bluuebunny/crossref_metadata_2025 huggingface dataset:
Storage of cane toad (Bufo marinus) sperm for 6 days at 0°C with subsequent cryopreservation
Authors: Browne R. K. , Davis J. , Clulow J. , Pomering M.
Published: September 2002

We investigated the recovery of motility of cane toad (Bufo marinus) sperm after storage for 6 days at 0°C (on ice) and after subsequent cryopreservation. Sperm suspensions were prepared from testes macerated in either simplified amphibian Ringer (SAR) or 10% (w/v) sucrose diluents, with 15% or 20% (v/v) glycerol or Me2SO as cryoprotectants, and were stored for 6 days. Alternatively, suspensions were prepared in either SAR or 10% (w/v) sucrose diluent and stored for 6 days, after which some of these suspensions were kept in diluents alone or, alternatively, had 15% or 20% (v/v) glycerol or Me2SO added. All treatments (suspensions) were then cryopreserved. Sperm motility was measured at Day 1 and Day 6 (before and after cryopreservation). A substantial and variable proportion (range 0%–40%) of sperm was immotile in suspensions immediately after preparation from testes macerates. Sperm stored in either SAR or 10% (w/v) sucrose diluent maintained approximately 75% motility for 6 days, but few sperm survived cryopreservation. After storage and cryopreservation, recovery of motility was substantially higher with Me2SO than in glycerol. However, both cryoprotectants exhibited toxicity at high concentrations. Glycerol was more toxic than Me2SO in 10% (w/v) sucrose than in SAR diluent, both before and after cryopreservation. The addition of some cryoprotectants to suspensions before storage gave greater recovery both before and after cryopreservation. After cryopreservation, the highest rate of sperm recovery was in suspensions with 10% (w/v) sucrose and 15% (v/v) Me2SO added prior to storage (mean (±SEM) 46 ± 7% relative to initial; 39 ± 6% absolute). Sperm were also stored for 6 days at 0°C in suspensions or testes (with suspensions then prepared from testes) and cryopreserved. Sperm maintained higher recovery and membrane integrity both before and after cryopreservation when stored in suspensions rather than in testes.
Adrenocorticotrophic hormone (ACTH) stimulation of sheep fetal adrenal cortex can occur without increased expression of ACTH receptor (ACTH-R) mRNA
Authors: Carter A. M. , Petersen Y. M. , Towstoless M. , Andreasen D. , Jensen B. L.
Published: September 2002

In the present study, it was hypothesized that the adrenocorticotrophin
hormone receptor (ACTH-R) would be up-regulated in the adrenal gland of the
sheep fetus following infusion of physiological amounts of ACTH, as shown for
adrenal cortical cells in culture. In chronically catheterized sheep, an
intravenous infusion of ACTH1–24 was given to 6
fetuses for 24 h at a rate of 0.5 g h–1, starting
on Day 126 or 127 of gestation (term ~147 days). Four control fetuses received
an infusion of vehicle (saline). Total RNA was extracted from the fetal
adrenal glands by the guanidinium thiocyanate method. Expression of specific
mRNAs was determined by ribonuclease protection assay using cRNA probes
directed against: ACTH-R; the steroid enzymes side-chain cleavage (P450scc),
3β-hydroxysteroid dehydrogenase (3β-HSD), 17 α-hydroxylase
(P450c17) and 21β-hydroxylase (P450c21); and β-actin. Ratios of mRNA
expression to β-actin mRNA expression (arbitrary units) were calculated to
correct for differences in RNA quality between samples. The concentration
(mean SEM) of immunoreactive cortisol in fetal plasma was greater after ACTH
infusion than after vehicle infusion (47 3 v. 13 2 ng
mL–1 respectively;
(P<0.001). Adrenal expression of P450scc and P450c21
mRNA increased after ACTH infusion (P<0.05), whereas
expression of P450c17 and 3β-HSD mRNA was unchanged. There was no
difference in ACTH-R mRNA expression between ACTH- and vehicle-infused fetuses
(254 48 v. 305 76 arbitrary units respectively). It was
concluded that ACTH is able to increase plasma cortisol concentrations in the
sheep fetus by up-regulating cortisol synthesis in the adrenal gland, but that
in vivo this does not require up-regulation of ACTH-R
mRNA.
Equine placentation
Authors: Allen W. R. , Stewart Francesca
Published: September 2002

