bluuebunny/crossref_metadata_2025 huggingface dataset:
Corrigendum to: Chromium(IV) leaching from large undisturbed soil lysimeters following application of a simulated copper-chromium-arsenic (CCA) timber preservative
Authors: Carey P. L. , Bidwell V. D. , McLaren R. G.
Published: January 2006

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.
Spatial and temporal variations of suspended sediment responses from the subtropical Richmond River catchment, NSW, Australia
Authors: Hossain Shahadat , Eyre Bradley , McConchie David
Published: January 2006

Suspended sediment exports from the Richmond River catchment were examined
during 2 hydrological years (1994–96). On a yearly basis, the Richmond
River catchment produced <2% suspended sediment load during dry
seasons, whereas about 75–91% of the yearly suspended sediments
were exported during floods which occurred <5% of the year. Annual
suspended sediment exports from the Richmond River catchment varied more than
7-fold from dry year to wet year. Among the 3 major subcatchments, Richmond
and Wilsons River subcatchments generated >93% of the suspended
sediment load, while sediment exports from the Bungawalbin Creek subcatchment
always remained low due to its flat topography and extensive forest coverage.
Suspended sediment hysteresis patterns exhibited a clockwise response for 2
steep and less forested subcatchments and an anti-clockwise response for
relatively low gradient and more forested subcatchment during all flood
events. Land use changes in the Richmond River subcatchments indicate a
possible increase of suspended sediment load of about 6-fold from their
pristine condition.
Nutrient leaching losses from undisturbed soil cores following applications of piggery wastewater
Authors: Phillips I. R.
Published: January 2006

Land disposal of wastewater from intensive livestock industries can result in
large amounts of nutrients and salts being applied to soils. When irrigated at
rates to meet crop phosphorus (P) requirements, nitrogen (N), calcium (Ca),
magnesium (Mg), potassium (K), sodium (Na), chloride (Cl), and sulfate
(SO4) applied in the wastewater often exceed crop
demands, and are susceptible to leaching. Leaching of surface-applied piggery
wastewater was investigated using large undisturbed soil cores (30 cm i.d. by
60 or 75 cm long) from 2 piggery wastewater disposal areas (Site 1, Vertosol;
Site 2, Sodosol) in south-east Queensland. About 3% of the total
wastewater P applied to the Vertosol, and about 10% of that applied to
the sodosol, was leached. The magnitude of these losses was consistent with
the chemical properties of each soil, and the availability of P sorption sites
(i.e. hydrous Fe oxides). The major forms of P in the leachate included both
molybdate reactive P (MRP) and unreactive P (UP, includes dissolved organic P,
soluble organic P, particulate P, and non-reactive P). Phosphorus leached from
the Vertosol was largely (≈80%) as UP because the MRP was sorbed by
the soil colloids. Much of the P leached from the sodosol was present as MRP
(≈70%) because the wastewater applied to this soil also contained
about 70% MRP, and this soil had only a limited ability to sorb MRP.
Losses of nitrogen (N) were found to be of a major environmental concern. Both
wastewater samples contained very high levels of N, with ammonium
(NH4-N) making up about 80%
of the total Kjeldahl N (TKN) and organic N about 20%. Negligible
amounts of applied NH4-N were
detected either sorbed by the soil or in the leachate because it was converted
to nitrate (NO3-N) within the soil
core. This NO3-N was highly
mobile, and was readily leached from the soil cores. Nitrogen represented the
major limitation to the long-term use of land for disposal of piggery
wastewater. For land disposal to be an effective management option, N applied
in piggery wastewater may need to be limited to about 200 kg/ha.year.
Significant amounts of Ca, Mg, K, and Na applied in the wastewater were
leached from the soil cores. It is recommended that more attention be placed
on the impact of N (TKN, NH4-N,
and NO3-N), Ca, Mg, K, and Na on
the receiving soil and water environments rather than focussing primarily on
wastewater P. Management strategies should be developed for disposal sites to
minimise leaching losses by maximising nutrient removal from the soil solution
through crop uptake, reaction with the soil colloids, and efficient irrigation
practices.
nitrogen, phosphorus, cations, nitrification, piggery wastewater.
Interpretation of morphological features in a salt-affected duplex soil toposequence with an altered soil water regime in western Victoria
Authors: Brouwer J. , Fitzpatrick R. W.
Published: January 2006

This paper is the first of two describing how soil macromorphological and chemical data can be combined with a minimum of hydrological data to distinguish between, and to quantify, past and present hydrological processes. These processes are relevant to both waterlogging and dryland salinity. The purpose of this first paper is to establish a methodological framework. It also describes the initial interpretation of the macromorphological features of the toposequence studied at Gatum on the Dundas Tablelands in western Victoria. A modified version of the soil feature–system–domain grouping method was used. Macromorphological data combined with only limited piezometric data showed that:

(1) The soil feature–system–domain grouping method makes it possible to distinguish between the effects of past and present hydrological processes on soil macromorphology at Gatum.

