ORCID Profile
0000-0002-4704-7178
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Publisher: PeerJ
Date: 16-01-2019
DOI: 10.7717/PEERJ.6002
Abstract: Soil physical parameter calculation by inverse modelling provides an indirect way of estimating the unsaturated hydraulic properties of soils. However many measurements are needed to provide sufficient data to determine unknown parameters. The objective of this research was to assess the use of unsaturated water flow and solute transport experiments, in horizontal packed soil columns, to estimate the parameters that govern water flow and solute transport. The derived parameters are then used to predict water infiltration and solute migration in a repacked soil wedge. Horizontal columns packed with Red Ferrosol were used in a nitrate diffusion experiment to estimate either three or six parameters of the van Genuchten–Mualem equation while keeping residual and saturated water content, and saturated hydraulic conductivity fixed to independently measured values. These parameters were calculated using the inverse optimisation routines in Hydrus 1D. Nitrate concentrations measured along the horizontal soil columns were used to independently determine the Langmuir adsorption isotherm. The soil hydraulic properties described by the van Genuchten–Mualem equation, and the NO 3 – adsorption isotherm, were then used to predict water and NO 3 – distributions from a point-source in two 3D flow scenarios. The use of horizontal columns of repacked soil and inverse modelling to quantify the soil water retention curve was found to be a simple and effective method for determining soil hydraulic properties of Red Ferrosols. These generated parameters supported subsequent testing of interactive flow and reactive transport processes under dynamic flow conditions.
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/SR06169
Abstract: Changes in the soil structure and hydraulic conductivity of an Acidic Red Ferrosol were measured in a long-term (1968–2003) fertiliser experiment on pasture in north-western Tasmania, Australia. Studies were initiated following observations of both softer soil surface and cracking on plots that had received 15 t/ha of ground agricultural limestone. Liming decreased penetration resistance and increased hydraulic conductivity. These structural improvements were associated with increased mean dry aggregate size, a small increase in wet aggregate stability, higher exchangeable calcium levels, and increased plant growth, but a 9% decrease in total soil organic carbon in the surface 50 mm. This decrease in organic carbon was not associated with deterioration in soil structure, as may have been anticipated. This was probably because total organic C was still 82 g/kg on unlimed plots. Decreases in soil penetration resistance due to liming increased the likelihood of pugging from livestock but may improve ease of tillage. This research demonstrates that liming can improve the structure of a well-aggregated Ferrosol as well as its previously reported effects of increasing soil pH and yields of pasture and barley despite decreasing organic C.
Publisher: Elsevier BV
Date: 02-2016
Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 12-2012
Publisher: Elsevier BV
Date: 11-2016
Publisher: Springer Science and Business Media LLC
Date: 04-2016
Publisher: Elsevier BV
Date: 08-2016
Publisher: Elsevier BV
Date: 04-2016
Publisher: Humana Press
Date: 2012
DOI: 10.1007/978-1-61779-986-0_28
Abstract: Soil salinity is a form of land degradation in which salts accumulate in the soil profile to an extent that plant growth or infrastructure are negatively affected. A range of both field and laboratory procedures exist for measuring soil salinity. In the field, soil salinity is usually inferred from apparent electrical conductivity (EC(a)) using a range of devices, depending on the required depth of analysis, or size of the survey area. Field measurements of EC(a) require calibration to the actual salt content by laboratory analysis. In the laboratory, soil salinity is usually assessed by determining either the total soluble salts by evaporation of a soil water extract (TSS), or by determining the electrical conductivity (EC) of either a 1:5 distilled water:soil dilution, or a saturated paste extract. Although procedures for measuring soil salinity appear relatively straightforward, differences in methodology have considerable influence on measured values and interpretation of results.
Publisher: Wiley
Date: 30-03-2006
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier
Date: 2016
Publisher: Cambridge University Press (CUP)
Date: 05-2002
Publisher: Informa UK Limited
Date: 2013
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/SR13166
Abstract: Acacia hybrid (A. mangium × A. auriculiformis) is the main species planted for short-rotation forestry in Vietnam. In this study, the effect of these plantations on some key properties of degraded gravelly soils in Central Vietnam was assessed. Soil s les were collected from second- or third-rotation plantations representative of five age classes (0.5–5 years old), and in adjacent abandoned lands as controls. Compared with abandoned land, stock of total soil carbon (C) was significantly higher at ages 0.5, 1.5, 2.5 and 5 years (18.4–19.5 v. 13.0 Mg ha–1), total nitrogen (N) at 0.5 and 1.5 years (1.5–1.7 v. 1.0 Mg ha–1), exchangeable calcium at 0.5, 1.5 and 2.5 years (215–294 v. 42 Mg ha–1), magnesium at 0.5, 1.5, 2.5 and 3.5 years (39–48 v. 19 Mg ha–1), and sodium at all ages (46–59 v. 5 Mg ha–1). Electrical conductivity was significantly higher at all ages (58.5–69.4 v. 32.7 µS cm–1). Differences in extractable phosphorus and exchangeable potassium were not significantly different between plantations and abandoned land. Bulk density was significantly lower in plantations than abandoned land at all ages (1.36–1.42 v. 1.55 Mg ha–1), pHCaCl2 at 0.5 and 5 years (3.78–3.84 v. 3.98), and pHH2O at 5 years (4.30 v. 4.52). Because the soils were gravelly, differences in concentration of total C and nutrients between abandoned land and plantations were not the same as those for stocks after correction for gravel content and bulk density. Within a rotation, most soil properties did not change significantly with plantation age, although they appeared to decrease during the first 3 years total C then recovered to initial levels, but total N and exchangeable cations remained lower. Some soil properties were strongly related to gravel content and elevation, but not to growth rate. We conclude that consecutive plantings of short-rotation Acacia hybrid on degraded and abandoned land can lead to changes in some soil properties.
Publisher: Elsevier BV
Date: 08-2004
Start Date: 2016
End Date: 2019
Funder: Australian Grape and Wine Authority
View Funded ActivityStart Date: 2016
End Date: 2019
Funder: Department of Primary Industries, Parks, Water & Environment
View Funded ActivityStart Date: 2009
End Date: 2012
Funder: Department of Agriculture
View Funded ActivityStart Date: 2013
End Date: 2013
Funder: Office for Learning & Teaching
View Funded ActivityStart Date: 2010
End Date: 2014
Funder: Australian Centre for International Agricultural Research
View Funded Activity