bluuebunny/crossref_metadata_2025 huggingface dataset:
A synoptic approach for crop loss assessment used to study wheat. I. An appraisal of the physical and chemical soil properties in the study area
Authors: Stynes BA , Wallace HR , Veitch LG
Published: April 2005

A synoptic approach to crop loss assessment is proposed whereby the relative importance of various factors in the environment can be assessed in relation to the growth and yield of plants. A degree of simplification of complex sets of data, collected in field surveys, can be achieved by analysing natural subsets of the data using multivariate statistical procedures. The concepts that emerge form a basis for constructing regression models to predict growth and yield by influencing the selection of variables for inclusion that ensure statistical stability and biological realism. Wheat crops on Yorke Peninsula, South Australia, were studied to evaluate this approach. This paper, comprising part of the study, is a principal component analysis of the soil properties which form a natural subset of the variables measured. It shows that the variation of soils in the study area can be characterized by the variation of relatively few soil properties.
Prediction of depth to water table in bauxite residue ponds
Authors: Carbon BA , Murray AM , Bartle GA
Published: April 2005

Measurements were taken of the rate of water loss from the water table in columns of bauxite residue. The data were used to develop a simple model to predict the changes in depth to water table, using inputs of weekly rainfall and estimates of potential evaporation. The model was successfully validated against a further experiment and then used to predict water-table behaviour for hypothetical residue ponds in south-west Australia. Evaporative loss from the water table occurred only when the water table was less than 1 m below the soil surface. Unless drained, the water table in many residue ponds would rise above the ground surface in most years.
Isotopic studies of the nitrogen balance in a cracking clay. IV. Fate of the three nitrogen fertilizers in fallow soil in the field
Authors: Craswell ET
Published: April 2005

Urea, ammonium sulfate and calcium nitrate, labelled with 15N, were added to 30-cm diameter microplots at a cracking clay field site. Sorghum stubble was applied to one series of microplots, while another series was stubble-free. The plots were kept fallow for 14 weeks after which the loss, movement and immobilization of the 15N added in the fertilizers was measured. Losses totalled 9, 23 and 26% of the urea, ammonium sulfate and calcium nitrate respectively. Denitrification, which occurred during the sixth and seventh weeks of the experiment when the soil was waterlogged, was presumed to be the loss mechanism; the differences in rate of loss would then be related to the rate of nitrification of the urea and ammonium fertilizers. Adding sorghum stubble did not influence the rate of loss but caused net immobilization of an extra 5 % of the added nitrogen; immobilization was 11, 11 and 7% in the microplots receiving urea, ammonium sulfate and calcium nitrate respectively. The 155 mm of rain received during the 14 weeks leached 20% of the added nitrate and only 10% of the other fertilizers below 30 cm.
The insoluble copper phosphates in copper superphosphate and their availability to plants
Authors: Gilkes RJ , Lim-Nunez R
Published: April 2005

Three insoluble copper phosphates were found to occur in commercial copper superphosphates. These compounds have been characterized by chemical, X-ray diffraction, thermal and infrared analysis. Copper in these compounds is as available to plants as copper in water-soluble compounds.
Changes in the abundance of large soil animals and physical properties of soils following cultivation
Authors: Abbott I , Parker CA , Sills ID
Published: April 2005

Regular ploughing and stocking physically alter the soil. We hypothesized that these practices render soil unsuitable for large soil animals, and that the presence of large soil animals in turn enhances soil friability and infiltration of water. We found that regularly ploughed and stocked soil in the Western Australian wheatbelt was, with one exception, more compact and less permeable to water than virgin soil. Soil which had not been ploughed or stocked for seven years was as permeable to water as virgin soil, but was intermediate in compaction between virgin and cultivated soil. Virgin soils had more cavities and burrows, as well as more water-stable aggregates, than cultivated soils. Large soil animals were virtually eliminated from the regularly cultivated soils. There was little difference in the number of large soil animals between virgin soil and adjacent soil last cultivated and stocked in 1969. In summer, few large soil animals were found in any soil sampled. These findings are in agreement with the hypothesis stated above.
Weathering studies of Bougainville mine tailings in lysimeters
Authors: Hartley A
Published: April 2005

Lysimeter studies indicated that under wet tropical conditions, there was significant sulfur depletion in the upper strata of low sulfide tailing deposits within three years of exposure. The rate of acidification was influenced by drainage and aeration, and pH fell logarithmically with time. Copper mobilized by acidification was redeposited within the profile where the pH remained in excess of 7.
Note on the three-parameter functions for soil water diffusivity - Water content relationships
Authors: Murali V , Krishna Murti GSR , Sinha AK
Published: April 2005

Two three-parameter functions to describe soil water diffusivity (D)-moisture content (�) relationships were statistically tested with experimental data of 20 soils of India. The results showed that the shapes of the experimental D(�) relations could be accurately described by the three-parameter functions tested. The two functions used are D(�) = a. � m/( �c �)n log D = ao + a1 � + a2/(�c- �), where a, ao, a1, m and n are constants and �c is moisture content close to saturation.
An equivalent salt solutions method for predicting hydraulic conductivities of soils for different salt solutions
Authors: Jayawardane NS
Published: April 2005

