bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of altitude and aerosol on UV radiation
Authors: Pfeifer M. T. , Koepke P. , Reuder J.
Published: January 2006

Measurements of erythemally weighted UV radiation during about 600 days at different sites in Bolivia and Germany ranging from 550 to 5240 m above sea level have been used to derive the altitude effect AE under cloud‐free conditions. In Germany, AE values between 7 and 16%/km have been obtained. In Bolivia, the altitude effect between the lowlands and the Bolivian plateau reached values of 5–10%/km. An altitude effect of 8–23%/km has been measured between the plateau and a high‐mountain station. In accordance with previous studies these results indicate that the altitude effect of UV irradiance cannot be described by a single number in %/km, because it strongly depends on the atmospheric and surface parameters. In order to understand the high variability of the AE, the effects due to variations in solar elevation, albedo, and aerosol properties on UV radiation and the AE have been analyzed. To eliminate the influence of clouds, an algorithm for the selection of cloud‐free time intervals has been developed and applied. Furthermore, the measured data have been normalized to a fixed ozone content to avoid masking of the AE by different ozone amount. In addition, the background altitude effect, i.e., the AE resulting only from the reduced barometric pressure and reduced ozone content with increasing altitude, has been modeled. Depending on solar elevation and albedo, it ranges between 3 and 7%/km. Measured higher values of the AE, as well as negative values of the AE, are explained by the specific regional aerosol conditions, with important sources at high altitudes. The aerosol influence on UV is shown in detail for extreme conditions after strong bonfires in connection with a local holiday.
Elastoviscoplastic relaxation of impact crater topography with application to Ganymede and Callisto
Authors: Dombard Andrew J. , McKinnon William B.
Published: January 2006

We use an elastoviscoplastic rheological model to study the long‐term relaxation of impact crater topography on Ganymede and Callisto. We employ a complete set of rheological parameters for ductile creep in ice Ih and implement a new, shallower initial shape model. Under high heat flow conditions, stresses are relieved in deeper, less viscous material, and the remainder concentrates as flexural (bending) stresses in a viscously stiffer near‐surface layer. Essentially, a mechanical lithosphere forms that focuses stresses but with uplifts and stress levels that are always greater than those obtained for a purely viscous half space. We discuss how classic elastic flexure and purely viscous relaxation are special cases of this more generalized rheological model. Stress concentration in the flexing (i.e., bending) layer can exceed the plastic yield strength of ice for high enough heat flows, weakening the layer somewhat and increasing the total amount of relaxation. These plastic strains tend to be limited to small magnitudes (<0.5%) in a shallow region on the crater floor; such features may be observable in available imagery. The grain size sensitivity of the dominant creep mechanism in ice represents a new input parameter in crater relaxation studies on icy satellites (along with the elastic and plastic moduli, although to a lesser extent). Nevertheless, we find that for reasonable input parameters our simulations reproduce the continuum of relaxation states seen on Ganymede and Callisto. A combination of higher surface temperatures (∼120–130 K) and larger grain sizes (>1 mm) permits both retention and relaxation of topography at the lower and higher ends, respectively, of the anticipated heat flow range. Consideration of relaxed craters in Marius Regio and of the palimpsests and penepalimpsests suggests ancient heat flows in excess of 10 mW m−2, consistent with other estimates.
Calculation of the surface tension of oxygen using molecular-dynamics simulations
Authors: Bembenek Scott D.
Published: December 2005

The surface tension of oxygen at the liquid-vapor interface is calculated for the temperature range of 60–90K using molecular-dynamics simulations and is shown to be within 1.0% error of experimental values for most of the temperatures studied. The potential used here is the same as in our previous study on liquid oxygen alone [S. D. Bembenek and B. M. Rice, J. Chem. Phys. 113, 2354 (2000)] and was optimized with an innovative statistical-mechanical method. The potential does not use a long-range cutoff nor a tail correction, which are usually considered necessary to obtain accurate values for the surface tension. We reason that the accuracy in surface tension is directly related to our parametrization method for the potential.
Vibronic coupling in cyclopentadienyl radical: A method for calculation of vibronic coupling constant and vibronic coupling density analysis
Authors: Sato Tohru , Tokunaga Ken , Tanaka Kazuyoshi
Published: January 2006

A method of calculation of vibronic or electron-phonon coupling constant is presented for a Jahn-Teller molecule, cyclopentadienyl radical. It is pointed out that symmetry breaking at degenerate point and violation of Hellmann-Feynman theorem occur in the calculations based on a single Slater determinant. In order to overcome these difficulties, the electronic wave functions are calculated using generalized restricted Hartree-Fock and complete active space self-consistent-field method and the couplings are computed as matrix elements of the electronic operator of the vibronic coupling. Our result agrees well with the experimental and theoretical values. A concept of vibronic coupling density is proposed in order to explain the order of magnitude of the coupling constant from view of the electronic and vibrational structures. It illustrates the local properties of the coupling and enables us to control the interaction. It could open a way to the engineering of vibronic interactions.
Evidence of plasma-catalyst synergy in a low-pressure discharge
Authors: Rousseau Antoine , Meshchanov Alexander V. , Roepcke Jürgen
Published: January 2006