A tough, elastic glycoprotein capsule envelops the equine blastocyst between
Days 6 and 23 after ovulation. It maintains the spherical configuration of,
and provides physical support for, the embryo as it traverses the entire
uterine lumen during Days 6–17, propelled by myometrial contractions
that are stimulated by pulsatile release of prostaglandin
F2α and prostaglandin
E2. The capsule also accumulates constituents of the
exocrine secretions of the endometrial glands (‘uterine milk’) as
nutrients for the mobile embryo as it releases its antiluteolytic maternal
recognition-of-pregnancy signal to the whole of the surface of the
endometrium. Mobility ceases abruptly on Day 17 with a sudden increase in
uterine tonicity that ‘fixes’ the conceptus at the base of one of
the uterine horns. At Day 35, the trophoblast of the spherical conceptus has
separated into its invasive and non-invasive components. The former,
distinguished as the thickened, annulate chorionic girdle, invades the
maternal endometrium to form the unique endometrial cups. These secrete a
chorionic gonadotrophin that synergizes with pituitary follicle-stimulating
hormone to induce secondary luteal development in the maternal ovaries. The
cup cells express foreign fetal antigens that stimulate strong maternal
humoral and cell-mediated immune responses, which curtail their lifespan. The
non-invasive trophoblast of the allantochorion establishes a stable
microvillous contact with the endometrial epithelium around Day 40 and, over
the next 100 days, develops a complex multibranched interdigitation with the
endometrium to form the microcotyledonary haemotrophic exchange units that
cover the entire surface of the diffuse epitheliochorial placenta. Reduction
in the effective total area of fetomaternal contact at this placental
interface, by competition between twin conceptuses for the limited area of
available endometrium, by attachment of the allantochorion to an imperfect
endometrium in a mare with endometrosis, or following cross-breeding or embryo
transfer between a sire and dam of dissimilar size, will all induce
intrauterine growth retardation of the fetus and runting of the foal, which
persists into adult life. Over 40 years ago, Professor Roger Short and his
colleagues determined that the high concentrations of conventional and unique
ring B unsaturated oestrogens in the blood and urine of mares during the
second half of pregnancy stem from placental aromatization of large quantities
of C-19 precursor molecules secreted by the temporarily hypertrophic fetal
gonads. Placental production of progesterone and 5α-reduced
progestagens, on the other hand, depends on both maternal and fetal adrenal
sources of pregnenelone.
Embryo implantation and embryonic stem cell development in primates
Authors: Hearn John P.
Published: September 2002

The endocrine dialogue that results in implantation and the successful
establishment of pregnancy in primates relies on embryonic secretion of
chorionic gonadotrophin (CG). This hormone is a signal of embryo viability and
capacity to support the corpus luteum. The expression of CG is apparently
restricted to primates. Active or passive immunization of marmoset monkeys
against the beta subunit of CG prevented implantation and early pregnancy,
without disrupting the ovarian cycle. Studies of individual embryos cultured
in vitro showed that CG is secreted at low levels by the
blastocyst from before attachment, with secretion increasing exponentially
after attachment. Gonadotrophin releasing hormone (GnRH) was also secreted,
from mid-blastocyst stages, before the detection of CG. The secretion of GnRH
by the embryo continued through the attachment and outgrowth stages of
embryonic differentiation in vitro. The hypothetical
role of GnRH in regulating CG release during implantation was tested in
recently completed experiments. Individual embryos cultured with GnRH, or with
agonist or antagonist to GnRH, showed significant variations in their
secretion of CG and in their survival in culture, suggesting a causal
relationship between these hormones. Embryos cultured with natural GnRH showed
enhanced growth and development. Embryonic stem cells, from the inner cell
mass of marmoset and rhesus monkeys, were the first primate embryonic stem
cells to be isolated and characterized, enabling the subsequent isolation of
human embryonic stem cells.
Immunolocalization of sex steroid hormone receptors in canine vaginal and vulvar tissue and their relation to sex steroid hormone levels
Authors: Vermeirsch Hilde , Broeck Wim Van Den , Simoens Paul
Published: September 2002

The aim of this immunohistochemical study was to describe the cellular distribution of the estrogen receptor-α (ERα), progesterone receptor (PR) and androgen receptor (AR) in canine vaginal and vulvar tissue. Samples were taken from dogs in different stages of the estrous cycle. Nuclear staining for ERα, PR and AR was observed in surface epithelium, stromal and smooth muscle cells. Receptors were also expressed in vulvar skin. Cytoplasmic staining for AR was observed in basal and parabasal cell layers of vulvar and vaginal epithelium. For all three receptors, staining intensity was generally higher in stromal cells compared with epithelial cells, suggesting that stromal cells may be more receptive to steroid hormone action. Therefore, as in other tissues of the female genital tract, stromal-epithelial interactions induced by sex steroid hormones may be of importance in canine vaginal and vulvar tissues. No cyclic changes in receptor immunostaining were observed. Significant positive correlations were found between receptor immunostaining in some vaginal and vulvar cell groups and the serum concentrations of estradiol-17β and testosterone, but not with the serum progesterone concentration. Significant negative correlations were found between ERα immunostaining in epithelial and stromal cells of the vagina and the serum estradiol-17α concentration, suggesting a negative feedback mechanism between estradiol-17β and its receptor. Both cell types play a role in the differentiation of vaginal epithelium, under the influence of estradiol-17β
In vitro maturation and glutathione synthesis of porcine oocytes in the presence or absence of cysteamine under different oxygen tensions: role of cumulus cells
Authors: Bing Y. Z. , Hirao Y. , Iga K. , Che L. M. , Takenouchi N. , Kuwayama M. , Fuchimoto D. , Rodriguez-Martinez H. , Nagai T.
Published: September 2002

The present study was conducted to evaluate the effect of cumulus cells on the in vitro maturation (IVM) and glutathione (GSH) synthesis of porcine oocytes cultured in the presence or absence of cysteamine under different oxygen tensions, and on their subsequent male pronucleus formation after in vitro fertilization (IVF). Cumulus-oocyte complexes (COCs) and cumulus-denuded oocytes (DOs) were cultured for 45 h in modified TCM-199 supplemented with or without 150 m cysteamine under a humidified atmosphere of 5% CO2 in air (20%�O2) or 5% CO2, 5% O2 and 90% N2. When cultured in medium supplemented with cysteamine under 20% O2 tension, the rates of COC maturation to the metaphase II (MII) stage were significantly higher than those of DOs (P<0.05). Regardless of the addition of cysteamine and oxygen tension, the rates of male pronucleus formation in COCs after IVM and IVF were significantly higher than in DOs (P<0.05). The GSH content of oocytes was significantly increased by the addition of cysteamine to the maturation medium (P<0.05), with significantly higher GSH content in COCs than in DOs (P<0.05). However, the GSH content of COCs and DOs was not significantly different when cultured in medium without cysteamine. These results indicate that cumulus cells play an important role in nuclear maturation to MII, GSH synthesis in porcine oocytes cultured in the presence of cysteamine, and subsequent male pronucleus formation after IVF.
Intra- and interspecific allozyme variation in eucalypts from the spotted gum group, Corymbia, section 'Politaria' (Myrtaceae)
Authors: McDonald M. W. , Butcher P. A. , Bell J. C. , Larmour J. S.
Published: September 2002