Equivalent salt solutions are defined as solutions with combinations of sodium absorption ratio (SAR) and electrolyte concentration producing the same extent of clay swelling in a given soil. It is suggested that in the presence of different equivalent salt solutions a given soil will have the same pore geometry, the same saturated and unsaturated conductivities at specific pressure heads, and hence the same capacity to transmit such solutions under specific boundary conditions. This concept of equivalent salt solutions was used to develop a method for predicting the saturated hydraulic conductivities of soils for different salt solutions. The basic data required for such predictions in a given soil are the equivalent salt solution values and the relationship between saturated conductivity and electrolyte concentration at a given SAR. Saturated conductivities of a red-brown soil and an alluvial soil for salt solutions of SAR 20 and 10 and different electrolyte concentrations predicted by this method were fairly close to measured values. The significance of this concept to field problems involving flow of the salt solutions through soils is briefly discussed.
The soil water balance in a gragiaqualf and its effect on pasture growth in central New Zealand
Authors: Scotter DR , Clothier BE , Turner MA
Published: April 2005

A water balance model for pasture is described, which takes into account the effect of soil water deficits on evapotranspiration. Data from small lysimeters were used to evaluate methods for the estimation of weather-controlled evapotranspiration from well-watered pasture. The relatively simple Priestley and Taylor method was found to be as accurate as the Penman method or the use of Class A pan data. Three years of computed water balance data were found to agree within 40 mm with the soil water deficits measured with a neutron moisture probe. The computed soil water balance was used to assess whether growth would occur on a given day, and to predict unirrigated pasture growth rates for the period December-April of each irrigation season. Predicted and measured pasture growth rates were in reasonable agreement, with the December-April growth rate on unirrigated pasture averaging only half that for irrigated pasture over the four years of the study.
Evaluation of soil phosphate buffering indices
Authors: Holford ICR
Published: April 2005

Seven phosphate buffering indices were evaluated by determining the additional variance accounted for when each index was added to a regression of plant phosphorus uptake on labile soil phosphate. The study was done on two groups of soils: one relatively homogeneous group of 24 soils all formed on the same parent material, and a heterogeneous group of 30 soils formed on a variety of parent materials. A separate pot experiment was done on each group, ryegrass being grown on the homogeneous soils and white clover on the heterogeneous soils. Only two indices did not account for a large and significant increase in variance in phosphate uptake. The extra variance accounted for was much greater in the heterogeneous group than in the homogeneous group, although the total variance accounted for by both variables was greater in the homogeneous group. The much smaller volume of soil used in the ryegrass experiment may explain the smaller buffering effect in the homogeneous soils. The three most effective and consistent indices were a simple index of the maximum buffer capacity, determined from the Langmuir isotherm over a standard range of equilibrium solution concentrations, the slope of the isotherm at the natural solution concentration, and the amount of adsorption at a standard equilibrium concentration of 0.3 pg phosphorus/ml.
Effects of phosphate buffering on the extraction of labile phosphate by plants and by soil tests
Authors: Holford ICR , Mattingly GEG
Published: April 2005

In a glasshouse experiment on 24 calcareous soils, the uptake of isotopically exchangeable phosphorus by ryegrass was negatively related to the phosphate buffer capacity. The corresponding effect of buffering on the extraction of exchangeable phosphorus by sodium bicarbonate was almost identical. In four different soil tests, the greater the effect of buffering on extraction, the higher was the correlation between the soil test and phosphorus uptake by the ryegrass.
Calibration of a neutron moisture meter for catchment hydrology
Authors: Williamson RJ , Turner AK
Published: April 2005

A comprehensive method is described for obtaining calibration curves for a neutron meter. As part of a study of the hydrology of a catchment with swelling clay soils, 30 access tubes were each monitored at six depths, giving a total of about 200 measuring positions, with each position possibly needing its own calibration curve. Three sources of data were used to specify the calibration for each measuring position: (1) Calibration points were derived for each position from data obtained at the installation of each tube. (2) Detailed calibrations were derived for several access tubes in undisturbed soils, using a 'cylinder calibration method' developed for this project; this method enables two or more calibration points to be determined for each measuring position. (3) Neutron soil properties were obtained by direct measurement with simple equipment developed for this project, and used in a modified theoretical model to predict the calibration curves for undisturbed tubes. The technique of individual calibration removes possible errors in the derived soil moisture data over the catchment area.
Changes in aggregate stability and associated organic matter properties after direct drilling and ploughing on some Australian soils
Authors: Hamblin AP
Published: April 2005