A low-pressure pulsed dc discharge in air has been used to study the mechanisms of the activation of an oxidative catalyst by plasma irradiation. Porous alumina has been employed as the catalyst. The oxidation of acetylene (C2H2) has been monitored measuring simultaneously the concentrations of CO and CO2 by infrared laser absorption spectroscopy. It was found, that the oxidation efficiency and the CO2∕CO selectivity are greatly enhanced by the presence of the catalyst inside the plasma region and increase with the duty cycle ratio of the pulsed plasma.
Comparing observed and simulated water storage during drainage to select hydraulic parameters for volcanic soils
Authors: Tomer M. D. , Tomer M. D.
Published: January 2006

In soil-water modelling, hydraulic parameters must be chosen carefully to
simulate water fluxes accurately. This study aimed to parameterise the Soil
Water Infiiltration and Movement (SWIM) model for sandy volcanic soils that
are irrigated with wastewater from Rotorua, New Zealand. Three plots
1·5 by 1·5 m were dyked, flooded until soils approached
saturation, and then covered to prevent evaporation. Water-content
measurements were taken to 1 m depth during 20 days of drainage. For each
profile, this drainage process was simulated using 9 combinations of hydraulic
conductivity [K(θ)] and soil water
desorption θ(ψ) parameters. The θ(ψ) parameters were fitted
with different ranges of desorption data, using Campbell’s approach.
K(θ) parameters were obtained from flow
measurements using soil cores or disc permeameters, through use of
Campbell’s method, and by applying a unit-gradient analysis to the
drainage data. Model output was compared with measured water contents
graphically and statistically. Several combinations of parameters provided
good agreement between simulated and observed data, but no single combination
gave the best prediction for all 3 profiles. Campbell’s approach to
determine the slope of K(θ) function provided
excellent agreement for 2 of the profiles. In the third profile, a nearly
steady water content during drainage at 1 m depth was closely simulated using
parameters from the unit gradient approach. Total measured drainage ranged
between 8·6 and 15·9 cm amongst the 3 profiles. Results provide
3 parameterised profiles for modelling water movement in these soils, which
receive >4000 mm of rainfall and irrigation annually.
Groundwater level reductions under lucerne depend on the landform and groundwater flow systems (local or intermediate)
Authors: Ferdowsian Ruhi , Ryder Arjen , George Richard , Bee Geoff , Smart Rob
Published: January 2006

By 1994, an estimated 1.8 million hectares of cleared land in Western
Australia was affected by secondary dryland salinity to some extent. The area
affected is likely to double in the next 20 years. The cause of this salinity
is excessive recharge under traditional agriculture, leading to rising
groundwater levels. To effectively reduce land and water salinity a
deep-rooted perennial is needed to mimic the temporal and spatial distribution
of leaf area that existed prior to clearing. Previous studies have shown
lucerne lowers groundwater levels in areas with favourable conditions.
We present data showing that lucerne lowered groundwater levels in 4 different
landforms and under unfavourable conditions. All sites had very saline
groundwater, high sodium chloride chemistry and high groundwater levels. This
paper shows that the effectiveness of lucerne in salinity control measures
depends on the attributes of the groundwater flow system.
salinity, salinity management, monitoring, sustainability.
Lignin, carbohydrate, and amino sugar distribution and transformation in the tropical highland soils of northern Thailand under cabbage cultivation, Pinus reforestation, secondary forest, and primary forest
Authors: Möller A. , Kaiser K. , Zech W.
Published: January 2006

Structure and transformation processes of soil organic matter (SOM) are extremely complex, but advancing our knowledge on SOM cycling is a prerequisite for a sustainable soil management. To get a better insight to this issue, we determined the vertical distribution of lignin, carbohydrates, and amino sugars in bulk soils and NaOH-extracts using wet chemical techniques. These results were compared with those obtained by solution 13C nuclear magnetic resonance (NMR) spectroscopy after alkaline extraction. Soil samples were taken under a primary forest, a secondary forest, a 20-year-old Pinus kesiya (Royle ex Gordon) reforestation established following 15 years of cultivation, and a cabbage cultivation site in northern Thailand. Significantly lower contents of organic C and N at the cabbage cultivation and reforestation sites indicated that the replacement of forests by arable land at the reforestation and cabbage cultivation sites about 30 years ago resulted in enhanced breakdown of SOM. This means that after 20 years of Pinus growth, reforestation did not lead to a significant build-up of organic matter in the mineral soil. With increasing soil depth the sites showed comparable decreases in soil organic matter, exhibiting a typical pattern of decomposition expressed by a higher degree of side chain oxidation, increasing carboxyl functionality, and a decrease of lignin-derived phenols and aromatic compounds. Microbial contribution to SOM was determined using the carbohydrate and amino sugar biomarker approach. The amino sugars were predominantly of fungal origin in the organic layer. In the mineral soil, bacterial amino sugars dominated and the relative contribution of amino sugars to SOM increased with depth. Comparison of results from wet chemical analyses and of liquid-state 13C NMR signatures requires that alkaline-extractable organic matter is representative for bulk soil organic matter. This seemed to apply to lignin-derived phenols and amino sugars but not to neutral sugars and uronic acids. Significant correlations were found for lignin-derived phenols with phenolic C (R = 0.74, P < 0.01) for the bulk forest site samples and amino sugars with O-alkyl C (R = 0.93, P < 0.001) for the mineral soil horizons, whereas the carbohydrate contents did not show any clear correlation. Therefore, we concluded that most of the phenolic C signal intensity might be attributed to lignin, and the enrichment of O-alkyl C with depth may be a result of bacterial resynthesis with a significant contribution of amino sugars.
A simple phosphorus buffering index for Australian soils
Authors: Burkitt L. L. , Moody P. W. , Gourley C. J. P. , Hannah M. C.
Published: January 2006

