bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved nitrogen supply to cereals in Central Queensland following short legume leys
Authors: Armstrong R. D. , Walsh K. , McCosker K. J. , Millar G. R. , Probert M. E. , Johnson S.
Published: August 2004

Summary. The growth and ability of 12 summer-growing
annual and perennial legumes to fix nitrogen and the response of a subsequent
wheat crop was examined in a field trial on a deep cracking clay soil in the
Central Highlands of Queensland. Twelve legumes
[Lablab purpureus cv. Highworth,
Vigna radiata cv. Satin,
Macroptilium atropurpureum cv. Siratro,
Medicago sativa cv. Trifecta,
Vigna trilobata (CPI 13671),
Macroptilium bracteatum (CPI 27404),
Glycine latifolia (CQ 3368),
Desmanthus virgatus cv. Marc,
Desmanthus virgatus cv. Bayamo,
Stylosanthes sp. aff scabra (104710),
Clitoria ternatea cv. Milgarra,
Cajanus cajan cv. Quest)] and grain sorghum
(Sorghum bicolor cv. Tulloch) as a non-legume control
were established in November 1994 and their growth monitored until March 1995.
The legumes averaged greater than 5 t/ha dry matter production and 77 kg
N/ha (above-ground only). Dry matter production ranged from less than 2
t/ha for G. latifolia and
M. sativa to greater than 9 t/ha for
D. virgatus cv. Bayamo and
C. cajan. Annual legumes initially had much higher
relative growth rates than the perennial legumes but they rapidily exhausted
all the plant available water content of the soil thus allowing the
well-established perennials to eventually match this production. The
proportion of plant nitrogen (above ground) derived from
N2 fixation was generally low, reflecting high soil
NO3, but varied widely between species ranging from less
than 20% for D. virgatus cv. Marc and
G. latifolia to over 45% for
C. ternatea, S. scabra and
V. trilobata. The quantity of nitrogen derived from
fixation was correlated with above-ground dry matter and nitrogen content.
There was a significant (P<0.05) growth response by
wheat following legumes compared with that following sorghum in the increasing
order V. radiata =
M. atropurpureum =
L. purpureus > C. cajan
= M. sativa =
V. trilobata =
M. bracteatum =
G. latifolia > S. scabra
= D. virgatus =
C. ternatea. Previous legume growth had no significant
(P>0.05) effect on yield or nitrogen concentration in
a second ‘plant-back’ crop (sorghum). It was concluded that a wide
range of pasture-ley legumes have the potential to improve cereal crop
production in this region.
Packaging to reduce water loss can delay ripening of mango (Mangifera indica L. cv. ‘Kensington Pride’) fruit
Authors: Macnish A. J. , Joyce D. C. , Hetherington S. E.
Published: August 2004

Summary. Water loss and premature ripening during
postharvest handling reduce the market quality of mango fruit. Towards
investigating the use of moisture barrier liners for mango fruit trays,
relationships between in-package relative humidity and weight loss and
ripening of ‘Kensington Pride’ fruit were studied. Individual
fruit were held at 20°C in sealed plastic containers (small 1.2 L
buckets). The lid of each container had a single circular hole. Holes were of
various sizes, ranging from 5 to 135 mm diameter. Ripening mature green fruit
held at the lowest relative humidity of 57% (135 mm diameter hole) lost
weight at a significantly (P£0.05) greater rate (10 mg/g initial FW.
day) than fruit at higher relative humidities of 59 (open air), 60 (95 mm
diameter hole), 61 (55 mm diameter hole), 71 (35 mm diameter hole), 74 (25 mm
diameter hole) and 83% (25 mm diameter hole plus free water). These
fruit at higher relative humidities lost weight at rates ranging between 9 and
4 mg/g initial FW. day. Fruit softening and skin colouring rates were
similar across all relative humidities. In a second experiment, mango fruit
were allowed to ripen in containers with smaller holes, ranging from 5 to 95
mm diameter, in their lids. Fruit at the lowest relative humidity (60%,
95 mm diameter hole) lost weight at a significantly
(P≤0.05) greater rate (9 mg/g initial FW. day)
than fruit from other treatments. Furthermore, these fruit ripened about 2
days sooner than fruit at higher relative humidities: 85 (25 mm diameter
hole), 88 (15 mm diameter hole), 91 (10 mm diameter hole) and 93% (5 mm
diameter hole). Fruit at the higher relative humidities lost weight at rates
between 6 and 2 mg/g initial FW. day, and ripened in 6 to 12 days. Thus,
hole size can be varied in order to control in-package relative humidity and
regulate mango fruit weight loss and ripening. Australian Journal of
Experimental Agriculture, 1997, 37, 463–7 463
Effects of harvest maturity on the storage life of Japanese type plums
Authors: Abdi N. , Holford P. , McGlasson W. B.
Published: August 2004

Summary. Plums are highly perishable and once harvested
have a short commercial life. Hence, this crop would benefit from the
determination of conditions which permit extended storage. This study
investigates the effects of fruit maturity at harvest on the physical and
chemical characteristics of the plum cultivars, Radiant, Gulfruby and Shiro,
after periods of cool storage. Fruit from these cultivars were separated into
3 maturity categories according to either skin colour at harvest or time after
pit hardening. The storage disorders, internal breakdown and gel breakdown,
were measured after periods of storage at 0°C and subsequent ripening at
20°C. Skin colour, flesh firmness, concentration of soluble solids and
titratable acidity were measured at harvest and after ripening. Internal
breakdown and gel breakdown, symptoms of chilling injury, developed after 2
weeks cool storage in Gulfruby and Shiro and after 4 weeks in Radiant. These
symptoms were most severe in the oldest fruit. Significant differences were
also found in skin colour, firmness, soluble solids and acidity during
ripening and after cool storage. Fruit harvested at an earlier maturity
withstand cold storage better than more mature fruit. However, these less
mature fruit initially have a poorer quality than those which are more mature.
Therefore, it is important for the grower to be able to determine the precise
stage of crop development in order to allow harvesting at a time which is
optimal for the storage process.
The effect of livestock grazing on surface runoff and soil erosion from sloping pasture lands in the Ethiopian highlands
Authors: Mwendera E. J. , Saleem M. A. Mohamed , Dibabe A.
Published: August 2004