(2) Waterlogging of the surface horizons at Gatum is often caused by perching of soil water within the B-horizon (as opposed to on top of the B-horizon). Changes in soil structure and in colour of cutans and mottles can be an indicator of this first restricting layer.

(3) It is likely that interpedal cracks and old tree root holes act as preferred paths for water to flow through this first restricting layer.

(4) A second fresh perched water table can occur on top of the pallid zone. Where the pallid zone reaches close to the surface the two perched water tables may merge and cause a local increase in waterlogging, as indicated by local soil morphology. When this occurs, hillside seeps can occur quite high up on the slopes, even when there is no apparent irregularity in surface topography.

(5) The permanent saline water table occurs on top of the bedrock and causes salting problems where it comes too close to the soil surface. Salting problems at the bottom of a slope are more severe where fresh perched water tables increase waterlogging

On the basis of these findings the suitability of various management options to reduce waterlogging and salinisation is discussed. Further findings regarding restricting layers, flow paths through the soils, and relations between duration of saturation and soil morphological features, are discussed in a companion paper (by J. Brouwer and R. W. Fitzpatrick, pp. 927-946 in this issue).
Restricting layers, flow paths and correlation between duration of soil saturation and soil morphological features along a hillslope with an altered soil water regime in western Victoria
Authors: Brouwer J. , Fitzpatrick R. W.
Published: January 2006

This paper is the second of two describing how soil macromorphological and chemical data can be combined with soil hydrological data to distinguish between, and to quantify, past and present hydrological processes relevant to waterlogging and dryland salinity. The first paper provides a methodological framework for the study, and describes the initial interpretation of the macromorphological features of the toposequence studied, using the soil feature-system-domain grouping method. This second paper deals with the added value of extensive piezometric and other hydrological observations relative to soil macromorphological studies, and with quantitative relationships between soil colour and duration of waterlogging.

As with the first paper, this paper focuses on a soil toposequence at Gatum on the eastern Dundas Tableland in western Victoria. For the the broad crest with yellow gradational soils or Dermosols (Plinthoxeralfs), the hydrological data confirmed the conclusion from macromorphological observations that:

(1) There are three levels at which downward flow of water is restricted: at the top of the largely unaltered mottled zone, that is at 0.8-1.0 m depth, well below the top of the yellow Bt1-horizon (fresh water); at the top of the pallid zone, at about 3-3.5 m depth (fresh water); and on top of the unweathered ignimbrite (saline water).

(2) Below about 30 mm depth, down at least as far as 2.0 m and sometimes even more, the major pathways for downward movement of water are indeed root channels, with or without live roots, and not interpedal cracks. The 3-dimensional spacing of the rootholes above and through the less-permeable mottled zone, and the (horizontal) conductivity, storage capacity, and thickness of overlying horizons determine the extent of ponding, runoff, and deep infiltration taking place.

In addition, the hydrological observations showed that:

(3) If rainfall is regular, well-spaced, and not excessive, ponding is unlikely to take place even where there is a rainfall surplus and there are layers restricting downward flow of water.

Furthermore, along the toposequence with yellow duplex soils or Dermosols, Chromosols, and Hydrosols,

(4) There were generally good correlations between duration of saturation at the bottom of the E-horizon and colour aspects of the E-horizon (value and chroma of the matrix) and of the B2-horizon (hue, value, and chroma of the matrix).

Based on these findings additional suggestions are made for improving identification and management of water logging and salinisation processes.
Prediction of hydraulic conductivity for some Australian soils
Authors: Paydar Zahra , Ringrose-Voase Anthony J.
Published: January 2006

Pedotransfer functions and their use in simulation modelling have attracted much attention during recent years. In the absence of measured hydraulic conductivity data, prediction from other soil properties would be most useful. A functional form relating near-saturated hydraulic conductivity to the soil water retention curve based on the Kozeny–Carman equation was investigated on Australian soils. For a dataset comprising a range of soil textures and structural conditions (107 samples with bulk density >1.2 Mg/m3) a power-law relationship between near-saturated hydraulic conductivity, effective porosity, and pore size distribution index was obtained. The function was tested on 2 different datasets for independent evaluation. The results showed poor predictions for most soils in this study. While the reasons for poor predictions might be the difference in the measurement techniques or potentials, it is thought that the proposed function mostly fails predictions on soils with high organic matter and management practices affecting macropores and soil structure (e.g. crust). The proposed function did not show much improvement over the more general form of the Kozeny–Carman equation with empirical coefficients. In the absence of other data, the modified Kozeny–Carman equation (with or without water retention parameters) can be used, with caution, on similar soils and larger scale applications. More data are needed to test the reliabilty of these functions for use in specific locations.
Age of loess deposits in the Central Tablelands of New South Wales
Authors: Hesse Paul P. , Humphreys Geoff S. , Smith Barton L. , Campbell James , Peterson Elizabeth K.
Published: January 2006