Soil phosphorus (P) buffering capacity (PBC) is an important soil property
that influences the amount of P fertiliser available for plant uptake.
However, current methods of determining PBC are time-consuming and uneconomic
in most commercial soil testing programs. The current study examined simpler
methods of measuring the PBC of a wide range of Australian soils. Phosphorus
sorption and extractable P data from 290 soils (initial data set) were
collated to define the range of PBC values of Australian agricultural soils.
Independently, detailed chemical and physical analyses were undertaken on a
second set of 90 agricultural soils (principal data set), which were selected
to represent the range of soil properties measured on the initial data set.
Relationships between PBCO&S (Ozanne and Shaw 1968)
values (P sorbed between solution P concentrations of 0.25 and 0.35 mg
P/L) and 11 different single-point P sorption indices and selected soil
properties were examined for the principal data set. Whilst relationships
between PBCO&S values and selected soil properties
such as oxalate-extractable iron and aluminium, and clay content, were
generally poor, strong relationships existed between all of the single-point P
sorption indices and PBCO&S. Results suggest that
PBCO&S values were most closely related to the P
buffering indices (PBI+ColP and
PBI+OlsP) when a single addition of 1000 mg
P/kg was added to soil and either the Colwell or 4.59 Olsen extractable P
were added to the amount of P sorbed:
PBI+ColP =
(Ps + Colwell
P)/c0.41
PBI+OlsP =
(Ps + 4.59 Olsen
P)/c0.41
where Ps is the amount of P sorbed
(mg P/kg) from a single addition of 1000 mg P/kg, and
c is the resulting solution P concentration (mg
P/L).
This index provides a simple and accurate method for estimating PBC, a
fundamental soil property that influences the P fertiliser requirements of
different soil types.
phosphorus sorption capacity, single-point phosphorus sorption index,
phosphorus retention index, soil properties, Colwell phosphorus, Olsen
phosphorus.
Soil properties under organic and conventional management in southern New South Wales
Authors: Derrick J. W. , Dumaresq D. C.
Published: January 2006

From 1991 to 1993 a program of soil sampling was undertaken on neighbouring
properties, under organic and conventional management, at Ardlethan in
southern NSW. The organic farm was long established, as organic management had
commenced in 1963. The conventional farm was well managed in typical fashion
for the district. Soil sampling took place in the autumns of 1991, 1992, and
1993. Samples were taken to a depth of 150 mm and analysed for a range of
nutrients. Soil on the organic farm contained significantly lower
concentrations of extractable P and exchangeable Mn, and had higher pH and
higher concentrations of exchangeable Na, Ca, and K. There was no
statistically significant difference between the farms in the concentrations
of total Mg, Na, N, Mn, and K, nor in exchangeable Mg and organic carbon
content.
The four laws of soil chemistry: the Leeper lecture 1998
Authors: Barrow N. J.
Published: January 2006

The proposed 4 laws of soil chemistry are: ions react with charged surfaces;
soil surfaces are heterogeneous; an initial adsorption reaction is followed by
a penetration of the adsorbed ions into the interior of the reacting
particles; and it is impossible to re-apply fertiliser to the same soil
because the soil has changed. These laws can explain the observed behaviour of
the reactions of cations and anions with soil. These include the effects of
the level of application, period of reaction, effects of temperature,
interactions between pH and salt concentration, desorption, and the isotopic
exchangeability.
Accessibility of subsoil potassium to wheat grown on duplex soils in the south-west of Western Australia
Authors: Wong M. T. F. , Edwards N. K. , Barrow N. J.
Published: January 2006

The B horizon of duplex soils in the wheatbelt of Western Australia is
sometimes enriched with potassium (K). K supply from this source is, however,
not taken into account in fertiliser recommendations based on soil tests on
samples from the 0–10 cm layer. Grain yield responses of wheat to K were
measured over 4 years on 10 duplex soils in the medium rainfall (400–600
mm) regions of the West Australian wheatbelt. The depth at which the texture
changed markedly ranged from 25 to 75 cm. K was measured through the profile
and the concentration was reduced to a single value with a weighting equation
that takes account of the distribution of root length. The weights chosen by
the fitting procedure discounted the K content of the subsoil severely and
provided no evidence that subsoil K was important in determining yield.
Furthermore, the improvement obtained by using the weighted K concentration in
the 0–1 m layer compared with using the topsoil (0–10 cm) analysis
was not statistically significant. K deficiency can be diagnosed in those
soils using analysis of the 0–10 cm samples only.
Annual denitrification rates in agricultural and forest soils: a review
Authors: Barton L. , McLay C. D. A. , Schipper L. A. , Smith C. T.
Published: January 2006