After 3-8 years' continuous cropping with conventional cultivation and direct drilling, five Australian soils were examined for changes in structural stability attributable to tillage methods. Some increase in organic carbon was found in four direct drilled soils, and the proportion of carbon in the greater than 2 �m fractions was also higher in these soils after short ultrasonic treatment. Direct drilled soils had significantly greater stability with at least one of the stability tests used, but no soil showed consistently greater stability to five different tests. One direct drilled soil was more stable than its ploughed equivalent after alkaline and neutral salt extraction of metal ions and associated humic substances. One direct drilled soil was more dispersed by polysaccharide extraction. Three direct drilled soils retained greater stability after selective extraction of trivalent metal ions complexed to humic fractions. Structural improvement takes place in Australian soils after several years of direct drilling, but may be at a slower rate and to a lesser extent than has been reported for wetter environments.
The adsorption of lead and other heavy metals on oxides of manganese and iron
Authors: McKenzie RM
Published: April 2005

Measurements were made of the adsorption of cobalt, copper, manganese, nickel, lead, and zinc on nine synthetic manganese oxides and three synthetic iron oxides, to determine the mechanism by which lead accumulates in the manganese oxides in soils. Adsorption of lead by the manganese oxides was up to 40 times greater than that by the iron oxides, and lead was adsorbed more strongly than any of the other ions studied by all of the oxides except goethite. This is considered to be the reason for the accumulation of lead in the manganese oxides in soils. No evidence was found for the oxidation of lead, nor for the formation of specific lead-manganese minerals.
Poorly soluble phosphates in Australian superphosphate: their nature and availability to plants
Authors: Gilkes RJ , Lim-Nunez R
Published: April 2005

Australian superphosphates contain approximately 20 % of their phosphorus content as residual apatite and two water-insoluble phosphates, Ca(Fe0.12Al0.88)H(HPO4)2F2.2H20 and (Fe1.88Al1.12) (K0.28Na0.72)H8(PO4)6.6H20 that result from the use of impure rock phosphates. These compounds resemble phosphates occurring in American and New Zealand fertilizers, and comprise the acid and citrate soluble phosphorus fractions that are determined by statutory chemical tests. Glasshouse trials with wheat indicate that they are less effective phosphorus sources than monocalcium phosphate and will probably reduce the agronomic effectiveness of superphosphate.
Some aspects of the biology and pedological significance of mound-building termites in a red and yellow earth landscape near charters towers, north Queensland
Authors: Holt JA , Coventry RJ , Sinclair DF
Published: April 2005

The five species of mound-building termites occurring in red and yellow earths in a semi-arid woodland near Charters Towers, north Queensland, were found to be Amitevmes vitiosus Hill, Dvepanotermes vubviceps (Froggatt), Nasutitevmes longipennis (Hill), Tumulitevmes pastinatov (Hill), and Tumulitevmes sp, indet.; their distributions and associations with nine other inquiline termite species are discussed. Amitermes vitiosus mounds accounted for 68% of all the mounds examined. Although no significant difference was found in total numbers of mounds per hectare between soils, significantly more mounds of harvester than forager termite species were found on the yellow earths. The number of termite mounds per hectare was estimated at 283 and the total soil material in all the mounds, if spread evenly over the ground, would form a layer 1.25 mm thick. Some of the uncertainties involved in the determination of the amount of soil reworked by termites are discussed. Conservatively estimated rates of accumulation of soil of 0.50-0.025 mm/year indicate that one generation of termite mounds could rework up to 20 t/ha of soil. The 20 cm thick sandy loam A horizons of both the red and yellow earths may have accumulated from the erosional degradation of termite mounds over the past 8000 years.
A pragmatic method to determine the parameters that characterize ponded infiltration
Authors: Collis-George N
Published: April 2005

A procedure is outlined to define those parameters which characterize the infiltration behaviour of a ponded soil. The parameters derive from actual field behaviour and are closely related to but not identical with soil physical properties of established theoretical significance, such as sorptivity and hydraulic conductivity of the transmission zone. For some soils an 'instantaneous' infiltration parameter is required as well as the long-term integral of the sorptivity phenomenon. Results are presented to illustrate the use of these parameters: (1) to distinguish between the infiltration behaviour of different soils; (2) to distinguish changes in the behaviour of a soil under different seasonal conditions; and (3) to test whether soil management practices affect infiltration behaviour. The advantages of the procedure are briefly discussed
Redistribution of caesium-137 by erosion and deposition on an Australian soil
Authors: McCallan ME , O'Leary BM , Rose CW
Published: April 2005

Caesium-137, a nuclear fallout product which is carried down to the ground by rainfall and becomes tightly adsorbed to soil particles, is being used to study soil erosion and accumulation. The measurement of 137Cs activity in soil cores in an upland catchment on the Darling Downs has revealed a vertical and areal distribution of this isotope which is in general agreement with expectations based on the topography, the observed erosion and deposition sites, the variation in 137Cs fallout through time, and hypotheses of 137Cs redistribution. Such information may allow the development of a practical technique for estimating soil erosion and accumulation rates using this isotope; it also allows testing of mathematical models of erosion/deposition processes.
Basic relationships for salinity evaluation from measurements on soil solution
Authors: McIntyre DS
Published: April 2005