Basal optically stimulated luminescence (OSL) ages of more than 50 000 years in loessic (parna) mantles on the Central Tablelands of New South Wales indicate significant aeolian silt (c. 30 μm mode) deposition commenced well before the onset of the last glacial maximum. Each mantle consists of >1 m of reddish silty clay loam–silty clay with an earthy fabric which sits atop manganese and iron pans and saprolite. Mixing of saprolite-derived material into the pans and also into the silty layer indicates a site history of steady accumulation of aeolian loess and continual pedogenesis. No palaeosols are found. The OSL chronology of both sites, while low resolution, indicates an almost constant mass accumulation rate from 50 000 years ago through the last glacial maximum and into the Holocene. Local factors affecting retention of deposited dust may be responsible for the apparent passivity of the sites.
Sowing wheat or field pea as rotation crops after irrigated cotton in a grey Vertosol
Authors: Hulugalle N. R. , Entwistle P. C. , Cooper J. L. , Allen S. J. , Scott F. , Nehl D. B. , Finlay L. A.
Published: January 2006

The effects of green manured field pea (Pisum sativum
L.), low-input (LI) wheat (Triticum aestivum L.)
(seeding rate of 40 kg/ha and 85 kg/ha of diammonium phosphate), and
high-input (HI) wheat (seeding rate of 100 kg/ha, 85 kg/ha of
diammonium phosphate, and 180 kg/ha of urea) sown as rotation crops after
cotton on soil quality; cotton growth, yield and nutrient uptake; and gross
margins ($AU/ha and $AU/ML of irrigation water) were
evaluated from 1993 to 1998 in an irrigated Vertosol in the central-west of
New South Wales. Soil quality indicators monitored were aggregate stability
(dispersion index), compaction (air-filled porosity), soil resilience to
structural destruction (as geometric mean diameter of soil aggregates formed
after puddling and drying of soil), exchangeable cations, calcium carbonate,
nitrate-N, pH, organic C, development of arbuscular mycorrhiza (AM), and
incidence of cotton root diseases (black root rot). In comparison with wheat,
field pea increased soil nitrate-N levels during the early stages of the
experiment and formed smaller aggregates after puddling and drying, but it was
ineffective in ameliorating soil compaction. In contrast wheat was very
effective in ameliorating soil compaction. Nitrate-N values under
wheat–cotton rotations increased with time such that after 4 years they
were similar to that under the field pea–cotton rotation. Soil chemical
fertility indicators such as organic C, pH, EC, and exchangeable cations were
not affected consistently by either wheat or field pea, whereas minimum
tillage, retention of crop residues, and cropping phase (i.e. rotation crop or
cotton) affected them more. A net decrease in organic C and an increase in EC
was observed with time in all treatments. By sowing either field pea or wheat,
the mycorrhizal colonisation of cotton roots was improved. Black root rot
incidence was increased 3-fold by sowing field pea, but was not significantly
affected by wheat. Cotton lint yield was unaffected by rotation crop, although
profitability shown as gross margins/ha and gross margins/ML
irrigation water were greater with wheat compared with field pea. Gross
margins/ha were in the order HI wheat > LI wheat > field pea, and
gross margins/ML irrigation water were in the order LI wheat > HI wheat
> field pea. In terms of ameliorating soil compaction, minimising black
root incidence, and maximising returns to the cotton grower, wheat is a better
rotation crop than field pea. The decision to apply fertiliser and sow wheat
at a higher seeding rate will depend on whether land or water is the major
limiting factor.
Palygorskite-cemented crusts (palycretes) in Southern Portugal
Authors: Stahr K. , Kühn J. , Trommler J. , Papenfuß K-H. , Zarei M. , Singer A.
Published: January 2006

In the Oriola depression of Southern Portugal near the town of Evora, field
examinations revealed the presence of Tertiary sedimentary deposits that had
the consistency of duricrusts. These duricrusts, occurring close to the land
surface, were examined in the field as well as in the laboratory, with the
objective of establishing their composition and formation. Micromorphological
examinations showed that the duricrusts were composed of clasts of fine sand
to fine gravel sizes cemented together by a matrix dominated by either
palygorskite or carbonate. The matrix : clasts ratio varied from about 1 : 3
when the cement was carbonate, to 3 : 1 or higher when the matrix was
palygorskite. Occasionally the ratio in the latter was even higher. The clasts
consisted of quartz, feldspar, and some Mg-rich metamorphic minerals. The
palygorskite matrix fibres were arranged in mats within which they had
parallel orientation. The mats or ‘domains’, which had a length of
15–25 □m and a width of about 40 □m, showed random
orientation. In analogy to the term ‘calcrete’ the term
‘palycrete’ is used for the palygorskite duricrusts. The
palycrete, of an average thickness of 0.5 m, frequently rested directly on the
Hercynian basement rocks, and was covered by a recent solum. In the B horizons
of the solum, the palygorskite appeared to undergo recent weathering and
transformation into smectite. The duricrusts were proposed to have formed by
authigenic calcite or palygorskite, which filled the interstices between
clastic particles that had been deposited on Hercynian basement rocks
following their peneplanation in the early Tertiary. The proposed environment
of deposition and formation was that of an intermittent playa-lake in a
semi-arid, seasonal climate, where strong evaporative processes had been
active. Alteration and weathering of the mafic minerals contained in some of
the clasts, in addition to interstitial solutions rich in Si and Mg, had
created the chemical environment required for palygorskite neoformation. From
the state of weathering–disintegration of the palygorskite in the soils
formed on the palycrete, it is inferred that the environment for palygorskite
neoformation had ceased to exist after palycrete formation.
Fate of applied phosphorus in an effluent-irrigated Pinus radiata plantation
Authors: Falkiner R. A. , Polglase P. J.
Published: January 2006

