bluuebunny/crossref_metadata_2025 huggingface dataset:
Conservation of recognition of antibody and T-cell-defined alloantigens between species of equids
Authors: Baker Jessica M. , Stidworthy M. , Gull Tamara , Novak Jodi , Miller Jane M. , Antczak D. F.
Published: September 2002

Serological and cellular assays and molecular techniques were used to define
features of the major histocompatibility complex (MHC) of the donkey. With
this information in hand, immune recognition of MHC determinants within and
between donkeys and horses was compared. An antibody-mediated,
complement-dependent, microcytotoxicity assay using a variety of antisera to
donkey histocompatibility antigens, including those induced as a result of
intraspecies or interspecies pregnancy in horse mares and jenny donkeys,
delineated five donkey leukocyte antigen (DoLA) specificities. Antisera raised
across species barriers (horse anti-donkey and donkey anti-horse) recognized
polymorphic antigenic determinants in the target species. These determinants
were often indistinguishable from polymorphic antigens recognized by
alloantisera raised within horses or donkeys. The data indicate that a strong
correlation exists between the serological antigenic types identified and the
specificity of cytotoxic T lymphocytes raised by lymphocyte co-cultures,
either within or between species. Moreover, in an analysis of a small number
of donkey MHC class I cDNA gene sequences, no features distinguishing horse or
donkey MHC class I molecules were identified. These molecular findings explain
in large measure why antibody- and T-cell-defined alloantigen recognition is
conserved among these closely related equids.
Sex down under: the differentiation of sexual dimorphisms during marsupial development
Authors: Renfree Marilyn B. , Pask Andrew J. , Shaw Geoffrey
Published: September 2002

Marsupials have many characteristic features that make them ideal models to
study the control of sexual differentiation and development. They are
distinguished from eutherian mammals in their mode of reproduction and their
greater dependence on the teat and mammary gland than on the placenta for
development. They give birth to a highly altricial young which completes its
development while firmly attached to a teat, usually within the confines of a
pouch. At birth, the marsupial neonate has a well-developed digestive,
respiratory and circulatory system, but retains its fetal excretory system
with a fully functional mesonephric kidney and undifferentiated gonads and
genitalia.
Paradoxical effects of tumour necrosis factor-α on rat granulosa cell DNA synthesis
Authors: Lanuza Guillermo M. , Saragüeta Patricia E. , Bussmann Ursula A. , Barañao J. Lino
Published: September 2002

Tumour necrosis factor- α (TNF-α ) has been proposed as an intraovarian modulator of granulosa cell function. The effect of TNF-α on DNA synthesis in cultured rat granulosa cells was examined. Tumour necrosis factor-α stimulated thymidine incorporation when added in the presence of transforming growth factor-β (TGF-β). In contrast, the co-mitogenic effect of follicle-stimulating hormone (FSH) and TGF-β was inhibited in a dose-dependent manner by TNF-α . Inhibition of FSH-dependent DNA synthesis by TNF-α was also found when cultures were co-stimulated with activin A. The inhibitory action of TNF-α on FSH-treated cultures was not associated with changes in cell viability. The inhibitory effects of TNF-α could not be solely explained by a decrease in cAMP levels, since TNF-α was also able to inhibit the stimulation by dibutyryl-cAMP and TGF-β on granulosa cell DNA synthesis. These results suggest that TNF-α regulation of granulosa cell growth is elicited either independently or downstream from gonadotrophin-induced cAMP production. The actions of TNF-α could be only partially mimicked by a cell-permeable analogue of ceramide, thus indicating that actions of this cytokine can not be fully ascribed to an activation of sphingomyelinase. Data presented here indicate that, in addition to its previously demonstrated inhibitory effects on gonadotrophin-induced cell differentiation, TNF-α may also exert a marked inhibition on hormonally stimulated immature granulosa cell proliferation. In contrast to this inhibitory action, this cytokine could amplify the mitogenic action of putative intraovarian growth regulators such as TGF-β. These observations add further support to the notion that TNF-α plays a physiological role as a paracrine modulator of follicle development and may be also relevant to the alteration of ovarian function during physiopathological processes.
Molecular cloning and tissue expression of the gonadotrophin-releasing hormone receptor in the tammar wallaby (Macropus eugenii)
Authors: Cheung Timothy C. , Hearn John P.
Published: September 2002

Gonadotrophin-releasing hormone (GnRH) plays a pivotal role in the endocrine control of both reproduction and embryonic development. This first study of the marsupial GnRH receptor (GnRH-R) gene in the tammar wallaby provides information on the complex molecular events that regulate hypothalamic-pituitary- gonadal function in marsupials, and allows a comparison with eutherian mammals. Two identical wallaby GnRH-R cDNA clones were obtained, one isolated from cDNA generated from the testis of a 79-day-old pouch young and the other from the pituitary of an adult. Wallaby GnRH-R is composed of 328 amino acid residues. Sequence analysis showed that wallaby GnRH-R contains 7 transmembrane domains and is a member of the G protein- coupled receptor family. A putative protein kinase A phosphorylation site and a putative protein kinase C (PKC) phosphorylation site were found in the first intracellular loop, and an additional PKC phosphorylation site was located in the third intracellular loop. Comparisons with the eutherian GnRH-Rs show a greater diversity in the N-terminal extracellular domain. Wallaby GnRH-R has approximately 80% amino acid sequence homology with eutherian GnRH-Rs and 93% homology with the brush-tail possum, another member of the Diprotodontia semiorder.
Determinants of the annual pattern of reproduction in mature male Merino and Suffolk sheep: modification of responses to photoperiod by an annual cycle in food supply
Authors: Martin Graeme B. , Hötzel Maria J. , Blache Dominique , Walkden-Brown Stephen W. , Blackberry Margaret A. , Boukhliq Rachid , Fisher James S. , Miller David W.
Published: September 2002