Relationships among total ion concentration, electrical conductivity and osmotic potential have been determined on 137 saturation extracts from Australian soils. The results are presented in graphical form with linear regression equations of best fit, and are compared with results for western U.S.A. soils. If the relationships fitted to the US. data are corrected to the temperature at which the present measurements were made, the differences between the two are less than 20%. As well, the electrical conductivity, and the osmotic potential, have been estimated from the measured compositions of the extracts, and compared with the measured values. Good agreement is found for electrical conductivity over a large range, but only over a small range for osmotic potential.
Differences amongst a wide-ranging collection of soils in the rate of reaction with phosphate
Authors: Barrow NJ
Published: April 2005

Samples of soil were collected by colleagues in New Zealand, Thailand, Alabama, California and Hawaii and in four widely spaced locations in Australia. The soils were incubated with a range of levels of added phosphate and the changes in phosphate concentration in the solution were followed for up to 90 days. Eight of the soils were also used in a pot trial which compared the availability of freshly applied phosphate with that of phosphate that had been incubated with the soil. Adsorption was described by a modified Freundlich equation in which the effects of concentration and time were both described by exponent terms. The values of the exponent terms differed between the soils. There was more variation amongst the whole group of soils than amongst the soils collected from within one region. The two exponents were strongly correlated. Differences between the soils in the effects of time, as characterized by the exponent, were not related to the iron or aluminium content of the soil. The soils differed in the extent to which the availability of phosphate to plants decreased when phosphate was incubated with the soil. Equations were formulated to relate the exponent terms measured in the laboratory to the glasshouse measurements of the effect of availability to plants.
Mossbauer spectra of proto-ferrihydrite at 77 K and 295 K, and a reappraisal of the possible presence of akaganeite in New Zealand soils
Authors: Childs CW , Johnston JH
Published: April 2005

The Mossbauer spectra of a synthetic proto-ferrihydrite and a synthetic aluminous proto-ferrihydrite are similar broad paramagnetic doublets at both 77 K and 295 K, with � ~ 0.75 mm s-1 and � ~ 0.33 mm s-1 (295 K), ~ 0.43 mm s-1 (77 K). Each spectrum can be fitted by two Lorentzian doublets, having � ~ 0.60mm s-1, 0.95 mm s-1, but the iron nuclei probably exist in a range of very similar sites, related to the poorly ordered nature of the material, rather than in two specific sites. An earlier assignment of akagankite as one of the iron-containing minerals in some soil and soil concretion samples, from Mossbauer evidence, is now considered to be an error. Those peaks attributed previously to akagankite can equally well be accounted for in terms of ferrihydrite phases, and this is supported by evidence from other techniques.
Weathering and development of two contrasting soils formed from granodiorite in south-east Queensland
Authors: Koppi AJ , Williams DJ
Published: April 2005

Mineral weathering in two soils, contrasting in colour and clay distribution, formed from granodiorite, was studied by X-ray diffraction, chemical and optical techniques. The feldspars, hornblende, and quartz become comminuted and appear to be weathering entirely by solution. The main source of clay is from the weathering of biotite which gives hydrobiotite, vermiculite, smectite and kaolin. Clay coatings lining cracks and voids are restricted mostly to the weathered rock and lower part of the soil, and their main source is from decomposing biotite nearby. This weathering study permits details of the clay distribution to be postulated. The clay-rich horizons seem to be formed by settling of residual material as other constituents are lost by solution. The resulting reduced permeability would be expected to increase surface run-off and lateral flow through the upper part of the soil, giving rise to the clay-depleted upper horizons. Clay illuviation seems to be insignificant in forming the horizon of maximum clay content.
Seasonal soil temperature regimes in south-eastern Australia
Authors: Watson CL
Published: April 2005

The soil temperature regimes of 15 locations in south-eastern Australia were categorized by using criteria adopted by the US. Soil Taxonomy. On the basis of mean annual and seasonal soil temperatures from depths of 50-61 cm, all sites but one were classed as thermic, having mean annual soil temperatures between 15� and 22�C and seasonal differences of more than 5�C. Mean annual and seasonal soil temperatures were significantly correlated with the corresponding mean air temperatures. Estimates of soil temperature regimes at other similar locations in the region may therefore be made, provided the appropriate air temperature data are available. It appears that the thermic category will not apply to certain areas of southern Victoria or to the high altitude areas of the Great Dividing Range, that extend from western Victoria through to northern New South Wales.
Potassium and chloride movement in a forest soil under simulated rainfall
Authors: Talsma T , Mansell RS , Hallam PM
Published: April 2005

