bluuebunny/crossref_metadata_2025 huggingface dataset:
Eucryphia (Cunoniaceae) reproductive and leaf macrofossils from Australian cainozoic sediments
Authors: Barnes Richard W. , Jordan Gregory J.
Published: September 2002

The first fossil capsule of Eucryphia,E. reticulata R.W.Barnes & G.J.Jord. sp. nov.,is described from Lea River (Early Oligocene), and, like capsules of the twoextant South American species of E. glutinosa (Poepp. etEndl.) Baill. and E. cordifolia Cav., is large and has arelatively large number of valves. The capsule occurs with aEucryphia leaf macrofossil that was probably a leaflet from a compound leaf as it is highly falcate. The leaflet may be derived fromthe same parent plant as E. reticulata but in theabsence of an organic connection it is described as a new species,E. leaensis R.W.Barnes & G.J.Jord. sp. nov.Additional leaf macrofossil specimens of E. aberensisR.S.Hill from the type locality (Loch Aber; Middle–Late Eocene) and anew locality record for the species, Little Rapid River (Early Oligocene),indicate that the species had compound leaves formed by serrate and entiremargin leaflets. Another incomplete Eucryphia capsuleoccurs at Little Rapid River (Early Oligocene) but it is too poorly preservedto assign it to an extant or extinct species. It may be derived from the sameparent plant asE. aberensis, with which it occurs, but cannot be confirmed as there is no organic connection. A new leaf macrofossil with serrate margins, E. mucronata R.W.Barnes & G.J.Jord. sp. nov., is also described from ?Latest Eocene–EarlyOligocene sediments at Wilson’s Creek, central Tasmania. Leafmacrofossils previously assigned to E. aff.milliganii from Early Pleistocene sediments at RegattaPoint in western Tasmania are shown to be conspecific with the two extant Tasmanian species, E. lucida (Labill.) Baill. andE. milliganii Hook.f. ssp.milliganii on the basis of foliar hair distribution patterns and density. The oldest fossil Eucryphiaspecies, E. falcata R.S. Hill (Lake Bungarby; LatePaleocene), had compound leaves formed by leaflets with serrate margins, whichis possibly the plesiomorphic condition for all Cunoniaceae genera. WithinEucryphia, there has been an evolutionary trend towardssimple leaves with entire margins and well-developed peltiform cuticular extensions.
Systematics of the Xanthosia pilosa complex (Apiaceae: Hydrocotyloideae)
Authors: Hart J. M. , Henwood M. J.
Published: September 2002

Xanthosia pilosa Rudge is a common shrub found ineastern Australia. The species complex displays a wide range of variation inleaf and inflorescence morphology which has resulted in the application ofnumerous species names and its informal division into numerous variants in New South Wales. As part of a revision of the genus, the history of the speciescomplex is reviewed and the morphology of the numerous variants, examined bothin the field and herbarium, is discussed.Xanthosia pilosa sens. lat. is here divided into fourspecies: two new species (X. scopulicola J.M.Hart & Henwood and X. stellataJ.M.Hart & Henwood) are described and illustrated, a substitute name(X. ternifolia J.M.Hart & Henwood) is providedfor the illegitimate X. tasmanica Gand., andX. pilosa s.s., which remains a polymorphic species inwhich further segregation of variants is not recommended. A key toXanthosia species in eastern Australia is provided.
Ancestral area analysis of Nothofagus (Nothofagaceae) and its congruence with the fossil record
Authors: Swenson Ulf , Hill Robert S. , McLoughlin Stephen
Published: September 2002

The evolutionary centre of origin of Nothofagus
(Nothofagaceae) remains an open question. Competing hypotheses suggest either
a South American or Australasian source area for
Nothofagus. Antarctica, once part of Gondwana and
densely vegetated in the Cretaceous, was certainly important for the
diversification of the genus but cannot be included in current modelling due
to its lack of extant species. By using Bremer’s (1992),
Ronquist’s (1994) and Hausdorf’s (1998) methods, all based on
cladistic philosophy, analyses of the modern areas of endemism being part of
the ancestral area of Nothofagus were undertaken.
Southern South America was distinctly identified as the likely ancestral area
by Bremer’s and Hausdorf’s methods. This result is supported by
the current fossil record. Ronquist’s method was not decisive and
yielded ambiguous results, suggesting a larger, combined ancestral area. These
results do not favour Australasia, or parts thereof, being an important area
for Nothofagus origin. Bremer’s and
Hausdorf’s methods identified New Zealand as the second most plausible
source area, a result partly supported by the fossil record.
Shallow groundwater dynamics in smectite dominated clay on the Liverpool Plains of New South Wales
Authors: Timms W. , Acworth R. I. , Berhane D.
Published: September 2002

Dynamic shallow (<5 m) groundwater levels are an important indicator of
water and salt fluxes in smectite-dominated clay on the Liverpool Plains in
north-eastern New South Wales. Previous hydrogeological assessments of shallow
groundwater related salinity risk have focused on regional scale distribution
and interaction with rising pressure levels in confined aquifer systems. In
this study, groundwater levels over a 7-year period for the saline Yarramanbah
subcatchment are presented, along with data from 60 new and existing shallow
piezometers and precise elevation surveying and intensive automated monitoring
at selected sites.
The shallow groundwater system is shown to respond to recharge; however, over
the medium-term it is in hydrologic balance, with no evidence of increased
water storage. A proportion of recharge is lost by discharge into deeply
incised surface channels. Groundwater salinity in the banks of Warrah Creek
indicate that flushing of salts from clay is related to increased flux of
fresh water.
Concern exists that there may be increased salt export from the catchment. If
this is in fact occurring while the plains are in hydrologic equilibrium, then
increased salt fluxes must be related to factors other than rising groundwater
levels.
Phosphorus sorption and desorption in oxide-rich Ferralsols of New Caledonia
Authors: Dubus I. G. , Becquer T.
Published: September 2002