Denitrification is an important soil process for assessing nitrogen cycling
and controlling nitrogen pollution in the environment. Numerous studies of
denitrification rates in soils have been reported over the last decade, many
with sampling protocols that are more reliable than in the past. In this
paper, we review denitrification rates for agricultural and forest soils that
have been reported in the literature, discuss factors that appear to be
important in controlling the amount of denitrification that occurs in these
soils, and summarise modelling approaches that have been used to predict
annual denitrification rates.
Most studies of in situ denitrification in upland soils
have been conducted in agricultural grassland and forest ecosystems, with a
paucity of studies reported from other ecosystems. A large range of annual,
in situ, denitrification rates have been reported
(0–239 kg N/ha.year), with the highest rates typically occurring in
irrigated, nitrogen-fertilised soils. However, most annual denitrification
rates reported in the literature appear to be fairly low, with over half of
the rates in forest soils being <1 kg N/ha.year (mean of 1.9 kg
N/ha.year). Rates of denitrification in agricultural soils tend to be
higher than in forest soils, with 85% of rates reported being >1 kg
N/ha.year, and a mean rate of 13 kg N/ha.year. Numerous soil, site,
and management factors have been reported to affect the denitrification
process in situ. The literature indicates that the
highest rates of denitrification can be expected in nitrogen-fertilised soils,
or where site management increases soil nitrate availability. Where nitrate is
non-limiting, denitrification rates appear to be highest in irrigated loam
soils. The review suggests that it is difficult to predict denitrification
rates based on our current understanding, and that pilot studies should still
be conducted if soil nitrogen balances are required.
Salinity increases cadmium uptake by wheat and Swiss chard from soil amended with biosolids
Authors: Weggler-Beaton K. , McLaughlin M. J. , Graham R. D.
Published: January 2006

Soil salinity has been shown to significantly increase cadmium (Cd)
concentrations in crops grown on soils fertilised with phosphatic fertilisers
containing Cd. However, the effect of soil salinity on plant availability of
Cd derived from biosolids is unknown. This paper reports the influence of
increasing chloride (Cl) (NaCl) concentrations in soil solution on the
phytoavailability of Cd in soils amended with biosolids (equivalent to 50
t/ha). Wheat (Triticum aestivum cv. Halberd) and
Swiss chard (Beta vulgaris cv. Foodhook Giant) were
grown in biosolids-amended soil and watered daily with a dilute NaCl solution
(0–27.4 mМ). After 30 days, plant shoots were analysed for Cd and
soil solution was displaced. Major cations and anions in soil solution were
determined and Cd speciation was calculated with the computer program
GEOCHEM-PC. Cadmium concentrations in soil solution and shoots of wheat and
Swiss chard plants increased linearly with increasing Cl concentration in soil
solution of the biosolids-amended soil. The activity of
CdCl+ species correlated best with the Cd uptake of
both plant species. Increases in shoot Cd concentrations were unrelated or
only weakly correlated to the activity of the free
Cd2+ ion in solution. It was concluded that
chloro-complexation of Cd increased the phytoavailability of Cd in
biosolids-amended soil.
The distribution of net nitrogen mineralisation within surface soil. 1. Field studies under a wheat crop
Authors: Purnomo Erry , Black A. S. , Smith C. J. , Conyers M. K.
Published: January 2006

To test the hypothesis that net nitrogen (N) mineralisation is concentrated in
the surface few centimetres following minimal soil disturbance for crop
establishment, mineralisation was measured during the growth of wheat. The
soil was a Red Kandosol located in southern New South Wales. Mineralisation
was estimated usingin situ incubations inside capped PVC
tubes, which were sampled every 3 weeks. Soil from the tubes was sampled at
depth intervals of 2 cm to a depth of 10 cm and at 5-cm intervals from 10 to
20 cm.
The results showed that net N mineralisation decreased with depth to 20 cm.
Over the season, an average of 32% of the N mineralised in the top 20
cm of soil originated from the 0–2 cm layer, 72% was from the
0–6 cm layer, and only 13% was from soil below 10 cm. The
decrease in N mineralisation with soil depth was highly correlated with
decreases in the organic carbon
(r2 = 0.84,
P < 0.05) and total N
(r2 = 0.83,
P < 0.05) concentration. The soil's N-supplying
ability is concentrated near the surface where it is susceptible to erosional
loss. The N supply may also be inhibited by temperature and moisture extremes,
which are common in the surface few centimetres of soil where mineralisation
was concentrated. The PVC enclosures created artefacts in soil temperature and
moisture, although it is argued that the effects on net N mineralisation were
small in most sampling periods.
The distribution of net nitrogen mineralisation within surface soil. 2. Factors influencing the distribution of net N mineralisation
Authors: Purnomo Erry , Black A. S. , Conyers M. K.
Published: January 2006

