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The Influence of Soil Reconstruction Methods on Mineral Sands Mine Soil PropertiesMeredith, Kelly Robyn 13 February 2008 (has links)
Significant deposits of heavy mineral sands (primarily ilmenite and zircon) are located in Virginia in Dinwiddie, Sussex and Greensville counties. Most deposits are located under prime farmland, and thus require intensive reclamation when mined. The objective of this study was to determine the effect of four different mine soil reconstruction methods on soil properties and associated rowcrop productivity. Treatments compared were 1) Biosolids-No Tillage, 2) Biosolids-Conventional Tillage, 3) Lime+NPK fertilized tailings (Control), and 4) 15-cm Topsoil over lime+P treated tailings. Treated plots were cropped to corn (Zea Mays L.) in 2005 and wheat (Triticum aestivum L.) in 2006. Yields were compared to nearby unmined prime farmland yields. Over both growing seasons, the two biosolids treatments produced the highest overall crop yields. The Topsoil treatment produced the lowest corn yields due to relatively poor physical and chemical conditions, but the effect was less obvious for the following wheat crop. Reclaimed land corn and wheat yields were higher than long-term county averages, but they were consistently lower than unmined plots under identical management. Detailed morphological study of 20 mine soil pedons revealed significant root-limiting subsoil compaction and textural stratification. The mine soils classified as Typic Udorthents (11), Typic Udifluvents (4) and Typic Dystrudepts (5). Overall, mined lands can be successfully returned to intensive agricultural production with comparable yields to long-term county averages provided extensive soil amendment and remedial tillage protocols are implemented. However, a significant decrease (~25 to 35%) in initial productivity should be expected relative to unmined prime farmland. / Master of Science
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Mapping Peat Depth Using Remote Sensing and Machine Learning to Improve Peat Smouldering Vulnerability PredictionSherwood, Emma January 2023 (has links)
Peat is an accumulation of soil formed from partially decomposed organic matter. Peat can burn, especially in hot, dry weather which is happening more often due to climate change; smouldering releases stored carbon to the atmosphere. Peat that has higher organic bulk density and lower moisture content is more vulnerable to fire: it will burn more severely (more deeply) if ignited. Shallower peat is less able to retain moisture during droughts and is therefore likely more vulnerable to fire; however, mapping peat depths at high spatial resolution is expensive or requires extensive fieldwork. This project uses remote sensing in combination with machine learning to estimate peat depth across a peatland and rock barren landscape. A Random Forest model was used to map peat depths across the landscape at a 1 m spatial resolution using LiDAR data and orthophotography. The resulting map was able to predict peat depths (R2 = 0.73, MAE = 28 cm) and showed that the peat depths which are especially vulnerable to high severity fire are distributed in numerous small patches across the landscape. This project also examined peat bulk density and found that the Von Post scale for peat decomposition can be used as a field method for estimating bulk density (R2 = 0.71). In addition, in this landscape, peat bulk densities at the same depth (within the top 45 cm) are higher in shallower peat because in shallower peat, more decomposed peat was found closer to the surface, and because peat with high mineral content was found close to the bedrock or mineral soil. The findings of this project will be valuable for wildfire managers to determine which areas on the landscape are most vulnerable to fire, allowing them to mobilize resources more rapidly for wildfire suppression. / Thesis / Master of Science (MSc) / Peat is organic soil made from decomposing plant material. Peat can burn, especially in the hot, dry weather which is happening more often due to climate change. Dense, dry peat is more vulnerable to fire: it will burn more deeply. Because it is known that areas with deeper peat can retain moisture better, peat depth can be used as a proxy for vulnerability to fire. Since peat depth is expensive and time consuming to map directly, remotely sensed data such as aerial imagery was used in a model to predict peat depths. The model was able to predict peat depths and displayed that the most vulnerable areas are scattered across the landscape in small patches. This project also found that denser peat is found farther from the surface in deeper peat areas, further supporting the use of peat depth as a proxy for vulnerability to smouldering.
