scholarly journals Repeated electromagnetic induction measurements for mapping soil moisture at the field scale: validation with data from a wireless soil moisture monitoring network

2016 ◽  
Author(s):  
Edoardo Martini ◽  
Ulrike Werban ◽  
Steffen Zacharias ◽  
Marco Pohle ◽  
Peter Dietrich ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Moisture ◽  
Spatial Pattern ◽  
Soil Properties ◽  
Electromagnetic Induction ◽  
Scale Validation ◽  
Monitoring Network ◽  
Clay Content ◽  
Temporal Variations ◽  
Dynamic Factor

Abstract. Electromagnetic induction (EMI) measurements are widely used for soil mapping, as they allow fast and relatively low-cost surveys of soil apparent electrical conductivity (ECa). Although the use of non-invasive EMI for imaging spatial soil properties is very attractive, the dependence of ECa on several factors challenges any interpretation with respect to individual soil properties or states such as soil moisture (θ). The major aim of this study was to further investigate the potential of repeated EMI measurements to map θ, with particular focus on the temporal variability of the spatial patterns of ECa and θ. To this end, we compared repeated EMI measurements with high-resolution θ data from a wireless soil moisture and soil temperature monitoring network for an extensively managed hillslope area for which soil properties and θ dynamics are known. For the investigated site, i) ECa showed small temporal variations whereas θ varied from very dry to almost saturation; ii) temporal changes of the spatial pattern of ECa differed from those of the spatial pattern of θ; and iii) the ECa-θ relationship varied with time. Results suggest that i) stable soil properties are the major control on ECa measured with EMI, and ii) for soils with low clay content, the electrical conductivity of the soil solution rather than θ is likely to be the dynamic factor controlling temporal variations of ECa. Further, our study provides the opportunity to discuss the complex interplay between factors controlling ECa and θ, and the use of EMI-based ECa data with respect to hydrological applications.

scholarly journals Repeated electromagnetic induction measurements for mapping soil moisture at the field scale: validation with data from a wireless soil moisture monitoring network

2017 ◽  
Vol 21 (1) ◽  
pp. 495-513 ◽  
Author(s):  
Edoardo Martini ◽  
Ulrike Werban ◽  
Steffen Zacharias ◽  
Marco Pohle ◽  
Peter Dietrich ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Moisture ◽  
Spatial Pattern ◽  
Soil Properties ◽  
Electromagnetic Induction ◽  
Scale Validation ◽  
Low Cost ◽  
Monitoring Network ◽  
Clay Content ◽  
Temporal Variations

Abstract. Electromagnetic induction (EMI) measurements are widely used for soil mapping, as they allow fast and relatively low-cost surveys of soil apparent electrical conductivity (ECa). Although the use of non-invasive EMI for imaging spatial soil properties is very attractive, the dependence of ECa on several factors challenges any interpretation with respect to individual soil properties or states such as soil moisture (θ). The major aim of this study was to further investigate the potential of repeated EMI measurements to map θ, with particular focus on the temporal variability of the spatial patterns of ECa and θ. To this end, we compared repeated EMI measurements with high-resolution θ data from a wireless soil moisture and soil temperature monitoring network for an extensively managed hillslope area for which soil properties and θ dynamics are known. For the investigated site, (i) ECa showed small temporal variations whereas θ varied from very dry to almost saturation, (ii) temporal changes of the spatial pattern of ECa differed from those of the spatial pattern of θ, and (iii) the ECa–θ relationship varied with time. Results suggest that (i) depending upon site characteristics, stable soil properties can be the major control of ECa measured with EMI, and (ii) for soils with low clay content, the influence of θ on ECa may be confounded by changes of the electrical conductivity of the soil solution. Further, this study discusses the complex interplay between factors controlling ECa and θ, and the use of EMI-based ECa data with respect to hydrological applications.

scholarly journals Using Multivariate Geostatistics to Assess Patterns of Spatial Dependence of Apparent Soil Electrical Conductivity and Selected Soil Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Glécio Machado Siqueira ◽  
Jorge Dafonte Dafonte ◽  
Montserrat Valcárcel Armesto ◽  
Ênio Farias França e Silva
Keyword(s):  
Electrical Conductivity ◽  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Clay Content ◽  
Data Sets ◽  
Soil Electrical Conductivity ◽  
Multivariate Geostatistics ◽  
Northwestern Spain