We examined the fate of applied phosphorus (P) in a young
Pinus radiata plantation in south-eastern Australia,
spray-irrigated with secondary-treated municipal effluent. Measurements
included changes (before irrigation, and after 5 years) in total P, total
organic P, total inorganic P, labile P, and sorption and desorption
characteristics. During the first 5 years a total of 363 kg/ha of P was
applied at an average concentration of 5.4 mg/L. Irrigation changed the
forms and distribution of P throughout the profile (0–1 m). Increases in
labile inorganic P (membrane-exchangeable, bicarbonate-extractable, and in
soil solution) were confined mostly to the 0–0.5 m horizon, and wholly
within the 0–0.7 m horizon. In addition, large amounts of organic P (204
kg/ha) were mineralised within the surface 0.7 m, due to stimulation of
decomposer activity by increased soil water. Mineralisation, therefore,
provided a significant and additional input of inorganic P to soil.
Irrigation and P additions changed both the placement and curvature of soil
sorption isotherms. Retention capacity (0–0.5 m), calculated from P
sorption isotherms, decreased by 180 kg/ha. Desorbable P, determined by
sequential extraction with dilute acid, increased by 184 kg/ha. Thus,
these 2 independent methods of measuring the changes in exchangeable P gave
the same result. Of the total inorganic P added to the soil (in effluent and
mineralised), 25% remained in the exchangeable form; the rest was
retained unavailable for short-term exchange and migration through soil.
After 5 years, fluxes (kg/ha) of P in the 0–0.7 m horizon were:
input in effluent less storage in vegetation (323), change in total organic P
(–204), change in total inorganic P (517), net change in total P (313).
Thus, 97% of the net amount of P added in effluent was recovered in the
surface 0.7 m. Results have implications for the way in which P retention
capacity is calculated under effluent irrigation.
Evaluation of surface and groundwater management strategies for drained sulfidic soil using numerical simulation models
Authors: Blunden B. G. , Indraratna B.
Published: January 2006

The effective management of acid sulfate soils is a major issue for many
coastal regions in Australia. Simulations were conducted to evaluate 4
different water management strategies that could be applied to agricultural
land on the south coast of New South Wales, Australia, to minimise acid
generation from acid sulfate soils. The water management strategies are
compared with the existing extensively drained situation which generates and
discharges large quantities of acidic pyrite oxidation products. The 4 water
management strategies include elevated drain water levels using a weir, 25 mm
irrigation on a 7- or 14-day cycle, and elevated drain water levels with
irrigation. All of these strategies were designed to minimise the generation
of acid by reducing the transport of oxygen to the sulfidic soil. Simulations
were conducted for weather and site conditions experienced during a 12-month
period starting in July 1997.
Model simulations showed that maintenance of elevated drain water levels using
a weir in the drain significantly reduced the amount of acid generated by
75% and 57%, at 10 and 90 m distance from the drain,
respectively, by comparison with the existing drained state. The addition of
25 mm irrigation on a 14-day cycle to the weir simulation reduced the
oxidation of pyrite by a further 1–2%. Application of irrigation
only on a 7-day cycle also reduced the acid generated by 89% and
94% at 10 and 90 m distance from the drain, respectively, by comparison
with the existing drained state. Irrigation on a 14-day cycle was not as
successful in reducing pyrite oxidation as either the 7-day irrigation or weir
strategies. Evaluation of the 4 water management options showed that
significant improvements can be made with respect to the amount of acid
generated by relatively simple and cost-effective land management practices.
Nature of organic carbon and nitrogen in physically protected organic matter of some Australian soils as revealed by solid-state 13C and 15N NMR spectroscopy
Authors: Knicker H. , Skjemstad J. O.
Published: January 2006