Summary. Effects of livestock grazing on surface runoff
and soil erosion at varying slopes were studied in pasture lands within Ginchi
watershed, Ethiopia. The results showed that livestock grazing in the
watershed followed distinct seasonal and spatial patterns. During the rainy
season, grazing pressure was greatest on the upper slopes (>5%
slope) while the pressure shifted to the lower slopes during part of the dry
season. Seasonal grazing pressure in different parts of the watershed was
further complicated by the fact that during the rainy season and immediately
after the rains, grazing was limited to individually designated pasture lands
while during most part of the dry season, the entire watershed became a common
grazing resource for livestock of watershed residents as well as those farmers
outside the watershed. It was observed that, on pastures above 4.2%
slope, there is the risk of erosion rates exceeding the estimated soil loss
tolerable limit under the current grazing pressures (heavy grazing), while
slopes exceeding 5.8% are likely to suffer soil erosion under moderate
grazing pressure at the current level of biomass productivity. Since livestock
are mobile, farmers tend to take advantage of this attribute by seasonally
moving the livestock to different parts of the watershed. This study has
demonstrated the need for better understanding of the resource use patterns
beyond the individual farmlands, most preferably at watershed level, so that
on-site and off-site effects of seasonal concentration of livestock can be
incorporated into developing feed production and management strategies for
improving the system productivity and environmental protection.
Liming and re-liming needs of acidic soils used for crop - pasture rotations
Authors: Slattery W. J. , Ganning G. W. , Burnett V. F. , Coventry D. R.
Published: August 2004

Summary. In a long-term liming experiment in
north-eastern Victoria, we have re-applied lime and applied gypsum (1992
season) to assess wheat grain yield responses with on-going changes in soil pH
and extractable aluminium. An acid-sensitive wheat (cv. Oxley) was grown in 2
seasons (1992–93), 12 years after initial applications of lime. Where
lime (2.5 t/ha) was applied in 1992 to a previously unlimed soil, grain
yield was increased by 19 and 46% respectively in the 2 seasons.
However, the yield from these newly limed plots was well below the yields
obtained from plots limed in 1980. Re-liming plots limed in 1980 resulted in
further yield increases, with lime re-applied at 2.5 t/ha increasing
yields by 12% in both seasons. Gypsum decreased grain yields on unlimed
soil in the year of application but in the second year gave increases in
yield. Whilst pH had changed little in the unlimed soil over the 12 years, the
concentrations of extractable aluminium in the root zone increased
substantially such that these concentrations far exceed levels which may
affect acid-sensitive wheats. Liming at 2.5 t/ha did reduce the aluminium
at 0–10 cm depth, but the concentrations at 10–20 cm depth (11.7
mg/kg) are likely to restrict grain yield. The data illustrate the
progressive nature of soil acidification and the risk to wheat productivity
through delaying treating this soil degradation problem.
A comparison of proton excretion of twelve pasture legumes grown in nutrient solution
Authors: Tang C. , Barton L. , McLay C. D. A.
Published: August 2004

Summary.The use of legumes to improve the productivity
of pastures has usually been associated with an increase in soil
acidification. The present study compared the acidification potential of 12
N2-fixing pasture legume species/genotypes using a
solution culture assay. The legumes were chosen because of their use or
potential use in farming systems in the mediterranean zones of southern
Australia. The species grown were Trifolium subterraneum
L. (vars. Dalkeith, Yarloop and Clare),
Trifolium glomeratum L.,
Trifolium tomentosum L.,
Medicago murex Willd.,
Medicago polymorpha L.,
Medicago truncatulaGaertn.,
Ornithopus compressus L.,
Ornithopus sativusBrot.,
Trifolium vesiculosum and
Trifolium balansae. Proton excretion was measured over a
period of 21 days from days 40 to 61 after germination. The amount of protons
excreted into solution varied between 143 and 265 cmol
H+ /kg dry matter for the different species and
genotypes. In general, T. tomentosum and
T. glomeratum excreted greater amounts of protons per
unit biomass than Medicago species and
T. subterraneum, which, in turn, excreted more protons
than Ornithopus species. The amount of proton excreted
per kilogram biomass was well correlated with the concentrations of excess
cations over anions and ash alkalinity in plants across all the species. Total
acid production was highly correlated with accumulation of excess cations and
ash alkalinity, total dry matter production and total nitrogen fixation during
the study period. It is suggested that the potential proton excretion by new
pasture legume species should be considered when they are introduced into
farming systems.
Influence of sex ratio and sexual lability on seed production in the dioecious perennial shrub Atriplex amnicola (Chenopodiaceae)
Authors: Strawbridge M. , Bell R. W. , McComb J. A. , Barrett-Lennard E. G.
Published: August 2004