Phosphorus (P) availability in soils is one of the main limiting factors for
crop production in Ferralsols that contain high amounts of aluminium and iron
oxides. Highly weathered Geric Ferralsols cover large surface areas of south
Pacific islands, some of which are required for agricultural development.
Sorption and desorption of P in Geric Ferralsols of the island of Maré
(New Caledonia) were investigated. The soils contain large quantities of
oxides, especially of aluminium. The clay fraction consisted exclusively of
fine, discrete oxide particles. Both Freundlich and Langmuir equations
provided a good fit to the data for equilibrium P concentrations ranging from
0.05 to 850 mg P/L. The extremely high P sorption capacities of New
Caledonian Geric Ferralsols were exemplified by the large Langmuir sorption
maxima which ranged from 6400 to 9250 mg P/kg. A strong negative
correlation between P sorption and organic matter was noted, resulting in a
larger P availability in topsoils. This relationship can be used to provide a
first assessment of P sorption capacities of Geric Ferralsols across the
island. Management of organic matter is likely to be of major importance in
the control of P availability in Geric Ferralsols of south Pacific islands.
Mineralisation of nitrogen contained in mature subterranean clover, capeweed and annual ryegrass, and subsequent nitrogen use by wheat in dryland farming systems in southern Australia
Authors: Thompson R. B. , Fillery I. R. P.
Published: September 2002

Net nitrogen (N) mineralisation in soil and N uptake by wheat from mature
shoots and roots of subterranean clover, capeweed, and annual ryegrass, and
from clover burrs were assessed with 15N-labelled plant
material in 2 field studies, using confined micro-plots. In the first study,
shoot residues of the 3 species (150 g DM/m2) were
placed on the soil surface, and roots of the 3 species (75 g
DM/m2) were mixed into 0–10 cm soil. The
treatments were applied in March 1991. The shoot residues were incorporated
into soil in early June 1991. Net 15N mineralisation
from the clover, capeweed, and ryegrass shoots during the 8-month experimental
period was estimated to be, respectively, 15%, 12%, and
12%, and for the corresponding roots was 10%, 7%, and
6%. Negligible net mineralisation of 15N occurred
during the 2.5 months that the shoot residues were on the soil surface. Crop
15N recoveries in wheat, at maturity, in November 1991
were 9%, 7%, and 7%, respectively, of that applied in the
clover, capeweed, and ryegrass shoot residues. The respective crop recoveries
from the root residues were 6%, 5%, and 3%. Less than
5% of N taken up by wheat was obtained from shoot or root residues. In
a second similar study, 15N-labelled subterranean clover
shoots (200 g DM/m2) and burrs (75 g
DM/m2) were applied in December 1992; 3% of
15N in the clover shoots was net mineralised during the
5 months they were on the soil surface. Crop recoveries of
15N in October 1993, at the time of wheat anthesis, from
the clover shoots and burrs were, respectively, 14% and 17% of
applied 15N. The results of these field studies suggest
that mature shoot residues and the associated intact roots (recoverable by
wet-sieving), and clover burrs, make only a small direct contribution to the N
response of cereals immediately following ley pasture in southern Australia.
They also indicate that, under Mediterranean climatic conditions, generally
very little net N mineralisation occurs from mature shoot residues until the
shoots are incorporated into soil.
pasture, shoots, roots, 15N, rotation, cereals, burr.
The significance of the threshold and turbidity concentrations in relation to sodicity and microstructure
Authors: Quirk J. P.
Published: September 2002

Quirk and Schofield (1955) in their paper on the effect of electrolyte
concentration on soil permeability in relation to sodicity designated 2
concentrations: the threshold concentration, which
related to the first discernible effect on soil structure; and
the turbidity concentration, at which the dismantling of
the soil microstructure is indicated by the appearance of dispersed particles
in the percolate—this occurs when the electrolyte concentration is about
one-quarter of the threshold concentration.
This behaviour is explained in terms of clay domains,
which are assemblages of many clay particles in parallel alignment. Within a
clay domain, slit-shaped pores with surface separations about equal to the
thickness of clay crystals exist. When calcium is the dominant exchangeable
ion the clay domains are stable because where contiguous crystals overlap the
surfaces reside in a potential well as a result of strong attractive forces.
These attractive forces are similar to those responsible for the stability of
Camontmorillonite and Ca-vermiculite crystals.
A model of 3 clay crystals is used to illustrate how crystal interaction
within a clay domain, in terms of classical repulsive diffuse double-layer
forces and modern attractive forces, affect domain stability. Attention is
drawn to a misconception, now prevalent in the literature, which does not
recognise the basic significance of the turbidity concentration with respect
to microstructure and wrongly contends that the concentration of electrolyte
required to effect the dispersion to flocculation transition in soil
suspensions can be used for predicting the level of electrolyte required to
sustain soil permeability or infiltration rate in irrigation practice. It is
shown that the flocculation concentration is almost 8 times the turbidity
concentration.
The application of the threshold concentration concept in irrigation practice
is discussed. It is demonstrated that the threshold and turbidity
concentration comfortably explain the behaviour of a heavy clay soil subjected
to border-check irrigation and Cajon sandy loam in Arizona.
Resolution of the 15N balance enigma?
Authors: Clough T. J. , Sherlock R. R. , Cameron K. C. , Stevens R. J. , Laughlin R. J. , Müller C.
Published: September 2002