This investigation examined the magnitude of gradients in net nitrogen (N)
mineralisation through the surface 20 cm of soils used for cropping, and
factors influencing these gradients. Soils used were W (Red Kandosol) from a
previous field study, CT (conventional tillage) and DD (direct drilled) from a
long-term rotation experiment on a Red Kandosol, and YS (Yellow Sodosol) from
under wheat established by reduced tillage. Soil was collected in 2-cm
intervals to a depth of 10 cm and at 5-cm intervals between depths of 10 and
20 cm. All depths were used from soil W but only depths of 0–2,
8–10, and 15–20 cm were used for the remaining soils. Soils were
incubated for 0, 2, 4, 8, and 16 weeks under controlled conditions (soil
water, 80% of water-holding capacity; temperature, 20˚C; aeration,
1 h/week). Net N mineralisation and carbon dioxide
(CO2) evolution were measured.
Heterotrophic activity as measured by CO2 evolution
decreased with depth but was still evident in soil from below 10 cm. This
activity was strongly correlated with the concentration of organic carbon (C)
(r = 0.88, P < 0.05) and
soil pH (r = 0.80, P <
0.05). The percentage of organic C released as CO2 was
highly correlated with pH (r = 0.86,
P < 0.05), implying that, when sampled at an
appropriate scale, acidity limits heterotrophic activity. Net N mineralisation
decreased with depth in all soils. In soil W, 59% of net N mineralised
originated from 0 to 2 cm, 87% was from the surface 6 cm, and only
1% was from below 10 cm. This was similar to the distribution of net N
mineralisation found in the field experiment reported in the previous paper.
Net N mineralisation was correlated with CO2 evolution
(r = 0.97, P < 0.01) and
pH (r = 0.73, P < 0.05).
The C : N ratio increased from 18 in the surface 6 cm to 27 between 10 and 20
cm. The lack of net N mineralisation below 10 cm was attributed to this
increase in the C : N ratio.
This is the first observation of gradients in net N mineralisation with depth
at this scale in different tillage systems.
Magnesium fertiliser dissolution rates in pumice soils under Pinus radiata
Authors: Mitchell A. D. , Loganathan P. , Payn T. W. , Tillman R. W.
Published: January 2006

Application of Mg fertilisers has been suggested as a means of reducing the
incidence of Mg deficiency of forest trees in New Zealand and Europe. The
objective of this study was to determine the rates of dissolution of a range
of Mg fertilisers applied to a pumice soil (Typic Udivitrand).
The rate of fertiliser dissolution was little influenced by whether the
fertiliser was applied directly on to the soil surface (litter removed) or on
to the litter layer in a Pinus radiata plantation.
Twenty-seven months since fertiliser application the mean (with and without
litter) percentage of Mg dissolved was in the sequence: Epsom salts >
calcined magnesite 1–2 mm > granmag (a partially acidulated and
granulated calmag product) > calcined magnesite 2–4 mm > forestry
grade dolomite. The specific dissolution rate constants
(mg/cm2 .day of fertiliser) for the slowly soluble
Mg fertilisers calculated using an elemental sulfur oxidation cubic model were
587 for calcined magnesite 1–2 mm, 426 for calcined magnesite 2–4
mm, 385 for granmag, and 18 for forestry grade dolomite. In a laboratory
incubation study the elemental sulfur oxidation cubic model described the rate
of dissolution of Mg fertilisers within narrow fertiliser particle size
ranges. The specific fertiliser dissolution rate constants, however, increased
with decreases in particle size, suggesting that the rate of dissolution
depends on factors other than surface area when particle sizes varied widely.
Slowly soluble, alkaline Mg fertilisers had a significant liming effect on the
soil. They were more effective in increasing soil exchangeable Mg than soluble
Mg salts over a long-period and therefore, they are better fertilisers for
P. radiata.
Physical and chemical protection of soil organic carbon in three agricultural soils with different contents of calcium carbonate
Authors: Clough A. , Skjemstad J. O.
Published: January 2006

The amount of organic carbon physically protected by entrapment within
aggregates and through polyvalent cation–organic matter bridging was
determined on non-calcareous and calcareous soils. The composition of organic
carbon in whole soils and <53 m soil fractions was determined by
13C NMR analysis. High energy photo-oxidation was
carried out on <53 m fractions and results from the NMR spectra showed
17–40% of organic carbon was in a condensed aromatic form, most
likely charcoal (char).
The concept that organic material remaining after photo-oxidation may be
physically protected within aggregates was investigated by treating soils with
a mild acid prior to photo-oxidation. More organic material was protected in
the calcareous than the non-calcareous soils, regardless of whether the
calcium occurred naturally or was an amendment. Acid treatment indicated that
the presence of exchangeable calcium reduced losses of organic material upon
photo-oxidation by about 7% due to calcium bridging.
These results have implications for N fertiliser recommendations based upon
organic carbon content. Firstly, calcium does not impact upon degradability of
organic material to an extent likely to affect N fertiliser recommendations.
Secondly, standard assessment techniques overestimate active organic carbon
content in soils with high char content.
A mesoscale model application to fire weather winds
Authors: Gómez-Tejedor José A. , Estrela María J. , Millán Millán M.
Published: January 2006