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Investigation of the acoustic impedance variations of the upper shallow marine sandstone reservoirs in the Bredasdorp basin, offshore South AfricaMagoba, Moses January 2019 (has links)
Philosophiae Doctor - PhD / Investigation of the acoustic impedance variations in the upper shallow marine sandstone reservoirs was extensively studied from 10 selected wells, namely: F-O1, F-O2, E-M4, E-CN1, E-G1, E-W1, F-A10, F-A11, F-A13, and F-L1 in the Bredasdorp Basin, offshore, South Africa. The studied wells were selected randomly across the upper shallow marine interval with the purpose of conducting a regional study to assess the variations in the acoustic impedance across the reservoirs using wireline log and core data. The datasets used in this study were geophysical wireline logs, conventional core analysis, geological well completion reports, core plugs, and core samples. The physical rock properties such as lithology, fluid type, and hydrocarbon bearing zone were identified while different parameters like the volume of clay, porosity, and water saturation were quantitatively estimated. The reservoirs were penetrated at a different depth ranging from a shallow depth of 2442m at well F-L1 to a deeper depth of 4256.7m at well E-CN1. The average volume of clay, average effective porosity from wireline log, and average water saturation ranged from 8.6%- 43%, 9%- 16% and 12%- 68%, respectively. Porosity distribution was fairly equal across the field from east to west except in well F-A10, F-A13, and F-A11 where a much higher porosity was shown with F-A13 showing the highest average value of 16%. Wells E-CN1, E-W1, F-O1, F-L1 and E-G1 had lower porosity with E-CN1 showing the lowest average value of 9%.
The acoustic properties of the reservoirs were determined from geophysical wireline logs in order to calculate acoustic impedance and also investigate factors controlling density and acoustic velocities of these sediments. The acoustic impedance proved to be highest on the central to the western side of the field at E-CN1 with an average value of 11832 g/cm3s whereas, well F-A13 reservoir in the eastern side of the field proved to have the lowest average acoustic impedance of 9821 g/cm3s. There was a good linear negative relationship between acoustic impedance and porosity, compressional velocity vs porosity and porosity vs bulk density. A good linear negative relationship between acoustic impedance and porosity was obtained where the reservoir was homogenous, thick sandstone. However, interbedded shale units within the reservoir appeared to hinder a reliable correlation between acoustic impedance and porosity. The cross-plots results showed that porosity was one of the major factors controlling bulk density, compressional velocity (Vp) and acoustic impedance. The Gassmann equation was used for the determination of the effects of fluid substitution on acoustic properties using rock frame properties. Three fluid substitution models (brine, oil, and gas) were determined for pure sandstones and were used to measure the behaviour of the different sandstone saturations. A significant decrease was observed in Vp when the initial water saturation was substituted with a hydrocarbon (oil or gas) in all the wells. The value of density decreased quite visibly in all the wells when the brine (100% water saturation) was substituted with gas or oil. The fluid substitution affected the rock property significantly. The Vp slightly decreases when brine was substituted with water in wells F-A13, F-A10, F-O2, F-O1 F-A11, F-L1, and E-CN1. Wells E-G1, E-W1, and E-M4 contain oil and gas and therefore showed a notable decrease from brine to oil and from oil to gas respectively. Shear velocity (Vs) remained unaffected in all the wells. The acoustic impedance logs showed a decrease when 100% water saturation was replaced with a hydrocarbon (oil or gas) in all the wells. Clay presence significantly affects the behaviour of the acoustic properties of the reservoir rocks as a function of mineral type, volume, and distribution. The presence of glauconite mineral was observed in all the wells. Thirty-two thin sections, XRD and SEM/EDS from eight out of ten wells were studied to investigate lithology, diagenesis and the effect of mineralogy on porosity and acoustic properties (Compressional velocity and bulk density) within the studied reservoir units. Cementation (calcite and quartz), dissolution, compaction, clay mineral authigenesis, and stylolitization were the most significant diagenetic processes affecting porosity, velocity, and density.Well E-CN1 reservoir quality was very poor due to the destruction of intergranular porosity by extensive quartz and illite cementation, and compaction whereas well F-A13 show a highly porous sandstone reservoir with rounded monocrystalline quartz grain and only clusters of elongate to disc-like, authigenic chlorite crystals partly filling a depression within altered detrital grains.
