. Such estimated
breeding values would best be used in an economic selection index to account
for genetic correlations with other traits, including feed intake of the
breeding herd, and the economic value of feed in relation to other traits.
Future research should be directed towards understanding the genetic
relationships between feed intake and other traits in the breeding objective,
and to find ways to reduce the cost of measurement of feed intake, including a
search for genetic markers.
Irrigation of grapevines with saline water at different growth stages. 1. Effects on soil, vegetative growth, and yield
Authors: Stevens R. M. , Harvey G. , Partington D. L. , Coombe B. G.
Published: November 2005

Mature field-grown grapevines, Colombard on Ramsey rootstock, grown in a
semi-arid climate were irrigated with saline water during any one of 4 growth
stages within the season: pre-flowering, during berry development, during
berry ripening, and post-harvest. At other times, plots were irrigated with
river water (EC 0.5 dS/m) as was the control throughout the season. Saline
water (EC 3.5 dS/m) with a high sodium absorption ratio was produced by
addition of sodium chloride brine. Soil cation exchange capacity was 14
cmolc/kg, and at the end of the trial, the soil
exchangeable sodium percentage in the control was 6%, in the treatment
salinised pre-flowering 13%, during berry development 20%,
during berry ripening 20%, and post-harvest 19%. Treatments were
applied for 6 consecutive seasons. Vines were highly productive, with the
average yield in the control equal to 62 t/ha of grapes. Saline irrigation
caused significant, but small, declines in yield in 3 seasons, in pruning
weights in 2 seasons, and in berry weights in 4 seasons. Effects on growth,
once established, often persisted unchanged through one or more subsequent
seasons of saline irrigation. The growth stage shown to be most sensitive to
saline irrigation was berry development; saline irrigation during berry
development reduced the yield by 7% and during berry ripening by
3%, and pre-flowering it reduced the berry weight by 1%, during
berry development by 6%, and during berry ripening by 4%. The
amounts of irrigation applied in each of the 4 growth stages were not equal,
and hence, treatments did not receive equal additions of salt. Normalising
data to remove this effect showed that the rate of yield decline per unit
dS/m increase in the seasonal average salinity during berry development,
7%/dS.m, was 3-fold greater than the 2%/dS.m during
berry ripening. We conclude that this scion/rootstock combination, grown
under these conditions, can maintain high productivity despite
‘slugs’ of saline irrigation.
Effects of timing of heat stress and drought on growth and quality of barley grains
Authors: Savin Roxana , Nicolas Marc E.
Published: November 2005

In order to determine the importance of timing of short periods of high
temperature and drought on grain weight and grain quality, a glasshouse
experiment was carried out in which Schooner barley was exposed to short
periods of heat stress (40˚C for 6 h/day for 5 consecutive days) or
drought at early grain filling (10–15 days after anthesis, DAA), mid
grain filling (20–25 DAA), or late grain filling (30–35 DAA).
Individual grain weight was most sensitive to heat stress and drought
treatments imposed early in grain filling and was less sensitive to later
treatments. The reduction in grain weight was greater under heat stress
(average 13%) than under drought in this study (average 6%).
Starch was reduced in amount and quality, especially with early stresses
during grain filling, but grain nitrogen percentage was similar between
treatments.
Fertiliser use efficiency by containerised nursery plants. 3. Effect of heavy leaching and damaged fertiliser prills on plant growth, nutrient uptake, and nutrient loss
Authors: Huett D. O. , Morris S. C.
Published: November 2005

Nutrient leaching loss, plant growth, and nutrient uptake of 4-week
(transplanting to sale) ground-cover species were investigated under a range
of leaching conditions and with different sources of a controlled- release
fertiliser (CRF), Osmocote NPK (3–4 month) (Osm). Osm was applied
pre-planting at a rate equivalent to 800 g N/m3 to
pots containing sand, and composted pinebark and hardwood sawdust medium that
had received nutrient amendment during formulation.
Two experiments were conducted in a glasshouse over summer–autumn where
irrigation treatments produced defined leachate volumes. In Expt 1, leachate
volumes of <5, 50, and 200 mL every 2 days each received an additional
single heavy leaching event of 400 mL after 1, 2, or 3 weeks. In Expt 2, the 3
leachate volumes were each fertilised with new Osm (a newly purchased Osm) or
old Osm (a 2-year-old source), where both of these sources contained
0.5–1.5% visibly damaged prills; and damaged Osm, where damaged
prills were used exclusively.
In both experiments, increasing leachate volume increased
(P < 0.001) leaching of N (nitrate + ammonium),
P, K, Ca, and Mg. In Expt 1, leaching was highest (P
< 0.01) when the heavy leaching event occurred after 2 or 3 weeks for N and
after 2 weeks for P. When damaged Osm was used, N, P, and K loss was
3–15 times higher (P < 0.001) than from new and
old Osm (98.5–99.5% undamaged). The highest leaching loss of N,
P, K, Ca, and Mg occurred in the first week after potting up, with damaged
prills at highest leaching volume.
Increasing leachate volume (in the presence of a heavy leaching event) reduced
(P < 0.001) electrical conductivity (EC) of potting
medium after 4 weeks from 1.02 to 0.54 dS/m. Damaged prills reduced
(P < 0.001) EC at the high leachate volume in
relation to new Osm (2.38 v. 0.29 dS/m).
Treatments that increased (P < 0.05) nutrient
leaching generally reduced (P < 0.05) nutrient
concentrations in shoots and depressed the growth of some plant species. Shoot
growth of 2 of 5 species was reduced (P < 0.001) at
the highest leachate volume with an additional heavy leaching event in Week 1
or 2, and root growth of all but the slowest growing species declined with
increasing leachate volume. Damaged prills reduced (P
< 0.001) shoot growth of 2 of the 5 ground-cover species.
This study demonstrated that excessive leaching and the use of damaged prills
for containerised nursery plants fertilised with CRF results in high nutrient
loss, low residual nutrient content, reduced nutrient uptake in shoots, and
reduced shoot growth of some species.
Timing of 15N fertiliser application, partitioning to reproductive and vegetative tissue, and nutrient removal by field-grown low-chill peaches in the subtropics
Authors: Huett D. O. , Stewart G. R.
Published: November 2005

