Marc Meirvenne - Profile on Academia.edu (original) (raw)

Papers by Marc Meirvenne

Research paper thumbnail of Characterization of nitrogen dynamics in a pasture soil by electromagnetic induction

The aim of this study was to investigate how electromagnetic induction can be used to improve the... more The aim of this study was to investigate how electromagnetic induction can be used to improve the characterization of N dynamics in a 1.2 ha pasture. The soil apparent electrical conductivity (ECa) was measured by electromagnetic induction using an EM38DD. At 116 locations, soil samples were taken according to a clustered sampling design, three times during one winter, and analyzed for the NO 3 − -N content in the topsoil (0-60 cm). Management zones were delineated using a fuzzy k-means classification of the interpolated ECa measurements. Two ECa zones were found, reflecting mainly differences in soil texture. Since the mean NO 3 − -N content was different for the two ECa zones (24 and 65 kg/ha in November 2002), the residuals were interpolated using stratified simple kriging. This allowed evaluating the NO 3 − dynamics during the winter in both zones; one ECa zone showed a higher risk for NO 3 − losses than the other calling for a site-specific N management. As a validation, NO 3 − -N was interpolated using orinary kriging without stratification. This resulted in similar zones confirming the usefulness of the ECa measurements to assess N-specific management zones, even within small fields.

Research paper thumbnail of An efficient calibration procedure for correction of drift in EMI survey data

Journal of Applied Geophysics, 2014

Frequency domain electromagnetic induction (EMI) sensors with a small coil separation are used fo... more Frequency domain electromagnetic induction (EMI) sensors with a small coil separation are used for near-surface surveys in a variety of domains. Regardless of the application, the instrument response(s) may suffer from a drift, meaning that a response at one given location may vary over time, despite no appreciable changes above or underneath the surface. Drift is unwanted as it may introduce global trends or abrupt changes in EMI data not related to the underground. In this paper, the effects of drift on the quadrature and in-phase responses of a ground-based system are researched by evaluating several multi-receiver EMI datasets. First, a stationary recording illustrates the need for a versatile drift compensation. For area surveys we propose an efficient drift correction procedure. To start, a calibration line that crosses the entire survey area within a short time frame is recorded. An approach to account for spatial offset between sensor midpoint and global navigation satellite system antenna is also detailed given the bearing it has on accurate localization. The residuals of coincident calibration and survey data can then be used to model and subtract the drift from the sensor data. This is performed by applying outlier detection and removal, followed by curve fitting of the comparison data. The developed procedure allows a near continuous evaluation of drift, without the need for ancillary data and is time efficient. The approach is shown to be suitable for various survey setups and drift effects.

Research paper thumbnail of A floating sensing system to evaluate soil and crop variability within flooded paddy rice fields

Continuous paddy rice cultivation requires fields to be flooded most of the time limiting serious... more Continuous paddy rice cultivation requires fields to be flooded most of the time limiting seriously the collection of detailed soil information. So far, no appropriate soil sensor technology for identifying soil variability of flooded fields has been reported. Therefore, the primary objective was the development of a sensing system that can float, acquire and process detailed geo-referenced soil information within flooded fields. An additional objective was to determine whether the collected apparent electrical conductivity (EC a ) information could be used to support soil management at a within-field level. A floating sensing system (FloSSy) was built to record EC a using the electromagnetic induction sensor EM38, which does not require physical contact with the soil. Its feasibility was tested in an alluvial paddy field of 2.7 ha located in the Brahmaputra floodplain of Bangladesh. The high-resolution (1 9 1 m) EC a data were classified into three classes using the fuzzy k-means classification method. The variation among the classes could be attributed to differences in subsoil (0.15-0.30 m below soil surface) bulk density, with the smallest EC a values representing the lowest bulk density. This effect was attributed to differences in compaction of the plough pan due to differential puddling. There was also a significant difference in rice yield among the EC a classes, with the smallest EC a values representing the lowest yield. It was concluded that the floating sensing system allowed the collection of relevant soil information, opening potential for precision agriculture practices in flooded crop fields.