Overall, the results show that the porosity, lithology mineralogy, compaction and pore fluid were the major factors causing the acoustic impedance variations in the upper shallow marine sandstone reservoirs. / 2021-09-01
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Estimating Canopy Fuel Parameters with In-Situ and Remote Sensing DataMutlu, Muge 2010 December 1900 (has links)
Crown fires, the fastest spreading of all forest fires, can occur in any forest type
throughout the United States and the world. The occurrence of crown fires has become
increasingly frequent and severe in recent years. The overall aim of this study is to
estimate the forest canopy fuel parameters including crown base height (CBH) and
crown bulk density (CBD), and to investigate the potential of using airborne lidar data in
east Texas. The specific objectives are to: (1) propose allometric estimators of CBD and
CBH and compare the results of using those estimators to those produced by the
CrownMass/FMAPlus software at tree and stand levels for 50 loblolly pine plots in
eastern Texas, (2) develop a methodology for using airborne light detection and ranging
(lidar) to estimate CBD and CBH canopy fuel parameters and to simulate fire behavior
using estimated forest canopy parameters as FARSITE inputs, and (3) investigate the use
of spaceborne ICEsat /GLAS (Ice, Cloud, and Land Elevation Satellite/Geoscience Laser
Altimeter System) lidar for estimating canopy fuel parameters. According to our results
from the first study, the calculated average CBD values, across all 50 plots, were 0.18 kg/m³ and 0.07 kg/m³, respectively, for the allometric equation proposed herein and
the CrownMass program. Lorey’s mean height approach was used in this study to
calculate CBH at plot level. The average height values of CBH obtained from Lorey’s
height approach was 10.6 m and from the CrownMass program was 9.1 m. The results
obtained for the two methods are relatively close to each other; with the estimate of CBH
being 1.16 times larger than the CrownMass value. According to the results from the
second study, the CBD and CBH were successfully predicted using airborne lidar data
with R² values of 0.748 and 0.976, respectively. The third study demonstrated that
canopy fuel parameters can be successfully estimated using GLAS waveform data; an R²
value of 0.84 was obtained. With these approaches, we are providing practical methods
for quantifying these parameters and making them directly available to fire managers.
The accuracy of these parameters is very important for realistic predictions of wildfire
initiation and growth.
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Effect of paraplowing on soil properties and crop yield under irrigated management2015 March 1900 (has links)
Limitations on water infiltration and soil aeration through compaction processes have the potential to limit production in irrigated agricultural fields. This project was conducted to determine the impact of sub-soiling with a paraplow (Howard Rotavator) on soil physical properties and processes that are important in affecting soil-water relations and productivity. The paraplow was the subsoiler selected for use in this study because of its ability to loosen the soil at the depth of plowing while producing minimal surface disturbance. The research plots were located on Chernozem and Vertisol soils in the Brown soil zone in the Lake Diefenbaker irrigation district near Birsay, SK. Irrigated and dryland sites were used for comparison. Sub-soiling was able to consistently reduce bulk density of the soil and effects persisted for one to two years under normal precipitation conditions.
Excessively wet conditions (2010 and 2011) reduced the effectiveness of the sub-soiling. Tillage induced porosity in the soil was associated with a greater infiltration capacity measured in the field. Yield benefits in crops grown (canola, flax, wheat) from sub-soiling were variable under the wet conditions of 2010 and 2011. A greater benefit was observed under the normal precipitation conditions of 2012 on sites that were paraplowed in 2011. Subsoiling at a depth of 45cm and a row spacing of 45cm (manufacturer’s recommended configuration) was more effective than shallower depth and wider row spacing treatments. A significant yield benefit was only observed at the dryland site established in 2011, and limited yield benefit was observed in the irrigated sites. Over the three years of the study, annual yields from sub-soiling were on average about 5% higher than the un-tilled control. However, yield benefits were variable depending on crop and year. Given an estimated cost of subsoiling of ~$30 per acre, a benefit of sub-soiling that lasts one year would produce close to break-even conditions, and sub-soiling benefits that are consistent and last longer than one year are needed to be cost effective.