The enigma of soil nitrogen balance sheets has been discussed for over 40
years. Many reasons have been considered for the incomplete recovery of
15N applied to soils, including sampling uncertainty,
gaseous N losses from plants, and entrapment of soil gases. The entrapment of
soil gases has been well documented for rice paddy and marshy soils but little
or no work appears to have been done to determine entrapment in drained
pasture soils. In this study 15N-labelled nitrate was
applied to a soil core in a gas-tight glovebox. Water was applied, inducing
drainage, which was immediately collected. Dinitrogen and
N2O were determined in the flux through the soil
surface, and in the gases released into the glovebox as a result of irrigation
or physical destruction of the core. Other components of the N balance were
also measured, including soil inorganic-N and organic-N. Quantitative recovery
of the applied 15N was achieved when the experiment was
terminated 484 h after the 15N-labelled material was
applied. Nearly 23% of the 15N was recovered in
the glovebox atmosphere as N2 and
N2O due to diffusion from the base of the soil core,
convective flow after irrigation, and destructive soil sampling. This
15N would normally be unaccounted for using the sampling
methodology typically employed in 15N recovery
experiments.
Effect of biosolids compost on two NSW coastal soils used to grow vegetables
Authors: Sarooshi R. A. , Cresswell G. C. , Tesoriero L. , Milham P. J. , Barchia I. , Harris A. M.
Published: September 2002

The study compares the effects of biosolids compost (BC) and inorganic fertiliser (IF) on the nutrient status of a clay loam at Rydalmere in Western Sydney, and an earthy sand at Somersby, 85 km north of Sydney. The soils represent the textural range used for vegetable production in the Sydney Basin of New South Wales. The soils had been under permanent sod (Rydalmere) or native vegetation (Somersby) for at 40 years prior to the experiment. There were 3 treatments during February 1994: IF, fallow (F), and BC. The same plots were treated again during September 1994 to give the combinations: IF followed by IF (IF + IF); F by BC (F + BC); BC by BC (BC + BC). The 4 replicates of each treatment were randomised in blocks. Treatments were incorporated into raised beds to a depth of 15 cm and vegetables were planted in March and again in October 1994. The total amounts of C and N initially present in the soil in the beds (0-15 cm) at Rydalmere were at least 3 times greater than at Somersby and the ratio was greater for S, P, Ca, Mg, K, and Na. By April 1995, the quantities of the 8 monitored nutrients had decreased at both sites for the IF + IF treatment; increased at Somersby, but not at Rydalmere for F + BC; and increased at both sites for the BC + BC treatment. The changes caused by the BC + BC treatment were greater in relative terms at Somersby, because of the initial difference in fertility between the 2 soils. For example, the C and N content increased by an approximate factor of 2 at Somersby, and by greater factors for the other elements. BC + BC was also the only treatment to increase other indices of fertility, such as effective cation exchange capacity (ECEC) and Bray-P, in the surface 15 cm. The treatments did not affect pH in the soil profile (0-50 cm) and increases in EC were ephemeral. The nutrient composition of the 20-30 cm zone was affected at both sites. By the end of the experiment the concentration of C, N, P, Ca, and Bray-P increased and Mg decreased. For C and N between-treatment differences were small, indicating that the observed effects were mostly caused by leaching of the products of mineralisation of soil organic matter. Treatment effects were larger for P, Ca, Mg, and Bray-P, and the final concentrations for the F + BC and BC + BC treatments exceeded those for the IF + IF treatment. At Somersby, both BC treatments increased ECEC, consistent with the importance of leaching as a process of nutrient loss at this site. Consequently, intensive vegetable cropping may pose serious environmental risks particularly on sandy sites.
Gaseous nitrogen losses from urea applied to maize on a calcareous fluvo-aquic soil in the North China Plain
Authors: White R. E. , Cai G. , Chen D. , Fan X. H. , Pacholski A. , Zhu Z. L. , Ding H.
Published: September 2002