Summary. Pollen supply can limit seed set in dioecious
species such as Atriplex amnicola Paul G. Wilson (river
saltbush). Clonal populations, with 4 different male : female ratios (0 : 1, 1
: 8, 1 : 1 and 5 : 1), were set up in widely spaced field plots at Tammin,
Western Australia. After 1 season, plants were examined for fruit fill and
fruit germination. The optimal male : female ratio for
Atriplex amnicola seed production was between 1 : 8
(11% males) and 1 : 1 (50% males). These ratios resulted in mean
fruit fills of 24 and 36%, respectively.
Genotype had a significant effect on fruit fill. The 3 clones tested had fruit
fills of 40, 36 and 31%. These differences in fruit fill were as
significant as those obtained from reducing the percentage of males from 50 to
11%.
A population of 700 seedlings of A. amnicola examined
over 5 years was shown to be sexually labile, with a slight decrease over time
in males and an increase in females and monoecious plants. Sexual lability
appeared to be linked to plant aging rather than to environmental stimuli. It
was concluded that plantations of river saltbush set up for seed production
should be planted with selected genotypes at a male : female ratio of between
1 : 8 and 1 : 1 and that plantations need to be monitored for change in sex
ratio with time, to ratios suboptimal for seed quality and production.
Sustaining productivity of a Vertisol at Warra, Queensland, with fertilisers, no-tillage or legumes 4. Nitrogen fixation, water use and yield of chickpea
Authors: Strong W. M. , Dalal R. C. , Cooper J. E. , Doughton J. A. , Weston E. J. , McNamara G. T.
Published: August 2004

Summary. Continuous cereal cropping in southern
Queensland and northern New South Wales has depleted native soil nitrogen
fertility to a level where corrective strategies are required to sustain grain
yields and high protein content. The objective of this study was to examine
the performance of chickpea in chickpea–wheat rotations in terms of
yields, water use and N2 fixation. The effects of sowing
time and tillage practice have been studied.
Chickpea grain yields varied from 356 kg/ha in 1995 to 2361 kg/ha in
1988; these were significantly correlated with the total rainfall received
during the preceding fallow period and crop growth. Almost 48% of total
plant production and 30% of total plant nitrogen were below-ground as
root biomass.
Mean values of water-use efficiency for grain, above-ground dry matter, and
total dry matter were 5.9, 14.2 and 29.2 kg/ha.mm, respectively. The
water-use efficiency for grain was positively correlated with the total
rainfall for the preceding fallow and crop growth period although cultural
practices modified water-use efficiency. The potential
N2 fixation was estimated to be 0.6 kg
nitrogen/ha.mm from 1992 total dry matter nitrogen yields assuming all of
the nitrogen contained in chickpea was derived from the atmosphere.
Sowing time had a much larger effect on grain yield and
N2 fixation by chickpea than tillage practice
(conventional tillage and zero tillage) although zero tillage generally
increased grain yields. The late May–early June sowing time was found to
be the best for chickpea grain yield and N2 fixation
since it optimised solar energy use and water use, and minimised frost damage.
Nitrogen fixation by chickpea was low, less than 40% nitrogen was
derived from atmosphere, representing less than 20 kg nitrogen/ha.year.
The potential for N2 fixation was not attained during
this period due to below-average rainfall and high soil
NO3-N accumulation because of poor utilisation by the
preceding wheat crop. Increased soil NO3-N due to
residual from fertiliser N applied to the preceding wheat crop further reduced
N2 fixation. A simple soil nitrogen balance indicated
that at least 60% of crop nitrogen must be obtained from
N2 fixation to avoid continued soil nitrogen loss. This
did not occur in most years.
The generally negative soil nitrogen balance needs to be reversed if chickpea
is to be useful in sustainable cropping systems although it is an attractive
cash crop. Sowing time and zero tillage practice, possibly combined with more
appropriate cultivars, to enhance chickpea biomass, along with low initial
soil NO3-N levels, would provide maximum
N2 fixation.
Effects of Brassica residues and other organic amendments on abundance and sex ratio of Tylenchulus semipenetrans in soil
Authors: Walker G. E.
Published: August 2004

Summary. The activity of soil-incorporated residues of 9
commercial Brassica cultivars and the weed
B. tournefortii, and of 5 organic mulches against
Tylenchulus semipenetrans was evaluated in laboratory
experiments. Residues of all Brassica spp. reduced soil
populations of T. semipenetrans. Humus rape had the
highest activity (81% reduction in numbers of second-stage female
larvae at 40 g/kg of soil) in an experiment comparing the effectiveness of
fresh residues of greenhouse-grown plants, but Rangi, Arran and Hobson rapes
and Simax hybrid were also effective at 80 g/kg.
Tylenchulus semipenetrans was undetectable in soil
amended with freeze-dried residues of Indian mustard meal at rates of 10
g/kg of soil or higher. Residues of B. tournefortii
plants grown artificially with fertilisers were more effective against
T. semipenetrans than those of naturally grown weeds.
Leaf residues of B. tournefortii weed plants were more
effective than either whole shoots or roots. Of 5 organic mulches tested, only
chicken litter reduced the T. semipenetrans population
when incorporated into soil.
Soil amendment with shoots or roots of B. tournefortii
weeds, or with low rates of Indian mustard residues, increased the
T. semipenetrans population, suggesting that
incorporation of poor stands or ineffective Brassica
green manure crops could increase the risk from
T. semipenetrans to citrus replants.
Soil amendment with B. tournefortii weed residues, low
rates of Indian mustard residues or with 3 of the mulches (organic compost,
composted green waste or chicken litter) reduced the ratio of males (adults
and larvae) to female larvae. Organic matter is postulated to have a
significant influence on sex differentiation of
T. semipenetrans.
Strategic nitrogen fertiliser use on perennial ryegrass and white clover pasture in north-western Tasmania
Authors: Eckard R. J. , Franks D. R.
Published: August 2004