The apparent soil electrical conductivity (ECa) was continuously recorded in three successive dates using electromagnetic induction in horizontal (ECa-H) and vertical (ECa-V) dipole modes at a 6 ha plot located in Northwestern Spain. One of the ECadata sets was used to devise an optimized sampling scheme consisting of 40 points. Soil was sampled at the 0.0–0.3 m depth, in these 40 points, and analyzed for sand, silt, and clay content; gravimetric water content; and electrical conductivity of saturated soil paste. Coefficients of correlation between ECaand gravimetric soil water content (0.685 for ECa-V and 0.649 for ECa-H) were higher than those between ECaand clay content (ranging from 0.197 to 0.495, when different ECarecording dates were taken into account). Ordinary and universal kriging have been used to assess the patterns of spatial variability of the ECadata sets recorded at successive dates and the analyzed soil properties. Ordinary and universal cokriging methods have improved the estimation of gravimetric soil water content using the data of ECaas secondary variable with respect to the use of ordinary kriging.

scholarly journals Evaluations of the effects of soil properties and electrical conductivity on the water content reflectometer calibration for landfill cover soils

2017 ◽  
Vol 12 (No. 1) ◽  
pp. 10-17 ◽  
Author(s):  
K. Kim ◽  
J. Sim ◽  
T.-H. Kim
Keyword(s):  
Electrical Conductivity ◽  
Soil Properties ◽  
Water Content ◽  
Clay Content ◽  
Liquid Limit ◽  
Time Domain Reflectometry ◽  
Volumetric Water Content ◽  
Unit Weight ◽  
Landfill Cover ◽  
Dry Unit Weight

This study presents soil-moisture calibrations using low-frequency (15–40 MHz) time domain reflectometry (TDR) probe, referred to as water content reflectometer (WCR), for measuring the volumetric water content of landfill cover soils, developing calibrations for 28 different soils, and evaluating how WCR calibrations are affected by soil properties and electrical conductivity. A 150-mm-diameter PVC cell was used for the initial WCR calibration. Linear and polynomial calibrations were developed for each soil. Although the correlation coefficients (R<sup>2</sup>) for the polynomial calibration are slightly higher, the linear calibrations are accurate and pragmatic to use. The effects of soil electrical conductivity and index properties were investigated using the slopes of linear WCR calibrations. Soils with higher electrical conductivity had lower calibration slopes due to greater attenuation of the signal during transmission in the soil. Soils with higher electrical conductivity tended to have higher clay content, organic matter, liquid limit, and plasticity index. The effects of temperature and dry unit weight on WCR calibrations were assessed in clayey and silty soils. The sensor period was found to increase with the temperature and density increase, with greater sensitivity in fine-textured plastic soils. For typical variations in temperature, errors in volumetric water content on the order of 0.04 can be expected for wet soils and 0.01 for drier soils if temperature corrections are not applied. Errors on the order of 0.03 (clays) and 0.01 (silts) can be expected for typical variations in dry unit weight (± 2 kN/m<sup>3</sup>).

scholarly journals Impact of recreational transformation of soil physical properties on micromolluscs in an urban park

2021 ◽  
Vol 29 (2) ◽  
pp. 78-87
Author(s):  
V. S. Budakova ◽  
N. V. Yorkina ◽  
P. M. Telyuk ◽  
A. K. Umerova ◽  
O. M. Kunakh ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Moisture ◽  
Physical Properties ◽  
Soil Properties ◽  
Principal Component ◽  
Feature Space ◽  
Penetration Resistance ◽  
Soil Physical Properties ◽  
Urban Park ◽  
Soil Penetration Resistance