Gaseous nitrogen losses, by NH3 volatilisation and denitrification, are mainly responsible for the low recovery of N fertiliser applied to irrigated maize on the North China Plain. Two field experiments were conducted to measure NH3 volatilisation and nitrification-denitrification losses from urea applied to maize (Zea mays L.) grown on a calcareous fluvo-aquic soil (Aquic Inceptisol) in Fengqiu County, Henan Province. The first was carried out in June 1998 (urea applied at 75 kg N/ha 3 weeks after sowing), and the second in July 1998 (urea applied at 200 kg N/ha 6 weeks after sowing). Each experiment included 3 treatments-control, surface-broadcast (SB), and deep point placement (DP) or broadcast followed by irrigation (BI). NH3 loss was measured by a micrometeorological method (NH3 sampler). Denitrification (N2 + N2O) was measured by the acetylene inhibition-intact soil core technique, and N2O emission was also measured in the absence of acetylene. The recovery of applied N was measured by a 15N balance technique.
When urea was surface broadcast (SB) 3weeks (75 kg N/ha) and 6weeks (200 kg N/ha) after sowing, 44 and 48% of the applied N was lost by NH3 volatilisation, respectively. The corresponding losses from the BI and DP treatments were only 18% and 11%, respectively. Denitrification was a significant process in this well-drained sandy soil, with average loss rates of 0.26-0.43 kg N/ha.day in the controls (from resident soil N), compared with 0.52-0.63 kg N/ha.day in the surface fertiliser treatments. Deep placement of urea reduced the denitrification rate to an average of 0.3 kg N/ha.day. The net denitrification loss from the fertiliser was <2% of the applied N, except for the SB urea treatment in the second experiment. The application of N fertiliser as urea increased N2O emissions from c. 0.3 to c. 2.3 kg N/ha over 57 days in the second experiment, with average N2O emission rates in the control and SB treatment of 0.006 and 0.042 kg N/ha.day, respectively. The significantly lower ratio of N2 /N2O in the urea treatments compared with the control suggested that nitrification of applied N may have contributed to N2O production. Alternatively, the ratio of N2 /N2O during denitrification may have changed with the greater supply of NO3
-.

denitrification, maize, NH3 volatilisation, N2O emission.
Effects of Bauxsol on the immobilisation of soluble acid and environmentally significant metals in acid sulfate soils
Authors: Lin Chuxia , Clark Malcolm W. , McConchie David M. , Lancaster Graham , Ward Nick
Published: September 2002

The effects of Bauxsol, an abundant industrial by-product, on the immobilisation of soluble acid and a range of potentially environmentally toxic metals in artificial and natural acid sulfate soils were investigated. The acid neutralising capacity of Bauxsol increased with decreasing pH, which is probably provided not only by basic metal hydroxides, carbonates, and hydroxycarbonates but also by protonation of variably charged particles (e.g. gibbsite and hematite) present in Bauxsol. Simulation experiment results show that the removal of 9 tested environmentally significant heavy metals can be enhanced by addition of BauxsolTM; an exception was Co. The removal of the added soluble heavy metals by the BauxsolTM-soil mixtures shows a preferential order of Pb > Fe > Cr > Cu > Zn > Ni > Cd > Co > Mn. For the natural acid sulfate soil without added synthesised metal solution, the retention of the investigated environmentally significant metals is in the following decreasing order : Al > Zn > Fe > Co > Mn.
Organic matter characteristics under native forest, long-term pasture, and recent conversion to Eucalyptus plantations in Western Australia: microbial biomass, soil respiration, and permanganate oxidation
Authors: Mendham D. S. , O'Connell A. M. , Grove T. S.
Published: September 2002

The influence of land-use management on Walkley-Black soil carbon (C) concentration, 3 concentrations of permanganate oxidisable C (33, 167, and 333 mm), microbial biomass, and soil respiration in a laboratory incubation was tested in surface soil from 10 sites in south-western Australia. The sites ranged in total C concentration from 1.9 to 8.3%, and represented a broad climatic and soil-type distribution across south-western Australia. At each of the sites, 0-10 cm soil was collected from plots in pasture (20-71 years old), Eucalyptus globulus plantation (7-10 years old, established on ex-pasture), and native vegetation. Soil profiles and position in the landscape for each of the land-use types were matched as closely as possible at each site to minimise influences other than land use. Total C was highly correlated with clay content. Land use caused no significant change in the relationship between total C and soil texture, and land use had little effect on total C concentration. Permanganate-oxidisable C was highly correlated with Walkley-Black organic C (R2�>�0.90) for all 3 concentrations that were investigated. Only the most dilute concentration of permanganate-oxidisable C (33 mm) was sensitive enough to detect small changes in soil organic matter with land use (P = 0.045). Microbial biomass and respiration at 25 kPa matric potential moisture content and 35°C temperature were used as biological indicators of soil organic matter lability. Cumulative respired C was more sensitive to land use than Walkley-Black organic C, with lower respiration in native soils compared with managed soils with low C concentrations, but higher than the managed soils at sites with high C concentrations. Microbial biomass was not significantly affected by land use. Microbial biomass and cumulative respired C were strongly influenced by soil texture, with the microbial quotient (proportion of microbial biomass in total carbon) and the proportion of total C respired significantly lower in soils with higher silt and clay contents. Land use had no significant effect on these relationships. Overall, land use caused only minor differences in the biological and chemical indicators of organic matter quality across a broad range of sites in south-western Australia.
Nitrate in soil humic acids revealed by 14N nuclear magnetic resonance spectroscopy
Authors: Mao Xi-an , Xu Zhi-hong , Luo Ren-sheng , Mathers Nicole J. , Zhang Yong-hong , Saffigna Paul G.
Published: September 2002

Ecosystem management such as plant residue retention and prescribed burning can significantly affect soil organic matter (SOM) composition and, thereby, the closely associated carbon (C) and nitrogen (N) cycling processes, which underpin terrestrial ecosystem productivity and sustainability. Humic acid (HA) is an important SOM component and its chemical composition has attracted much attention. Here we report the first application of 14N nuclear magnetic resonance (NMR) spectroscopy to soil HA study, revealing the surprising existence of nitrate-N and ammonia-N in the HAs. This newly discovered HA nitrate-N, though in a relatively low concentrations, is closely related to soil N availability and responsive to plant residue management regimes in contrasting forest ecosystems. The HA nitrate-N may be a useful and sensitive biochemical indicator of SOM quality in response to different ecosystem management regimes.
A spatial analysis of lateral and vertical fluxes of water associated with a perched watertable in a duplex soil
Authors: Eastham J. , Gregory P. J. , Williamson D. R.
Published: September 2002