Research paper thumbnail of Comparing apparent electrical conductivity measurements on a paddy field under flooded and drained conditions

Every growing season, paddy fields are kept both flooded and drained for a significant period of ... more Every growing season, paddy fields are kept both flooded and drained for a significant period of time. As a consequence, these soils develop distinct physico-chemical characteristics. For practical reasons, these soils are mostly sampled under dry conditions, but the question arises how representative the results are for the wet growing conditions. Therefore, the apparent electrical conductivity (EC a ) of a 1.4 ha alluvial paddy field located in the Brahmaputra floodplain of Bangladesh was measured in both dry and wet conditions by a sensing system using the electromagnetic induction sensor EM38, which does not require physical contact with the soil, and compared both surveys. Due to the smooth water surface under wet conditions which ensured increased stability of the sensing platform, the results of the survey showed considerably reduced micro-scale variability of EC a . Furthermore, the wet survey results more reliably furnished soil-related information mainly due to the absence of soil moisture dynamics. The differences between EC a under wet and dry conditions were attributed to differences in soil texture, mainly the sand content variation having considerable effect on soil moisture differences when flooded following drainage. Accordingly, the largest differences between EC a under wet and dry conditions were found in those parts of the field with a large sand content. Hence, the conclusion was that an EC a survey on flooded fields has an added value to precision soil management.

Research paper thumbnail of Characterization of nitrogen dynamics in a pasture soil by electromagnetic induction

The aim of this study was to investigate how electromagnetic induction can be used to improve the... more The aim of this study was to investigate how electromagnetic induction can be used to improve the characterization of N dynamics in a 1.2 ha pasture. The soil apparent electrical conductivity (ECa) was measured by electromagnetic induction using an EM38DD. At 116 locations, soil samples were taken according to a clustered sampling design, three times during one winter, and analyzed for the NO 3 − -N content in the topsoil (0-60 cm). Management zones were delineated using a fuzzy k-means classification of the interpolated ECa measurements. Two ECa zones were found, reflecting mainly differences in soil texture. Since the mean NO 3 − -N content was different for the two ECa zones (24 and 65 kg/ha in November 2002), the residuals were interpolated using stratified simple kriging. This allowed evaluating the NO 3 − dynamics during the winter in both zones; one ECa zone showed a higher risk for NO 3 − losses than the other calling for a site-specific N management. As a validation, NO 3 − -N was interpolated using orinary kriging without stratification. This resulted in similar zones confirming the usefulness of the ECa measurements to assess N-specific management zones, even within small fields.

Research paper thumbnail of Geostatistical Assessment of the Impact of World War I on the Spatial Occurrence of Soil Heavy Metals

AMBIO, 2011

Previous research showed a regional Cu enrichment of 6 mg kg -1 in the top soil of the Ypres war ... more Previous research showed a regional Cu enrichment of 6 mg kg -1 in the top soil of the Ypres war zone (Belgium), caused by corrosion of WWI shell fragments. Further research was required since in addition to Cu, also As, Pb, and Zn were used during the manufacturing of ammunition. Therefore, an additional data collection was conducted in which the initial Cu data set was tripled to 731 data points and extended to eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) which permitted (1) to evaluate the environmental impact of the heavy metals at a regional scale and (2) to assess their regional spatial occurrence by performing an optimized geostatistical modeling. The results showed no pollution at a regional scale, but sometimes locally concentrations exceeded the soil sanitation threshold, especially for Cu, Pb, and Zn. The spatial patterns of Ni and Cr were related to variations in soil texture whereas the occurrences of Cu and Pb were clearly linked to WWI activities. This difference in spatial behavior was confirmed by an analysis of coregionalization.

Research paper thumbnail of Integrated geophysical archaeological prospection resulting in the discovery of the school of gladiators in the Roman town of Carnuntum in Austria

Summary In the Roman town of Carnuntum 40 km south-east of Vienna (Austria) the unique discovery ... more Summary In the Roman town of Carnuntum 40 km south-east of Vienna (Austria) the unique discovery of a school of gladiators was made using a multi-disciplinary approach based on high-resolution near-surface geophysical prospection. The outstandingly well preserved architecture was revealed through non-invasive mapping using latest highly efficient multichannel ground penetrating radar systems. Foundations of a building complex including a circular training arena surrounded by wooden stands, the gladiator's living ...