Summary. The strategic application of nitrogen (N)
fertiliser on temperate pasture is a popular management tool for boosting
pasture production, particularly when low soil temperatures limit
clover-derived N availability. The responsiveness of a perennial ryegrass and
white clover pasture to increasing rates of N fertiliser (0, 15, 30, 45 and 60
kg N/ha), applied as a single application, was investigated for 5 pre and
5 post mid winter N application dates. The trial was laid out in a randomised
split-plot design, replicated 4 times, with N application date in the whole
plots and N fertiliser rate in subplots. Herbage yields were estimated by
mowing small plots, with animals excluded for the duration of a single
regrowth period on each plot.
The data are presented as averages for the 5 pre and 5 post mid winter
responses separately, as the means of the pre and post winter partitions were
significantly (P<0.001) different at all rates of N
fertiliser for both years. Significant (P<0.05) yield
responses were noted between increments of N fertiliser up to the 45 kg
N/ha application rate. In contrast, no significant
(P>0.05) increases in dry matter yield were noted
between the 45 and 60 kg N/ha rates in all but one response, consistent
with diminishing returns.
The efficiency with which N fertiliser was utilised ranged between 9.0 and
15.9 kg N dry matter/kg. Nitrogen efficiency was consistently lower at the
60 kg N/ha rate than for lower rates of N fertiliser. The application of N
fertiliser increased pasture dry matter yields by between 582 and 703 kg dry
matter/ha. Based on the 1997 cost of urea, the additional forage produced
cost between 6.4 and 10.1 cents/kg dry matter.
The data are reviewed in terms of the potential for strategic N fertiliser
applications during the winter, while still maximising utilisation of
clover-derived N during the warmer months.
A simple non-destructive method for laboratory evaluation of fruit firmness
Authors: Macnish A. J. , Joyce D. C. , Shorter A. J.
Published: August 2004

Summary. Devices which offer simple, inexpensive,
reliable and non-destructive objective measurement of fruit firmness assist in
the monitoring of quality. For the present study, the Analogue CSIRO Tomato
Firmness Meter (AFM), which measures fruit deformation under a 500 g load
applied for 30 s was modified by replacing the analogue displacement gauge
with a digital gauge and by using a laboratory jack for positioning the fruit
in the vertical dimension. Non-destructive measurements of tomato fruit
softening during ripening and determined with the Digital Firmness Meter (DFM)
were strongly correlated with both firmness measured with the AFM
(r2 = 0.96,
n = 19) and with firmness determined subjectively
by hand pressure (r2 =
0.93, n = 19). Similarly, mango fruit softening
during ripening was monitored and DFM and hand firmness measurements were well
correlated (r2 = 0.95,
n = 10). The firmness of individual fruit could
be measured around 20% faster with the DFM than with the AFM, and
displacement was easier to read from the digital than from the analogue
display. The DFM proved to be a suitable device for measuring fruit firmness
in postharvest laboratory studies and warrants evaluation under commercial
packing and handling conditions.
Detection of floral initiation in broccoli (Brassica oleracea L. var. italica Plenck) based on electron micrograph standards of shoot apices
Authors: Tan D. K. Y. , Wearing A. H. , Rickert K. G. , Birch C. J.
Published: August 2004

Summary. Detecting floral initiation is fundamental to
predicting the ontogeny of broccoli (Brassica oleracea
L. var. italica Plenck). Scanning electron micrographs
of the apical meristem of broccoli (cv. ‘Fiesta’) were made for
the transition from the vegetative to advanced reproductive stage. Seven
identifiable stages were observed. During the early vegetative stage (stage
1), the apical meristem was a small, pointed, shoot tip surrounded by leaf
primordia. The transitional stage (stage 2) was marked by a widening and
flattening to form a dome-shaped apical meristem. In the floral initiation
stage (stage 3), the 1st-order floral primordia were observed in the axils of
the developing bracts. Further work from a field experiment showed that apex
diameter at floral initiation averaged 500 ± 3 m when examined under a
light microscope. Apex diameter was not affected by photoperiod, planting time
or cultivar. These descriptions and micrographs will enhance broccoli research
by standardising the descriptions of floral development in broccoli, and will
also be used as the basis of future work in the field identification of floral
initiation and the prediction of the timing of phenological events in
broccoli.
Shade preferences of lactating Holstein - Friesian cows
Authors: Gaughan J. B. , Goodwin P. J. , Schoorl T. A. , Young B. A. , Imbeah M. , Mader T. L. , Hall A.
Published: August 2004

Summary. Shade-type preferences by
Holstein–Friesian cows were investigated under natural climatic
conditions. The trial was conducted in south-east Queensland, Australia, over
88 days in summer. Forty-two cows were placed in a dirt-floored yard (zero
grazing) provided with different shade types. Shade types provided were a 3 m
high galvanised iron roof, Sechium edule (choko) vines
on a 3 m high trellis, 70% shade cloth on a 3 m high frame and natural
shade trees. The floor area under the shade structures was concrete. An
unshaded area (the remainder of the yard) was also provided. Each cow was
scored for coat colour based on the proportion of black and white. Number of
cows using a particular shade type and their respiration rates were recorded
daily at 1300 hours. Ambient temperature, relative humidity, solar radiation
and wind speed were also measured. Cows selected the galvanised iron roof most
frequently when temperatures rose above 30°C, with no significant
differences between the other shade types. At temperatures below 30°C,
animals did not seek shade. As ambient temperature, solar radiation and
relative humidity rose, respiration rate rose. Cows with a high percentage of
black coat preferred shade, while those with a high percentage of white coat
did not seek shade.
A comparison of growth rates and carcass quality of steers receiving maize silage as a supplement to annual pasture or as a component of a feedlot ration
Authors: Wales W. J. , Moran J. B. , Harris R. W.
Published: August 2004