The <53-□m particle-size fractions of 5 different Australian soils
were subjected to high energy ultraviolet (UV) photo-oxidation for a period of
2 h in order to remove most of the physically unprotected organic material.
Solid-state 13C and 15N nuclear
magnetic resonance (NMR) spectroscopy was applied for characterising the
chemical nature of the remaining organic fraction. The
13C NMR spectroscopic comparison of the residues after
UV photo-oxidation and the untreated bulk soils revealed a considerable
increase in condensed aromatic structures in the residues for 4 of the 5
soils. This behaviour was recently shown to be typical for char-containing
soils. In the sample where no char was detectable by NMR spectroscopy, the
physically protected carbon consisted of functional groups similar to those
observed for the organic matter of the bulk sample, although their relative
proportions were altered. The solid-state 15N NMR
spectrum from this sample revealed that some peptide structures were able to
resist UV photo-oxidation, probably physically protected within the core of
microaggregates. Heterocyclic aromatic nitrogen was not detected in this
spectrum, but pyrrolic nitrogen was found to comprise a major fraction of the
residues after photo-oxidation of the <53-□m fractions of the char-
containing soils. Acid hydrolysis of these samples confirmed that some
peptide-like material was still present. The identification of a considerable
amount of aromatic carbon and nitrogen, assignable to charred material in 4 of
the 5 investigated soils, supports previous observations that char largely
comprises the inert or passive organic matter pool of many Australian soils.
The influence of such material on the carbon and nitrogen dynamics in such
soils, however, requires further research.
Leaching and degradation of triasulfuron, metsulfuron-methyl, and chlorsulfuron in alkaline soil profiles under field conditions
Authors: Sarmah A. K. , Kookana R. S. , Alston A. M.
Published: January 2006

A field study was conducted on an alkaline cropping soil (plot size 4 m by 1
m), representative of cereal growing regions in southern Australia, to examine
the degradation and leaching behaviour of triasulfuron, metsulfuron-methyl,
and chlorsulfuron (150 g a.i./ha), along with a non-reactive tracer (KBr,
50 kg/ha), under 2 water treatments (‘rainfall’ and
‘rainfall + irrigation’). The results showed that the
distributions of water content, Br– , and the 3
herbicides were influenced by the amount of rainfall/irrigation received,
and the biological activity as well as the physico-chemical properties of the
soil within the profile. The largest concentrations of
Br– were detected in the 10–20 cm depth
under both treatments. No additional peak of Br–
was observed in the plots which received only rainfall; however, there was
another peak at 100 cm depth after a cumulative rainfall and irrigation of 158
mm. The spatial distribution of Br– in the plots
was attributed to preferential flow through cracks or the presence of
‘mobile’ and ‘immobile’ water, which gave rise to
bimodal distribution in the profile. Metsulfuron-methyl showed the greatest
mobility, followed by chlorsulfuron and triasulfuron under both the
treatments, with metsulfuron-methyl being detected at 120 cm depth under
rainfall + irrigation. A bimodal distribution was also observed for the 3
herbicides, but the location of peaks was dependent on the solute. Rates of
degradation of the herbicides could be described reasonably well with
first-order reaction kinetics (r2
= 0.72–0.91). The half-lives for triasulfuron,
metsulfuron-methyl, and chlorsulfuron were 44, 45, and 32 days, respectively,
under rainfall (69 mm), and 46, 59, and 48 days under rainfall +
irrigation (158 mm).
Tracing the nitrogen, sulfur, and carbon released from plant residues in a soil/plant system
Authors: Konboon Yothin , Blair Graeme , Lefroy Rod , Whitbread Anthony
Published: January 2006

Matching plant residue mineralisation rate to plant nutrient demand is one way
of increasing the efficiency of nutrient cycling. A glasshouse experiment was
conducted in a Soloth soil with a
C4d13 C signature using drained
pots to examine the effect on the yield of Japanese millet
(Echinochloa frumentocea) and the fate of
15 N, 35 S, and C (using d
13 C shift) from the C 3 plants
Flemingia macrophylla,
Medicago truncatula hay, and wheat
(Triticum aestivum) straw applied at 3 t/ha in the
presence of N and NPKS fertiliser. The yield of Japanese millet at 91 days was
highest where medic hay had been added (13.7 g/pot) and lowest where wheat
straw was used (11.5 g/pot). Recovery of 35 S by the
millet was highest in the wheat straw and medic hay treatments (mean
11.5%), whilst recovery of 15 N was highest from
medic hay (15.8%). Leaching losses of 35 S were
highest in the Flemingia and medic treatments (mean
8.1%), and 15 N loss in leachate was highest in
the medic hay treatment (6.6%). A maximum of 1.5% of the C added
in residues was recovered in the leachate of the medic hay treatment.
Plant effects on soil carbon storage and turnover in a montane beech (Nothofagus) forest and adjacent tussock grassland in New Zealand
Authors: Tate K. R. , Scott N. A. , Ross D. J. , Parshotam A. , Claydon J. J.
Published: January 2006