Rates of lateral and vertical movement of water were investigated when severe
waterlogging occurred as a result of a perched watertable over a clay subsoil
in a duplex soil on a low (1.6%) slope in Western Australia. The
severity of waterlogging and both the lateral and vertical fluxes of water at
the 1.4 ha site were very spatially variable. Lateral water movement occurred
in response to topographical gradients in the soil surface and the depth of
the clay layer. As a result of this lateral redistribution of water, the depth
of the watertable was greater in some areas, causing higher rates of vertical
water loss (1.6–1.7 mm/day) compared with the rest of the site
(1.2–1.5 mm/day).
Net gains or losses in water in experimental plots at the site due to lateral
flow were 1–2 orders of magnitude smaller than vertical losses. Net
lateral losses were less than 0.3 mm/day, but vertical losses ranged from
1.2 to 1.7 mm/day. We conclude that vertical drainage beneath crops
growing on a duplex soil with a heavy clay subsoil can be significant when a
head of water develops under climatic conditions conducive to waterlogging. In
contrast, net lateral movement was generally small because of the low slope at
the site (gradient of 0.016), and is likely to be insignificant at this site
and other sites with duplex soils on similarly low slopes.
Soil stripping and replacement for the rehabilitation of bauxite-mined land at Weipa. II. Soil organic matter dynamics in mine soil chronosequences
Authors: Schwenke G. D. , Ayre L. , Mulligan D. R. , Bell L. C.
Published: September 2002

Concern over the long-term sustainability of post-mining ecosystems at Weipa
(North Queensland, Australia) led to investigations of soil organic matter
dynamics, a key process linking soil and vegetation development in
maintenance-free systems. Paper I of this series examined the short-term
effects of rehabilitation operations on soil organic matter. Here, we assess
the medium-term development of post-rehabilitation soil organic matter
quantity and quality using mine soil chronosequences of up to 22 years
post-rehabilitation at Weipa. Soils had been respread either immediately after
stripping or after stripped soil had been stockpiled for several years. Sites
surveyed were revegetated with native tree and shrub species, forestry
(Khaya senegalensis), or pasture
(Brachiaria decumbens/Stylosanthes
spp.). Three areas of undisturbed native forest were included for comparison.
Compared with the undisturbed forest, rehabilitated soils were shallower and
more compacted, contained more gravel, and, as a result of
topsoil–subsoil mixing, stored less organic matter in the surface soil.
Rehabilitated sites respread with stockpiled soil were more compacted and
lower in all quantitative and qualitative measures of organic matter than
freshly replaced soils. With time, organic matter accumulated in the surface
soil under all vegetation types at rates of up to 1.25 t C/ha.year, but
new equilibrium levels were yet to be reached. Accumulated organic matter was
mostly associated with clay and silt-sized particles, indicating effective
cycling of litter to humus. Nitrogen mineralisation capacity increased with
time under all vegetation types. The incidence of fire led to increased total
and light-fraction organic C, but this was probably as charcoal C. Sites where
volunteer grass biomass was reduced pre-planting by late-season stripping or
disc-ploughing accumulated less organic C.
To optimise post-mining soil organic matter development, we recommend that
soil stockpiling be avoided, that more volunteer grasses be retained to ensure
continuity of organic inputs, and that attention be focussed on minimising
soil compaction and gravel incorporation—both permanent limitations to
plant growth.
An assessment of requirements of neutralising materials of partially oxidised pyritic mine waste rock
Authors: Gurung S. R. , Stewart R. B. , Gregg P. E. H. , Bolan N. S.
Published: September 2002

The objective of this study was to assess the ameliorating properties of
selected neutralising materials added to partially oxidised pyritic mine waste
rock from Martha mine pitwall, Waihi, New Zealand.Chemical characterisation
showed that the partially oxidised pyritic pitwall rock material had very low
pH (<2.1), high electrical conductivity and elevated levels of Al,
SO42–, Fe, Mn, and a total
non-oxidised sulfide-S content of 2.6%. Acid-base accounting analysis
of the material indicated that it had nil acid-neutralising capacity and a net
acid-producing potential of 82 kg CaCO3/t.
The standard buffer method indicated that a lime requirement of 29 kg
CaCO3/t was required to neutralise the total acidity
generated from oxidation of liberated pyrite grains. Incubation for 90 days of
the pyritic pitwall rock with varying rates of amendments of neutralising
materials showed that limestone, dolomite, and fluidised bed boiler ash were
all equally effective in raising the pH above 6.0 at a
CaCO3 content equivalent rate
(CER) of 30 kg CaCO3/t. The
reactive phosphate rock, however, did not raise the pH above 6.0 even at the
highest CER of 50 kg CaCO 3 /t. Amendment with neutralising materials also
significantly reduced EC, Al, SO4
2–, Fe, and Mn in the incubated pitwall rock.
Physical examination of the incubated pitwall rock material showed that a
large fraction of the coarse-grained neutralising material remained unreactive
due to oxyhydroxide coatings.
Mid Pleistocene arid shift in southern Australia, dated by magnetostratigraphy
Authors: Pillans Brad , Bourman Robert
Published: September 2002