The distribution of genetic variation within and among species inCorymbia section‘Politaria’ was examined using allozymes.This section consists of four species,Corymbia citriodora (Hook.) K.D.Hill & L.A.S.Johnson, C. maculata (Hook.) K.D.Hill & L.A.S.Johnson, C. henryi (Blake) K.D.Hill & L.A.S.Johnson and C. variegata (F.Muell.) K.D.Hill & L.A.S.Johnson, which are of commercial interest for plantation and farmforestry. Thirty populations representing the species’ range-widedistributions were studied, extending from upland tropical regions of northQueensland, south to eastern Victoria. Despite relatively low allozymedivergence between species, there was a relationship between geographicdistribution patterns of populations and allozyme variation. The section wasshown to comprise very closely related species with only 15% of thetotal genetic diversity attributed to differences between species. Twodistinct genetic alliances were evident:C. maculata–C. henryi andC. citriodora–C. variegata.Corymbia citriodora andC. variegata, however, could not be distinguished bytheir allozyme profiles. The lack of genetic differentiation between thesetaxa suggests that they represent one species composed of two chemical races.Corymbia maculata and C. henryiwere shown to be closely allied but genetically distinct.Corymbia henryi had the highest genetic diversity in thegroup and lowest differentiation among populations, whileC. maculata had the lowest diversity but the highestgenetic differentiation among populations. There was evidence ofisolation-by-distance among populations ofC. citriodora, C. maculata andC. variegata but not in C. henryi,which has a smaller geographic range. The inclusion in the study ofC. torelliana (F.Muell.) K.D.Hill & L.A.S.Johnson asan outgroup accentuated the small genetic differences between species in thegroup. The patterns of genetic diversity are discussed in relation to thespecies’ taxonomic relationships, breeding systems and utilisation.
A phylogeny inferred from large-subunit (26S) ribosomal DNA sequences suggests that Burmanniales are polyphyletic
Authors: Neyland Ray
Published: September 2002

According to several authors, the Burmanniales are an order that includes the
families Burmanniaceae, Thismiaceae and Corsiaceae. At present, there is no
consensus concerning the circumscription of Burmanniales. All members of
Thismiaceae and Corsiaceae are mycoheterotrophic; Burmanniaceae are composed
of both mycoheterotrophic and autotrophic species. Other than
mycoheterotrophy, there are few characters that unite members of the order.
Because mycoheterotrophy has resulted in extreme vegetative reduction that may
have contributed to homoplasy in the form of character convergence, the
systematics of Burmanniales is problematic. A phylogeny inferred from
large-subunit (26S) ribosome-DNA sequences suggests that the order
Burmanniales is polyphyletic. Specifically, the Burmanniaceae appears as
strongly supported monophyletic group with Thismia as
sister. Corsia is distinct and may be associated with
the Liliales.
The genus Taxithelium (Bryopsida, Sematophyllaceae) in Australia
Authors: Ramsay H. P. , Schofield W. B. , Tan B. C.
Published: September 2002

In our review of the genus Taxithelium in Australia, the following six species are recognised: Taxithelium. instratum (Brid.) Broth., T. kerianum (Broth.) Broth., T. merrillii Broth., T. muscicolum (Broth.) B.C.Tan, H.P.Ramsay & W.B.Schofield, T. nepalense (Schw�gr.) Broth. and T. planum (Brid.) Mitt. Some names listed under Taxithelium in Streimann & Curnow (1989) have been reduced to synonyms or transferred to other genera, e.g. T. novae-valesiae (Broth) Broth., T. papillatum (Harv.) Broth., T. trachychaetum (F.Muell.) Paris and T.�wattsii Broth. The Australian records of T. petrophilum Williams are identified as T. instratum (Brid.) Broth., while those of Taxithelium selenithecium (M�ll. Hal.) Paris in Bartram (1952) fit into Taxithelium planum.
Seed and seedling morphology, and seed anatomy of Lasiopetaleae (Malvaceae s.l. or Sterculiaceae)
Authors: Wilkins C. F. , Chappill J. A.
Published: September 2002

Seed and seedling morphology and seed anatomy of Lasiopetaleae sensu Whitlock et al. (Malvaceae s.l.) and related genera are described. All seed of Lasiopetaleae, except Maxwellia, have arils that develop adjacent to the funicle. Some species have flexible, stellate hairs on their seeds. Seed size, shape, aril form, presence of hair and exotesta pattern can be definitive at generic and/or specific levels.
Morphometric analysis of variation in Geleznowia verrucosa Turcz. (Rutaceae)
Authors: Broadhurst Linda
Published: September 2002

