Description:
In this study, a novel and enhanced soil-structure model is developed adopting the direct analysis method using FLAC 2D software to simulate the complex dynamic soil-structure interaction and treat the behaviour of both soil and structure with equal rigour simultaneously. To have a better judgment on the inelastic structural response, three types of mid-rise moment resisting building frames, including 5, 10, and 15 storey buildings are selected in conjunction with three soil types with the shear wave velocities less than 600m/s, representing soil classes Ce, De and Ee, according to Australian Standards. The above mentioned frames have been analysed under two different boundary conditions: (i) fixed-base (no soil-structure interaction) and (ii) flexible-base (considering soil-structure interaction). The results of the analyses in terms of structural displacements and drifts for the above mentioned boundary conditions have been compared and discussed. It is concluded that considering dynamic soil-structure interaction effects in seismic design of moment resisting building frames resting on soil classes De and Ee is essential.
Description:
Reclamation of salt-affected soil has been identified by the FAO as being critical to meet the needs to increase agricultural productivity. This paper reviews commonly used reclamation methods for salt-affected soils, and provides critical identifiers for an effective reclamation practice of salt-affected soil. There are widely used methods to reduce salinity and sodicity of salt-affected soils, including salt leaching, addition of amendments, revegetation using halophytes and salt scrapping. Not all reclamation techniques are suitable for salt-affected land. The reclamation strategy must be tailored to the site, and based on understanding the soil, plant and climate interactions. On some occasions, a combination of techniques may be required for reclamation. This can include salt scrapping to remove salts from the surface soil, the addition of physical amendments to improve soil pore systems and enhance salt leaching, followed by amelioration of soil by chemical amendments to preserve soil physical conditions, and then halophyte establishment to expand the desalinization zone. This study reveals that soil hydro-geochemical models are effective predictive tools to ascertain the best reclamation practice tailored to salt-affected land. However, models need to be calibrated and validated to the conditions of the land before being applied as a tool to combat soil salinity.
Description:
Reclamation of salt-affected soil has been identified by the FAO as being critical to meet the needs to increase agricultural productivity. This paper reviews commonly used reclamation methods for salt-affected soils, and provides critical identifiers for an effective reclamation practice of salt-affected soil. There are widely used methods to reduce salinity and sodicity of salt-affected soils, including salt leaching, addition of amendments, revegetation using halophytes and salt scrapping. Not all reclamation techniques are suitable for salt-affected land. The reclamation strategy must be tailored to the site, and based on understanding the soil, plant and climate interactions. On some occasions, a combination of techniques may be required for reclamation. This can include salt scrapping to remove salts from the surface soil, the addition of physical amendments to improve soil pore systems and enhance salt leaching, followed by amelioration of soil by chemical amendments to preserve soil physical conditions, and then halophyte establishment to expand the desalinization zone. This study reveals that soil hydro-geochemical models are effective predictive tools to ascertain the best reclamation practice tailored to salt-affected land. However, models need to be calibrated and validated to the conditions of the land before being applied as a tool to combat soil salinity.