In coastal sections at Hallett Cove and Sellicks Beach, south of Adelaide, and
at Redbanks section on Kangaroo Island, the Brunhes/Matuyama polarity
transition (780 ka) is identified in the strongly oxide-mottled Ochre Cove
Formation. At all 3 sections, the Ochre Cove Formation is overlain by a
calcareous grey-green aeolian clay, called Ngaltinga Clay, which in turn is
overlain by calcareous sediments of the Taringa and Christies Beach
Formations. The marked change from an oxide-dominated weathering regime to a
carbonate-dominated weathering regime, estimated to have occurred at about
500–600 ka, is interpreted as a major arid shift in regional climates.
Similar arid shifts are known from Lake Bungunnia in the Murray Basin and Lake
Lefroy in southern Western Australia, where changes from lacustrine clays to
evaporites and dune sediments are estimated to have occurred between 400 and
700 ka, and about 500 ka, respectively. An increase in aeolian dust accession
in south-eastern Australia, consistent with increased aridity in the interior
source area, occurred after 780 ka, and was probably coeval with increased
dust input to Tasman Sea sediments since 350 ka.
Between 600 and 900 ka, oxygen isotope fluctuations in deep-sea cores showed a
pronounced change in frequency, from a 40 ka (obliquity dominated) to a 100 ka
(eccentricity dominated) pattern. At the same time, glacial-interglacial
amplitudes increased, with a marked enrichment of glacial
d18O values consistent with larger continental based
ice-sheets. Colder global temperatures, and lower sea levels during glacials,
may have played a part in the mid Pleistocene arid shift recorded in southern
Australia. Associated variations in the strength of the warm Leeuwin Current
may also have affected regional rainfall patterns in southern Australia.
Variability of δ15N in soil and plants at a New Zealand hill country site: correlations with soil chemistry and nutrient inputs
Authors: Hawke D. J.
Published: September 2002

This study investigated 15N enrichment and nutrient
cycling in hill country used for semi-extensive pastoral agriculture, at a
site where pre-European seabird breeding occurred. Soil (0–15 cm)
and plant samples were taken from 18 ridgeline and sideslope transects. Three
stock camps (locations which grazing animals frequent) were identified within
the study area, two on the ridgeline and one on the sideslope. Soil
15N enrichment was greatest at stock camps, and lowest
where stock input was minimal. Soil natural abundance 15N (δ15N) was therefore an index of stock
nutrient inputs. Soil δ15N increased with
decreasing C: N ratio, consistent with N loss through volatilisation
and/or nitrate leaching from net mineralisation. Plant δ15N from stock camps was lower than its associated
soil, implying that 15N enrichment of plant-available N
was lower than that of total soil N. However, the correlation between plant
δ15N and soil δ15N
varied between stock camps, indicating differences in N cycling. Olsen P was
higher at stock camps, although again differences were found between stock
camps. Total P and N were correlated neither with stock camps nor topography,
but were higher than expected from parent material concentrations and
literature results, respectively. It is postulated that significant
contributions of both elements from former seabird breeding remain in the
soil.
The red clay mantle in the Wagga Wagga region, New South Wales: evaluation of an aeolian dust deposit (Yarabee Parna) using methods of soil landscape mapping
Authors: Chen Xiang Yang
Published: September 2002

The aeolian dust deposits (parna) in the Wagga Wagga region have formed the
most common soil material of the region, ‘red clay’, which has a
distribution closely related to landforms. On high plains it occurs across
>90% of the total area, forming a nearly continuous mantle. On rises
and low hills with average slope <10%, the red clay covers most
crests and side-slopes, but does not occur in drainage depressions. On hills
with average slope steeper than 30%, the red clay contains a
significant amount (up to >50%) of gravels and exists only at lower
and foot-slopes. On hills with average slope gradient of 10–30%,
the distribution and gravel contents of the red clay vary between the above
two situations. In floodplains the red clay is absent.
These distribution patterns are consistent with the aeolian origin of the red
clay and may be explained mainly by landform and pedogenic processes occurring
since the aeolian dust deposition, including: (1) erosion and deposition,
which are more dominant in hills and f loodplains; (2) disturbance by soil
creep and bio-turbation; (3) other pedogenic processes which may cause colour
changes, and loss or accumulation of colloids and soluble components; and (4)
development of soil structures. These post-deposition processes explain the
presence or absence of the ‘red clay’ in various landforms and its
variations in field texture from light clay to light-medium clay, colour (hue)
from 2.5YR to 5YR, structure from weak to moderate, pH from 5.0 to 8.0, and
thickness from 30 to >80 cm. Although this relatively uniform ‘red
clay’ forms the subsoil, different soil types occur mainly due to the
more variable topsoils.
The influence of aeolian dust deposits on alpine soils in south-eastern Australia
Authors: Johnston Stuart William
Published: September 2002

Aeolian sediment collected from 2 locations across the ‘Main
Range’ of Kosciuszko National Park, along with a series of soil profiles
that were analysed for particle size, were used as a baseline from which to
estimate the effects of aeolian sedimentation in this region. Laboratory
analysis of the soil profiles indicated that the properties of the surface
horizons of the alpine humus soils were heavily influenced by aeolian dust
accumulation; however, the sub-surface horizons were mainly derived from the
natural bedrock. The surface and subsurface horizons differed in texture bulk
density, pH, electrical conductivity, exchangeable cations, and clay
mineralogy. This study confirmed that the snow patch meadow soils exhibited
particle size and mineralogy consistent with dust enrichment, with distinct
bands being found in some profiles.
Towards a single-point method for measuring phosphate sorption by soils
Authors: Barrow N. J.
Published: September 2002