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RESTORATION OF RIPARIAN BUFFER FUNCTION IN RECLAIMED SURFACE MINE SOILS IN SOUTHERN ILLINOISRahe, Nathan 01 May 2013 (has links)
Riparian buffers have been proven to reduce nutrient and sediment transport to streams in agricultural watersheds. Southern Illinois offers a unique opportunity to study functions of riparian buffers in reclaimed mine soils. In Perry County, Illinois three stream segments of Bonnie Creek, Galum Creek and Pipestone Creek were restored to their approximate original position following mining. Between 1980 and 2000, as part of the restoration, vegetative buffers of grasses and trees were planted along the streams to minimize nutrient and sediment inputs from adjacent restored agricultural land. Our research objective was to determine whether riparian soil function was being restored in the vegetated buffers by comparing multiple soil properties to the adjacent reclaimed soils in agricultural production. Four transects were established on each study site through the buffer and agricultural field. Ten one meter plots were evenly spaced along each transect in each of the land uses. In summers 2010 and 2011, water infiltration rates, bulk density, total carbon concentration, total nitrogen concentration, and C:N ratio measurements were made to assess the restoration of soil function. Soil water infiltration was significantly higher and bulk density was significantly lower in the riparian buffers compared to the adjacent agricultural fields. In the riparian buffer, roots likely helped to break up the soil adding pore space, which reduced the bulk density and increased the water infiltration rates. Soil total carbon, total nitrogen, and C:N ratio were significantly higher in the riparian buffers than the agricultural fields. The additional organic matter inputs from the roots of the riparian vegetation along with incorporation of litter from the soil macrofauna likely helped to increase the soil carbon and nitrogen levels compared to the agricultural fields. Even though the soil C:N ratio was significantly higher in the riparian buffers than the agricultural fields, more time is needed to restore the ratio to levels where nitrogen will be immobilized not mineralized in the riparian soils. Soil function in the riparian areas should continue to develop at a faster rate compared to the agricultural fields due to the impact of the perennial vegetation. Restoration of landscapes is not estimated by the return of structure alone, it also includes the re-establishment of function such as soil quality improvement, water quality improvement, and wildlife habitat restoration.
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Slumping of cultivated sandy soils : factors, processes and indicators / Slumping des sols cultivés sableux : processus, facteurs et indicateursHao, Hongtao 10 December 2010 (has links)
Les sols sableux peuvent constituer une réserve potentielle de sols cultivables mais leur mise en valeur entraîne toujours des dégradations de la structure et une baisse du potentiel agricole. Une dégradation très fréquente est l’affaissement des couches labourées sous l’action de la pluie, ou slumping. Notre objectif était d’identifier les mécanismes et les facteurs déterminants du slumping afin de proposer des techniques de prévention. L’étude a été conduite sous pluies naturelles (au champ) et simulées (au laboratoire). Au champ, la cinétique d’évolution des caractéristiques hydriques et physiques du sol a été suivie après un labour à 20 ou à 40 cm de profondeur, dans un sol sableux tropical Thaïlande. Au laboratoire, un sol cultivé modèle a été élaboré dans un cylindre (h et Ø = 20 cm) à partir i) du sol prélevé dans le champ expérimental, ii) de la fraction sable (> 50 μm) extraite de ce même sol. Les sols modèles ont subi des pluies d’intensité variable (de 20 à 120 mm/h) après mise en place sur une table à succion (20 à 90 hPa). Le slumping se produit lorsque deux conditions sont réunies: (1) l’eau doit atteindre un potentiel proche de 0 hPa ce qui réduit la cohésion et aboutit à un équilibre fragile du sol comme décrit par la physique des milieux granulaires; (2) ce potentiel doit être maintenu assez longtemps pour qu’une instabilité se produise et entraine une brusque et importante diminution de la cohésion, donc l’effondrement du matériau. Si la fraction fine (<50 μm) est retirée du sol, aucun effondrement n’est observé, démontrant l’importance de cette fraction