An initial appraisal of the mechanisms involved in reactive solute transport through a weathered soil profile was made by following the movement of potassium and chloride during prolonged leaching on a sprinkle-irrigated native forest plot. The soil was an acid, strongly base-unsaturated red duplex soil with a high surface and subsurface hydraulic conductivity. Water movement was followed by tensiometers located at regular depth intervals to 1.5 m, and soil water samplers with ceramic cups were used to collect soluble potassium and chloride. Some 650 mm of water moved beyond 1.5 m depth in the profile, but chloride did not move beyond 1 m. Nearly all of the potassium was retained in the soil above 0.6 m depth. Although both ions underwent ion exchange, adsorption of potassium was reasonably uniform through the profile, whereas chloride adsorption increased with depth. Immediate ground- and stream-water contamination did not occur under these conditions.
The development of a red-brown earth. II. Uniformity of the parent material
Authors: Chittleborough DJ , Oades JM
Published: April 2005

Five criteria based on the particle-size distribution of resistant minerals in the non-clay fraction and the ratio of two resistant minerals in the 5-125 �m fraction were applied to establish the uniformity of the parent material of the Urrbrae loam (a Rhodoxeralf). It was concluded that the parent material of the Urrbrae loam was uniform and that there was no basis for the hypothesis that A and B horizons had a separate sedimentary origin. The validity of assigning elemental percentages to specific resistant minerals was confirmed following analysis of the light mineral fraction (<2.96 g cm-3) for zirconium, yttrium, titanium and phosphorus, and finding that there was only a minor amount of these elements present.
The development of a red-brown earth. III. The segree of weathering and translocation of clay
Authors: Chittleborough DJ , Oades JM
Published: April 2005

The degree of weathering of coarse particles throughout the profile of the Urrbrae loam was evaluated by measuring the CaO: ZrO2 and Na2O: ZrO2 ratios in the 5-125 �m fraction. Ratios showed little variation throughout the profile. There was therefore no evidence to suggest that the large amount of clay in the B horizon was due to a greater intensity of weathering of primary minerals in that part of the profile. Thin sections of soil revealed few void argillans and therefore little direct evidence of clay movement. However, the vo-masepic plasmic fabric and thick stress cutans throughout the B horizon were evidence that forces associated with shrinking and swelling may have disrupted any argillans or prevented their formation. High coefficient of linear extensibility values support this argument. Estimation of volume and weight changes accompanying soil formation showed that there had been a 20 % increase in volume of the soil (and a 126% increase in the B2) but only 1.8% increase in weight. The bulk density of the whole profile decreased 15%. Losses and gains of clay, and the elemental oxides of iron, potassium, silicon and magnesium were partitioned between those due to formation of clay and those caused by migration of clay. The majority of changes were ascribed to clay migration. Clay formation by weathering in position cannot account for the strong textural differentiation of the Urrbrae loam (a Rhodoxeralf). Illuviation of fine clay is the most likely mechanism to account for the high content of clay in the B horizon. The relationship between this work, and that of others on the same profile, is discussed.
Effects of phosphate buffer capacity on critical levels and relationships between soil tests and labile phosphate in wheat growing soils
Authors: Holford ICR
Published: April 2005

Thirty-nine soils from northern New South Wales were used to examine the effects of phosphate buffer capacity on (i) the extraction of labile phosphate by four soil tests, (ii) the relationships between the four soil tests, and (iii) the critical level of each soil test required for near-maximum yield of wheat under field conditions. The results confirmed the principle, recently proposed by the author, that the larger the negative effect of buffer capacity on extraction of labile phosphate by a soil test, the higher is the correlation between the soil test and plant yield response to phosphate. The acidic ammonium fluoride extractant of Bray and Kurtz was the most sensitive to buffering in this respect, while the alkaline sodium bicarbonate extractant of Olsen et al. was less sensitive and the modified sodium bicarbonate test of Colwell least sensitive to buffering. Whereas a previous glasshouse study suggested that the ammonium fluoride test was over-sensitive to buffering, and hence underestimated available phosphate in strongly buffered soils, this field study showed that the test is correctly sensitive to buffering. Consequently critical levels for near-maximum wheat yields do not vary for the ammonium fluoride tests, but increase with increasing buffer capacity for the sodium bicarbonate tests. The additional measurement of buffer capacity is therefore required to give precision in the use of the sodium bicarbonate soil test and particularly the Colwell test. The results also suggest that a high correlatiori between two soil tests can only be expected where each test is similarly sensitive to buffering, provided of course that both tests extract phosphate mainly from the labile pool.
The management of ryegrass to stabilise aggregates of a red brown earth
Authors: Tisdall JM , Oades JM
Published: April 2005

An experiment was conducted with ryegrass growing in pots containing soil from the 0-10 cm layer of a red-brown earth to determine how the grass should be managed to improve stable aggregation of the soil. The quickest way to stabilize aggregates was to grow ryegrass with ample water and to clip the tops at monthly intervals. Clipping appeared to stimulate the growth of hyphae. Stressing the plants by allowing them to wilt reduced the stability of aggregates. The mycorrhizal hyphae persisted for at least several months after the plants had died. Although the hyphae may not have been viable they continued to bind particles of soil in stable aggregates.
Reactions of copper with soil affecting its availability to plants. I. Effect of soil type and time
Authors: Brennan RF , Gartrell JW , Robson AD
Published: April 2005