Research paper thumbnail of Characterization of nitrogen dynamics in a pasture soil by electromagnetic induction

The aim of this study was to investigate how electromagnetic induction can be used to improve the... more The aim of this study was to investigate how electromagnetic induction can be used to improve the characterization of N dynamics in a 1.2 ha pasture. The soil apparent electrical conductivity (ECa) was measured by electromagnetic induction using an EM38DD. At 116 locations, soil samples were taken according to a clustered sampling design, three times during one winter, and analyzed for the NO 3 − -N content in the topsoil (0-60 cm). Management zones were delineated using a fuzzy k-means classification of the interpolated ECa measurements. Two ECa zones were found, reflecting mainly differences in soil texture. Since the mean NO 3 − -N content was different for the two ECa zones (24 and 65 kg/ha in November 2002), the residuals were interpolated using stratified simple kriging. This allowed evaluating the NO 3 − dynamics during the winter in both zones; one ECa zone showed a higher risk for NO 3 − losses than the other calling for a site-specific N management. As a validation, NO 3 − -N was interpolated using orinary kriging without stratification. This resulted in similar zones confirming the usefulness of the ECa measurements to assess N-specific management zones, even within small fields.

Research paper thumbnail of An efficient calibration procedure for correction of drift in EMI survey data

Journal of Applied Geophysics, 2014

Frequency domain electromagnetic induction (EMI) sensors with a small coil separation are used fo... more Frequency domain electromagnetic induction (EMI) sensors with a small coil separation are used for near-surface surveys in a variety of domains. Regardless of the application, the instrument response(s) may suffer from a drift, meaning that a response at one given location may vary over time, despite no appreciable changes above or underneath the surface. Drift is unwanted as it may introduce global trends or abrupt changes in EMI data not related to the underground. In this paper, the effects of drift on the quadrature and in-phase responses of a ground-based system are researched by evaluating several multi-receiver EMI datasets. First, a stationary recording illustrates the need for a versatile drift compensation. For area surveys we propose an efficient drift correction procedure. To start, a calibration line that crosses the entire survey area within a short time frame is recorded. An approach to account for spatial offset between sensor midpoint and global navigation satellite system antenna is also detailed given the bearing it has on accurate localization. The residuals of coincident calibration and survey data can then be used to model and subtract the drift from the sensor data. This is performed by applying outlier detection and removal, followed by curve fitting of the comparison data. The developed procedure allows a near continuous evaluation of drift, without the need for ancillary data and is time efficient. The approach is shown to be suitable for various survey setups and drift effects.

Research paper thumbnail of A floating sensing system to evaluate soil and crop variability within flooded paddy rice fields

Continuous paddy rice cultivation requires fields to be flooded most of the time limiting serious... more Continuous paddy rice cultivation requires fields to be flooded most of the time limiting seriously the collection of detailed soil information. So far, no appropriate soil sensor technology for identifying soil variability of flooded fields has been reported. Therefore, the primary objective was the development of a sensing system that can float, acquire and process detailed geo-referenced soil information within flooded fields. An additional objective was to determine whether the collected apparent electrical conductivity (EC a ) information could be used to support soil management at a within-field level. A floating sensing system (FloSSy) was built to record EC a using the electromagnetic induction sensor EM38, which does not require physical contact with the soil. Its feasibility was tested in an alluvial paddy field of 2.7 ha located in the Brahmaputra floodplain of Bangladesh. The high-resolution (1 9 1 m) EC a data were classified into three classes using the fuzzy k-means classification method. The variation among the classes could be attributed to differences in subsoil (0.15-0.30 m below soil surface) bulk density, with the smallest EC a values representing the lowest bulk density. This effect was attributed to differences in compaction of the plough pan due to differential puddling. There was also a significant difference in rice yield among the EC a classes, with the smallest EC a values representing the lowest yield. It was concluded that the floating sensing system allowed the collection of relevant soil information, opening potential for precision agriculture practices in flooded crop fields.