Geleznowia Turcz. (Rutaceae) is a monotypic but
morphologically variable genus endemic to Western Australia. Small and large
forms can be recognised in the field by flower size and abundance, and leaf
size. Between these two forms are a series of populations exhibiting
intermediate and/or mixed characters. Uni- and multivariate analyses were
undertaken of 17 adult leaf and floral characters from 17 populations (20
sites) representing the two forms and the intermediate populations from across
the species’ range. Univariate analyses between populations showed the
small form exhibited significantly shorter leaves, bracts and sepals than the
intermediate populations and the large form as well as more rounded leaves.
Discriminant analysis of the 371 individuals correctly classified
90.84% of the plants, with leaf and bract characters and ratios between
floral characters contributing most to separation of the small form from all
other plants. Non-metric multidimensional scaling and cluster analyses also
clearly separated the small form from the other forms. Consistent placement of
the small form at Pleshkes with the intermediate populations and large form
further supports allozyme evidence that gene flow and introgression is/has
occurred within this population. The possibility of hybridisation within the
genus does present some difficulties for systematic clarification.
Molecular systematics of Australian Podolepis (Asteraceae: Gnaphalieae): evidence from DNA sequences of the nuclear ITS region and the chloroplast matK gene
Authors: Konishi N. , Watanabe K. , Kosuge K.
Published: September 2002

The generic circumscription and intra-generic relationships of the genus
Podolepis Labill., with various chromosome numbers from
n = 12 to n = 3,
were examined by sequences of the internal transcribed spacers (ITS) of
nuclear ribosomal DNA and the matK gene of chloroplast
DNA. The topology of the ITS tree for 17 species and the matK tree for 18
species of the genus Podolepis sensu Davis (1957) and
Anderberg (1991) and 15 taxa from eight related genera (Anderberg 1989, 1991,
1994) are basically concordant. Except for P. georgei
Diels andP. kendallii F.Muell., parsimony analyses
support the monophyly of the genus Podolepis sensu Davis
(1957) and Anderberg (1991). The genera of Asteridea Lindl. and
Pterochaeta Steetz are sisters
toPodolepis in the combined tree based on the ITS and
matK sequences. Within the monophyletic clade of the
genus Podolepis, three lineages are identified. The
chromosome base number of x = 12 may be ancestral
in the genus Podolepis. The dysploidal reduction in
chromosome number from n = 12 to
n = 10 and 9, from n
= 12 to n = 8 and 7, and from
n = 12 to n = 11 and
3 in three lineages, respectively, is the primary mode of chromosomal
evolution in this genus. Total karyotypic length (= genome size) is
much greater in perennials than in annuals within the genus
Podolepis. The number of pappus bristles on outer female
florets tends to decrease and they are absent in some annuals of this genus,
while myxogenic cells on the pericarp become prominent.
Nitrogen leaching from soil lysimeters irrigated with dairy shed effluent and having managed drainage
Authors: Singleton P. L. , McLay C. D. A , Barkle G. F.
Published: September 2002

The leaching of nitrogen (N) from agricultural soils is undesirable for
environmental and health reasons. We investigated the effects of adding dairy
shed effluent (DSE), irrigated on a weekly basis during the milking season, on
the amounts and forms of N leached from large undisturbed soil monolith
lysimeters of a Gley Soil over a period of 2 years. Drainage was managed using
a weir that maintained the water table at 3 depths: 25 (high), 50 (medium), or
75 (low) cm below the soil surface. The low water table treatment represented
the usual situation for the soil when drained. If undrained, it would be usual
during wet periods in the field for a perched water table to form on the
slowly permeable horizon at 75 cm depth.
The total amount of N irrigated onto the lysimeters in the first milking
season was equivalent to a total of 511 kg N/ha.year, and up to 33.3 kg
N/ha.year leached from the soil. The losses from lysimeters receiving
effluent were nearly double those from lysimeters receiving an equivalent
amount of water only, when the high and medium water tables were imposed.
Adding effluent caused only a small increase (7 kg N/ha) in total N
leached in the low drainage treatment. In the second milking season, the
effluent-N loading was increased to 1518 kg N/ha.year and the pasture was
managed to simulate a ‘cut and carry’ land treatment system. Under
these conditions, up to 131.4 kg N/ha.year leached from the soil, which
was nearly 100 kg N/ha more than lysimeters receiving only water. The
total N leaching losses represented a similar proportion of added N (7%
and 9%) for years 1 and 2, respectively. Most of the leached N
(80—90%) was in organic N form.
The managed drainage treatment in which the water table was nearest the soil
surface resulted in less N being leached in the nitrate-N (NO
3 -N) form (<2.5 kg N/ha.year) than the other
drainage treatments (6—12 kg N/ha.year); however, it did result
in the greatest amount of organic and total N leached (33 and 131 kg N/ha
for Year 1 and 2, respectively). The smaller amount of NO
3 -N leached from the high water table treatment is
attributed to enhanced denitrification, and the greater amount of organic N is
attributed to preferential flow. Although NO 3 -N
concentrations in leachate generally remained below World Health Organisation
(WHO) standards in all treatments, the large amount of N leached in organic
form would suggest that inorganic N should not be the only form of N
considered when measuring N leaching losses.
Factors controlling N mineralization, nitrification, and nitrogen losses in an Oxisol amended with sewage sludge
Authors: Sierra J. , Fontaine S. , Desfontaines L.
Published: September 2002