Description:
A 10-month study of surface waters in Canadian Creek (Ballarat, Victoria, Australia) showed the significant influence of historic gold mining waste material. The investigation focussed on the hydrogeochemistry of the surface waters and soils in order to: (1) document the levels and seasonal trends in major, minor and trace elements in the creek, (2) identify the process by which As is released from the soil/waste mining material to surface waters. For most dissolved major and trace elements (Na, Ca, Mg, K, and As) in surface waters, the concentrations decreased with the increasing rainfall and flow conditions except for Al and Fe. Two sites selected along the creek (<1 km apart) allowed evaluation of the possibility that mining waste material is contributing to the elevated As concentrations (up to 145
Description:
Although only representing 0.05% of global freshwater, or 0.001% of all global water, soil water supports all terrestrial biological life. Soil moisture behaviour in most models is constrained by hydraulic parameters that do not change. Here we argue that biological feedbacks from plants, macro-fauna and the microbiome influence soil structure, and thus the soil hydraulic parameters and the soil water content signals we observe. Incorporating biological feedbacks into soil hydrological models is therefore important for understanding environmental change and its impacts on ecosystems. We anticipate that environmental change will accelerate and modify soil hydraulic function. Increasingly, we understand the vital role that soil moisture exerts on the carbon cycle and other environmental threats such as heatwaves, droughts and floods, wildfires, regional precipitation patterns, disease regulation and infrastructure stability, in addition to agricultural production. Biological feedbacks may result in changes to soil hydraulic function that could be irreversible, resulting in alternative stable states (ASS) of soil moisture. To explore this, we need models that consider all the major feedbacks between soil properties and soil-plant-faunal-microbial-atmospheric processes, which is something we currently do not have. Therefore, a new direction is required to incorporate a dynamic description of soil structure and hydraulic property evolution into soil-plant-atmosphere, or land surface, models that consider feedbacks from land use and climate drivers of change, so as to better model ecosystem dynamics.
Description:
The clay mineralogy and heavy metal/metalloid (As, Pb and Cu) contents of soils developed on the various rock units in a central highlands environment in Victoria (Creswick, Australia) have been investigated. The clay minerals identified showed an order of abundance as: kaolinite - illite > smectite > mixed-layer (ML) ≈ vermiculite. The soil clay mineralogy did not change systematically with depth (0- 10, 10- 20 and 20- 30 cm) and showed large variations spatially. The high proportion of kaolinite was probably due to the removal of 2:1 phyllosilicates by the formation of 1:1 kaolinite through weathering, which also reduced the cation exchange capacity (CEC) and electrical conductivity (EC, soil: water ratio of 1:5) of soils by aging. Soils were classified as silty loam to loam with a low clay size (≤ 2
Description:
In this study, the effects of Plasticity Index (PI) variation on the seismic response of mid-rise building frames resting on soft soil deposits are investigated. To achieve this goal, three structural models including 5, 10, and 15 storey buildings are simulated in conjunction with a clayey soil representing soil class Ee according to the classification of AS1170.4-2007 (Earthquake actions in Australia) and then varying the Plasticity Index. Structural sections of the selected frames were designed according to AS3600-2009 (Australian Standard for Concrete Structures) after undertaking dynamic analysis under the influence of four different earthquake ground motions. The frame sections are modelled and analysed, employing finite difference method adopting FLAC 2D software under two different boundary conditions: (i) fixed base (no Soil-Structure Interaction), and (ii) flexible base considering soil-structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted and the results in terms of maximum lateral displacements and inter-storey drifts for the above mentioned boundary conditions are obtained, compared, and discussed. Base on the results of the numerical investigations, it becomes apparent that as the Plasticity Index of the subsoil increases, the base shears of mid-rise building frames resting on soft soil deposits increase, while the lateral deflections and corresponding inter-storey drifts decrease. It is concluded that reduction of the Plasticity Index could noticeably amplify the effects of soil-structure interaction on the seismic response of mid-rise building frames.
Description:
A method is described for rapid and reliable determination of ultra-trace concentrations of mercury in plant and soil samples by cold vapour inductively coupled plasma-optical emission spectrometry (CV-ICP-OES). Under the established optimum conditions, a detection limit of 3 ng g− 1 was achieved. Rapid decomposition of soil and plant samples were achieved with microwave digestion with a 3:1 HNO3:HCl mixture for only 10 min, enabling close to 100% recovery of mercury. Choice of sample storage condition and nature of sample (dried, wet or frozen) had significant influence on mercury concentrations found in plant and soil samples. Storage of samples as frozen, followed by digestion without drying or on as received basis gave optimum recovery of mercury in the samples. Verification of the effectiveness of the CV-ICP-OES method for reliable mercury determination in plants and soil with microwave digested certified soil and spiked plant samples gave close to 100% and 95–103% recoveries, respectively. The CV-ICP-OES method was successfully applied to the determination of mercury in plant and soil samples from a local Australian forest. The mercury concentrations found in plants range from 23.5 to 78.5 ng g− 1, while those found in soils range from 30.1 to 61.7 ng g− 1.