The paper assesses the effect of transformation of soil physical properties on the abundance of micromolluscs in the conditions of an urban park. The studies were carried out in Novooleksandrivskiy Park (Melitopol, Ukraine). An experimental polygon was represented by 7 transects with 18 sampling points in each. The interval between the points in the transect, as well as the interval between transects, was 3 meters. The total area of the polygon was 1,134 m2. The tree species growing within the polygon were Quercus robur, Sophora japonica, and Acer campestre. Shrubs were represented by Ulmus laevis, Tilia cordata, Celtis occidentalis, and Morus nigra. The locations of the trees and shrubs were mapped. The crowns of tree and shrub plants formed a dense canopy and a shady light regime. The grass cover was practically absent. The soil mechanical resistance, soil aggregate-size distribution, electrical conductivity of soil, soil moisture and bulk density were measured. We recorded 618 individuals of Vallonia pulchella, 120 individuals of Cochlicopa lubrica, and 58 individuals of Acanthinula aculeata within the surveyed polygon. We extracted three principal components, which could explain 60.9% of the variation in the feature space of the soil properties. The principal component 1 explained 42.0% of the variation of the feature space and depended on the soil penetration resistance throughout the whole profile, aggregate composition, density, electric conductivity and moisture content of soil. This component reflected a tendency for soil penetration resistance and soil density to increase near recreational trails. The principal component 1 was used to indicate the gradient of recreational transformation of the soil. The principal component 2 was able to explain 10.6% of the variation in the feature space. It negatively correlated with the distance from the recreational trail, soil penetration resistance at the depth of 35 cm or more, soil electrical conductivity, and the proportion of aggregates greater than 3 mm in size. This component positively correlated with soil penetration resistance at 0–5 cm depth and the proportion of aggregates less than 0.5 mm in size. This component can be interpreted as a "halo" from the recreational trail, or a gradient of indirect soil transformations adjacent to the zone of intense recreational load. The principal component 3 was able to explain 8.3% of the variation in the feature space. It positively correlated with soil penetration resistance at the depth of 20–40 cm, the proportion of 0.5–7.0 mm aggregates, and soil moisture. It negatively correlated with the proportion of aggregates larger than 7 mm and smaller than 0.25 mm. This component indicated a variation in soil properties that was induced by causes independent of recreational exposure. The extracted gradients of soil properties significantly influenced the abundance of micromollusc populations. The abundance of all species decreased after increase in recreational load. Micromollusc species responded to direct recreational exposure as plateau (C. lubrica) and asymmetric unimodal responses (V. pulchella and A. aculeata).

CONVERSION OF ELECTROMAGNETIC INDUCTANCE READINGS TO SATURATED PASTE EXTRACT VALUES IN SOILS FOR DIFFERENT TEMPERATURE, TEXTURE, AND MOISTURE CONDITIONS

1989 ◽  
Vol 69 (1) ◽  
pp. 25-32 ◽  
Author(s):  
R. C. McKENZIE ◽  
W. CHOMISTEK ◽  
N. F. CLARK
Keyword(s):  
Electrical Conductivity ◽  
Soil Moisture ◽  
Soil Temperature ◽  
Key Words ◽  
Soil Salinity ◽  
Electromagnetic Induction ◽  
Linear Equations ◽  
Temperature Correction ◽  
Available Soil Moisture ◽  
Moisture Conditions

Linear equations were developed for converting electromagnetic induction readings (ECa) from EM38 meters to saturated paste electrical conductivity values (ECc). To correlate EM38 readings with measured ECe values, field sites representing a range of salinity conditions were sampled in 0.30-m increments to a depth of 1.5 m. Adapting a weighting procedure based on the EM38 meter's response to depth, ECe values were condensed into a single weighted value. The weighted ECe values were linearly correlated with temperature-corrected ECa readings. Equations were designed for soils of various textures under varying temperature and moisture conditions. For accurate ECa to ECe conversions, soil temperature correction of ECa is essential. When a frozen layer is present, EM38 readings are unreliable. EM38 horizontal and vertical modes show different ECa readings for the same depth-weighted ECe. Variability of ECa to ECe conversion was greater on coarse-textured than medium- or fine-textured soils. Available soil moisture should be above 30% for accurate ECe determinations from ECa readings. Key words: Salinity methods, soil salinity, saturated paste extract method, electromagnetic inductance meters, soil temperature

scholarly journals Combined impact of local climate and soil properties on soil moisture patterns