Laboratory incubations and a field experiment were carried out to determine
the factors controlling N mineralization and nitrification, and to estimate
the N losses (leaching and volatilization) in a sewage-sludge-amended Oxisol.
Aerobically digested sludge was applied at a rate equivalent to 625 kg
N/ha. The incubations were conducted as a factorial experiment of
temperature (20˚C, 30˚C, and 40˚C) soil water (–30 kPa
and –1500 kPa) sludge type [fresh (FS) water content 6230 g/kg;
dry (DS) water content 50 g/kg]. The amount of nitrifiers was
determined at the beginning and at the end of the experiment. The incubation
lasted 24 weeks. The field study was conducted using bare microplots (4 m) and
consisted of a factorial experiment of sludge type (FS and DS) sludge
placement (subsurface, I+; surface, I–). Ammonia volatilization and
the profile (0–0.90 m) of mineral N concentration were measured during 6
and 29 weeks after sludge application, respectively.
After 24 weeks of incubation at 40˚C and –30 kPa, net N
mineralization represented 52% (FS) and 71% (DS) of the applied
N. The difference between sludges was due to an initial period of N
immobilization in FS. Nitrification was more sensitive than N mineralization
to changes in water potential and it was fully inhibited at –1500 kPa.
The introduction of a large amount of nitrifiers with FS did not modify the
rate of nitrification, which was principally limited by soil acidity (pH 4.9).
Although N mineralization was greatest at 30˚C, nitrification increased
continuously with temperature. Nitrogen mineralization from DS was well
described by the double-exponential equation. For FS, the equation was
modified to take into account an immobilization-remineralization period.
Sludge placement significantly affected the soil
NO-3/NH+4 ratio in the
field: 16 for I+ and 1.5 for I–, after 11 weeks. In the I–
treatment, nitrification of the released NH+4 was
limited by soil moisture because of the dry soil mulch formed a few hours
after rain. At the end of the field experiment, the estimated losses of N by
leaching were 432 kg N/ha for I+ and 356 kg N/ha for I–.
Volatilization was not detectable in the I+ microplots and it represented
only 0.5% of the applied N in the I– microplots. The results
showed that placement of sludge may be a valuable tool to decrease
NO-3 leaching by placing the sludge under unfavourable
conditions for nitrification.
Management practices for control of runoff losses from cotton furrows under storm rainfall. II. Transport of pesticides in runoff
Authors: Silburn D. M. , Simpson B. W. , Hargreaves P. A.
Published: September 2002

Pesticide transport in runoff was measured using a rainfall simulator on
cotton hill–furrow systems with a range of on-ground cover
(0–60%), each with and without prior wheel traffic. The scenario
was a 65-mm storm, 3 weeks after planting cotton with associated herbicide
applications and 2 endosulfan applications after planting. Concentrations of
α, β, and total endosulfan in runoff decreased significantly with
increasing cover, irrespective of cover type (wheat stubble or cotton trash)
or placement (in furrow or overall). Concentrations of endosulfan sulfate,
trifluralin, and DDE decreased with cover, but were affected by cover
placement. With 45–60% cover, concentrations were reduced 5-fold
for α, β, and total endosulfan; halved for endosulfan sulfate,
trifluralin, and DDE; and unchanged for prometryn. Cover had more effect on
endosulfan because cover intercepted and dissipated the sprayed endosulfan,
reducing concentrations in surface soil and therefore in runoff. This is a
mechanism for reducing pesticide runoff additional to effects of cover on
runoff and sediment. Cover placement affected pesticide concentrations because
cover in the furrows was more effective in trapping larger sediment than
evenly spread cover. Pesticide concentrations (mg/kg) were apparently
greater in larger, aggregated sediment than in fines, probably because of more
organic matter in larger sediment.
Cover had more effect on total pesticide losses (g/ha) than on
concentrations, because cover reduced runoff and soil loss considerably. With
45–60% cover, total losses of α, β, and total
endosulfan were 1.4% of losses from bare plots, endosulfan sulfate and
DDE 3%, trifluralin 5%, and prometryn 8%. Avoiding wheel
traffic gave 20–30% lower concentrations and 40% lower
losses, due to lower transport in the water phase and enhanced the effect of
cover, but did not prevent large pesticide losses from bare plots. Prometryn
was transported mostly in the water phase while other pesticides were
transported mostly with sediment. Cover provided more control of more
soil-sorbed pesticides (endosulfan, trifluralin, and DDE) due to a large
reduction in soil loss with cover. Control of the less sorbed prometryn was
largely due to cover reducing runoff.
agricultural chemicals, endosulfan, prometryn, trifluralin, DDE, cover,
controlled traffic, water quality.
Immobilisation and mineralisation of carbon and nitrogen from dairy farm effluent during laboratory soil incubations
Authors: Barkle G. F. , Stenger R. , Sparling G. P. , Painter D. J.
Published: September 2002

To investigate the microbial turnover of dairy farm effluent (DFE) irrigated
onto soils we applied two loading rates (standard DFE, high DFE) onto a silt
clay loam. Additionally, we investigated the microbial availability of the
soluble DFE fraction compared with that of a glucose plus ammonium solution.
The soil was incubated at 25˚C for up to 244 days. A water-amended
treatment was used as the control. Net carbon mineralisation in the standard
DFE treatment was finished within 13 days and amounted to 29.7 2.4% of
the carbon applied, whereas in the high DFE treatment it continued until the
end of the measurements (Day 50) and reached 48.4 0.5%. DFE application
at the standard rate had only a minor effect on soil microbial biomass, but
the high DFE application supported a higher microbial biomass over a longer
period. Nitrogen immobilisation persisted in the standard DFE treatment
throughout the experiment, while the high DFE treatment shifted to the net
mineralisation phase by Day 113. Approximately 60% of the amended C was
mineralised within 13 days in both the soluble DFE and glucose treatments,
indicating similar microbial availability. Microbial growth, however, occurred
only in the glucose treatment.
An overview of land application of pig effluent-P using soil P chemistry and mass balance calculations
Authors: Redding Matt R. , Biggs Andrew , Gardner Ted , Duperouzel David
Published: September 2002