limonoargileuse, pourtant minoritaire (<10-15 % en masse), dans l’instabilisation et le slumping. La prévention du slumping et la gestion des sols sableux sont discutées en guise de conclusion. / The sandy soil can serve as a potential reserve for cultivation. However, they are often considered as marginal because prone to have low productivity and problems of structure degradation. One of the degradations is compaction caused by rainfall or irrigation, which is called slumping. Our objective is to identify the processes and factors that affect slumping. The study had been done under natural conditions (field) and simulated conditions (laboratory) respectively. In the field, a tropical sandy soil in Thailand was selected. After 20 cm and 40 cm depth tillage, the dynamic of hydraulic and physical characteristics were measured. In laboratory, a cultivated soil model was build in a cylinder (height and diameter was 20 cm). We used two materials: 1) the original soil from the experiment field site, and 2) the sand fraction (> 50 μm) extracted from this soil. These model soils were submitted to rainfalls with different intensity (20 to 120 mm h-1), combined with different suction (20 to 90 hPa) on a suction table which can support the cylinder. The slumping for soil happens when two conditions were met: 1) the water potential reached a threshold value near 0 hPa. In this value, the soil cohesion decreased and a fragile equilibrium conditions were reached according to granular material theory; 2) the potential value was kept long enough and the cohesion continue decrease until they can no more support the equilibrium, so slumping happens. Surprisingly, in our treatment, when the fine particles (<50 μm) were taken out from the soil, no slumping was observed. This demonstrates the particles of clay and silt are very important to soil stability, even their content were very low as less than 10 percent. The possible ways to prevent slumping and management of sandy soils are also discussed.
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Physical and Chemical Soil Properties of Ten Virginia Department of Transportation (VDOT) Mitigation WetlandsFajardo, Gabriela Isabel 09 March 2006 (has links)
In 1998, the Virginia Department of Transportation (VDOT) adopted standards for soil handling and amendments to improve created non-tidal wetland soil conditions. This study was conducted in sites where these new reconstruction practices were supposedly being implemented. Specific objectives were (i) to determine the relative effects of soil reconstruction practices on mitigation site soils, (ii) to assess the degree to which hydric soil indicators were present, and (iii) to evaluate the relative edaphic potential of mitigation site soils. Soil physical, chemical and morphological properties were analyzed in ten mitigation wetlands located in Virginia's Piedmont and Coastal Plain. Surface soil pH was high due to liming, although some sites demonstrated low subsoil pH, indicating the presence of sulfidic materials. Nutrient levels varied, while C:N ratios were low (<25:1), suggesting a high quality organic matter complex. Organic amendments were generally applied at a rate of 4% soil organic matter content. Actual measured carbon content was <2.6% (<50 Mg ha⁻¹). Sites not receiving organic materials and associated tillage had root-limiting bulk densities at the surface, while the majority of sites had root-limiting subsoil (30 cm) bulk densities due to weakly developed soil structure and a lack of deep ripping practices. Many sites also contained high sand content (>50%), which may negatively affect other soil properties. Nine sites had confirmed Hydric Soil Indicators, with their occurrence in a site as high as 70%. Soil reconstruction methods need to incorporate higher organic amendment rates and/or routine disking/ripping practices to improve mitigation wetland soil conditions. / Master of Science
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The Forest Fire in Västmanland, South Central Sweden, and its Effects on Soils and Forest Recovery / Skogsbranden i Västmanland, sydvästra Sverige, och dess inverkan på markegenskaper och skogens återhämtningSjödin, Sophia January 2016 (has links)