In this work, a mesoscale model has been used to simulate the wind flow in a
real fire situation in the Spanish Mediterranean basin in July 1991. The model
simulation results for the wind field are shown, and compared to the fire
evolution, and to some real observations taken in the area during the fire
event. The most important conclusion is that, in spite of the presence of the
fire, the mesoscale model was still able to predict the local winds accurately
without taking the fire heating processes into account.
Soil Erosion and Forestry Management After Wildfire in a Mediterranean Woodland, Mt. Carmel, Israel
Authors: Inbar M , Wittenberg L , Tamir M
Published: January 2006

Forestry management is crucial in mitigating erosion processes after extensive fires in Mediterranean woodlands. Fire alters forest ecosystems, causing an increase in rates of geomorphic processes. The September 1989 fire in Mt. Carmel covered an area of 4 km2 in the main recreation area of a typical Mediterranean forest area. Six experimental plots, covering an area of 300-500 m(2) each, were established in order to determine the effect of forestry management practice on soil erosion after the fire; runoff and sediments were collected during and after each rainstorm. Rainfall was measured by two recorders and several rain gauges at the study site. During the first year following the fire, sediment yield was 100-500 times higher than on vegetated slopes. Sediment movement was increased mainly by the lack of vegetation. Results show that there is a clear trend of decrease in sediment yield between the first year and the next five. After this period the burnt areas recovered to similar rates of erosion as in the unburnt areas. The clearings of burnt logs by machine and cable sliding increased the sediment yield in the experimental plots. After vegetation development in the second season following the fire, no significant differences were found among the types of management practice plots.
Wildland Fire Danger Zoning - a Methodology
Authors: Gouma V , Chronopoulou-Sereli A
Published: January 2006

A mountain area in Southeastern Greece exposed to wildland fire problems was used to establish a method for fire danger zoning. Meteorological risk (MR), fuel susceptibility (FS) and fire occurrence (FO) maps are created. The method integrates these maps and produces the constant and variable danger (CFD,VFD) zones that require respective activities for wildland fire prevention. A Geographic Information System (GIS) was used to perform the overlay analysis of thematic maps and delineate the fire danger zones.
Relationships Between Fire Severity and Atmospheric and Leaching Nutrient Losses in British Columbia's Coastal Western Hemlock Zone Forests
Authors: Belillas CM , Feller MC
Published: January 2006

The relationships between fire severity and fire-induced nutrient losses to the atmosphere and through soil leaching were investigated using small (4m2) plots in logging slash. The study utilized (Pseudotsuga menziesii - Tsuga heterophylla - Thuja plicata) slash in southwestern British Columbia, Canada, in an area where overland flow was negligible. Twenty-two plots containing a range of slash fuel loads were burned, nutrient (N, P, S, K, Mg, and Ca) losses to the atmosphere were measured, and nutrient (N, P, K, ME, and Ca) losses in soil leachate were quantified for the first year postburn. For a given nutrient, total (atmospheric plus leachate) fire-induced losses were similar to atmospheric losses and could be reliably predicted from them due to the relatively low magnitude of leaching losses; Leaching losses were generally poorly related to atmospheric losses. Total, atmospheric, and most leaching losses increased as fire severity (defined as fuel consumption) increased. Nutrient losses were better estimated from fuel consumption variables than they were predicted from fuel load variables. As most of the results of the study were consistent with those of studies conducted elsewhere, these results likely apply to a wider geographic area and range of fire situations than those of the present study. The effort and cost of assessing total fire-induced losses in, at least, North American conifer forests can be minimized, without sacrificing much accuracy, by not measuring fire-induced soil leaching losses, but assuming these are 5-20 kg/ha, depending on the nutrient and the severity of the fire. If nutrient leaching into water bodies is to be quantified, then measurement of leaching losses would be necessary.
A New Method to Estimate Fuel Surface Area-to-Volume Ratio Using Water Immersion.
Authors: Fernandes PM , Rego FC
Published: January 2006

A fast, simple, low cost and general technique for estimating fuel surface area-to-volume ratio is presented. The technique requires particle density, the determination of fuel weight before and after immersion in water and the theoretical thickness of the adsorbed water pellicle that is assumed constant. Estimates by the technique were consistent and in good agreement with published surface area-to-volume ratios for the same fuels obtained through other methods, and its performance was judged appropriate for current fire behaviour modelling needs. This water immersion technique was applied to various shrubs and trees grown in Portugal. Limitations and possibilities for improvement of the newly developed technique are discussed.
Heat Content Variation of Sierra Nevada Conifers
Authors: Van Wagdendonk JW , Sydoriak WM , Benedict JM
Published: January 2006