Attention is directed at land application of piggery effluent (containing
urine, faeces, water, and wasted feed) as a potential source of water resource
contamination with phosphorus (P). This paper summarises P-related properties
of soil from the 0–0.05 m depth at 11 piggery effluent application
sites, in order to explore the impact that effluent application has had on the
potential for runoff transport of P.
The sites investigated were situated on Alfisol, Mollisol, Vertisol, and
Spodosol soils in areas that received effluent for 1.5–30 years
(estimated effluent-P applications of 100–310 000 kg P/ha in total).
Total (PT), bicarbonate extractable
(PB), and soluble P forms were determined for the soil
(0–0.05 m) at paired effluent and no-effluent sites, as well as texture,
oxalate-extractable Fe and Al, organic carbon, and pH.
All forms of soil P at 0–0.05 m depth increased with effluent
application (PB at effluent sites was 1.7–15 times
that at no-effluent sites) at 10 of the 11 sites. Increases in
PB were strongly related to net P applications
(regression analysis of log values for 7 sites with complete data sets:
82.6% of variance accounted for, P < 0.01).
Effluent irrigation tended to increase the proportion of soil
PT in dilute CaCl2-extractable
forms (PTC: effluent average 2.0%, no-effluent
average 0.6%). The proportion of PTC in
nonmolybdate reactive forms (centrifuged supernatant) decreased (no-effluent
average 46.4%, effluent average 13.7%). Anaerobic lagoon
effluent did not reliably acidify soil, since no consistent relationship was
observed for pH with effluent application. Soil organic carbon was increased
in most of the effluent areas relative to the no-effluent areas. The 4
effluent areas where organic carbon was reduced had undergone intensive
cultivation and cropping.
Current effluent management at many of the piggeries failed to maximise the
potential for waste P recapture. Ten of the case study effluent application
areas have received effluent-P in excess of crop uptake. While this may not
represent a significant risk of leaching where sorption retains P, it has
increased the risk of transport of P by runoff. Where such sites are close to
surface water, runoff P loads should be managed.
runoff, phosphorus, swine, hog.
Field and laboratory calibration and test of TDR and capacitance techniques for indirect measurement of soil water content
Authors: Lane P. N. J. , Mackenzie D. H.
Published: September 2002

Time domain reflectometry (TDR) and a frequency domain sensor, the Didcot
Capacitance Probe, were tested in the field and laboratory. The results from
an undisturbed large core TDR laboratory test found the Topp equation returned
a close correspondence to thermogravimetrically derived water content,
although there was a slight underestimation. Coefficients of determination and
efficiency were >0.98 and 0.92, respectively, for individual cores, and
0.98 and 0.97 for the whole data set. The field exercise revealed the Topp
equation to be superior to the laboratory derived equation and other published
empirical equations, suggesting the Topp equation to be adequate. A field test
of the capacitance probe found poor correspondence between measured and
predicted observations of profile point soil water content. Although
81% of the variance was explained by the calibration regression, there
was a poor fit to the 1:1 line (E = 0.34), and a
non-significant relationship between measured and predicted soil water content
for the A horizon. The instrument design proved problematic for use as a
determiner of point profile soil water content, and the recommended
calibration procedure was impossible in the study site soils.
Comparison of structural stability, carbon fractions and chemistry of krasnozem soils from adjacent forest and pasture areas in south-western Victoria
Authors: Carter M. R. , Skjemstad J. O. , MacEwan R. J.
Published: September 2002

Basalt-derived krasnozems are generally well-structured soils; however, there
is a concern that intensive agricultural practices may result in an adverse
decline in soil organic carbon, organic matter chemistry, and structural
quality over time. A study was conducted on loam to silty clay loam krasnozems
(Ferrosols) near Ballarat in south-western Victoria to assess changes in soil
C, soil structural stability, and C chemistry, at the 0–10 cm soil
depth, under 3 paired sites consisting of adjacent long-term forest (Monterey
pine or eucalyptus) v. 30 year cropping [3 year
pasture–2 year crops (potato and a root crop or grain)]. Soil
structural stability was also characterised in the A and B horizons under
long-term eucalyptus and several cropped sites. Organic C levels in the A
horizons for all the soils were relatively high, ranging from 46 to 89
g/kg. A lower organic C (30%), associated mainly with loss of the
sand-sized (>53 m) macro-C fraction, and a decrease in exchangeable Ca and
Mg was found in the agricultural soils, compared with forest soils. Physically
protected C in the <53 m fraction, as indicated by UV photo-oxidation, was
similar among soils. Wet sieving indicated a decline of both C and N
concentration in water-stable aggregates and the degree of macro-aggregation
under agricultural soils, compared with the forest soils. However, soil
structural changes under cropping were mainly related to a decline in the
>5 mm sized aggregates, with no deleterious increase in the proportion of
0.10 mm aggregates. Solid state 13C NMR spectroscopy
indicated a decrease in O-alkyl and alkyl C under pasture and cropping
compared with forest soils, which was in agreement with the decline in the
macro-C fraction. Characterisation of C chemistry following UV photo-oxidation
showed that charcoal C (dominant presence of aryl C) accounted for 30%
of the total soil organic C, while other functional groups (polysaccharides
and alkyl C) were probably protected within micro-aggregates. Based on soil
organic C and aggregate stability determinations alone, the implications for
soil physical quality, soil loss, and diffuse pollution appear minimal.
macroorganic carbon, soil aggregation, charcoal, photo-oxidation, potato
rotation, CP/MAS 13C NMR spectroscopy.
Measuring peat moisture content using the dual-probe heat pulse technique
Authors: Campbell David I. , Laybourne Claire E. , Blair Ian J.
Published: September 2002