Rams of a 'Mediterranean breed' (Merino) and a 'temperate breed' (Suffolk) were compared to determine how much of the differences between their reproductive seasons is owing to variation in their responses to photoperiodic and nutritional cues. In a previous study, both nutritional and photoperiodic inputs were held constant, and it was found that the two breeds show similar endogenous rhythms and, when the animals are challenged with a Mediterranean photoperiodic cycle, these endogenous rhythms are similarly modified. The present study tested whether an annual cycle in the supply of forage might modify the patterns that are generated by the interaction between photoperiod and endogenous rhythms. Both breeds were subjected to a simulated `Mediterranean' annual cycle in photoperiod (10L : 14D to 14D : 10L) and provided with either constant food supply or a simulated `Mediterranean' annual cycle in food supply. In Merino rams, testicular growth responded to photoperiod, but nutrition dominated those responses. In Suffolk rams, changes in testicular size can be completely out of phase with changes in body mass because they are driven primarily by photoperiod, with only subtle responses to changes in diet. The cycle of testicular growth in the Suffolk was driven by changes in the secretion of gonadotrophins (follicle-stimulating hormone concentrations and luteinizing hormone pulse frequency). By contrast, in the Merino, the nutritionally driven seasonal cycle of testicular growth was associated primarily with changes in body mass and this relationship could not always be explained by changes in gonadotrophin secretion. Melatonin secretion was not affected by food supply. Thus, the `Mediterranean' and `temperate' genotypes have similar endogenous rhythms that are similarly modified by photoperiod but, with respect to seasonal changes in nutrition, they differ in both the nature of their reproductive response and the physiological mechanisms that mediate those responses.
Pituitary responsiveness to diurnal and nocturnal GnRH pulses in melatonin-treated ewe lambs
Authors: Recabarren Sergio E. , Lobos Alejandro , Cendoyya Emilio , Correa Cristian , Rudolph Isolde
Published: September 2002

It has been shown that oral administration of melatonin to Suffolk ewe lambs,
from 10 weeks of age onwards, advances the onset of puberty compared with
control lambs maintained under the same natural photope-riod. Luteinizing
hormone (LH) pulse frequency at 20 and 26 weeks of age was unchanged by
melatonin. However, LH pulse amplitudes greater than 1 ng mL
–1 were consistently observed in melatonin-treated
lambs, suggesting either a high responsiveness of the pituitary gland to
endogenous gonadotrophin-releasing hormone (GnRH) pulses, or a large amount of
GnRH released by each pulse. The purpose of the present study was to assess
the pituitary responsiveness to six diurnal and six nocturnal exogenous pulses
of GnRH (10 ng kg–1 bodyweight) in
melatonin-treated ewe lambs (3 mg melatonin daily at 1600 hours, from 10 weeks
of age; n = 5) and control lambs of the same age
(n= 5), born in the spring and kept under natural
photoperiod. Pulses of GnRH were given intravenously at 60-min intervals by
means of an indwelling jugular catheter from 0900 to 1400 hours and from 2100
to 0200 hours to ewe lambs of 20 and 26 weeks of age. Blood samples were
collected at 10-min intervals using a contralateral jugular vein catheter from
1 h before and up to 1 h after the last GnRH pulse. The difference (delta)
between plasma LH concentrations at 0 min and the greatest concentration of LH
after each GnRH pulse was calculated and compared in the same group. The total
area under the GnRH response curve (AUC) was also calculated and compared
within and between the groups. The AUC of melatonin-treated lambs (66.1 5.94
and 52.24 7.42 ng mL–1 /6 h, diurnal and
nocturnal respectively) was greater than that of control lambs (39.42 4.29 and
32.82 3.6 ng mL –1 /6 h diurnal and nocturnal
respectively; P<0.05) at 20 weeks of age. At 26 weeks
of age, only the diurnal total AUC was greater in melatonin-treated lambs than
in control lambs (60.17 7.98 and 29.8 5.02 ng mL
–1 /6 h respectively;
P<0.05). Delta LH concentrations in response to the
first diurnal pulse of GnRH were greater than those in response to the fifth
diurnal GnRH pulse (P<0.05) in melatonin-treated
lambs of 20 weeks of age. Also, the delta LH concentrations in response to the
first three diurnal GnRH pulses were greater than to the last three nocturnal
pulses of GnRH (P<0.05). Delta LH concentrations were
greater in response to the second diurnal pulse of GnRH than to the last three
diurnal GnRH pulses, and greater than the responses to the first and the last
four nocturnal GnRH pulses (P<0.05), at 26 weeks of
age in melatonin-treated lambs. The response to nocturnal pulses of GnRH was
similar. In control lambs, the responses to diurnal and nocturnal GnRH pulses
were similar at 20 and 26 weeks of age. These results suggest that melatonin
enhances the pituitary responsiveness to GnRH pulses in ewe lambs.
Extra key words: luteinizing hormone, sheep.
Phylogenetic assessment of the monotypic genera Sundacarpus and Manoao (Coniferales: Podocarpaceae) utilising evidence from 18S rDNA sequences
Authors: Kelch Dean G.
Published: September 2002