The effect of moist incubation on the availability of applied copper to wheat was examined in a range of Western Australian soils. Incubating soil with copper reduced its availability relative to freshly applied copper by up to 70%. The availability of copper to wheat plants decreased with increasing time of incubation up to 120 days. The extent of the decline in availability differed among soils. The difference did not appear to be specifically related to any one of the following soil properties-pH, organic carbon content, clay content, free sesquioxide content and levels of total and extractable copper.
Approximate potential-distance relationship for clays
Authors: Sridharan A , Jayadeva MS
Published: April 2005

The conventional procedure of determining the surface potential of clay platelet and the variation of potential with distance is lengthy and time consuming. Simplified graphical procedures using Gouy theory have been developed and presented. The new procedures are simple, accurate and very much less time consuming.
A synoptic approach for crop loss assessment used to study wheat. III. Variables derived from soil properties and traditional soil classifications suitable for regression studies
Authors: Veitch LG , Stynes BA
Published: April 2005

The combined information in the physical and chemical soil properties and in the traditional soil classification data has been split into three nearly uncorrelated groups of independent variables. One group comprises three variables and is concerned specifically with the traditional classification, a second group comprises seven variables and includes information specific to the soil properties, and a third group comprises one variable and includes the remainder of the information in the soil properties, i.e. that which is most strongly related to the traditional soil classification data. The new variables, which are substantially independent linear combinations of the original variables, form a convenient basis for the subsequent regression work in this study where the contribution of soil information to the variability of growth and yield of wheat in the study area is to be considered.
Corrigenda - A synoptic approach for crop loss assessment used to study wheat. III. Variables derived from soil properties and traditional soil classifications suitable for regression studies
Authors: Veitch LG , Stynes BA
Published: April 2005

The combined information in the physical and chemical soil properties and in the traditional soil classification data has been split into three nearly uncorrelated groups of independent variables. One group comprises three variables and is concerned specifically with the traditional classification, a second group comprises seven variables and includes information specific to the soil properties, and a third group comprises one variable and includes the remainder of the information in the soil properties, i.e. that which is most strongly related to the traditional soil classification data. The new variables, which are substantially independent linear combinations of the original variables, form a convenient basis for the subsequent regression work in this study where the contribution of soil information to the variability of growth and yield of wheat in the study area is to be considered.
Effects of duration of anaerobiosis and reoxidation on phosphate sorption characteristics of an acid soil
Authors: Holford ICR , Patrick WH
Published: April 2005

Suspensions of a silt loam were incubated under reducing conditions for 1, 6, 9, 18, 27 and 45 days at a pH of 6.5 or 6.6. Additional suspensions of the same soil which had been previously reduced at varying pH levels were reoxidized. Phosphate sorption properties of the soil were determined after the various incubation periods using normal sorption isotherm techniques. There was a large increase in the phosphate sorption capacity after only 1 day of reduction. An apparent decrease in sorption between 1 and 18 days was caused by a consistent decrease in bonding energy. Increasing iron concentrations in solution suggested that these effects were due to increasing dissolution of iron hydrous oxides and exposure of equivalent but less energetic adsorption sites which were previously inaccessible. The largest adsorption occurred at 27 days due, apparently, to the precipitation of amorphous and more reactive ferroso-ferric hydroxides. By 45 days the sorption capacity had decreased and was only slightly greater than that of the untreated soil. Between 18 and 27 days of anaerobiosis were required to cause a large increase in labile and solution phosphate. After reoxidaton there was a large decrease in phosphate sorption capacity at pH 6.6 and 8.0 but little change at pH 5.0. There was a similar decrease in bonding energy at the higher pH levels, but a large increase at pH 5.0. A fourfold increase in solution phosphate concentration occurred at pH 8, while relatively small changes occurred-at the other pH levels. These differences were attributed to changes in the solubilities and surface properties of iron compounds associated with the previous reduced conditions and pH levels. The results suggest that reoxidation increases phosphate sorption only if the pH or Eh during reduction is low enough to maintain a high iron concentration in solution.
Salt-affected land in the shire of Wongan-Ballidu, Western Australia
Authors: Nulsen RA
Published: April 2005

A survey was conducted to measure the total area of salt affected land in the Wongan-Ballidu Shire. Initially two survey methods were used: an intense on-farm survey and a broadscale road traverse survey. In the test area there was no net difference in areas of salt land detected by the two survey methods. and the remainder of the shire was surveyed by the road traverse method. Difficulties in objective delineation of areas of primary and secondary salinity precluded accurate determination of each, and only the total salt-affected area could be measured. The total area was 51,975 ha. representing 15.4% of the shire area. Detailed surveys of three 2080 ha sites in the shire showed that in the 18 years between 1958 and 1976 the area of salt land increased by up to 237% with the mean area within sites increasing from 206 ha in 1958 to 541 ha in 1976.
Effects of pH and ionic strength on the cation exchange capacity of soils with variable charge
Authors: Gillman GP
Published: April 2005