The dual-probe heat pulse (DPHP) technique for measuring soil volumetric
moisture content (Θv) is evaluated for use in peat
soils with very high organic matter contents. The method has a greater
sensitivity in peat soils compared with mineral soils and excellent resolution
is possible, even at moisture contents as high as 90% by volume.
Advantages of the DPHP technique are that sensors are simple to construct from
inexpensive parts and calibration is not required since the method is based on
a physical model of radial heat flow in soil. A multiplexer method was
developed to allow multiple probes to be deployed in the field. DPHP
measurements of Θv for small peat samples compared
closely to reference measurements made using the gravimetric method, and in
the field were similar to results obtained using a time domain reflectometry
(TDR) method. Peat soils display a high level of spatial variation in
Θv at the scales of both DPHP and TDR probes, so
that multiple probes of each type are required for adequate spatial sampling
of Θv. Rapid changes in peat moisture content were
recorded following rainfall infiltration events yet moisture storage did not
remain elevated following rainfall, even for peat that was very dry.
wetlands, hydrology, soil moisture.
Simulating infiltration and the water balance in cropping systems with APSIM-SWIM
Authors: Connolly R. D. , Bell M. , Huth N. , Freebairn D. M. , Thomas G.
Published: September 2002

We test APSIM-SWIM's ability to simulate infiltration and interactions
between the soil water balance and grain crop growth using soil hydraulic
properties derived from independent, point measurements. APSIMSWIM is a
continuous soil-crop model that simulates infiltration, surface crusting, and
soil condition in more detail than most other soil-crop models. Runoff, soil
water, and crop growth information measured at sites in southern Queensland
was used to test the model. Parameter values were derived directly from soil
hydraulic properties measured using rainfall simulators, disc permeameters and
ponded rings, and pressure plate apparatus. In general, APSIM-SWIM simulated
infiltration, runoff, soil water and the water balance, and yield as
accurately and reliably as other soil crop models, indicating the model is
suitable for evaluating effects of infiltration and soil-water relations on
crop growth. Increased model detail did not hinder application, instead
improving parameter transferability and utility, but improved methods of
characterising crusting, soil hydraulic conductivity, and macroporosity under
field conditions would improve ease of application, prediction accuracy, and
reliability of the model. Model utility and accuracy would benefit from
improved representation of temporal variation in soil condition, including
effects of tillage and consolidation on soil condition and bypass flow in
cracks.
infiltration, crop models, APSIM, water balance, soil structure.
Chromium(VI) leaching from large undisturbed soil lysimeters following application of a simulated copper-chromium-arsenic (CCA) timber preservative
Authors: Carey P. L. , Bidwell V. J. , McLaren R. G.
Published: September 2002

Copper, chromium, and arsenic (CCA) solutions are commonly used in New Zealand
as a means of preserving softwood timbers such as
Pinus radiata. With stock working solutions of CCA salts
in timber treatment plants frequently 10% w/v or more, there exists
a potential for spillage and leaching of these compounds to groundwater.
High concentrations of Cr(VI) (up to 52 mg Cr/L) were found in the
leachates of large undisturbed soil lysimeters where a Templeton sandy loam
(Immature Pallic) had received surface applications of a simulated copper,
chromium, and arsenic (CCA) timber preservative. Leaching was produced by
using a combination of natural and imposed rainfall simulation over the
lysimeters for a period of 102 days after CCA application.
An average of 26% of the applied chromium was collected in the
leachates after 102 days. Of the mean 74% of Cr(VI) still retained
within the soil profile after leaching ended, almost half was located in the
top 100 mm of the profile. No copper or arsenic was detected in any of the
lysimeter leachates, with soil analysis indicating that these elements had
been retained within the soil profile.
In an incubation study, soil cores sampled from the same Templeton sandy loam
and split into alternate 50-mm segments (to 450 mm) were stored at 10˚C
for 102 days after addition of an identical CCA solution. These were
periodically extracted for available chromium. Results showed that the
reduction of dichromate/chromate anions
(Cr2O72–/CrO42–)
to the strongly sorbed chromic cation (Cr3+) was
largely first-order and greatest in surface layers where soil organic matter
contents were largest. After 102 days, <1% of the added Cr(VI) was
still extractable in the 0–50 mm soil cores whilst ≈60% of
Cr(VI) in the 400–450 mm cores (or deeper) was still extractable after
the same period.
A linear systems model comprising a series of conceptual mixing cells was used
to describe the individual and mean Cr(VI) leaching breakthrough curves
(BTCs). This State-Space Mixing Cell model proved effective in simulating the
Cr(VI) leaching using first-order kinetics to quantify rate-limited local
solute adsorption coupled to advective-dispersive transport. The solute mass
involved in the model process was ≈30%. The bulk of the remaining
70% of applied dichromate was assumed to have undergone reduction to
the non-mobile chromium cation.
This study shows that there exists a significant potential for Cr(VI) to be a
serious threat to groundwater in the event of a large uncontained spillage of
a concentrated CCA solution. This potential can be significantly lessened if
the Cr(VI) is reduced after retention in an organic matter rich layer.
Testing a soil-andscape model for dry greywacke steeplands on three mountain ranges in the South Island, New Zealand
Authors: Lynn I. H. , Lilburne L. R. , McIntosh P. D.
Published: September 2002