A study of fuels of Siena Nevada conifer species showed that percent ash content, heat content with ash, and heat content without ash of needle and duff fuels significantly varied by species, fuel component, and developmental stage of the overstory. Ash and heat contents of woody fuels varied by species and fuel component but not by developmental stage. Bark fuels significantly differed by species, while no factor significantly affected cone fuels. Regional variation in ash and heat content was evident but small. However, the values reported here for heat content with ash for fine fuels averaged 2.50 MJ kg-1 higher than the standard values used in fire behavior prediction systems. Using standard values can result in significant under predictions of fireline intensity of an average of 16 percent for all species of up to 47 percent for Pinus albicaulis.
Short-term ecological effects of rabbit haemorrhagic disease in the short-tussock grasslands of the South Island, New Zealand
Authors: Norbury Grant , Heyward Richard , Parkes John
Published: January 2006

Rabbit haemorrhagic disease (RHD) has reduced populations of rabbits (Oryctolagus cuniculus) across most rabbit-prone short-tussock grasslands of New Zealand, at scales rarely seen there before. Flow-on effects to other parts of these ecosystems will be inevitable. We report evidence for increases in pasture biomass, increases in abundance of other exotic herbivores, declines in abundance of rabbit-specialist predators, and short-term increases in predation rates of some native birds by these predators. At one site in Central Otago, RHD reduced an index of rabbit abundance by 88%, and an index of their grazing impacts by 77%. Recovered biomass consisted mostly of fast-growing exotic pasture species of moderate palatability to livestock. Spotlight counts and hunters' returns suggest increases in possum (Trichosurus vulpecula) and hare (Lepus europeaus) abundance, but their grazing pressure is unlikely to replace that originally imposed by rabbits. The apparent increase in possum numbers poses an increased risk from the spread and maintenance of bovine tuberculosis (Tb), although this risk may be offset by declines in the counts of ferrets (Mustela furo), which also carry Tb. Declines in predator numbers (including feral cats, Felis catus) may also, in the longer term, benefit some native fauna that are secondary prey of these predators. There is evidence for increased predation of some native birds' eggs since RHD arrived. It is not possible at this stage to generalise the effects of RHD-induced declines in rabbit abundance on New Zealand ecosystems. Effects are highly variable, and their implications for pastoral production, management of bovine Tb, and conservation of native species are likely to vary locally according to the suite of plant and animal species originally present.
Emerging epidemiological patterns in rabbit haemorrhagic disease, its interaction with myxomatosis, and their effects on rabbit populations in South Australia
Authors: Mutze Gregory , Bird Peter , Kovaliski John , Peacock David , Jennings Scott , Cooke Brian
Published: January 2006

The impact of rabbit haemorrhagic disease (RHD) on wild rabbit populations was assessed by comparing population parameters measured before the introduction of RHD into Australia in 1995 with population parameters after RHD. We used data from an arid inland area and a moist coastal area in South Australia to examine the timing and extent of RHD outbreaks, their interaction with myxomatosis and their effect on breeding, recruitment and seasonal abundance of rabbits. From this we propose a generalised conceptual model of how RHD affects rabbit populations in southern Australia. RHD decreased long-term average numbers of rabbits by 85% in the arid area. In the coastal area, RHD decreased numbers of rabbits by 73% in the first year but numbers gradually recovered and were only 12% below pre-RHD numbers in the third year. Disease activity generally begins a month or two after the commencement of breeding in autumn or winter, peaks in early spring and ceases to be apparent in summer. Where the disease is most active, the pattern of population change is almost the inverse of the former pattern. During the breeding season, RHD severely suppresses rabbit numbers. Compensatory recruitment of late-born young, protected by maternal antibodies until the disease becomes inactive at the end of spring (also the end of breeding), allows the observed rabbit abundance to increase during summer, albeit to lower levels than before RHD. Maternal antibodies are lost during summer and the population becomes susceptible to RHD. The seasonal peak in myxomatosis activity is pushed back from late spring to early summer or autumn. Survivors of myxomatosis breed after opening rains in autumn but many succumb to RHD before raising their litters. The reduced abundance of rabbits and changed pattern of seasonal abundance have potential consequences for vegetation recovery.
Using aspects of predator-prey theory to evaluate helicopter shooting for feral pig control
Authors: Choquenot David , Hone Jim , Saunders Glen
Published: January 2006

Because it achieves rapid reductions in pig density, helicopter shooting is
perceived to be a cost-effective option for feral pig control. In order to
evaluate the cost effectiveness of the technique and develop predictive models
of variation in costs, functional response models derived from
predator–prey theory were fitted to 3 data-sets describing variation in
kill rates with feral pig density. The data-sets were collected during
shooting programs conducted on the Mary River floodplain in northern
Australia, and on the Macquarie Marshes and Paroo River floodplain in western
New South Wales. Fitted models indicated that variation in kill rates with pig
density took the form of a Type 3 functional response for all 3 data sets,
kill rates approaching a constant maximum at high pig densities and declining
toward 0 at pig densities greater than 0. While maximum kill rates were
similar for the 3 shooting programs (average 60.49 kill
h–1, range 49.64–76.28), densities below
which no pigs would theoretically be killed varied significantly (average 2.79
pigs km–2, range 1.34–5.02). Similar maximum
kill rates for the 3 shooting programs indicates that, once located, the time
taken by shooting teams to dispatch pigs was relatively constant (0.023 h).
Variation in threshold densities below which no more pigs would theoretically
be shot, indicates that as the density of pigs was reduced, their
vulnerability to shooting teams differed between the 3 shooting programs. This
may have reflected differences between sites in either the capacity of
resident pigs to learn to evade shooting teams or, more likely, the
availability of refuge habitat. For 2 of the shooting programs, too few data
were available to estimate the effect of declining pig density on kill rate,
precluding detailed examination of differences in the efficiency with which
pigs were found (search efficiency). Using estimates of pig density below
which no pigs would theoretically be shot to set a limit to the effectiveness
of shooting programs, models predicting variation in hours per kill with pig
density were derived from each data set. These models demonstrated that hours
per kill increased exponentially as shooting reduced pig populations below
threshold densities of approximately 2–6 pigs
km–2. Generalised models relating variation in
cost per kill to pig density for the 3 shooting programs are described.
Optimising bait size and 1080 concentration (sodium monofluoroacetate) for the control of brushtail possums Trichosurus vulpecula)
Authors: Frampton C. M. , Warburton B. , Henderson R. , Morgan D. R.
Published: January 2006