The cation exchange capacity of six surface soils from north Queensland and Hawaii has been measured over a range of pH values (4-6) and ionic strength values (0.003-0.05). The results show that for variable charge soils, modest changes in electrolyte ionic strength are as important in their effect on caton exchange capacity as are changes in pH values.
Colour groups derived from numerical classification of the munsell soil colour chips
Authors: Coventry RJ , Robinson PJ
Published: April 2005

Judgments of soil colour differences rely almost entirely upon subjective assessments. This paper describes a more objective numerical technique for grouping the 350 possible colour chips on the 'Munsell Soil Color Charts' (235 actual chips and an additional 115 interjacent chips that correspond to integer steps of chroma for hues 5R to 5Y). A polythetic, divisive classification produced 10 internally consistent groups of colours that have been described and named. It is proposed that soil colours can be adequately described for many purposes simply by reference to these colour groups. The 10 groups have been used to define generalized soil colour names.
Variations in unit hydrographs on a very small agricultural catchment
Authors: Boughton WC , Freebairn DM
Published: April 2005

Unit hydrographs (5-min 1 mm) were derived from six storms in the period November 1976 to March 1979 on a 1.2 ha catchment at Greenmount, about 25 km south of Toowomba in south-east Queensland. Peak rates of runoff in the six storms ranged from 1,12mm/h to 50.13 mm/h. All unit hydrographs were derived from multiperiod storms using an iterative procedure. Considerable variation occurred among the unit hydrographs with peak ordinate values ranging from 2.18 mm/h to 9.45 mm/h. It was found that each unit hydrograph could be separated into two components, surface runoff and interflow. The proportion of surface runoff in the unit hydrograph increased as the intensity of rainfall excess increased, and ranged from 5% in the storm with peak runoff of 1.12 mm/h to 86% in the storm with peak runoff of 50.13 mm/h. A large amount of runoff from the catchment occurred as interflow, consisting of water moving downslope through the porous cultivated surface layers of soil. The traditional separation of interflow from surface runoff prior to derivation of the unit hydrograph could not be done because of the complexity of the storm patterns. The study showed that it is possible to derive unit hydrographs which include an interflow component and to separate surface runoff and interflow in the unit hydrograph itself. A simple model was developed in which the proportions of surface runoff and interflow were allowed to vary from storm to storm. The proportions were adjusted by trial and error to match estimated runoff with actual runoff. The simple model reproduced observed runoff hydrographs with only minor errors of fit. The surface runoff component of the simple model behaved in accordance with traditional linear unit hydrograph theory. Variations in the unit hydrographs were accounted for by variations in the proportions of surface runoff and interflow from storm to storm.
Enzyme status of some jute growing soils of West Bengal
Authors: Tarafdar JC , Roy AB , Mandal AK
Published: April 2005

The distribution of urease and acid and alkaline phosphatase in some jute-growing soils of West Bengal was investigated. Urease and alkaline phosphatase activities were significantly and positively correlated with organic carbon, fungal and bacterial populations, whereas acid phosphatase activity was only significantly correlated with organic phosphorus content. None of the soil enzyme activities was correlated significantly with pH, clay content or soil actinomycetes. Urease and alkaline phosphatase were significantly correlated with each other.
Comparison of methods for measuring severity of water repellence of sandy soils and assessment of some factors that affect its measurement
Authors: King PM
Published: April 2005

Rapid methods for measuring the severity of water repellence were assessed in 101 sandy soils from South Australia. The molarity of aqueous ethanol droplets that were absorbed by the soil in 10 s, the time of water droplet entry and the infiltration rate of water from a small ring infiltrometer were compared with the soil-water contact angle and with each other. Relationships between the tests were fitted by linear, quadratic and cubic regressions and were highly significant (100r2 = 70-92). The relationships were used to provide ratings of repellence normally found in the field. Factors which affect the measurement of repellence in the field were examined. Abrasion of sand particles during light sieving had only small effects on repellence, but more vigorous abrasion through rotational movement of the sand reduced repellence markedly. Repellence decreased with increasing temperature. Simple corrections for temperature were calculated and presented in figures as isorating charts. The moisture content of the soil had large and variable effects on the repellence tests. At moisture contents between oven and air dry (pF 5.6) there was little effect on the ethanol droplet or infiltration rate tests. Measurements by the ethanol droplet test were not reliable at moisture contents greater than air dry. At soil water contents between air dry and wilting point (pF 4.2), the infiltration rate of water was either unchanged or decreased in different soils. It then increased rapidly and reached a constant value near field capacity (pF 2.5). The infiltration rate also decreased when the time of moistening of the soil before the tests were made was extended from 20 to 168 h. It is recommended that repellence tests be made on oven- or air-dry soils. The aqueous ethanol and water droplet, and infiltration rate of water tests are all suitable for rapid assessment of repellence in the field.
Anion movement in a soil under pasture
Authors: Scotter DR , Kanchanasut P
Published: April 2005