2017 ◽  
Author(s):  
Thushara Gunda ◽  
Udeni P. Nawagamuwa ◽  
George M. Hornberger
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Soil Properties ◽  
Temporal Variations ◽  
Intermediate Zone ◽  
Water Dynamics ◽  
Climate Change Scenarios ◽  
Local Climate ◽  
Dry Zone ◽  
Wet Zone

Abstract. Soil plays a key role in terrestrial water dynamics by retaining precipitation on land. A water balance approach is used to evaluate spatial and temporal variations in soil moisture in Sri Lanka, a country characterized by high spatial variability as reflected in the recognition of three regions of the country, the wet zone, the intermediate zone, and the dry zone. We show that a combination of local climate and soil properties drive spatial patterns of soil moisture deficits on the island, with soils buffering climate variability in the wet zone and enhancing drought patterns in the dry zone. Changes in historical temporal patterns are most notable for the intermediate zone, a region characterized by consistently variable deficits. Counterfactuals of climate change scenarios indicate temperature will drive increases in deficit likelihoods (up to 20 %) in the future, with greatest impact in the intermediate and dry zones, where more than 80 % of the national rice production is concentrated. Given that temperature projections are less uncertain than other climate change impacts, further evaluation of future water stresses are needed. Coupled with remotely-sensed soil moisture data, the findings from this study have implications for infrastructural planning and seasonal crop water allocations in zones with a degree of variability (i.e., neither consistently wet nor consistently dry). Because soil hydrologic regimes reflect inherent, local vulnerabilities, water management decisions need to incorporate regional variabilities in soil moisture dynamics in assessments of climate change adaptations.

scholarly journals Zai Technology and Integrated Nutrient Management for Improved Soil Fertility and Increased Sorghum Yields in Kitui County, Kenya

2021 ◽  
Vol 5 ◽  
Author(s):  
Mercy Cheruto Kebenei ◽  
Monicah Mucheru-Muna ◽  
Felista Muriu-Ng'ang'a ◽  
Charles Kimani Ndung'u
Keyword(s):  
Electrical Conductivity ◽  
Soil Moisture ◽  
Soil Fertility ◽  
Soil Properties ◽  
Crop Yield ◽  
Total Nitrogen ◽  
Cattle Manure ◽  
Sub Saharan Africa ◽  
Cropping Seasons ◽  
The Impact

Deteriorating soil fertility, low unreliable rainfall and soil moisture stress has resulted to low crop yields among farmers of sub-Saharan Africa (SSA), necessitating a search for more sustainable production practices. Zai technology has the ability to promote soil moisture retention and enhances soil fertility. A four-seasons field experiment was conducted to assess the impact of Zai technology combined with cattle manure and inorganic fertilizer on selected soil properties and sorghum yields in Kabati, Kitui County. The experiment was set up in a Randomized Complete Block Design (RCBD) with eight treatments replicated thrice with sorghum Gadam as the test crop. Soil sampling was done at the beginning of the first season and at the end of the fourth season at a dept of 0–15 cm across each plot for laboratory analyses. From the results, the increase in electrical conductivity was significant at p &lt; 0.05 in all the treatments after four cropping seasons. Total organic carbon significantly increased in Zai with cattle manure (p = 0.045), conventional with no input (p = 0.038) and conventional with cattle manure (p = 0.045). Available phosphorous significantly (p &lt; 0.05) increased in treatments under Zai technology while total nitrogen significantly (p &lt; 0.05) reduced after the four cropping seasons. There was a significant (p &lt; 0.05) interactive effect of the tested factors on soil pH, electrical conductivity, total nitrogen, and available phosphorous at the end of the experiment. Moreover, there was significant (p &lt; 0.05) interactive effects on grain yields (SR18 and SR19 seasons) and stover yields (SR18, LR19, and SR19 seasons), with higher yields being recorded in treatments under Zai technology. This study demonstrates the importance of Zai technology in increasing crop yield by trapping water and enhancing its retention and infiltration into the soil for uptake by plants. This study concluded that positive impacts on important soil properties and crop yield could be realized when Zai technology is utilized alongside either sole inorganics or a combination of organic and inorganic amendments and this could be used as a strategy to improve crop production in eastern Kenya and other similar areas.

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