The effect of timing of nitrogen (N) application as
15N-enriched ammonium sulfate (50 kg N/ha) on the
growth response and N uptake by vegetative and reproductive tissues was
investigated in the low-chill peach cv. Flordagem growing on a krasnozem soil
at Alstonville. Nitrogen was applied in late August, late September, late
October, mid February, and early May. Tree parts were sampled for
15N at 4 and 8 weeks after application and after fruit
harvest in December the following season. After fruit yield was measured,
trees were excavated and divided into parts for dry weight and nutrient
concentration determinations, and fertiliser N recovery and to estimate tree
nutrient removal.
Nitrogen enrichment was detected in all plant parts within 4 weeks of N
application, irrespective of timing, and was greatest in rapidly growing
tissues such as laterals, leaves, and fruit. The most rapid
(P < 0.05) 15N enrichment in
vegetative tissues resulted from September, October, and February N
applications and for fruit from a September application. The level of
enrichment 4 weeks after fertiliser N application was similar for vegetative
and reproductive tissues. The timing of N application in the first season had
no effect on fruit yield and vegetative growth the following season.
At tree removal, the recovery of fertiliser N in most tree parts increased
(P < 0.05) as fertiliser N application was delayed
from October to May the previous season. Maximum contribution of absorbed N to
whole tree N was 10–11% for laterals, leaf, and fruit. Data from
this study indicate that vegetative and reproductive growth have similar
demand for absorbed N, and that uptake of fertiliser N is most rapid when an
application precedes a period of rapid growth. Over 2 seasons, recovery of
applied fertiliser N was 14.9–18.0% in the tree, confirming that
stored N and the soil N pool are the dominant sources of tree N. The recovery
of fertiliser N from the May application was 18% even though uptake in
all tree parts including roots at 4 weeks after application was very low,
indicating that tree fertiliser N uptake occurred when growth resumed after
the dormant winter period. The low proportion and recovery of fertiliser N in
the tree confirm the lack of immediate influence of applied N to vegetative
growth and yield.
Annual crop nutrient removal is a sound basis for fertiliser recommendations,
and for the Flordagem orchard (1000 trees/ha), it consisted of fruit plus
70% of laterals (removed at pruning) plus 20% of leaf. Removal
in vegetative tissues was relatively low at (kg/ha) 14 N, 1 P, 12 K, 13
Ca, and 2 Mg. The addition of fruit at a yield of 25 t/ha increased total
nutrient removal to (kg/ha) 46 N, 5 P, 54 K, 14 Ca, and 5 Mg.
Glycogen metabolism and ultimate pH of muscle in Merino, first-cross, and second-cross wether lambs as affected by stress before slaughter
Authors: Gardner G. E. , Kennedy L. , Milton J. T. B. , Pethick D. W.
Published: November 2005

This experiment compared the metabolism of muscle glycogen and the ultimate pH
(pHu) of muscle in Merino and crossbred lambs fed the same diet but subjected
to different levels of stress pre-slaughter. Twenty- five Merino, 24
first-cross (Merino dam × Poll Dorset sire), and 23 second-cross (Border
Leicester × Merino dam and Poll Dorset sire) wether lambs (6 months old,
30 kg liveweight) were maintained for 8 weeks on a complete pelleted diet
based on lupin seed, straw, and barley grain (metabolisable energy, 10.8
MJ/kg; protein, 17.4% in dry matter), with a feed intake of 1.3 kg
dry matter /day for each breed. At Week 6, muscle biopsies were taken from
15 lambs of each breed, and at Week 8, 5 animals from each breed were
slaughtered at an experimental abattoir 10 min after removal from their pens
(low pre-slaughter stress). The remaining lambs, separated into breeds, were
transported for 2 h and slaughtered after 24 h lairage at a commercial
abattoir. Muscle samples were taken at slaughter, and assayed with the biopsy
samples for glycogen concentration (corrected for lactate concentration),
myoglobin concentration, and citrate synthase activity. The pHu of muscle was
measured 48 h post slaughter.
Compared with commercially slaughtered lambs, the muscle tissues of lambs
subjected to low pre-slaughter stress had higher glycogen concentrations post
mortem, lower pHu, and no significant loss of glycogen between pen and
slaughter. Breed had no effect on glycogen, pH, or the colour of muscle under
low-stress slaughter conditions or when the muscle biopsy was taken. In
contrast, breed had a significant influence under commercial slaughter
conditions, the muscle of Merino lambs having the lowest glycogen
concentration post portem, and the highest pHu and loss of glycogen between
pen and slaughter. Irrespective of stress, second-cross lambs had higher
myoglobin concentrations and citrate synthase activities than the Merino
lambs, indicating greater pigmentation of muscle in the second-cross animals.
We conclude that higher proportions of Merino genes are associated with a
greater sensitivity to stress in lambs destined for slaughter.