Data from 4 separate studies using widely differing soils were used to assesswhether single-point estimates of the relative buffering could be used asestimates of buffering derived from fitted curves. The relative bufferingcapacity of soils for P was summarized using the ‘O&Svalue’. This is the increase in P sorption between concentrations of 0.25 and 0.35 mg P/L.Phosphate sorption curves were described by the modified Freundlich equation:S = acb – q, whereS ( g/g) is the measured sorption,c ( g/mL) the solution concentration, anda, b, and qare parameters. The fitted O&S value is given by:a (0.35 b – 0.25b ). If a single pair of values for sorption andconcentration is measured, rather than a sorption curve, thea value can be estimated from (S+ q)/cb . An estimate of the O&S value can beobtained from (S + q) (0.35b – 0.25 b)/c b .Because the b parameter occurs in both the numerator andthe denominator, the single-point estimate of the O&S value was notvery sensitive to the value allocated to b provided thevalue of c was in the range 2–5 mg P/L. Formost of the soils of low to moderate buffering, the P extracted by the Colwellreagent was a useful estimate of q. For these soils, thesingle-point estimates using this value of q weresimilar to the values found from the fitted curves. One group of exceptionswere some soils of low buffering which had received a single application ofphosphate at a high rate. For these soils, the Colwell reagent extracted largeamounts of phosphate. Another group of exceptions were soils of highbuffering. For these the Colwell reagent gave values much lower than thefitted value of q and was of little value in improvingthe calculation of single-point estimates. The single point estimates forthese soils were about 20% too low but nevertheless well correlatedwith the values from the fitted curves.
Effects of fire retardant chemical and fire suppressant foam on shrub steppe vegetation in northern Nevada
Authors: Larson Diane L. , Newton Wesley E. , Anderson Patrick J. , Stein Steven J.
Published: September 2002

The objectives of this study were to determine the effects of fire retardantchemical (Phos-Chek G75-F*) and fire suppressant foam (Silv-Ex) application,alone and in combination with fire, on Great Basin shrub steppe vegetation. Wemeasured growth, resprouting, flowering, and incidence of galling insects onChrysothamnus viscidiflorus andArtemisia tridentata. These characteristics were notaffected by any chemical treatment. We measured community characteristics,including species richness, evenness, and diversity, and number of stems ofwoody and herbaceous plants in riparian and upland plots. Of these characteristics, only species richness and number ofstems/m2 clearly responded to the chemicaltreatments, and the response was modified by fire. In general, speciesrichness declined, especially after Phos-Chek application. However, by the endof the growing season, species richness did not differ between treated andcontrol plots. Acanonical variate analysis suggested that burning had agreater influence on community composition than did the chemical treatments.In general, riparian areas showed more significant responses to the treatmentsthan did upland areas, and June applications produced greater changes inspecies richness and stem density than did July applications.*Use of Trade Names does not imply endorsement by the U.S.Government.
El Niño and its impact on fire weather conditions in Alaska
Authors: Hess Jason C. , Scott Carven A. , Hufford Gary L. , Fleming Michael D.
Published: September 2002

Examining the relationship of El Niño to weather patterns in Alaska
shows wide climate variances that depend on the teleconnection between the
tropics and the northern latitudes. However, the weather patterns exhibited in
Alaska during and just after moderate to strong El Niño episodes are
generally consistent: above normal temperature and precipitation along the
Alaskan coast, and above normal temperature and below normal precipitation in
the interior, especially through the winter. The warm, dry conditions in the
Alaskan interior increase summer wildfire potential. Statistics on the area
burned since 1940 show that 15 out of 17 of the biggest fire years occurred
during a moderate to strong El Niño episode. These 15 years account for
nearly 63% of the total area burned over the last 58 years. Evidence
points to increased dry thunderstorms and associated lightning activity during
an El Niño episode; the percentage of total area burned by lightning
caused fires during five episodes increased from a normal of less than
40% to a high of about 96%.
Estimating fuel response time and predicting fuel moisture content from field data
Authors: Catchpole E. A. , Catchpole W. R. , N.R.Viney  , McCaw W. L. , Marsden-Smedley J. B.
Published: September 2002

We develop a method for estimating equilibrium moisture content (EMC) and fuel
moisture response time, using data collected for
Eucalyptus twig litter. The method is based on the
governing differential equation for the diffusion of water vapour from the
fuel, and on a semi-physical formulation for EMC (Nelson 1984), based on the
change in Gibbs free energy, which estimates the EMC as a function of fuel
temperature and humidity. We then test the model on data collected in Western
Australian mallee shrubland and in Tasmanian buttongrass moorland. This method
is more generally applicable than those described by Viney and Catchpole
(1991) and Viney (1992). The estimates of EMC and response time are in broad
agreement with laboratory-based estimates for similar fuels (Anderson
1990a ; Nelson 1984).
The model can be used to predict fuel moisture content by a book-keeping
method. The predictions agree wellwith the observations for all three of our
data sets.
Fire regime of a Elionorus muticus Spreng. savanna, western Chaco region, Argentina
Authors: Bravo Sandra , Kunst Carlos , Gimenez Ana , Moglia Graciela
Published: September 2002