Description:
This paper reports on the major cations (Ca, Mg, Na and K) and arsenic (As) compositions of surface waters collected from major creeks, rivers and lakes in Central Victoria (Australia). The surface waters were found to be neutral to alkaline (pH 6.7-9.4), oxidised (average redox potential (Eh) about 130 mV) and showed variable concentrations of dissolved ions (EC, about 51-4386
Description:
"Arsenic is a common soil contaminant in Australia and worldwide. There is a need to find safe, effective and economic methods to deal with this problem. The soils used in this research were collected from central Victoria. They were contaminated with arsenic by historic gold mining activity or by past sheep dipping practices. This research investigated ten different leaching agents for their effects on three different arsenic contaminated soils. [...] Electrokinetic experiments were conducted on three arsenic contaminated soils. [...] The arsenic in these soils appears to be relatively stable and immobile under oxidising conditions. The soils had a high iron content which assists in the stabilisation of arsenic. This is beneficial with respect to the environmental impact of the arsenic contamination, however, it remains an obstacle to low cost electrokinetic remediation."
Description:
"Arsenic is a common soil contaminant in Australia and worldwide. There is a need to find safe, effective and economic methods to deal with this problem. The soils used in this research were collected from central Victoria. They were contaminated with arsenic by historic gold mining activity or by past sheep dipping practices. This research investigated ten different leaching agents for their effects on three different arsenic contaminated soils. [...] Electrokinetic experiments were conducted on three arsenic contaminated soils. [...] The arsenic in these soils appears to be relatively stable and immobile under oxidising conditions. The soils had a high iron content which assists in the stabilisation of arsenic. This is beneficial with respect to the environmental impact of the arsenic contamination, however, it remains an obstacle to low cost electrokinetic remediation."
Description:
Estimating various properties of soil, including moisture, carbon, and nitrogen, is crucial for studying their correlation with plant health and food production. However, conventional methods such as oven-drying and chemical analysis are laborious, expensive, and only feasible for a limited land area. With the advent of remote sensing technologies like multi/hyperspectral imaging, it is now possible to predict soil properties non-invasive and cost-effectively for a large expanse of bare land. Recent research shows the possibility of predicting those soil contents from a wide range of hyperspectral data using good prediction algorithms. However, these kinds of hyperspectral sensors are expensive and not widely available. Therefore, this paper investigates different machine and deep learning techniques to predict soil nutrient properties using only the red (R), green (G), and blue (B) bands data to propose a suitable machine/deep learning model that can be used as a rapid soil test. Another objective of this research is to observe and compare the prediction accuracy in three cases i. hyperspectral band ii. full spectrum of the visual band, and iii. three-channel of RGB band and provide a guideline to the user on which spectrum information they should use to predict those soil properties. The outcome of this research helps to develop a mobile application that is easy to use for a quick soil test. This research also explores learning-based algorithms with significant feature combinations and their performance comparisons in predicting soil properties from visual band data. For this, we also explore the impact of dimensional reduction (i.e., principal component analysis) and transformations (i.e., empirical mode decomposition) of features. The results show that the proposed model can comparably predict the soil contents from the three-channel RGB data.
