A Laboratory Study on Non-Invasive Soil Water Content Estimation Using Capacitive Based Sensors

Soil water content is an important parameter in many engineering, agricultural and environmental applications. In practice, there exists a need to measure this parameter rather frequently in both time and space. However, common measurement techniques are typically invasive, time-consuming and labour-intensive, or rely on potentially risky (although highly regulated) nuclear-based methods, making frequent measurements of soil water content impractical. Here we investigate in the laboratory the effectiveness of four new low-cost non-invasive sensors to estimate the soil water content of a range of soil types. While the results of each of the four sensors are promising, one of the sensors, herein called the “AOGAN” sensor, exhibits superior performance, as it was designed based on combining the best geometrical and electronic features of the other three sensors. The performance of the sensors is, however, influenced by the quality of the sensor-soil coupling and the soil surface roughness. Accuracy was found to be within 5% of volumetric water content, considered sufficient to enable higher spatiotemporal resolution contrast for mapping of soil water content.

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Retrieving parameters of bare soil surface roughness and soil water content under arid environment from ERS-1, -2 SAR data

International Journal of Remote Sensing ◽

10.1080/01431161.2013.793862 ◽

2013 ◽

Vol 34 (17) ◽

pp. 6202-6215 ◽

Cited By ~ 6

Author(s):

Arthur Genis ◽

Leonid Vulfson ◽

Dan G. Blumberg ◽

Michael Sprinstin ◽

Alexey Kotlyar ◽

...

Keyword(s):

Surface Roughness ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Soil Surface ◽

Bare Soil ◽

Arid Environment ◽

Soil Surface Roughness ◽

Sar Data

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Calibration method to address influences of temperature and electrical conductivity for a low-cost soil water content sensor in the agricultural field

Agricultural Water Management ◽

10.1016/j.agwat.2021.107015 ◽

2021 ◽

Vol 255 ◽

pp. 107015

Author(s):

Yuhi Satoh ◽

Hideki Kakiuchi

Keyword(s):

Electrical Conductivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Low Cost ◽

Calibration Method ◽

Agricultural Field

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Non-invasive field measurements of soil water content using a pulsed 14MeV neutron generator

Soil and Tillage Research ◽

10.1016/j.still.2011.12.009 ◽

2012 ◽

Vol 120 ◽

pp. 130-136 ◽

Cited By ~ 3

Author(s):

S. Mitra ◽

L. Wielopolski ◽

R. Omonode ◽

J. Novak ◽

J. Frederick ◽

...

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Neutron Generator ◽

Field Measurements ◽

Non Invasive ◽

14Mev Neutron

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Using soil surface gray level to determine surface soil water content

Science China Earth Sciences ◽

10.1007/s11430-010-4049-1 ◽

2010 ◽

Vol 53 (10) ◽

pp. 1527-1532 ◽

Cited By ~ 3

Author(s):

YuanJun Zhu ◽

YunQiang Wang ◽

MingAn Shao

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Surface Soil ◽

Soil Surface ◽

Gray Level

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Using an inverse modelling approach to evaluate the water retention in a simple water harvesting technique

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-6-4265-2009 ◽

2009 ◽

Vol 6 (3) ◽

pp. 4265-4306 ◽

Cited By ~ 4

Author(s):