Our objective was to assess the current fire regime of a 600 ha savanna
dominated by the grass species Elionorus muticus
Spreng., located in Santiago del Estero Province, north-western Chaco region,
Argentina. The degree of tolerance of some native woody species to fire, the
fire mean fire frequency (FF), and Weibull median probability (WMPI) were
evaluated. Sampling sites were located in the ecotone between the savanna and
the surrounding forests. A database was developed from fire scars found in
cross sections of native tree and shrub species, cut at different heights
above ground; that covered the recent 70 years of fire history
(1925–1996). Results indicate that the savanna has a mean FF of 0.179
fires year–1 and an FI = 3 years. The mean
height of fire scars found in trees and shrubs which indicate medium to high
fireline intensities with flame lengths larger than 1 m are frequent in the
savanna. Native species have different degrees of tolerance:
Aspidosperma quebracho blanco (tree) and
Schinopsis quebracho colorado (tree) are more tolerant
to fire than Acacia furcatispina (shrub) and
A. aroma (shrub). Bark thickness of the tree species
(1–1.5 cm in mature individuals) allows them to withstand the frequent,
high intensity fires of the savanna.
Utilization of NOAA AVHRR for assessing the determinants of savanna fire distribution in Burkina Faso
Authors: Nielsen Thomas Theis , Rasmussen Kjeld
Published: September 2002

Temporal and spatial patterns of active fires, detected using NOAA AVHRR LAC
data, in Burkina Faso are identified and related to vegetation, tree cover and
land use classes. Initially, fires are classified into early and late dry
season fires (EDSF and LDSF). Early dry season fires are defined as fires
occurring earlier than 45 days after the start of the dry season, marked by a
levelling out in the post-rainy season temperature increase, determined on the
basis of surface temperature data derived from NOAA AVHRR. The date of the
start of the dry season, defined in this way, is shown to be a linear function
of the latitude. The distribution of fire occurrence are shown to display
distinctively different patterns. These distribution patterns are related to
information on vegetation class, woody biomass and land use intensity as well
as net primary productivity, estimated from NOAA AVHRR rainy season data. It
is shown that overall fire frequency and the ratio of early to late dry season
fire activity depend strongly on net primary productivity, land use intensity
and vegetation class. Late fires tend to occur mainly in agricultural areas,
whereas early fires are much more frequent in areas of low land use intensity
in the wooded savannas of southern Burkina Faso.
Water quality, substratum and biotic responses of five central Idaho (USA) streams during the first year following the Mortar Creek fire
Authors: Minshall G. Wayne , Brock James T. , Andrews Douglas A. , Robinson Christopher T.
Published: September 2002

The Mortar Creek Fire burned 26 000 ha of mixed-conifer Rocky Mountain forest
in July–August 1979. Changes in burn stream conditions were examined
relative to reference streams for various ecological factors on two to six
occasions, from October 1979 to August 1980. Factors included major ions and
nutrients, suspended and benthic particulate matter, periphyton (algae), and
macroinvertebrates. Elevated levels of most dissolved chemicals in the burn
streams were evident soon after the fire and again during spring runoff.
However, there were no major disruptions in the relative composition of
cations (and presumably of anions also) in the burn streams during the study.
Concentration (mg/L) and load (g/s) of some constituents were higher
(e.g. NO 3 -N) and of others (e.g. Ca) were lower in the
burn than in the reference streams during spring runoff, depending on whether
they were normally under biological or geological control, respectively.
Suspended sediment and particulate organic matter generally were higher in
burn streams, especially during snow-melt runoff or following heavy rain
storms. Benthic organic matter was higher in burn streams and was mainly
charcoal, compared to the usual leaf litter found in the reference streams.
Fine sediments increased and periphyton decreased in the burn streams. The
fire increased the sensitivity of the burn streams to more routine
smaller-scale disturbances, such as rainstorms, which had major impacts on the
burn streams but not on the reference streams. The macroinvertebrate
assemblage showed little direct effect from the fire but was severely altered
in composition and abundance by the subsequent runoff, scouring, and channel
alteration initiated by spring runoff. The burn streams showed considerable
individuality in their response to fire depending on the particular set of
conditions to which they were exposed.
A patch mosaic burning system for conservation areas in southern African savannas
Authors: Brockett B.H. , Biggs H.C. , van Wilgen B.W.
Published: September 2002

Fire-prone savanna ecosystems in southern African conservation areas are
managed by prescribed burning in order to conserve biodiversity. A prescribed
burning system designed to maximise the benefits of a diverse fire regime in
savanna conservation areas is described. The area burnt per year is a function
of the grass fuel load, and the number of fires per year is a function of the
percentage area burnt. Fires are point-ignited, under a range of fuel and
weather conditions, and allowed to burn out by themselves. The seasonal
distribution of planned fires over a year is dependent on the number of fires.
Early dry season fires (May–June) tend to be small because fuels have
not yet fully cured, while late season fires (August–November) are
larger. More fires are ignited in the early dry season, with fewer in the late
dry season. The seasonality, area burnt, and fire intensity are spatially and
temporally varied across a landscape. This should result in the creation of
mosaics, which should vary in extent and existence in time. Envelopes for the
accumulated percentage to be burnt per month, over the specified fire season,
together with upper and lower buffers to the target area are proposed. The
system was formalised after 8 years of development and testing in Pilanesberg
National Park, South Africa. The spatial heterogeneity of fire patterns
increased over the latter years of implementation. This fire management system
is recommended for savanna conservation areas of >20 000 ha in size.