The Podocarpaceae are the most morphologically diverse of conifer families. A
taxonomic trend has resulted in recognising this diversity via smaller generic
groupings, including several monotypes. A phylogenetic assessment of the
monotypic genera Sundacarpus and
Manoao was conducted employing maximum parsimony the
analysis of sequence data from 18S-ribosomal DNA from 34 gymnosperm taxa,
including 29 Podocarpaceae. In resulting trees, there is high bootstrap
support for Podocarpaceae, including Phyllocladus, but
the order of deep branches within the family is equivocal.
Prumnopitys (Sundacarpus)
amara (Blume) de Laub. and four other
Prumnopitys spp. comprise a clade with a bootstrap value
of 100%, supporting the retention of Sundacarpus
as a section of Prumnopitys.
Lagarostrobos franklinii (Hook.f.) Quinn and
L. (Manoao) colensoi (Hook.) Quinn comprise a clade with
equivocal bootstrap support, echoing previous results from parsimony analysis
of morphological data. A conservative approach (i.e. one avoiding unnecessary
monotypes) favours the retention of L. colensoi in
Lagarostrobos, pending further evidence of relationships
within the group.
Molecular phylogenetic relationships within and among diploid races of Glycine tomentella (Leguminosae)
Authors: Brown A. H. D. , Doyle J. L. , Grace J. P. , Doyle J. J.
Published: September 2002

DNA-sequence variation at the single-copy nuclear locus histone H3-D was
surveyed in 35 accessions of diploid Glycine tomentella
Hayata (2n = 38, 40) and samples of the closely
related new species Glycine aphyonota B.Pfeil and
Glycine pullenii B.Pfeil, Tindale & Craven. The
objective was a thorough analysis of the infraspecific variation in this
complex species as a prelude to the analysis of the evolutionary origin of its
tetraploid races. The shortest trees found by a heuristic search employing
parsimony all grouped the accessions into five wellsupported clades that
related closely to infraspecific taxa previously recognised from cytogenetic,
isozyme and ITSsequence studies. The most-differentiated race (isozyme label
D4) is related to the so-called A-genome species
G. clandestina Wendl.,
G. canescens F.J.Herm.,
G. latrobeana (Meissn.) Benth. and
G. argyrea Tind. This race is restricted to the central
uplands of Queensland. The two common races from Queensland are the aneuploid
(2n = 38) race and the euploid form from
north-east coastal regions (D3). Remarkably, an isolated
population of this race was found in the northern wetter fringes of the
Kimberley District, Western Australia. The remaining two races
(D5A and D5B) are centred on the
monsoonal tropics of Kimberley and Top End, Northern Territory. These two
groups have distinctive isozyme and morphological features that support the
recognition of such divergence, at least at subspecific level.
New taxa in Glycine (Fabaceae: Phaseolae) from north-western Australia
Authors: Pfeil B. E. , Craven L. A.
Published: September 2002

Three new taxa of Glycine are described, namely Glycine pullenii B.E.Pfeil, Tindale & Craven and G.�aphyonota B.E.Pfeil from Bungle Bungle-Purnululu National Park, Western Australia, and G. hirticaulis subsp. leptosa B.E.Pfeil from the Top End of the Northern Territory. A key to Glycine Willd. in north-western Australia is provided. A range extension for G. falcata Benth. is noted.
New chromosome numbers for Lasiopetaleae: Malvaceae s.l. (or Sterculiaceae)
Authors: Wilkins C. F. , Chappill J. A.
Published: September 2002

Previously unpublished chromosome numbers of n =
10 are reported for species of Lasiopetaleae genera
Lasiopetalum, Seringia and
Guichenotia. Additional new chromosome numbers of
n = 10 for species of
Keraudrenia and Thomasia match
published records for these genera and other Lasiopetaleae
Lysiosepalum and Hannafordia.
There is one count of n = 20 for
Thomasia angustifolia which is interpreted as a
polyploid number. New counts of n = 10 are
recorded for species of Rulingia and
Commersonia, traditionally included in Byttnerieae, but
with affinities to Lasiopetaleae. Comparison of
Lasiopetaleae chromosome numbers with other members of the subfamily
Byttnerioideae and the closely related Grewioideae (Malvaceae
s.l.) shows no clear evidence for a trend towards either
reduction or increase in chromosome number within the groups.
Systematic relationships within the Litsea complex (Lauraceae): a cladistic analysis on the basis of morphological and leaf cuticle data
Authors: Li Jie , Christophel David C.
Published: September 2002

The systematic relationships within the Litsea complex,
consisting of Litsea, Lindera,
Neolitsea, Actinodaphne,
Dodecadenia, Iteadaphne,
Parasassafras, Sinosassafras,
Umbellularia and Laurus, are
discussed. A cladistic analysis of morphological and leaf cuticle characters
resulted in three most parsimonious trees, with
Sassafras as sister group to other genera. The cladogram
of only cuticular characters does not show clear relationships, but highlights
the general integration of Litsea and
Lindera. The cladograms show that most genera in the
complex are polyphyletic. However, some monophyletic groups also appeared in
the cladograms, such as
Cylicodaphne–Cupuliformes
characterised by a cup-shaped fruit cupule,
Sinosassafras–Parasassafras
by a minute involucral bracts,
Uniumbellatae–Daphnidium by
trinerved leaves and
Litsea–Aperula by a
racemiform inflorescence. Additionally, the cladistics results imply that some
groups require further research.
Systematic studies in Paniceae (Poaceae): Homopholis and Whalleya gen. et sp. nov.
Authors: Wills Karen E. , Whalley R. D. B. , Bruhl Jeremy J.
Published: September 2002