Summary. We tested the hypothesis that liveweight gain
per hectare could be doubled in beef steers grazing irrigated annual pastures
by increasing stocking rate from 2.5 to 5.0 steers/ha and supplementing
the heavier stocked treatments with maize silage offered at either 2.4 or 5.6
kg dry matter/steer. day to replicated groups of 4 steers.
During an average period on feed of 172 days, liveweight gain was
substantially increased, from 245 kg/ha to either 464 or 576 kg/ha,
when maize silage was fed to steers at 2064 or 4816 kg dry matter/ha, in
association with an increase in stocking rate from 2.5 to 5.0 steers/ha.
However, such production systems increased the chance of feed shortages,
particularly in exceptionally wet winters such as the one experienced in the
experiment. Increasing the rate of supplementary feeding without increasing
stocking rate may not be economically viable. Other strategies, such as lot
feeding steers, were also tested. Diets where maize silage constituted either
46% dry matter (with the balance of the diet comprising wheat grain,
cottonseed meal, urea, bentonite, vitamins and minerals) or 97% dry
matter (with the balance of the diet comprising urea, vitamins and minerals)
led to steers achieving liveweight gain of 1.34 and 0.93 kg/steer. day
respectively. Carcasses from steers eating maize silage fed at pasture or
maize silage as a component of lot-fed diets had at least as adequate fat
cover and as good eating quality as carcasses from steers grazing at 2.5
steers/ha.
Production locality affects mango fruit quality
Authors: Hofman P. J. , Smith L. G. , Meiburg G. F. , Giles J. E.
Published: August 2004

Summary. Differences in mango (cv. Kensington Pride)
fruit quality under commercial and research conditions have been frequently
noted. To assess the potential for production conditions to influence fruit
quality, "Kensington Pride" mango fruit were obtained from 2
adjacent sites on an orchard on shallow nodular yellow podsolic soil in
tropical North Queensland, 1 block of trees growing on soil with river gravel
(site 1) and another without gravel (site 2). Fruit were also obtained from
trees on a gleyed podsolic soil (site 3) in subtropical south-east Queensland.
Fruit were harvested weekly for 4 weeks, with quality determined after
ripening at 22°C and after storage at 10°C for 4 weeks. Eating quality
and percentage dry matter increased, while days to eating soft decreased with
later harvests. Fruit from site 3 (cooler growing conditions, rain during the
harvest period) had acceptable eating quality at a lower dry matter than fruit
from sites 1 and 2. The percentage of green colour on the skin (GS) at ripe
was higher at harvest 2 in fruit from sites 1 and 2, but was lower at harvest
4 in fruit from all sites. Disease severity in fruit ripened without storage
was higher in site 3 fruit, while body rots (caused mainly by
Colletotrichum spp.) increased (site 3 only) and stem
end rots (caused mainly by Dothiorella spp.) decreased
with later harvests. Fruit firmness and GS decreased during storage at
10°C, but fruit from site 3 were generally softer, with higher GS, than
those from the other sites. Chilling injury was also higher in fruit from site
3.
Patterns of seed softening and seedling emergence of nineteen annual medics during three years after a single seed crop in southern Queensland
Authors: Lloyd D. L. , Taylor G. B. , Johnson B. , Teasdale K. C.
Published: August 2004

Summary. To produce seed to determine the rates of seed
softening of annual medics in the subtropics, 8 lines of barrel medic
(Medicago truncatula), 3 lines of burr medic
(M. polymorpha), 4 lines of snail medic
(M. scutellata), and 1 line of each of button medic
(M. orbicularis), strand medic
(M. littoralis) and gama medic
(M. rugosa) were grown at Warra in southern inland
Queensland, in 1993. Seed of a fourth line of burr medic, a naturalised line,
was harvested from Hermitage Research Station at that time. Pods were placed
on the soil surface and buried at a depth of 7 cm, both in flywire envelopes
and as free pods. Residual hard seed numbers were determined each year for 3
years from the envelopes, and seedlings were counted and removed from the free
pods after each germination event. Patterns of softening of seeds from the
same seed populations were also determined after placing them in a laboratory
oven with a diurnal temperature fluctuation of 60/15° C for periods of
16, 40 and 64 weeks followed, after each time period, by 4 diurnal cycles of
35/10°C.
More than 90% of the original seeds were hard. Seed softening at the
soil surface ranged from 26% after 3 years in button medic to almost
complete softening in the gama medic after only 2 years. Burial had little
effect on the rate of softening of the button medic but about halved the rate
of softening of the other lines. The barrel medics were vulnerable to losses
of large numbers of seedlings which softened and germinated in
January–February and the snail medics from seedlings emerging in
August–December. The proportion of soft seeds recovered as seedlings in
the buried compared with the surface pods was higher in the larger-seeded
medics, snail and gama, and lower in the other, smaller-seeded medics.
Laboratory techniques effectively ranked the medic lines for their rate of
seed softening in the field and provided some insight into their seasonal
patterns of seed softening.
A wide range of seed softening patterns is available for fitting the
requirements of various farming systems. The most appropriate pattern of
softening will depend on the variability of medic seed production between
years and the need for self regeneration of the medic after a cereal crop.
Genetic parameters and trends in a selection experiment for increased clean fleece weight involving South African Merinos
Authors: Cloete S. W. P. , Olivier J. J. , Snyman M. A. , Toit E. du
Published: August 2004