K. Verbist ◽

W. M. Cornelis ◽

D. Gabriels ◽

K. Alaerts ◽

G. Soto

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Retention ◽

Measurement Techniques ◽

Inverse Modelling ◽

Model Parameters ◽

Arid Zones ◽

Water Harvesting ◽

Data Set

Abstract. In arid and semi-arid zones runoff harvesting techniques are often applied to increase the water retention and infiltration on steep slopes. Additionally, they act as an erosion control measure to reduce land degradation hazards. Nevertheless, few efforts were observed to quantify the water harvesting processes of these techniques and to evaluate their efficiency. In this study a combination of detailed field measurements and modelling with the HYDRUS-2D software package was used to visualize the effect of an infiltration trench on the soil water content of a bare slope in Northern Chile. Rainfall simulations were combined with high spatial and temporal resolution water content monitoring in order to construct a useful dataset for inverse modelling purposes. Initial estimates of model parameters were provided by detailed infiltration and soil water retention measurements. Four different measurement techniques were used to determine the saturated hydraulic conductivity (Ksat) independently. Tension infiltrometer measurements proved a good estimator of the Ksat value and a proxy for those measured under simulated rainfall, whereas the pressure and constant head well infiltrometer measurements showed larger variability. Six different parameter optimization functions were tested as a combination of soil-water content, water retention and cumulative infiltration data. Infiltration data alone proved insufficient to obtain high model accuracy, due to large scatter on the data set, and water content data were needed to obtain optimized effective parameter sets with small confidence intervals. Correlation between observed soil water content and simulated values was as high as R2=0.93 for ten selected observation points used in the model calibration phase, with overall correlation for the 22 observation points equal to 0.85. Model results indicate that the infiltration trench has a significant effect on soil water storage, especially at the base of the trench.

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Field spatial and temporal patterns of soil water content and bulk density changes

Scientia Agricola ◽

10.1590/s0103-90162006000100009 ◽

2006 ◽

Vol 63 (1) ◽

pp. 55-64 ◽

Cited By ~ 32

Author(s):

Luís Carlos Timm ◽

Luiz Fernando Pires ◽

Renato Roveratti ◽

Robson Clayton Jacques Arthur ◽

Klaus Reichardt ◽

...

Keyword(s):

Water Content ◽

Bulk Density ◽

Soil Water ◽

Soil Water Content ◽

Soil Surface ◽

Temporal Patterns ◽

Temporal Changes ◽

Spatial And Temporal Patterns ◽

Wetting And Drying ◽

Wetting And Drying Cycles

Soil water content (theta) and bulk density (rhos) greatly influence important soil and plant processes, such as water movement, soil compaction, soil aeration, and plant root system development. Spatial and temporal variability of theta and rhos during different periods of the year and different phases of crops are of fundamental interest. This work involves the characterization of spatial and temporal patterns of theta and rhos during different climatic periods of year, aiming to verify whether there are significant temporal changes in rhos at the soil surface layer when submitted to wetting and drying cycles. The field experiment was carried out in a coffee plantation, Rhodic Kandiudalf soil, clayey texture. Using a neutron/gamma surface probe, theta and rhos were measured meter by meter along a 200 m spatial transect, along an interrow contour line. During the wet period there was no difference of spatial patterns of theta while during the dry period differences were observed, and can be associated to precipitation events. It was also observed that there are rhos temporal changes at the soil surface along the studied period as a consequence of the in situ wetting and drying cycles.

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Calibration of a Novel Low-Cost Soil Water Content Sensor Based on a Ring Oscillator

Vadose Zone Journal ◽

10.2136/vzj2012.0139 ◽

2013 ◽

Vol 12 (2) ◽

pp. vzj2012.0139 ◽

Cited By ~ 43

Author(s):

W. Qu ◽

H.R. Bogena ◽

J.A. Huisman ◽

H. Vereecken

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Low Cost ◽

Ring Oscillator

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Modelling leaching and recharge in a bare transitional red-brown earth ponded with low salinity water in summer

Australian Journal of Experimental Agriculture ◽

10.1071/ea9941085 ◽

1994 ◽

Vol 34 (7) ◽

pp. 1085 ◽

Cited By ~ 1

Author(s):