The taxonomy ofHomopholis C.E.Hubb. is revised, and anew genus Whalleya K.E.Wills & J.J.Bruhl isdescribed. Relationships among the known species ofHomopholis (H. belsonii C.E.Hubb.,H. proluta F.Muell., and a putative species,H. sp. nov.), and the relationships betweenHomopholis and other genera within the Paniceae were investigated. Morphological and anatomical data forHomopholis and selected species ofDigitaria and Panicum were analysed phenetically and cladistically. The value and contribution ofcharacters to the findings were assessed. In the phenetic analyses, threedistinct clusters of species were formed. The first cluster includedDigitaria coenicola (F.Muell.) Hughes,D. divaricatissima (R.Br.) Hughes andD. papposa (R.Br.) P.Beauv.; the second,Panicum effusum R.Br.,P. queenslandicum Domin var.queenslandicum and P. simileDomin; and the third, H. sp. nov.,H. proluta, H. belsonii andP. subxerophilum Domin. Specimens ofH. belsonii noticeably separated from the other threespecies. For the cladistic analyses, species ofEntolasia and Thyridolepis were used as outgroup taxa. One most parsimonious tree was produced.Homopholis belsonii was well supported as the most basalmember of the ingroup. The three species ofDigitariaformed a well-supported clade.Panicum effusum, P. queenslandicumvar. queenslandicum and P. simileformed a well-supported clade, and were the sister group toEntolasia marginata (R.Br.) Hughes andE. stricta (R.Br.) Hughes.Panicum subxerophilum was in a clade (=Whalleya) with H. sp. nov. andH. proluta, with P. subxerophilumand H. proluta as sister species.
Relationships of the endemic Australian genus Huxleya Ewart & Rees (Labiatae) based on of fruit and flavonoid characters
Authors: Kok Rogier P. J. de , de Kok Rogier P. J. , Grayer Renée J. , Grayer Renée J. , Kite Geoffrey C. , Kite Geoffrey C.
Published: September 2002

The mature fruits of Huxleya linifolia Ewart & Rees (Labiatae) and the flavonoid profile of the species are described for thefirst time. On the basis of this new information, it seems likely that thegenus Huxleya is more closely related toClerodendrum rather than to Oxeraand Faradaya as thought previously.
Marine and estuarine benthic green algae (Chlorophyta) of Lord Howe Island, south-western Pacific
Authors: Kraft Gerald T.
Published: September 2002

A taxonomic survey of marine and estuarine benthic green algae has been
conducted at Lord Howe Island, the site of the world’s southernmost (at
31.5˚S) consolidated coral reef. Thirty-two genera and 71 species are
described from habitats ranging from upper intertidal to 20–30-m depths.
Sixteen of the species are based on Lord Howe types, and 11 are described as
new. Twelve species are currently known only from the Island. Particularly
well represented in the flora are the genera
Enteromorpha (six species, one variety),
Chaetomorpha (four species),
Cladophora (13 species),Codium
(five species), Caulerpa (seven species, two varieties)
and Bryopsis (three species). The island is further
distinctive in having two representatives of some relatively obscure genera
(Cladophoropsis, Rhipiliopsis,
Pseudochlorodesmis) and in being the highest-latitude
collecting locality for several species. Affinities of the Lord Howe flora are
primarily tropical Indo-Pacific, with very few elements otherwise restricted
to southern Australia and New Zealand.
Notes on Myriocephalus Benth. s. lat. (Asteraceae: Gnaphalieae)
Authors: Short P. S. , Short P. S.
Published: September 2002

Two new species of Myriocephalus from Western Australia,
M. gascoynensis and M. walcottii,
are described and illustrated. Notes concerning the circumscription of the
genus, lists of included and excluded names and their type specimens, an
account of the M. rhizocephalus group, and a summary of
pollen : ovule ratios in species of
Myriocephalus s. str. are presented.
Two new species of Asteridea Lindl. (Asteraceae: Gnaphalieae)
Authors: Short P. S.
Published: September 2002

Two new species, Asteridea archeri and
A. morawana, both from Western Australia, are described
and illustrated. Notes on their distribution, habitat and conservation status
are provided. A key to the nine species of Asteridea now
recognised is included.
Revision of Pittosporum (Pittosporaceae) in Australia
Authors: Cayzer Lindy W. , Crisp Michael D. , Telford Ian R. H.
Published: September 2002

Following a phylogenetic analysis using morphology,
Pittosporum is here monographed and recircumscribed as a
monophyletic genus, by including the small genus
Citriobatus and by excluding a new genus, described in
the accompanying paper as Auranticarpa. Within Australia
and its associated territories, 20 species are now recognised in
Pittosporum, including the four from
Citriobatus, three of which are given new combinations
(P. spinescens, P. lancifolium and
P. multiflorum).
Citriobatus linearis requires a new name
(P. viscidum). Four species are reinstated or confirmed
at species level (P. angustifolium,
P. ligustrifolium, P. nativitatis
and P. wingii), and P. trilobum is
described for the first time.
Phylogenetic analysis of Australian Acacia (Leguminosae: Mimosoideae) by using sequence variations of an intron and two intergenic spacers of chloroplast DNA
Authors: Murphy Daniel J. , Udovicic Frank , Ladiges Pauline Y.
Published: September 2002