Land cover is a critical factor that influences, and is influenced by,
atmospheric chemistry and potential climate changes. As considerable
uncertainty exists about the effects of differences in land cover on
below-ground carbon (C) storage, we have compared soil C contents and turnover
at adjacent, unmanaged, indigenous forest
(Nothofagus solandri var.
cliffortiodes) and grassland
(Chionochloa pallens) sites near the timberline in the
same climo-edaphic environment in Craigieburn Forest Park, Canterbury, New
Zealand.
Total soil profile C was 13% higher in the grassland than in the forest
(19.9 v. 16.7 kg/m2 ), and based on bomb
14C measurements, the differences mainly resulted from
more recalcitrant soil C in the grassland (5.3 v. 3.0
kg/m2 ). Estimated annual net primary production was
about 0.4 kg C/m2 for the forest and 0.5 kg
C/m2 for the grassland; estimated annual root
production was about 0.2 and 0.4 kg C/m2 ,
respectively. In situ soil surface
CO2 -C production was similar in the grassland and the
forest. The accumulation of recalcitrant soil C was unrelated to differences
in mineral weathering or soil texture, but was apparently enhanced by greater
soil water retention in the grassland ecosystem. Thus, contrary to model
(ROTHC) predictions, this soil C fraction could be expected to respond to the
effects of climate change on precipitation patterns.
Overall, our results suggest that the different patterns of soil C
accumulation in these ecosystems have resulted from differences in plant C
inputs, soil aluminium, and soil physical characteristics, rather than from
differences in soil mineral weathering or texture.
A validation test of WEPP to predict runoff and soil loss from a pineapple farm on a sandy soil in subtropical Queensland, Australia
Authors: Yu B. , Ciesiolka C. A. A. , Rose C. W. , Coughlan K. J.
Published: January 2006

Monthly runoff and soil loss simulated by WEPP (Water Erosion Prediction
Project) were compared with field observations on a pineapple farm in
south-east Queensland for a 3-year period. The soil at the site is sandy.
Slope length and steepness are 36m and 5.5%, respectively. Three
treatments, namely bare, farmers’ conventional practice, and mulching of
the furrows, were used. Infiltration and erodibility parameters were
determined using WEPP-recommended equations and measurable soil properties.
These parameters were also calibrated using the runoff and soil loss data for
the bare plot only. Apart from the soil loss prediction for the mulching
treatment, for which WEPP did not perform well, the average coefficient of
efficiency in runoff and soil loss predictions was –0.02 using soil
property-based parameter values and 0.66 using calibrated parameter values.
The corresponding r 2 values are
0.57 and 0.81, respectively. On the whole, WEPP is able to reproduce the trend
and variations in runoff and soil loss among different treatments for the
site. Parameter values based on measurable soil properties would greatly
under-estimate the runoff and soil loss for the site. Thus, use of WEPP
outside its US database requires calibration with locally obtained data. It
was also found that WEPP does not seem to model effectively the situation
where there is considerable flow impediment with the furrows covered with
mulch. We are unable to reject WEPP because the statistical performance
indicators are reasonable for the site, and because the model is so complex
that it is nearly impossible to pinpoint the source of discrepancy and
articulate the model deficiency on physical grounds.
Dynamic modelling of upslope fire growth
Authors: Santoni P.A. , Balbi J.H. , Dupuy J.L.
Published: January 2006

A two-dimensional non-stationary model of fire spread including slope effects
is proposed. The numerical study of this model allows us to predict the rate
of spread, the fire front perimeter and the temperature distribution for a
fire spreading across a fuel bed under slope conditions. The numerical results
are compared with success to experimental data generated from two laboratory
point-ignition fire experiments which were conducted on dehydrated
Pinus pinaster litter with slopes of 20 and 30°.
Résumé
Nous proposons un modèle bidimensionnel évolutif de propagation
de feu prenant en compte les effets de la pente. L’étude
numérique du modèle présenté ici nous permet de
prédire la vitesse de propagation, le perimètre du front de feu
ainsi que la distribution de température pour un feu se propageant dans
une litière en présence d’une pente. Les résultats
numériques que nous obtenons sont comparés avec succés
aux données expérimentales issues de deux expériences qui
furent réaliseés dans une litière de pin maritime avec un
allumage ponctuel pour des pentes de 20 et 30 degrés.
Dynamic modelling of fire spread across a fuel bed
Authors: Balbi J.H. , Santoni P.A. , Dupuy J.L.
Published: January 2006