Laboratory and field studies of anion movement in soils were made. In the laboratory the movement of a solution containing chloride and phosphate through saturated field cores (143 mm in diameter and 170 mm long) was studied. Both the anions appeared in the effluent almost immediately after application to the soil surface. Dye studies showed the movement was highly preferential, occurring mainly through biogenic macropores such as root and worm channels. Unsaturated solute flow was also studied in the laboratory. When the matric potential in these field cores was reduced from zero to -2.0 J/kg (-20 mb), the volumetric water content decreased from 0.56 to 0.53, while the hydraulic conductivity decreased two orders of magnitude. The flow of surface-applied bromide and dye in the slightly unsaturated soil was much less preferential than in the saturated soil, a finding that agrees in general terms with [he predictions of theory previously published. In the field, the flow of a surface-applied chloride and phosphate solution to a mole drain (at 0.4 m depth) was also highly preferential. In one experiment the concentration of both chloride and phosphate in the mole effluent exceeded 0.8 of that in the applied solution within 5 min of its application to the soil surface, when only 20 mm of solution had infiltrated. Dye studies again showed root and worm channels, sometimes in association with incipient fracture planes, were the preferential pathways. This indicates the importance of biological factors in maintaining hydraulic conductivity and mole drain performance.
Potentially mineralizable nitrogen, decomposition rates and their relationship to temperature for five Queensland soils
Authors: Campbell CA , Myers RJK , Weier KL
Published: April 2005

The procedure of Stanford and coworkers was used to quantitatively relate net nitrogen mineralization in five Queensland semi-arid soils to temperature. The concentration of potentially mineralizable nitrogen (No) (1) ranged from 67 �g nitrogen g-1 for a red earth subsoil to 256 for a recently cultivated cracking clay surface soil, (2) was directly proportional to total soil carbon, (3) was greater in surface than in subsurface soil, and (4) was greater in subtropical than tropical soils. Expressed as a fraction of total nitrogen (No/Total N), it ranged between 8 and 21%, and was directly proportional to cation exchange capacity, perhaps implicating expanding lattice clays in stabilization of cell lysates and metabolites. The mineralization rate constant (k) was directly proportional to total carbon, the fuel for microbially mediated reactions in soil. The average k for surface soils was interpolated to be 0.058, 0.031, and 0.018 week-1, corresponding to half-lives of 11.9, 22.4 and 38.5 weeks, at 35�, 25� and 15�C, respectively; these values are similar to those reported for U.S.A. and Chilean soils. The Arrhenius relationship between k and temperature for surface soils (log k = 6.14-2285/T) was similar to that reported by Stanford for U.S.A. soils, and indicates that this relationship might be a general one.
Particle-size analyses of Widgelli Parna in South-east Australia
Authors: Blackburn G
Published: April 2005

Difficulties in using granulometry to characterize the non-clay fraction of the presumed aeolian sediments known as parna are considered by reference to the results of repeated analyses of samples. Incomplete dispersion of clap accounted for different results with two samples, one being from material identified as subplastic. Bimodal size frequency distributions were detected for several samples, a condition which should invalidate modal diameter as the measure of average grain size. Mean diameter is regarded as an appropriate measure for the samples. The more accurate results obtained for the samples do not upset the earlier conclusions regarding distribution of Widgelli parna, but they suggest an important distinction between the western and eastern samples of the material. Suggestions are made concerning determination of particle size for parna samples.
Amelioration of sodic soils with blue-green algae
Authors: Subhashini D , Kaushik BD
Published: April 2005

Algal growth resulted in significant reductions in pH, electrical conductivity, exchangeable sodium and in hydraulic conductivity and aggregation status of the soil. There was a significant increase in the total nitrogen content of the soil due to algal growth. Two out of the three inoculated species of algae could establish in the pots along with the indigenous algal flora. Combination of gypsum and algal application were found to have appreciable reclamative properties, and the possibility of using algae as a biological input for the reclamation of sodic soils has been indicated.
The distribution of red, yellow and grey earths in the Torrens Creek area, central north Queensland
Authors: Coventry RJ
Published: April 2005

Red, yellow, and grey earths mantle extensive plains in northern Australia. They have been studied in a semiarid, tropical area at Torrens Creek, some 200-300 km south-west of Townsville, Queensland. An examination of boreholes drilled along transects across these soils shows that the red earths usually occupy the lower slope sites and broad, non-channeled, drainage lines. The yellow and grey earths generally occur at midslope sites or over broadly convex upper regions of the low undulations that rise 10-30 m above the non-dissected parts of the plains. The distribution patterns of the red, yellow, and grey earths cannot be explained by differential weathering of the gently dipping Mesozoic sedimentary rock substrates. Nor can they be attributed to simple, topography-controlled, hydrological regimes in the soils. The distribution patterns of the different soils depend on factors related to the geology and the late Cainozoic geomorphic history of the area. These include the transported or sedentary nature of the soil parent materials, the hydrological regimes of the soils and of the weathered rock substrates, and the depth to the underlying, weathered rock.