Three regions of chloroplast DNA are assessed for their utility for
phylogenetic analysis of Acacia subgenus
Phyllodineae:
psbA–trnH intergenic spacer,
the trnL intron and the
trnL–trnF intergenic spacer.
There are large differences in the lengths of the
psbA–trnH spacer
(155–440 bp) and
trnL–trnF intergenic spacer
(101–422 bp) regions, and large multi-residue indels were coded as
multistate characters. Overall information content in these regions is
relatively low, but the total evidence tree has 12 nodes resolved, five with
jackknife support. By using Parkia timoriana as the
outgroup, Acacia subgenus Acacia
(A. farnesiana) is basal and
Acacia subgenus Aculeiferum
(A. senegal) is the sister taxon to subgenus
Phyllodineae. Although based on a small sample size,
within subgenus Phyllodineae, the results of this study
have shown that section Alatae is not monophyletic,
section Lycopodiifoliae is monophyletic and
Botrycephalae is related to members of section
Phyllodineae with racemose inflorescences.
The effect of mineralisation rates of atrazine in surface and subsurface soils on its groundwater contamination potential
Authors: Di H. J. , Sparling G. P. , Lee R. , Magesan G. N.
Published: September 2002

Atrazine is a widely used herbicide for weed control and has been found in
groundwater in many countries. The groundwater contamination potential of
atrazine in 2 soils on the east coast of the North Island of New Zealand was
modelled under 3 scenarios. Scenario 1 used atrazine mineralisation rates as
determined in an incubation experiment which showed higher rates of
mineralisation in subsoil layers than in surface soils. Scenario 2 assumed a
decreasing mineralisation rate with soil depth in proportion to changes in
microbial biomass. Scenario 3 used a logistic model to describe atrazine
mineralisation rates compared with the first-order model used in Scenarios 1
and 2. The results showed that serious errors could occur when modelling the
groundwater contamination potential by assuming a decreasing degradation rates
with soil depth, when in fact the degradation rates could be higher in some
subsoil layers. A site that had not been exposed to atrazine in the past was
shown to have a higher potential for groundwater contamination than a
neighbouring site of the same soil which had been treated with atrazine in the
past. The groundwater contamination potential was found to be higher in the Te
Awa soil than in the Twyford soil due to the longer mineralisation half-lives
in the Te Awa soil.
The influence of soil properties on the effectiveness of phosphate rock fertilisers
Authors: Bolland M. D. A. , Gilkes R. J. , Brennan R. F.
Published: September 2002

Eighteen soils from south-western Australia were used to measure the
effectiveness of 2 reactive phosphate rocks (RPR) [North Carolina and
Sechura (Bayovar) RPRs] relative to superphosphate (relative
effectiveness, or RE) using (i) yield of dried shoots of
30-day-old wheat plants (REyield ),
(ii) P content of the dried shoots (RE
Pcontent ), and (iii) bicarbonate
soil test P (RE bicP ) as measures of effectiveness. The
RE values were positively related to PR dissolution in soil, titratable
acidity, and to P and Ca retention by soil, and were negatively related to
soil pH. No single soil property adequately predicted
REyield , RE Pcontent, or RE
bicP . Stepwise multiple regression indicated that: (1)
PR dissolution, soil pH, and organic carbon together accounted for about half
the variation in RE yield ; (2) organic C, soil pH, and
titratable acidity together accounted for about 67% of the variation in
RE Pcontent ; (3) PR dissolution, P retention capacity,
and titratable acidity together accounted for about 71% of the
variation in RE bicP . We conclude that the agronomic
effectiveness of phosphate rock fertilisers is a consequence of complex
interactions of phosphate rock with soil that cannot be adequately predicted
by measurements of a single soil property.
Soil factors affecting the availability of potassium to plants for Western Australian soils: a glasshouse study
Authors: Pal Y. , Gilkes R. J. , Wong M. T. F.
Published: September 2002

A glasshouse experiment was conducted with 41 surface and 8 subsurface soils
to measure their potassium (K) supply capacities and K depletion of soils by
ryegrass growth for 260 days and harvesting at ~40-day intervals. Dry matter
yield ranged from 0.22 g to 25.4 g/kg soil, cumulative K uptake ranged
from 0.006 to 1.49 cmol/kg soil, and values of K concentration (%)
in the first cut herbage ranged from 0.40% to 5.97%. Some of the
light-textured soils were so impoverished in K that symptoms of K deficiency
appeared during the first growth period. Water-soluble K + exchangeable K
accounted for 43–100% of cumulative K uptake by the ryegrass.
Multiple regression analysis indicated that 68% of the variation in dry
matter yield and 90% of the variation in K uptake may be predicted by
the exchangeable K content of these soils. The 6 harvests of ryegrass
extracted only 0.21–12.07% of total K from these soils, which was
not sufficient to cause discernible mineralogical changes in most soils. For
some soils vermiculite was formed at the expense of illite/mica by K
release to plants. For soils containing vermiculite but no other K-bearing
clay minerals, vermiculite peaks broadened on K depletion by plants. Major
proportions of total K in these soils are present in silicate minerals, yet
only minor amounts are released to plants by very slow weathering processes.
For soils that do not contain any K bearing clay minerals, very minor amounts
of feldspar may have dissolved to release K.
Chemical reaction and Co-60 retardation in unsteady, unsaturated soil water flow: the effect of clay content
Authors: Smiles D. E.
Published: September 2002

The ability of the regolith to adsorb and retard radioactive and other noxious
chemicals is important when selecting repository sites. Because of its surface
charge and great specific surface, the clay in soil contributes significantly
to this retardation. This paper illustrates a novel analysis of unsteady water
and solute flow in unsaturated soil that quantifies these effects. Analysis
and experiments suggest that the use of a clay-based space-like coordinate
permits us to generalise results to account for variation in clay content and
soil structure across many materials. Results imply that clay content,
mineralogy, and charge permit quantitative material classification according
to their ability to retard cationic wastes. The approach appears to offer
significant economies in selecting materials where adsorption and retardation
of cation pollutants is desired.
A laboratory study of application of basalt dust to highly weathered soils: effect on soil cation chemistry
Authors: Gillman G. P. , Burkett D. C. , Coventry R. J.
Published: September 2002