Research paper thumbnail of Comparing apparent electrical conductivity measurements on a paddy field under flooded and drained conditions

Every growing season, paddy fields are kept both flooded and drained for a significant period of ... more Every growing season, paddy fields are kept both flooded and drained for a significant period of time. As a consequence, these soils develop distinct physico-chemical characteristics. For practical reasons, these soils are mostly sampled under dry conditions, but the question arises how representative the results are for the wet growing conditions. Therefore, the apparent electrical conductivity (EC a ) of a 1.4 ha alluvial paddy field located in the Brahmaputra floodplain of Bangladesh was measured in both dry and wet conditions by a sensing system using the electromagnetic induction sensor EM38, which does not require physical contact with the soil, and compared both surveys. Due to the smooth water surface under wet conditions which ensured increased stability of the sensing platform, the results of the survey showed considerably reduced micro-scale variability of EC a . Furthermore, the wet survey results more reliably furnished soil-related information mainly due to the absence of soil moisture dynamics. The differences between EC a under wet and dry conditions were attributed to differences in soil texture, mainly the sand content variation having considerable effect on soil moisture differences when flooded following drainage. Accordingly, the largest differences between EC a under wet and dry conditions were found in those parts of the field with a large sand content. Hence, the conclusion was that an EC a survey on flooded fields has an added value to precision soil management.

Research paper thumbnail of Characterization of nitrogen dynamics in a pasture soil by electromagnetic induction

The aim of this study was to investigate how electromagnetic induction can be used to improve the... more The aim of this study was to investigate how electromagnetic induction can be used to improve the characterization of N dynamics in a 1.2 ha pasture. The soil apparent electrical conductivity (ECa) was measured by electromagnetic induction using an EM38DD. At 116 locations, soil samples were taken according to a clustered sampling design, three times during one winter, and analyzed for the NO 3 − -N content in the topsoil (0-60 cm). Management zones were delineated using a fuzzy k-means classification of the interpolated ECa measurements. Two ECa zones were found, reflecting mainly differences in soil texture. Since the mean NO 3 − -N content was different for the two ECa zones (24 and 65 kg/ha in November 2002), the residuals were interpolated using stratified simple kriging. This allowed evaluating the NO 3 − dynamics during the winter in both zones; one ECa zone showed a higher risk for NO 3 − losses than the other calling for a site-specific N management. As a validation, NO 3 − -N was interpolated using orinary kriging without stratification. This resulted in similar zones confirming the usefulness of the ECa measurements to assess N-specific management zones, even within small fields.

Research paper thumbnail of Geostatistical Assessment of the Impact of World War I on the Spatial Occurrence of Soil Heavy Metals

AMBIO, 2011

Previous research showed a regional Cu enrichment of 6 mg kg -1 in the top soil of the Ypres war ... more Previous research showed a regional Cu enrichment of 6 mg kg -1 in the top soil of the Ypres war zone (Belgium), caused by corrosion of WWI shell fragments. Further research was required since in addition to Cu, also As, Pb, and Zn were used during the manufacturing of ammunition. Therefore, an additional data collection was conducted in which the initial Cu data set was tripled to 731 data points and extended to eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) which permitted (1) to evaluate the environmental impact of the heavy metals at a regional scale and (2) to assess their regional spatial occurrence by performing an optimized geostatistical modeling. The results showed no pollution at a regional scale, but sometimes locally concentrations exceeded the soil sanitation threshold, especially for Cu, Pb, and Zn. The spatial patterns of Ni and Cr were related to variations in soil texture whereas the occurrences of Cu and Pb were clearly linked to WWI activities. This difference in spatial behavior was confirmed by an analysis of coregionalization.

Research paper thumbnail of Integrated geophysical archaeological prospection resulting in the discovery of the school of gladiators in the Roman town of Carnuntum in Austria

Summary In the Roman town of Carnuntum 40 km south-east of Vienna (Austria) the unique discovery ... more Summary In the Roman town of Carnuntum 40 km south-east of Vienna (Austria) the unique discovery of a school of gladiators was made using a multi-disciplinary approach based on high-resolution near-surface geophysical prospection. The outstandingly well preserved architecture was revealed through non-invasive mapping using latest highly efficient multichannel ground penetrating radar systems. Foundations of a building complex including a circular training arena surrounded by wooden stands, the gladiator's living ...