The analysis of laboratory fire experiments led to the development of a
reaction-diffusion model for the spread of fire across a fuel bed in windless
and slopeless conditions. A method for the determination of coefficients in
this model based on the dynamic features of a spreading fire is given. The
numerical study of the mathematical problem proposed allows us to predict the
rate of spread, the fire front perimeter and the temperature distribution for
line-ignition and point-ignition fires. These results are compared with
success to experimental data. Furthermore, the model allows us to estimate the
acceleration of spread for a point-ignition fire in its initial stage and in
the steady-state phase.
Résumé
Une analyse menée sur des expériences de laboratoires nous a
permis de proposer un modèle de réaction-diffussion pour la
propagation du feu sans vent et sans pente au travers d’une
litière. Une méthode d’identification des coefficients du
modèle, à partir des caractéristiques dynamiques de la
propagation du feu, est donnée. L’étude numérique
du problème mathématique nous permet de prédire la
vitesse de propagation, le périmètre du front de feu et la
température dans le domaine d’étude pour des allumages en
ligne et pour des allumages ponctuels. Ces résultats sont
comparés avec succés à des données
expérimentales. De plus, nous sommes aussi en mesure de décrire
l’accélération du front de feu dans les premiers instants
suivant un allumage ponctuel.
Fire spread through a porous forest fuel bed: a radiative and convective model including fire-induced flow effects
Authors: Dupuy Jean-Luc , Larini Michel
Published: January 2006

A simplified physical model for the steady-state propagation of an infinite
fire front through a uniform forest fuel bed in still air is derived from a
mechanistic approach that considers a forest fire as a compressible, reactive
and radiative flow through a multiphase medium.
This model, named the PIF97 model for shortness, includes the effects of the
buoyancy induced gas flow on the preheating of the unburned fuel. Fuel is
composed of one type of motionless particles uniformly distributed in a fuel
bed of constant depth. The conservation equations used in the model are
integrated over the fuel bed depth. The spatial domain is divided into the
preheating zone ahead of the fire front and the flaming combustion zone. In
the preheating zone (model A), pyrolysis and chemical reactions are neglected,
and the gas flow is assumed to be one-dimensional. In the flaming combustion
zone (model B), some average parameters over this zone are given in order to
simplify the description of physical and chemical processes. Models A and B
are coupled to form the PIF97 model.
The predictions of this model are compared with experimental rates of spread
measured during laboratory fire experiments in pine needle fuel beds. That
shows the accomplished progress by comparison to the predictions of a purely
radiative model and also the limits of the PIF97 model. Under the present
experimental conditions, this model correctly predicts the effect of
surface-to-volume ratio, and may predict the effect of fuel load, but the
quantitative effect of slope is clearly underestimated. Possible reasons for
the remaining discrepancies between predictions and experimental results are
investigated through an analysis of separate predictions of model A and model
B.
Evaluation of ERS SAR data for prediction of fire danger in a Boreal region
Authors: Bourgeau-Chavez Laura L. , Kasischke Eric S. , Rutherford Mark D.
Published: January 2006

Research was conducted to determine the utility of Synthetic Aperture Radar
(SAR) data for measuring the fuel moisture status of boreal forests as
reflected in Fire Weather Index Codes. Three years (May to August
1992–1995) of SAR data from the European Remote Sensing Satellite (ERS)
were analysed over the 1990 Tok Alaska burned and adjacent unburned black
spruce forests. Corresponding Fire Weather Index Codes of the Canadian Forest
Fire Danger Rating System were obtained from Tok Area Forestry, Station number
500720. Strong relationships were expected between the SAR data and fire codes
because of the dependence of ERS SAR backscatter on the moisture status of
forests and exposed surfaces (burn scars). Astepwise multilinear regression
procedure was used to analyse the relationships. Three statistically
significant multilinear regression models resulted from this analysis
procedure. The models developed show there is potential for using ERS SAR
backscatter to generate indicators that are related to Fire Weather Index,
Duff Moisture Code, and Drought Code. This research could lead to the ability
for remote prediction of fire danger over large regions at relatively fine
spatial resolution with minimal weather information.
Influence of heat on seed germination of nine woody Cistaceae species
Authors: Herranz José M. , Ferrandis Pablo , Martínez-Sánchez Juan J.
Published: January 2006

The influence of high temperatures on germination of four
Cistus and five Halimium taxa is
analysed. Seeds were heated to a range of temperatures (from 50ºC to
150ºC) and a range of exposure times (from 1 to 60 min), simulating those
heat conditions registered on the soil surface during wildfires. After the
thermal pretreatments, seeds were sown in plastic Petri dishes and monitored
for germination over 60 days. For all the species, germination was increased
significantly over the control set (untreated seeds) by at least one of the
thermal pretreatments. Temperatures of 120 and 150ºC were the most
efficient temperatures promoting seed germination, although germination was
interrupted at 150ºC if exposure times were equal to or longer than 5
minutes for the majority of species. The preheating at 50ºC was effective
on;y for C. populifolius, but only at long exposure
times (60 min). H. atriplicifolium had the highest heat
requirements for stimulating germination, requiring at least 120ºC for 5
min. H. halimifolium subsp.
halimifolium seeds showed the highest heat resistance:
the final germination level reached at 150ºC for 7.5 minutes ranged
between 52.5 and 55.5%. The germination rates after preheating were
much lower than in mechanically scarified seeds, and closely resembled those
of the untreated seeds. In general, species sharing the same habitat showed
different heat requirements in promoting germination. For
C. crispus and H. halimifolium
subsp. halimifolium, the experiment was carried out on
seeds collected from two different localities. For both species the
germination patterns were similar between populations, although some high
temperature pretreatments showed different germination percentages.
A Markov chain model of day to day changes in the Canadian forest fire weather index
Authors: Martell David L.
Published: January 2006