We tested the accuracy of a soil–landscape model, previously developed
using a very low sampling density, for predicting soil properties in the dry
greywacke steeplands of the South Island, New Zealand. These deeply dissected
steeplands have relatively uniform geology and slope form, and in the model
development area, elevation and aspect largely controlled the soil pattern.
Predicted and sampled values of selected soil properties were compared at
randomly selected sites on the Benmore Range (the development area), the
adjacent Kirkliston Range, and a similar mountain range on Molesworth Station,
250 km distant. Considering the harsh environmental conditions, parent
material variability, management history, and vegetation change, none of which
were directly included in the model, model performance was adequate,
explaining up to 45% of the variability for 0–7.5 cm pH. The
model did not consistently perform better at any one test location, although
the mean absolute error increased with distance from the model establishment
area for 0–7.5 cm %C, pH, and A-horizon total C and total N.
Predictions were more accurate for properties based on one laboratory
measurement. Where several field measurements were used to derive values (e.g.
nutrient amounts in units of kg/ha), predicted values were less accurate
presumably because they incorporate more measurement error. We conclude that
at a broad management scale, the model adequately predicts the soil properties
on dominant landscape units. The model greatly improved prediction of soil
values in national inventories (e.g. A-horizon C) and also has application in
environmental risk prediction and economic development.
landscape, mountain, soil map, soil carbon.
Phosphorus sorption and nitrogen transformation in two soils treated with piggery wastewater
Authors: Phillips I. R.
Published: September 2002

Land application of piggery wastewater has the potential to contaminate
receiving water bodies due to the presence of elevated concentrations of
nitrogen (N) and phosphorus (P). This paper investigates P sorption and N
transformation using soil from 2 wastewater disposal sites in south-east
Queensland. Soil from Site 1 was classified as a clay (Vertosol) and soil from
Site 2 was classified as a sandy loam (Sodosol). Soil was collected from
wastewater disposal (irrigated) and non-disposal (non-irrigated) areas of each
site. Nutrient sorption kinetics and transformation were studied by reacting
each soil with either wastewater or an inorganic salt solution over a period
of 21 days. Solution P concentrations decreased with time for all soils. These
changes were greatest during the early stage of the study (<10 days), after
which time solution P concentrations remained relatively stable.
Concentrations of solution P tended to remain higher in irrigated than
non-irrigated soils. This was attributed to a loss of high-affinity sorption
sites due to past wastewater additions. Cation exchange (for times <3 days)
and nitrification (for times >3 days) were found to be the primary
mechanisms responsible for decreases in solution ammonium
(NH4-N) over the 21-day period. Phosphorus and
NH4-N sorption isotherms were determined using a
leaching procedure, and the data were adequately described
(r2 >0.95) by the Freundlich
equation. Irrigated samples generally sorbed less P than non-irrigated soils.
This was attributed to the loss of high-affinity P sorption sites due to
previous wastewater additions. Cation exchange and competition between added
and resident cations for the exchange sites was found to govern
NH4-N sorption by these soils. Results from this study
suggest that long-term land application of piggery wastewater may encourage
leaching of N and P from the plant root-zone in soils with limited capacity to
retain these nutrients. Appropriate management strategies to minimise these
losses need to be developed to avoid degradation of the receiving soil
and/or water environments.
sorption kinetics, nitrification, ammonium, nitrate.
Sediment yields and turbidity records from small upland subcatchments in the Warragamba Dam Catchment, southern New South Wales
Authors: Armstrong J. L. , Mackenzie D. H.
Published: September 2002

Accelerated rates of soil erosion, following European settlement in Australia, pose a major threat to river ecosystems and water supply storages with agricultural catchments, such as Warragamba Dam (the main water supply dam for Sydney).

Sediment yields from 1988 to 1999 have been determined by stream monitoring for 6 small grazing catchments located near Goulburn in southern New South Wales, in the outer Warragamba catchment. Average specific sediment yields were 0.07 t/ha.year from 3 small catchments of around 10 ha, where the drainage lines were not continuously gullied, and the drainage lines were undisturbed. Sediment yields from larger gullied catchments of 29, 52, and 510 ha were at least an order of magnitude higher than from the ungullied catchments at around 1 t/ha.year. Gullies continue to be the dominant source of sediment from these subcatchments despite indications that yields from gullies in the Southern Tablelands are much less than in the first few decades following settlement and are gradually declining as gullies move towards a stable vegetated state. Measured sediment yields from this study are comparable with yields for southern New South Wales determined using other methods, such as radionuclide and farm dam survey techniques. The impact of soil conservation works, such as sediment trapping and grade stabilisation works, on sediment yields can be mixed depending on the activity of the gully being treated and the mobility of the bed sediments.

Turbidity levels from runoff events from the gullied catchments were an order of magnitude higher than from the ungullied catchments. For the Warragamba catchment turbidity levels are scale dependent; at the farm paddock scale turbidities are generally low where the land use is grazing, they increase dramatically at the subcatchment scale where active gullies dominate the drainage network, and then drop back again at the large river catchment scale. Turbidity is positively correlated with sediment concentration, so works that reduce sediment loads will also reduce the turbidity of water leaving the subcatchment. However, the link between high turbidity levels in small upland catchments and downstream water quality in large complex river basins is tenuous.