Surface (0–10 cm) samples from 7 highly weathered soils in tropical
coastal Queensland were incubated for 3 months at room temperature and at
field moisture capacity with basalt dust applied in 2 size fractions:
<150 µm and 40 µm. The basalt application was mixed at 0,
1, 5, 25, and 50 t/ha to cover situations of moderate applications as well
as where the amendment might be banded to achieve high local concentrations.
Basalt dust application caused desirable increases in soil pH, reduced the
content of exchangeable acidic cations, increased soil cation exchange
capacity, and increased the content of base cations in all soils.
By determining fundamental surface charge characteristics of these variable
charge soils, it was possible to show that the additional base cations
released from the basalt dust were present as exchangeable cations, and that
the amounts released were controlled by the number of negatively charged sites
available, i.e. soil cation exchange capacity.
Selected treatments were then subjected to a strong leaching environment to
assess the longevity of the effects obtained. Soil properties remained
virtually unchanged by the leaching treatment, except that significant amounts
of monovalent K and Na were removed.
At the higher rates of application, the amounts of base cations released from
the basalt were small in comparison with the actual amounts applied,
indicating that the amendment could be effective over a considerable period of
time.
Brazilian latosols and their B horizon microstructure as long-term biotic constructs
Authors: Schaefer Carlos E. R.
Published: September 2002

This paper discusses micropedological evidence for the biological formation of
microstructure in tropical soils, placing emphasis on latosol (oxisol)
formation promoted by termite activity. The microstructure of selected
latosols from Brazil was investigated using standard chemical and physical
methods, optical microscopy, and high resolution scanning electron microscopy
coupled with energy-dispersive X-ray analysis to provide microchemical
analysis of discrete microaggregates in thin section. The results showed that,
in spite of great variability of parent materials, the B horizon of these
soils displayed uniform microgranular structure, with little lithodependence
and no apparent relationship to particle-size. Lithorelicts of oval pellets of
100–1000 mm diameter, similar to those in the B horizon, were observed
in the upper parts of the C horizon (saprolite). In addition, microparticles
of charcoal (<50 m) were found in the inner microaggregates. The basic
skeleton of the inner microaggregates was formed of quartz grains, generally
smaller than 100 mm diameter. In contrast, the quartz grains of the soil
skeleton ranged between 30 and 5000 mm. These microaggregates were not
distinguishable from those built by termites on shallowsaprolite. I present a
general model of latosol genesis, which considers the close interdependence
between the advent of angiosperm-dominated landscapes, neotectonics, and the
synchronous appearance of termites and latosols on tropical land, dating back
to late Cretaceous/early Tertiary times. The microaggregation of latosols
is viewed as a long-term strategy favouring physical characteristics to
counteract the irreversible trend of increasing nutrient losses. The degree of
microaggregation appears related to high gibbsite and Fe-oxide concentrations,
although these minerals are not responsible for microaggregate formation.
However, it is postulated that gibbsite and Fe-oxides are associated only with
the persistence of microaggregates in tropical soils. Because of a tendency to
form face-to-face structures, kaolinite does not favour the microaggregation
phenomenon, and hence, highly kaolinitic latosols display coalesced
aggregates.
Clay mineral associations in melanic soils of South Africa
Authors: van der Merwe Gertruida M. E. , Laker Michiel C. , Bühmann Christl
Published: September 2002

The melanic horizon is 1 of 5 diagnostic topsoil horizons distinguished in the
South African soil classification system. Melanic soils span a wide spectrum,
ranging from those that intergrade with a vertic to those that intergrade with
a humic horizon. Melanic soils are therefore expected to vary considerably
with respect to a variety of physical, chemical, and clay mineralogical
properties. The objective of the present study was to determine the clay
mineral compositions of melanic horizons from 58 modal profiles and to
establish to what extent melanic soil properties are related to clay
mineralogy. Special emphasis was placed on the characterisation of the clay
fraction in terms of group and species identification. X-ray diffractometry
was employed almost exclusively as the investigative technique in mineral
identification and quantification. Melanic A horizons showed a large degree of
variation with regard to their clay mineral associations. More than half of
the soils were dominated by smectite, 30% by kaolinite, and the rest by
an association of about equal proportions of mica, kaolinite, and smectite.
Talc and hydroxy-interlayered vermiculite occurred in a number of soils while
one horizon was dominated by an illite/smectite interstratification. The
smectite component was identified as belonging to either beidellite or
vermiculite species, depending on the method employed. About a quarter of the
smectitic soils contained montmorillonite as well but not as the dominant
swelling phase.
mollisols, clay mineralogy, layer charge.
Effects of agricultural management on dermosols in northern Tasmania
Authors: Cotching W. E. , Cooper J. , Sparrow L. A. , McCorkell B. E. , Rowley W.
Published: September 2002

Attributes of 15 Tasmanian dermosols were assessed using field and laboratory
techniques to determine changes associated with 3 typical forms of
agricultural management: long-term pasture, cropping with shallow tillage
using discs and tines, and cropping (including potatoes) with more rigorous
and deeper tillage including deep ripping and powered implements. Soil organic
carbon in the surface 75 mm was 7.0% under long-term pasture compared
with 4.3% and 4.2% in cropped paddocks. Microbial biomass carbon
concentrations were 217 mg/kg, 161 mg/kg, and 139 mg/kg,
respectively. These differences were negatively correlated with the number of
years cropped. Greater bulk densities were found in the surface layer of
cropped paddocks but these were not associated with increased penetration
resistance or decreased infiltration rate and are unlikely to impede root
growth. Long-term pasture paddocks showed stronger structural development and
had smaller clods than cropped paddocks. Vane shear strength and penetration
resistance were lower in cropped paddocks than under long-term pasture. Many
soil attributes showed no significant differences associated with management.
Including potatoes in the rotation did not appear to affect these dermosols,
which indicates a degree of robustness in these soils.
clay loams, organic carbon, soil strength, aggregate stability, land
management, cropping.
Prediction of three key hydraulic properties in a soil survey of a small forested catchment
Authors: O'Connell D. A. , Ryan P. J.
Published: September 2002