Forest fires can have a great impact on the relationship between soil organic matter (SOM) and soilbulk density (SBD). SOM will reduce with increased fire intensity, which ultimately leads to more compaction of the soil. The compaction rate might increase to the limit of where root growth will be absent thus leading to actions to restore the soil. This study investigates changes in the relationship between SOM and SBD in spodosol and histosol in Seglingsberg, located in South-central Sweden, where a forest fire occurred summer 2014. In addition, changes of pH values in the two types of soilwere examined in order to receive information about the chemical states of the different soil types.A total of 29 samples at depths of 0-17 cm were received from one day of fieldwork and these were later analysed concerning the pH, the SBD and the SOM content. The results showed an increase of pH-values in the fire-exposed area compared to pH values measured at the reference site (pH ~5). More importantly, the results from the SBD and SOM analyses indicated that there was in fact an inversely proportional relationship between the two soil parameters. In addition, high pH values were measured at the same subareas of which the highest SBD- and the lowest SOM values were obtained.Statistical analyses were applied on the results in order to conclude if the soil property changes caused by the fire were significantly different from normal conditions or not. The results from the statistical analyses revealed that 25% of the fire-exposed sites had changed significantly. However, more samples should have been taken while in field, since lack of data is thought to have had a great impact on the final results.Although there were no strong statistical evidence for the hypothesis, it is clear that the forest firein Västmanland year 2014 affected both the SOM, SBD and pH values in the soils. / Under sommaren år 2014 utbröt en omfattande skogsbrand i Västmanlands län, vilket medföljdedramatiska konsekvenser för framförallt ett flertal skogsbolag, men även för boende i området. Med skogsbränder följer negativa såväl som positiva konsekvenser, där de positiva framförallt gäller med avseende på arter som har evolverat i samband med bränder. Förutom ovannämnda konsekvenser så finns det risk för att markförhållandena ändras till följd av en skogsbrand. I denna studie undersöktes hur markegenskaper i torv- samt podsoljordar hade förändrats med avseende på pH, halten avorganiskt material samt packningsgrad. Fältstudien genomfördes i ett drabbat brandområde strax norrom Seglingsberg, Surahammars kommun. Totalt togs 29 stycken jordprover inom fem stycken transekter i området. Av dessa kunde 25 stycken användas till alla tre analyserna. Resultaten från jordprovsanalyserna användes därefter till att genomföra statistiska undersökningar. Detta för att se hur stor spridningen var mellan och inom de fem transekterna samt för att kunna avgöra om jordproverna visade sig vara signifikant förändrade från ursprungsförhållanden.Resultaten från jordprovsanalyserna visade att det fanns mest organiskt material kvar i de östra delarna av området, medan det var kraftigt reducerat ju längre nordväst jordproverna hade hämtats. I samband med att markens organiska material hade reducerats kunde man även bevittna att jordtäcket hade blivit mer kompakterat. Resultaten från pH-analysen pekar också på att förändringarna varit som störst i de nordvästliga delarna. pH-analysen bevisade att markkemin ser annorlunda ut än innanbranden, då värdena ibland låg 2 enheter för högt än vad man vanligen brukar observera i podsol- ochtorvjordar. Då pH-skalan är logaritmisk innebär detta en minskad försurning med 100 gånger. Resultaten från alla jordprovsanalyser tyder att branden varit som mest intensiv i den nordvästra delen av undersökningsområdet, i området bestående av ungskog.Även om resultaten från jordprovsanalyserna pekade på att branden orsakat tydliga mark- förändringar, visade majoriteten av de statistiska undersökningarna inte på signifikanta förändringar. Det är därför inte möjligt att generalisera resultaten och således applicera dessa på hela brandområdet i Västmanland.Eftersom att naturligt förekommande skogsbränder är relativt få till antalet i Sverige, finns därmed få studier tillgängliga inom ämnesområdet. Det finns en upplaga av studier inom kontrollerade och anlagda brandfält, men i och med att dessa förhållanden är fixerade, så påverkas markegenskaperna sällan avsevärt. Forskningsrapporter indikerar på ett mer extremt klimat i framtiden, som förmodas leda till en ökad omfattning samt ett ökat antal naturligt förekommande skogsbränder. Om denna prognos stämmer är det viktigt att undersöka markförhållandena, då en skogsbrand kan ha direktavgörande effekt på återväxten.