Description:
Estimating various properties of soil, including moisture, carbon, and nitrogen, is crucial for studying their correlation with plant health and food production. However, conventional methods such as oven-drying and chemical analysis are laborious, expensive, and only feasible for a limited land area. With the advent of remote sensing technologies like multi/hyperspectral imaging, it is now possible to predict soil properties non-invasive and cost-effectively for a large expanse of bare land. Recent research shows the possibility of predicting those soil contents from a wide range of hyperspectral data using good prediction algorithms. However, these kinds of hyperspectral sensors are expensive and not widely available. Therefore, this paper investigates different machine and deep learning techniques to predict soil nutrient properties using only the red (R), green (G), and blue (B) bands data to propose a suitable machine/deep learning model that can be used as a rapid soil test. Another objective of this research is to observe and compare the prediction accuracy in three cases i. hyperspectral band ii. full spectrum of the visual band, and iii. three-channel of RGB band and provide a guideline to the user on which spectrum information they should use to predict those soil properties. The outcome of this research helps to develop a mobile application that is easy to use for a quick soil test. This research also explores learning-based algorithms with significant feature combinations and their performance comparisons in predicting soil properties from visual band data. For this, we also explore the impact of dimensional reduction (i.e., principal component analysis) and transformations (i.e., empirical mode decomposition) of features. The results show that the proposed model can comparably predict the soil contents from the three-channel RGB data.
Description:
Organic amendments are often reported to improve soil properties, promote plant growth, and improve crop yield. This study aimed to investigate the effects of the biochar and compost produced from sewage sludge and olive pomace on soil hydraulic properties, water flow, and P transport (i.e., sorption) using numerical modeling (HYDRUS-1D) applied to two soil types (Terra Rosa and Rendzina). Evaporation and leaching experiments on soil cores and repacked soil columns were performed to determine the soil water retention, hydraulic conductivity, P leaching potential, and P sorption capacity of these mixtures. In the majority of treatments, the soil water retention showed a small increase compared to the control soil. A reliable fit with the modified van Genuchten model was found, which was also confirmed by water flow modeling of leaching experiments (R2 0.99). The results showed a high P sorption in all the treatments (Kd 21.24 to 53.68 cm3 g−1), and a high model reliability when the inverse modeling procedure was used (R2 0.93–0.99). Overall, adding sewage sludge or olive pomace as compost or biochar improved the Terra Rosa and Rendzina water retention and did not increase the P mobility in these soils, proving to be a sustainable source of carbon and P-rich materials.
Description:
Organic amendments are often reported to improve soil properties, promote plant growth, and improve crop yield. This study aimed to investigate the effects of the biochar and compost produced from sewage sludge and olive pomace on soil hydraulic properties, water flow, and P transport (i.e., sorption) using numerical modeling (HYDRUS-1D) applied to two soil types (Terra Rosa and Rendzina). Evaporation and leaching experiments on soil cores and repacked soil columns were performed to determine the soil water retention, hydraulic conductivity, P leaching potential, and P sorption capacity of these mixtures. In the majority of treatments, the soil water retention showed a small increase compared to the control soil. A reliable fit with the modified van Genuchten model was found, which was also confirmed by water flow modeling of leaching experiments (R2 0.99). The results showed a high P sorption in all the treatments (Kd 21.24 to 53.68 cm3 g−1), and a high model reliability when the inverse modeling procedure was used (R2 0.93–0.99). Overall, adding sewage sludge or olive pomace as compost or biochar improved the Terra Rosa and Rendzina water retention and did not increase the P mobility in these soils, proving to be a sustainable source of carbon and P-rich materials.
Description:
"Three sampling campaigns were conducted in the Ballarat, Creswick and Maldon areas. The sampling area is part of the Golden Triangle region where significant gold-mining activities took place from the 1850s to the present day. [...] Locations were chosen to evaluate arsenic distribution in soils, surface waters and plants in different environments. Easy access to sampling locations allowed detailed scientific sampling, especially in the seasonality study. The different range of environments such as agricultural, state forest, mining, urban and rural provided an opportunity to compare the concentrations of arsenic and other elements in the study area. The study of the three selected areas combined provided further understanding of possible exposure and pathways through which arsenic can get into the food chain. "The objective of the study is to measure levels of heavy metals/metalloids in soils, water and plants in various environments, identify whether the heavy metals/metalloids are mobile and bioavailable and understand the importance of clays and oxide complexes in the fixation of metals."