Direct measurement of ψ(θ) and K(θ) relationships at all
observation sites in soil survey is not feasible. Three key hydraulic
properties — water content at field capacity
(θ–5 kPa), water content at wilting point
(θ–1.5 MPa), and saturated hydraulic
conductivity (Ks) — can be used to derive K(θ)
and ψ(θ) when combined with bulk density. These properties were
measured in 'calibration' horizons in a soil survey in Yambulla
State Forest in south-east New South Wales.
Pedotransfer functions (PTFs) for predicting
θ-5 kPa,
θ–1.5 MPa, and Ks from the physical and
morphologic soil attributes are presented and evaluated here. Models for
predicting θ–5 kPa and
θ–1.5 MPa relied on per cent clay. An
R2 of 0.64 (for
θ–5 kPa) to 0.67 (for
θ–1.5 MPa) was obtained for linear
regressions using only morphologic explanatory variables. An
R2 of 0.73 (for
θ–5 kPa) to 0.90 (for
θ–1.5 MPa) was obtained if
laboratory-measured clay content was included as an explanatory variable.
Ks was measured in situ using well
permeameters, and used for developing PTFs. Large cores were taken from a
small subsample of horizons and measurements of Ks,
K–0.1 kPa, K–0.2 kPa,
and K–0.5 kPa were made in the laboratory.
Ks measurements from well permeameters were similar to
K-0.5 kPa from laboratory measurements.
Regression and tree models were used to predict Ks. The
linear regression had an R2 of
0.55, while the tree models accounted for approximately 40% reduction
in deviance. Bulk density was the most useful predictor in all
Ks models. The inclusion of per cent rock fragments,
bulk density, and estimated percentage clay as useful explanatory variables
demonstrated the utility of functional descriptors not routinely measured in
soil survey.
The models are empirical and were locally calibrated for use in a soil survey.
They may be applicable in target domains similar to the source domain (i.e.
coarse-grained adamellite soils in similar climatic regimes).
surrogates, saturated hydraulic conductivity, K(θ), ψ(θ), Ks, pedotransfer functions, soil survey, soil morphology, PTF.
Prediction of K-Ca-Mg ternary exchange from binary isotherms in volcanic soils using the Rothmund-Kornfeld approach
Authors: Escudey M. , Diaz P. , Förster J. E. , Galindo G. , Pizarro C. , Beltrán L.
Published: September 2002

The Gaines-Thomas formulation of the Rothmund-Kornfeld equation was used to predict the K-Ca-Mg exchange in variable surface charge soils. Binary and ternary equilibria were carried out at 25°C and at constant ionic strength of 0.050 mol/L. The selectivity sequence K > Ca > Mg was observed in binary isotherms. The experimental ternary isotherms are well described from binary data. When experimental v. calculated equivalent fractions were plotted, slopes between 0.901 and 1.051, and correlations between 0.970 and 0.986, were obtained. The design used assures in volcanic soils that no, or minor, changes in surface charge, cation exchange capacity, and selectivity occur, but the predicted ternary values are restricted to the same binary experimental conditions employed.
Influence of pH on a secondary effect of phosphate reaction: the decrease in sorption of newly added phosphate
Authors: Barrow N. J.
Published: September 2002

Secondary effects occur as a consequence of previous applications of phosphate to soil. They are caused by the decrease in charge and potential resulting from reaction of phosphate with soil. Such effects on the sorption of newly added phosphate were largest between about pH 3.5 and 5.0. At higher pH, the smaller effects are ascribed to the fact that the potentials are already low and the extra effect of phosphate is small. At lower pH, previously sorbed phosphate was more readily desorbed. It is suggested that this increased lability means that the secondary effects are decreased.
Soil properties of a widely spaced, planted poplar (Populus deltoides)pasture system in a hill environment
Authors: Guevara-Escobar A. , Mackay A. D. , Hodgson J. , Kemp P. D.
Published: September 2002

Planting poplars is an effective technology for controlling hill soil erosion in New Zealand pastureland. However, the effects of widely spaced poplars on soil properties are not documented. Soil was sampled from 3 soil depths (0-75, 75-150, and 150-300 mm) in poplar-pasture (PP) and adjacent open pasture (OP) systems. Four sites were examined, 3 unreplicated sites with mature poplars (>29 years, 37-40 stems/ha) and a replicated experiment with immature poplars (5 years, 50-100 stems/ha). Pastures at all sites were dominated by low fertility species and were grazed by sheep and cattle. Pasture species were used in a glasshouse experiment to assess the production potential of the topsoil media (0-20 mm) from the PP and OP soils, and the OP topsoil amended with 5% poplar leaf litter.
A comparison using the caesium-137 technique of the relative importance of cultivation and overland flow on soil erosion in a steep semi-tropical sub-catchment
Authors: Wiranatha A. S. , Rose C. W. , Salama M. S.
Published: September 2002