A method is presented for quantitatively assessing the likely effectiveness of
specific bait size and 1080 concentration for controlling brushtail possums
with a known weight distribution. Data from aerial 1080 operations for the
control of brushtail possums in New Zealand show that estimates of the bait
size and toxic concentration required derived from the mean parameters
[pest weight, bait size, and lethal dose (LD
95)] will not be accurate. This inaccuracy is most
likely to lead to an underestimate of the amount of toxin presented to each
animal, so that many operations currently run the risk of sub-lethally dosing
possums and thereby possibly inducing some degree of poison shyness. On the
basis of more accurate quantitative assessments of bait effectiveness we
recommend that the 1080 concentration be increased to 0.15% and that
baits less than 5 g be excluded to ensure that when mean possum weights are
less than 3 kg more than 95% of possums are lethally dosed by a single
bait.
Home range and movement of foxes (Vulpes vulpes) in coastal New South Wales, Australia
Authors: Meek Paul D. , Saunders Glen
Published: January 2006

Data on the home range and activity of 14 foxes was collected from coastal
habitat in Jervis Bay, New South Wales during 1993–95. Radio-collared
foxes had a mean home range of 135 ha and core activity areas of 23 ha
(determined by the Minimum Convex Polygon method). There were no significant
differences in the home ranges of male and female foxes. The home ranges of
some foxes shifted throughout the study. Some animals went on long forays
beyond their normal range. All animals displayed nocturnal activity patterns
except during the breeding season or after long spells of wet weather when
some foraging occurred during daylight hours. The information collected in
this study is discussed in the context of fox control.
Feeding ecology and population dynamics of the feral cat (Felis catus) in relation to the availability of prey in central-eastern New South Wales
Authors: Molsher Robyn , Newsome Alan , Dickman Chris
Published: January 2006

The diet of feral cats (Felis catus) was studied at Lake
Burrendong, central-eastern New South Wales, from July 1994 to June 1997.
Mammals were the major prey in 499 scats that were analysed. Rabbits
(Oryctolagus cuniculus) were the staple prey, while
carrion was an important secondary food. Invertebrates, other mammalian prey,
vegetation, birds and reptiles were generally minor components of the diet.
Few significant seasonal differences in diet were found; however,
invertebrates contributed less and possums more to the diet in winter and
summer respectively. A significant dietary response was found to changes in
rabbit abundance, but not for the other prey types. Cats continued to prey
heavily on rabbits even after a 90% decline in rabbit abundance
occurred, which coincided with the advent of Rabbit Calicivirus Disease (RCD).
House mice (Mus domesticus) increased in importance in
the diet ten months post-RCD. Although the abundance of cats was correlated
with the abundance of some prey species, other factors may have influenced the
observed patterns; these are discussed.
Aerial baiting of feral pigs (Sus scrofa) for the control of exotic disease in the semi-arid rangelands of New South Wales
Authors: Fleming Peter J. S. , Choquenot David , Mason Richard J.
Published: January 2006

An experiment that held the density of feral pigs constant while varying the
effective density of aerially distributed baits was conducted at three sites
in north-western New South Wales. Meat baits, containing one of the biomarkers
iophenoxic acid, tetracycline or rhodamine B, were distributed at different
intensities over each site, and a sample of pigs was shot from a helicopter at
each site to determine bait uptake. Serum and tissue samples taken from each
pig were analysed for the occurrence of the biomarkers; the proportions of
pigs exhibiting biomarkers represented the proportions of the feral pig
populations that had consumed baits at different baiting intensities
(expressed as baits per unit of pig density).
The maximum percentage of sampled pigs that had eaten baits varied from
31% to 72% across the three sites. Bait uptake was regressed
against baiting intensity. For two of the trials, the quantity of bait
hypothetically required to eliminate a population of feral pigs was
extrapolated to be 1577 baits per unit of pig density, while for the third
trial 1874 baits per unit of pig density would have been required. Bait-uptake
by non-target animals was substantial, posing potential hazards to birds and
reducing the availability of baits to feral pigs. Most likely, seasonal
conditions affected bait-uptake by feral pigs. We discuss the implications of
these results for exotic disease contingency planning.