Summary. Data of 3603 to 7385 progeny of a Merino line
selected for an increased clean fleece weight with a limitation on fibre
diameter in sires and an unselected control group were used to estimate
heritability for liveweight and wool traits. Estimated breeding values were
obtained by backsolution and averaged within birth years to obtain genetic
trends. Direct additive heritability (± s.e.) estimates were 0.29
± 0.02 for clean fleece weight, 0.52 ± 0.03 for liveweight, 0.68
± 0.02 for clean yield, 0.35 ± 0.02 for staple length, 0.63
± 0.02 for fibre diameter and 0.42 ± 0.03 for total fold score.
Fitting maternal additive effects to the model of analysis resulted in an
improvement (P≤0.05) in the log likelihood ratio for
clean fleece weight and liveweight. These effects were relatively small in
magnitude, resulting in maternal additive effects (± s.e.) of 0.04
± 0.01 for both traits. Genetic and phenotypic correlations of clean
fleece weight with the other traits were positive. Genetic trends for fleece
traits in the control group were less than 0.1% of the overall
phenotypic mean per year. A substantial increase, depicted by a regression
(± s.e.b) amounting to 0.14 ± 0.01
kg/year (0.28% of the phenotypic mean) was, however, found for
liveweight (r = 0.91). The direct response in
clean fleece weight in the selection line amounted to 0.039 ± 0.001
kg/year (r = 0.99), or 0.97% of the
overall phenotypic mean. Correlated responses ranged from 0.78% of the
overall phenotypic mean (r = 0.97) for liveweight
to 0.17% per year (r = 0.51) for clean
yield. The genetic change in mean fibre diameter (the trait under observation
because an increase was unwanted) amounted to 0.020 ± 0.002 m/year
(r = 0.69) or 0.10% of the overall
phenotypic mean. The relaxation of the limitation on fibre diameter in sires
used during 1986–90 probably contributed to this trend. A substantial
increase in clean fleece weight was thus possible while unwanted increases in
fibre diameter were limited.
Propagation from cuttings of two woody ornamental Australian shrubs, Boronia megastigma Nees (brown boronia) and Hypocalymma angustifolium Endl. (white myrtle)
Authors: Day J. S. , Loveys B. R.
Published: August 2004

Summary. While many woody plant cuttings respond to
propagation conditions in similar ways, results presented here indicate that
some responses are species specific. Propagation of
Boronia megastigma and
Hypocalymma angustifolium cuttings was successful except
when cuttings were struck without auxin treatment in a pinebark-based
propagation medium. More stem H. angustifolium cuttings
(100%) produced roots than terminal (shoot tip) cuttings
(45.2%). Benzyladenine and gibberellic acid treatment of stock plants
decreased endogenous starch concentration and propagation success of both
species. Boronia megastigma cuttings propagated poorly
when taken in winter when flowers were developing on stock plants. Conversely,
adventitious rooting of H. angustifolium had greatest
success when cuttings were taken in winter during flower development. Seasonal
variation in propagation success may be mediated through changes in the
endogenous plant growth regulator or carbohydrate concentrations.
Effects of annual pasture composition on subsequent wheat yields in the Waite Permanent Rotation Trial, South Australia
Authors: Moore A. D. , Grace P. R.
Published: August 2004

Summary. Legume-based annual pastures are commonplace in
southern Australian dryland farming systems. By using the long-term wheat and
pasture yield records from the Waite Permanent Rotation Trial (established in
1925), we have quantified how changes in the production and composition of a
ley pasture will affect subsequent cereal yields and profitability. An
analysis of the 1965–89 record reveals that 43% of the variance
in wheat yield can be accounted for by the equation: WY
= 3.42 + 0.0165AOR –
0.0000165AOR2 +
0.12PL – 2.64PG +
0.39PG2 –
0.019PG3 where WY is wheat yield
(t/ha), AOR is April –October rainfall in the
wheat year (mm), PL is pasture legume yield in the
preceding year (t/ha) and PG is pasture grass yield
in the preceding year (t/ha).
By comparison with other published data, our results support the claim that
nitrogen from legume sources is economically more efficient than fertiliser
nitrogen, but the largest effect of increasing legume content comes from
avoiding yield loss associated with grassy pastures.
Bracken litter as mulch: glasshouse evaluation of phytotoxicity
Authors: Taylor J. E. , Thomson J. A.
Published: August 2004

Summary. Austral bracken
(Pteridium esculentum) has a major impact on forestry
and the pastoral industries in Australia and New Zealand, as does
P. aquilinum in parts of the northern hemisphere. There
is a large body of, often conflicting, evidence on the toxicity of
P. aquilinum to growth of other plants but there is
little evidence for P. esculentum. Control of bracken is
currently expensive and difficult to maintain as there is neither a marketable
product based on bracken, nor a significant use for it on site. Current
interest in commercial uses for bracken as mulch or compost requires analysis
of the effects of bracken fronds on germination and growth of a representative
range of plants.
We report the effects of a mulch of chopped recently-dead (standing) bracken
fronds on germination and early growth (to 9 or 12 weeks) of white mustard
(Sinapis alba), of the improved pasture species, white
clover (Trifolium repens) and perennial ryegrass
(Lolium perenne), and of 2 native woodland species brown
barrel (Eucalyptus fastigata) and yellow teatree
(Leptospermum polygalifolium). A control mulch was
prepared from chopped recently-dead bracken fronds by boiling and washing to
extract possible allelochemicals and destroy associated microbiota.
Bracken mulch stimulated seedling growth of white mustard, white clover,
perennial ryegrass and brown barrel to a statistically significant, although
moderate, extent (8–20%). Shoot length of perennial ryegrass and
brown barrel, and leaf number and leaf size of brown barrel were more markedly
enhanced (≥30%) by the application of bracken mulch. In contrast,
bracken mulch reduced germination of yellow teatree to 25%, and leaf
number, during early growth, to about one-third of that in the controls. The
effects of bracken mulch may be due to release of active phytochemicals and
mineral nutrients, with or without mediation by associated microflora
including mycorrhizae.
These glasshouse experiments suggest that recently-dead fronds of
P. esculentum may prove a generally useful mulch,
although monitoring for adverse effects on establishment and growth of
particular species will be required.
Milk production responses to turnips fed to dairy cows in mid lactation
Authors: Moate P. J. , Dalley D. E. , Martin K. , Grainger C.
Published: August 2004