The spatial pattern of net soil loss on 6 downslope transects in a small
semi-tropical sub-catchment was measured in 1990—91 using the
resident caesium-137 deficit technique. The sub-catchment consisted of 2
opposing hillslopes which shed water to an intermittent stream in the valley
bottom of the sub-catchment. There were 3 transects on each of the opposing
hillslopes, and measurement indicated net soil loss from all 6 transects.
Furthermore, the spatial pattern of caesium-137 deficit did not indicate the
accumulation of soil expected due to the slope decrease toward the bottom of
the valley. Possible explanations of this finding could be the effect of
periodic flooding of the intermittent valley stream, or seepage-accelerated
erosion.
Pineapple cultivation in the sub-catchment since 1950 included intensive
cultivation at 4-year intervals by downslope-moving rotary hoe. The paper
develops a theoretical prediction of the spatial pattern of net soil loss
expected due to such cultivation, as well as the expected pattern of soil loss
due to overland flow on the hillslopes. The spatial patterns of soil loss due
to these 2 different soil erosion mechanisms were then compared with the
pattern of net soil loss indicated by caesium-137 depletion to provide an
assessment of their likely relative importance in contributing to soil loss.
In the upper part of each hillslope, this comparison of spatial trends did not
allow the dominant cause of soil erosion to be distinguished. Both the model
of erosion due to cultivation and that due to hillside overland flow predicted
soil accumulation in the lower valley sides where slope decreased. Neither
model represented the net loss of such accumulated soil indicated by
caesium-137 deficit, and this loss possibly occurred during periodically
observed flooding of the valley floor, or due to surface burial with
caesium-137 depleted subsoil.
Soil organic matter in rainfed cropping systems of the Australian cereal belt
Authors: Dalal R. C. , Chan K. Y.
Published: September 2002

The Australian cereal belt stretches as an arc from north-eastern Australia to
south-western Australia (24˚S–40˚S and
125˚E–147˚E), with mean annual temperatures from 14˚C
(temperate) to 26˚C (subtropical), and with annual rainfall ranging from
250 mm to 1500 mm. The predominant soil types of the cereal belt include
Chromosols, Kandosols, Sodosols, and Vertosols, with significant areas of
Ferrosols, Kurosols, Podosols, and Dermosols, covering approximately 20 Mha of
arable cropping and 21 Mha of ley pastures.
Cultivation and cropping has led to a substantial loss of soil organic matter
(SOM) from the Australian cereal belt; the long-term SOM loss often exceeds
60% from the top 0–0.1 m depth after 50 years of cereal cropping.
Loss of labile components of SOM such as sand-size or particulate SOM,
microbial biomass, and mineralisable nitrogen has been even higher, thus
resulting in greater loss in soil productivity than that assessed from the
loss of total SOM alone. Since SOM is heterogeneous in nature, the
significance and functions of its various components are ambiguous. It is
essential that the relationship between levels of total SOM or its identif
iable components and the most affected soil properties be established and then
quantif ied before the concentrations or amounts of SOM and/or its
components can be used as a performance indicator. There is also a need for
experimentally verifiable soil organic C pools in modelling the dynamics and
management of SOM. Furthermore, the interaction of environmental pollutants
added to soil, soil microbial biodiversity, and SOM is poorly understood and
therefore requires further study. Biophysically appropriate and cost-effective
management practices for cereal cropping lands are required for restoring and
maintaining organic matter for sustainable agriculture and restoration of
degraded lands. The additional benefit of SOM restoration will be an increase
in the long-term greenhouse C sink, which has the potentialto reduce
greenhouse emissions by about 50 Mt CO2
equivalents/year over a 20-year period, although current improved
agricultural practices can only sequester an estimated 23% of the
potential soil C sink.
Nutrient status of pasture ecosystems established on rehabilitated overburden and topsoil sites in the Hunter Valley, New South Wales
Authors: Brown G. M. C. , Grant C. D.
Published: September 2002

The rehabilitation of disturbed areas at the Howick Coal Mine (Hunter Valley,
New South Wales) involves re-creating pasture ecosystems. Some sites are
rehabilitated using topsoil, whereas others are established directly into the
overburden mine waste due to the low availability and poor quality of topsoil.
Pastures on both substrate types are then maintained by periodic applications
of fertiliser. A comparison was made between nutrient levels held in the soil
and the roots and stems of the dominant pasture grass (Rhodes grass,
Chloris spp.) in an overburden (rehabilitated in 1990)
and a topsoil site (rehabilitated in 1991). Sampling was conducted in autumn
1998 at 3 random locations along 3 replicate transects established on both
substrates. Laboratory analyses were conducted to determine levels of N, P, S,
Ca, K, Mg, and Na for both soil and plants samples; Mn, Fe, Zn, Cu, and Al for
the plant samples only; and NO 3-N, PO
4-P, organic carbon, pH, and EC for the soil samples
only.
Multivariate analysis showed a distinct difference in the nutrient status of
topsoil and overburden sites, across the 7 nutrients common to the roots,
stems, and soil. The concentration of all macronutrients was significantly
higher in the overburden compared with the topsoil sites. The majority of
macronutrients were in greatest concentrations in the stems but the highest
levels of micronutrients were found in the roots. There was a higher
concentration of micronutrients in the overburden sites. Both of the
rehabilitated sites had adequate macronutrient concentrations of S, Ca, Mg,
and K. However, there were deficient concentrations of
NO3-N in both the topsoil and overburden sites and a
deficient concentration of PO4-P in the topsoil site.
Long-term management options to improve the nutrient status of rehabilitated
coal mines in the Hunter Valley include increased grazing, increasing
fertiliser inputs, and burning the rehabilitated areas.