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Combined sensor of dielectric constant and visible and near infrared spectroscopy to measure soil compaction using artificial neural networksAl-Asadi, Raed January 2014 (has links)
Soil compaction is a widely spread problem in agricultural soils that has negative agronomic and environmental impacts. The former may lead to poor crop growth and yield, whereas the latter may lead to poor hydraulic properties of soils, and high risk to flooding, soil erosion and degradation. Therefore, the elimination of soil compaction must be done on regular bases. One of the main parameters to quantify soil compaction is soil bulk density (BD). Mapping of within field variation in soil BD will be a main requirement for within field management of soil compaction. The aim of this research was to develop a new approach for the measurement of soil BD as an indicator of soil compaction. The research relies on the fusion of data from visible and near infrared spectroscopy (vis-NIRS), to measure soil gravimetric moisture content (ω), with frequency domain reflectometry (FDR) data to measure soil volumetric moisture content (θv). The values of the estimated ω and θv, for the same undisturbed soil samples were collected from selected locations, textures, soil moisture contents and land use systems to derive soil BD. A total of 1013 samples were collected from 32 sites in the England and Wales. Two calibration techniques for vis-NIRS were evaluated, namely, partial least squares regression (PLSR) and artificial neural networks (ANN). ThetaProbe calibration was performed using the general formula (GF), soil specific calibration (SSC), the output voltage (OV) and artificial neural networks (ANN). ANN analyses for both ω and θv properties were based either on a single input variable or multiple input variables (data fusion). Effects of texture, moisture content, and land use on the prediction accuracy on ω, θv and BD were evaluated to arrive at the best experimental conditions for the measurement of BD with the proposed new system. A prototype was developed and tested under laboratory conditions and implemented in-situ for mapping of ω, θv and BD. When using the entire dataset (general data set), results proved that high measurement accuracy can be obtained for ω and θv with PLSR and the best performing traditional calibration method of the ThetaProbe with R2 values of 0.91 and 0.97, and root mean square error of prediction (RMSEp) of 0.027 g g-1 and 0.019 cm3 cm-3, respectively. However, the ANN – data fusion method resulted in improved accuracy (R2 = 0.98 and RMSEp = 0.014 g g-1 and 0.015 cm3 cm-3, respectively). This data fusion approach gave the best accuracy for BD assessment when only vis-NIRS spectra and ThetaProbe V were used as an input data (R2 = 0.81 and RMSEp = 0.095 g cm-3). The moisture level (L) impact on BD prediction revealed that the accuracy improved with soil moisture increasing, with RMSEp values of 0.081, 0.068 and 0.061 g cm-3, for average ω of 0.11, 0.20 and 0.28 g g-1, respectively. The influence of soil texture was discussed in relation with the clay content in %. It was found that clay positively affected vis-NIRS accuracy for ω measurement and no obvious impact on the dielectric sensor readings was observed, hence, no clear influence of the soil textures on the accuracy of BD prediction. But, RMSEp values of BD assessment ranged from 0.046 to 0.115 g cm-3. The land use effect of BD prediction showed measurement of grassland soils are more accurate compared to arable land soils, with RMSEp values of 0.083 and 0.097 g cm-3, respectively. The prototype measuring system showed moderate accuracy during the laboratory test and encouraging precision of measuring soil BD in the field test, with RMSEp of 0.077 and 0.104 g cm-3 of measurement for arable land and grassland soils, respectively. Further development of the prototype measuring system expected to improve prediction accuracy of soil BD. It can be concluded that BD can be measured accurately by combining the vis-NIRS and FDR techniques based on an ANN-data fusion approach.
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