Description:
"Three sampling campaigns were conducted in the Ballarat, Creswick and Maldon areas. The sampling area is part of the Golden Triangle region where significant gold-mining activities took place from the 1850s to the present day. [...] Locations were chosen to evaluate arsenic distribution in soils, surface waters and plants in different environments. Easy access to sampling locations allowed detailed scientific sampling, especially in the seasonality study. The different range of environments such as agricultural, state forest, mining, urban and rural provided an opportunity to compare the concentrations of arsenic and other elements in the study area. The study of the three selected areas combined provided further understanding of possible exposure and pathways through which arsenic can get into the food chain. "The objective of the study is to measure levels of heavy metals/metalloids in soils, water and plants in various environments, identify whether the heavy metals/metalloids are mobile and bioavailable and understand the importance of clays and oxide complexes in the fixation of metals."
Description:
Preformed biodegradable and next generation sprayable biodegradable polymer membrane (SBPM) formulations, which biodegrade to non-harmful products (water, carbon dioxide and microbial biomass), have been introduced as an alternative to plastic mulch films in order to mitigate plastic pollution of the environment. In this preliminary field study on cotton (Gossypium hirsutum L.), a novel SBPM technology was compared to preformed slotted oxo-degradable plastic (ODP) mulch film and no mulch control (CON) in terms of yield, crop water productivity (CWP), and soil temperature. The first results showed higher CWP and crop yield, and increased soil water content under the SBPM cover. This study indicates that SBPM technology could perform at similar level as ODP or comparable films under field conditions and, at the same time, provide environmentally sustainable agricultural cropping practices. Additionally, the fully treated, non-replicated SBPM plot had a wetter soil profile throughout the entire crop season. This innovative technology has shown a high potential even at this early stage of development, indicating that advances in formulation and further testing can lead to significant improvements and thus increased use in crop production systems.
Description:
This research aims to assess the impacts of soil use management on runoff, soil losses, and their main soil controls in vegetable cropland (CROP), tilled olives (OT), and grass-covered olive orchards (OGC) on Leptosol in Croatia. Soil analysis and rainfall simulation experiments were conducted to quantify runoff (Run), soil, and nutrient losses. Bulk density (BD) was significantly higher at OT plots, in addition to the CROP plots. Water-stable aggregates (WSA), mean weight diameter (MWD), and soil organic matter (OM) were significantly higher in OGC plots compared to the other land uses. Run and soil loss (SL) were significantly higher in CROP and OT plots compared to the OGC plots. The CROP plots showed soil management that can be considered as unsustainable with 52, 68- and 146-times higher losses of phosphorus (P loss), nitrogen (N loss), and carbon (C loss) compared to the OGC plots. The principal component analysis showed that MWD was associated with vegetation cover (VC), water-holding capacity (WHC), WSA, OM, total nitrogen (TN), time to ponding (TP), and time to runoff (TR). These variables were negatively related to P2O5, Run, SL, and P, N, and C loss. Results indicate the need for the adoption of conservation strategies in croplands and olive orchards.
Description:
This research aims to assess the impacts of soil use management on runoff, soil losses, and their main soil controls in vegetable cropland (CROP), tilled olives (OT), and grass-covered olive orchards (OGC) on Leptosol in Croatia. Soil analysis and rainfall simulation experiments were conducted to quantify runoff (Run), soil, and nutrient losses. Bulk density (BD) was significantly higher at OT plots, in addition to the CROP plots. Water-stable aggregates (WSA), mean weight diameter (MWD), and soil organic matter (OM) were significantly higher in OGC plots compared to the other land uses. Run and soil loss (SL) were significantly higher in CROP and OT plots compared to the OGC plots. The CROP plots showed soil management that can be considered as unsustainable with 52, 68- and 146-times higher losses of phosphorus (P loss), nitrogen (N loss), and carbon (C loss) compared to the OGC plots. The principal component analysis showed that MWD was associated with vegetation cover (VC), water-holding capacity (WHC), WSA, OM, total nitrogen (TN), time to ponding (TP), and time to runoff (TR). These variables were negatively related to P2O5, Run, SL, and P, N, and C loss. Results indicate the need for the adoption of conservation strategies in croplands and olive orchards.