Summary. Recently, many dairy farmers in Victoria have
grown turnips as a summer fodder crop for lactating dairy cows. This paper
reports on a 1 month experiment in which cows were individually fed indoors,
and milk yield responses to feeding combinations of turnips and barley were
measured. Forty cows in mid lactation were evenly allocated to 5 treatment
groups. The control group were offered a basal diet of pasture hay and pasture
silage which is similar to that available on many Victorian dairy farms during
summer. Cows in the other 4 groups were offered the basal diet and various
combinations of turnips and/or barley. Marginal milk responses from
barley, turnips and a 50 : 50 mixture of turnips and barley were 0.62, 0.49
and 0.59 L/kg dry matter of supplement eaten. Milk composition of all
groups was similar. Despite diets differing greatly in the proportions and
physical form of dietary constituents, the mean milk production of each group
was accurately predicted by their mean dry matter intake. Measurement of
plasma minerals (calcium, magnesium, sodium, potassium and phosphorus) and
rumen fluid pH showed that dietary treatments caused some significant
(P<0.05) differences but all values were within the
normal range.
In this experiment, the milk production responses from barley, turnips and
combinations of barley and turnips were similar. Since the cost of turnips is
generally about half that of barley, it is concluded that turnips are an
economic alternative to barley as a feed supplement for summer milk
production.
Critical sulfur concentrations in oilseed rape (Brassica napus) in relation to nitrogen supply and to plant age
Authors: Pinkerton A.
Published: August 2004

Summary. Oilseed rape was grown in a sand culture
experiment in a glasshouse to derive values for plant testing for the
diagnosis of sulfur (S) deficiency and for the prediction of seed yield. Five
rates of S, combined factorially with 4 rates of nitrogen (N), maintained
constant throughout the experiment, were used to determine critical
concentrations of S fractions and ratios (total S, St;
sulfate-S, SO4; total N/total S,
N/St;
SO4/St). The most satisfactory
indices of rapeseed S status for diagnosis or prediction were
St and SO4. Whole shoots and
youngest fully expanded leaves exhibited similar critical values in plants at
the rosette stage, and critical values (St =
0.20–0.25%; SO4 = 230–460
mg/kg) changed little with time. Critical values for
N/St changed with time, required 2 analyses, and
gave no indication of the degree of deficiency when used to predict yield.
Critical values of SO4/St
depended on N supply, so 3 analyses were needed. It is argued that high
critical values reported previously for prediction of seed yield have been
obtained when there was a decline in soil-available S and plants relied on S
taken up during early growth.
Selection and asexual inheritance of a dwarf variant of Cavendish banana resistant to race 4 of Fusarium oxysporum f. sp. cubense
Authors: Tang C. Y. , Hwang S. C.
Published: August 2004

Summary. A dwarf variant (TC1-229) of banana resistant
to race 4 of Fusarium oxysporum f. sp. cubense was
identified from a tall, resistant Cavendish cultivar, ‘Tai Chiao No.
1’. This study showed that the dwarf characteristic of TC1-229 was
retained over 4 clonal generations. Although 3% of tissue-cultured
plants of TC1-229 were found to be a tall reversion, the dwarf characteristic
of TC1-229 appears to be a relatively stable genetic trait. The average
pseudostem height of TC1-229 in the plant crop was 229 cm which was about 62
cm shorter than its source plant. TC1-229 retained the resistance to fusarium
wilt in a wide range of environments. Unlike Dwarf Cavendish, the leaf bases
of TC1-229 were not crowded and the bunch stalk was normal, thus
‘choking’ was not observed. This study shows that the step-wise
selection of beneficial traits by using somaclonal variation can be useful in
banana improvement.
The growth of Yellow Bells (Geleznowia verrucosa) seedlings in response to additions of nitrogen, potassium and phosphorus fertiliser
Authors: Brennan R. F. , Crowhurst A. M. , Webb M. G.
Published: August 2004