A Markov chain is used to model day to day changes in the Fire Weather Index
(FWI) component of the Canadian Forest Fire Weather Index System. The results
of statistical analyses of 26 years (1963 through 1988) of fire weather data
recorded at 15 fire weather stations located across the province of Ontario
suggest that it is reasonable to partition the fire season into three
subseasons and model day to day changes in the Fire Weather Index class within
each subseason as a Markov chain of order 1.
Fire Growth and Acceleration
Authors: Cheney NP , Gould JS
Published: January 2006

The use of the terms "growth" and "acceleration" appears to be inconsistent in the literature and we believe this inconsistency has hindered our understanding of behaviour in the early stages of a fire.
The development of a fire from a point ignition to some equilibrium state and the associated increase in fire size and intensity has been referred to variously as the fire growth (Pyne 1984); build-up (Luke and McArthur 1978); or acceleration (Chandler et al. 1983) phase of the fire.
More specifically the "acceleration phase" has been used to describe the increase in rate of spread from ignition to a quasi-steady rate of spread (Luke and McArthur 1978, McAlpine and Wakimoto 1991). Characteristic curves showing the increase in rate of spread are illustrated for
different fuel and weather conditions (Luke and McArthur 1978). Hypothetical models to describe these curves have been proposed by Cheney and Bary (1969), Van Wagner (unpublished) and McAlpine and Wakimoto (1991). They have been called acceleration curves and acceleration
models.
The terms growth and acceleration, however, represent different concepts that are not interchangeable. We would like to clarify these concepts and discuss the practical implications for fire managers.
Improved Calibration of a Large Fuel Burnout Model
Authors: Albini FA , Reinhardt ED
Published: January 2006

Calibration and testing of a computer simulation of the burning of large woody natural fuels has been presented previously in this journal. This note describes an improved calibration of the model for better prediction of fuel loading reductions. Using the same data as before, fuel consumption predictions are improved substantially by making the area influence factor a function of fuel moisture content.
Numerical Predictions on the Soil Thermal Effect Under Surface Fire Conditions
Authors: Oliveira LA , Viegas DX , Raimundo AM
Published: January 2006

A control volume numerical method is used to predict the temperature distribution inside a soil extent, the surface of which has been swept by a two-dimensional flame front with pre-defined velocity and temperature distributions. Natural and forced convection, as well as radiation effects are included in the specification of the soil surface thermal boundary condition. The flame residence time and maximum temperature are identified as two major parameters to characterize the flame front. As expected, the heat penetration depth is confined to the near vicinity of the soil surface. Moreover, horizontal heat conduction throughout the soil has not always a significant effect on its global, transient temperature distribution. The influence of wind velocity and of soil thermal diffusivity upon its temperature distribution are analysed. Radiation is the dominant contribution in the whole heat transfer process between flame and ground surface.
Project Aquarius 2. Limitations of Maximum Oxygen Uptake for Predicting the Strains of Building Fireline With a Rakehoe
Authors: Brotherhood JR , Budd GM , Hendrie AL , Jeffery SE , Beasley FA , Costin BP , Zhien W , Baker MM , Cheney NP , Dawson MP
Published: January 2006

In three-stage graded work tests we compared men's responses to laboratory step tests with their responses to building fireline with a rakehoe (McLeod tool) in dry eucalypt forest. The subjects were experienced firefighters and the scientific observers (novices at raking fireline) who carried out the investigation. At the average energy expenditure of raking fireline in bushfire suppression (655 W, oxygen uptake 1.9 1 min-1) the firefighters' heart rate (HR), pulmonary ventilation ((V)E), and rating of perceived exertion (RPE) were higher in raking than in stepping by 18 beats min-1, 13 1 min-1 and 0.5 units RPE respectively. At higher work rates the average difference in the response to raking and stepping decreased for HR (the opposite response to that found in laboratory studies of arm work), increased for (V) E, and did not change for RPE. Contrary to the usual finding for arm work, the firefighters' average maximal oxygen uptake (VO2max) was the same for raking and stepping, although the observers' raking (VO2max) was 10 % (P<0.01) less than their stepping (VO2max). These findings imply that firefighters rake mainly with their arms and upper body at normal work rates, but recruit additional trunk and leg muscles at higher work rates to achieve a 'whole-body' (VO2max) — which is greater than could be achieved with the arm work of normal raking and would thus lead to underestimates of strain and fatigue. Seventeen (50%) of the firefighters, but only one (8%) of the observers, had greater (VO2max) for raking than for stepping, suggesting that regular practice with hand tools had enhanced the firefighters' raking performance through local muscle training and improved technique.