Summary. Native plants are increasingly grown in Western
Australia to produce flowers for export. The nitrogen (N), phosphorus (P) and
potassium (K) requirements for optimum production of one of these species,
Geleznowia verrucosa (Yellow Bells), was measured for
17-week-old seedlings in a glasshouse experiment reported here.
There was a significant (P<0.05) growth response to
all levels of N fertilisers. At all levels of P and K, except for the nil K
treatments, the lowest level of applied N (20 mg N/kg soil) gave the
maximum dry weight of shoots. The dry weight of shoots increased with the
addition of P fertiliser to the highest level (160 mg P/kg soil),
particularly for the lower levels of applied K (0 and 30 mg/kg soil) and
the lowest level of applied N (20 mg/kg soil). Combinations of high levels
of P (P160) and N (N80) fertiliser
severely depressed shoot growth. When applied at greater than 30 mg K/kg
soil, K fertiliser depressed plant growth at all levels of N and P when
compared with the lower levels of applied K.
At the seedling stage of growth, critical concentrations for deficiency of
both N and K were 1.3% in shoots. The critical concentrations for
toxicity in whole shoots of Yellow Bells appeared to be about 1.7% for
N and about 2.2% for K. Adequate concentrations of N were
1.4–1.5%, while 1.7% K appeared adequate for growth of
Yellow Bell shoots.
Non-living soil organic matter: what do we know about it?
Authors: Skjemstad J. O. , Janik L. J. , Taylor J. A.
Published: August 2004

Summary. Non-living soil organic matter is a small but
critical component of soils contributing to soil structure, fertility and a
range of other chemical, physical and biological functions. Although
considerable work has contributed to our knowledge of its distribution,
chemical structure, mineral associations and turnover, there is still little
information on which fractions or pools of non-living soil organic matter are
implicated in various soil functions and to what extent. This review paper
summarises some of what is known about the distribution, chemistry, mineral
associations and soil structure, turnover and the measurement of non-living
soil organic matter, with particular emphasis on Australia. It also discusses
some of the difficulties in using current methods for describing the function
of this material in soil.
Plant analysis using near infrared reflectance spectroscopy: the potential and the limitations
Authors: Batten G. D.
Published: August 2004

Summary. International Standards Committees have
formally accepted methods using near infrared spectroscopy for the analysis of
protein, moisture and hardness in grains, and protein, acid detergent fibre
and moisture in forages. In addition, near infrared spectroscopy is used
world-wide for the routine analysis of many constituents in various tissues of
many plant species.
The reasons for near infrared spectroscopy being adopted as the preferred
analytical method in many laboratories include: minimal sample preparation is
needed, analysis time is short, it is cost effective to analyse a single
sample or large batches of samples, several constituents can be determined
simultaneously, the samples are not destroyed during analysis, neither a
laboratory nor a skilled operator are required for routine analyses, the use
of hazardous chemical reagents is eliminated, and, depending on the method,
the results are usually more precise and can be more accurate than, as
accurate as, or of acceptable accuracy, when compared with the method usually
employed.
It is the responsibility of the analyst to choose the most appropriate
analytical technique and to follow standard procedures in order to obtain
accurate and precise results from routine analysis. This paper summarises some
of the applications of near infrared spectroscopy which are being used to
analyse plant samples and lists some of the criteria which can be used to
decide if near infrared spectroscopy is the most appropriate technique.
Wheat response to alternative crops on a duplex soil
Authors: Asseng S. , Fillery I. R. P. , Gregory P. J.
Published: August 2004

Summary. Rates of crop growth (including the root
system), water extraction from specific soil layers, leaf water potential and
crop nitrogen content were measured in a field experiment of wheat
(Triticum aestivum L.) grown after alternative crops.
The previous crops of lupin (Lupinus angustifolius L.),
faba bean (Vicia faba L.), chickpea
(Cicer arietinum L.), vetch
(Vicia sativa L.), canola
(Brassica napus L.), and Indian mustard
(Brassica juncea L.) all showed a ‘break
crop’ effect compared with wheat after wheat. In addition, the legumes
lupin, faba bean, chickpea and vetch stimulated biomass production of
successive wheat crops via increased nitrogen supply. When the previous crop
was lupin, wheat root length density at depth in a duplex soil tended to be
increased and post-anthesis water uptake by wheat was enhanced. Wheat after
lupin resulted in a 42–76% higher yield than wheat after the
other legumes, a 37–68% higher yield than wheat after the
non-legumes and a 131% higher yield than wheat after wheat. Wheat
yields did not relate to previous crop root depth, but correlated well with
residue nitrogen from the various alternative crops.
Possible role for wild genotypes of Pisum spp. to enhance ascochyta blight resistance in pea
Authors: Wroth J. M.
Published: August 2004

Summary. There are no cultivars with effective field
resistance to ascochyta blight currently available in Australia but a number
of wild genotypes of Pisum have been identified as
possible sources of resistance and these were evaluated in crosses with a
commercial cultivar. Pisum fulvum JI 1006, used as the
pollen parent, was crossed with P. sativum cv. Wirrega
using wild type P. sativum JI 252 as a bridging cross.
JI 1006 and JI 252 both respond to
Mycosphaerella pinodes infection by inducing a rapid
hypersensitive response. All F2 seedlings
(17–20-day-old) from the cross Wirrega × (JI 252 × JI 1006)
were screened for their responses to M. pinodes
infection in a controlled environment and plants with the highest levels of
resistance were then screened as F3 progeny families in
the field to determine their responses to natural
M. pinodes infection. Nine percent of these families
were significantly more resistant for both leaf and stem disease compared with
Wirrega and among them were 9 lines which flowered at the same time or earlier
than Wirrega. However, even the most resistant line had 30% of the
foliage destroyed by disease, indicating disease control was insufficient. A
second resistance mechanism which impeded M. pinodes
hyphal penetration in leaves (P. sativum SA 1160) was
combined with the hypersensitive response in the cross SA 1160 × (JI 252
× JI 1006). The level of resistance to disease was now significantly
higher than any plant in the original F3 population,
despite the wild-type growth habit of these plants. It is suggested that
breeding programs should focus first on maximising field resistance through
isolation of some optimal combinations of resistance mechanisms in wild
genotypes before turning to improving the agronomic performance through
backcrossing to advanced breeding lines.