L Cai ◽

SA Prathapar ◽

HG Beecher

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Soil Profile ◽

Soil Surface ◽

Saturated Hydraulic Conductivity ◽

Rate Dependent ◽

Water And Salt Movement ◽

Winter Fallow

A modelling study was conducted to evaluate water and salt movement within a transitional red-brown earth with saline B horizon soil when such waters are used for ponding in summer. The model was calibrated using previously published experimental data. The calibrated model was used to evaluate the effect of depth to watertable, saturated hydraulic conductivity, and ponding water salinity on infiltration, water and salt movement within the soil profile, and recharge. The study showed that when initial soil water content and the saturated hydraulic conductivity (Ks) are low, infiltrating water will be stored within the soil profile even in the absence of a shallow watertable. Once the soil water content is high, however, recharge will be significant in winter, even if there is no net infiltration at the soil surface. Infiltration rates depend more on Ks than the depth to watertable if it is at, or below, 1.5 m from the soil surface. When Ks is high, recharge under ponding will be higher than that under winter fallow. Subsequent ponding in summer and fallow in winter tend to leach salts from the soil profile, the leaching rate dependent on Ks. During winter fallow, due to net evaporation, salts tend to move upwards and concentrate near the soil surface. In the presence of shallow watertables, leached salts tend to concentrate at, or near, the watertable.

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Using satellite data in the Land Surface Model to estimate water availability of arid agricultural region

10.5194/egusphere-egu2020-13037 ◽

2020 ◽

Author(s):

Eugene Muzylev ◽

Zoya Startseva ◽

Elena Volkova ◽

Eugene Vasilenko

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Availability ◽

Land Surface ◽

Land Surface Model ◽

Soil Surface ◽

Surface Model ◽

Heat Regime ◽

Vegetation Characteristics

The water availability of agricultural arid regions can be assessed at presence using the physical-mathematical model of water and heat exchange between land surface and atmosphere LSM (Land Surface Model) adapted to satellite-derived estimates of meteorological and vegetation characteristics. The LSM is designed to calculate soil water content W, evapotranspiration Ev, vertical heat fluxes and other water and heat regime elements. Soil and vegetation characteristics were used in the LSM as parameters and meteorological characteristics were utilized as input variables.The case study was carried out for the territory of the Saratov and Volgograd Trans-Volga region (the left-bank part of the Saratov and Volgograd regions) of 66600 km2 for the vegetation seasons 2016-2018.The satellite measurement data from radiometers AVHRR/NOAA, SEVIRI/Meteosat-10, -11, -8, and MSU-MR/Meteor-M No. 2 in visible and IR ranges were thematic processed to built estimates of vegetation index NDVI, emissivity E, vegetation cover fraction B, leaf index LAI, land surface temperature LST and precipitation.LAI and B estimates were obtained using empirical dependencies on NDVI. The adequacy of the LAI and B estimates obtained from all sensor data was verified when comparing the LAI time behavior built for named vegetation seasons. Errors of determining B and LAI were 15 and 20%, respectively.Satellite-derived estimates of daily, decadal and monthly precipitation sums for each pixel were obtained using the Multi Threshold Method (MTM) for detecting clouds, identifying its types allocating precipitation zones and determining their maximum intensity. The MTM is based on the developed algorithm of the transition from the assessment of precipitation intensity to the assessment of their daily amounts. Testing of the method was carried out when comparing these amounts with observed at meteorological stations. The probability of satellite-detected precipitation zones corresponded to the actual ones was ~ 80% for all radiometers.Based on the MTM, computational algorithm to evaluate the LST was developed and verified on the study region data. Comparison of ground-measured and satellite-derived LST showed that the latter estimates for the overwhelming number of observation turned out to be comparable in accuracy with each other and with the ground-based data.Calculations of water and heat regime elements (being the final products of the simulation) were carried out when replacing ground-based estimates of precipitation, LST, LAI and B in the LSM by satellite-derived ones at each time step in all nodes of the computational grid. The efficiency of such replacement procedures was confirmed by comparing measured and calculated values of W and Ev (the difference between them didn&#8217;t exceed 15% for W and 25% for Ev).The possibility of using soil surface moisture estimates obtained from all-weather measurements by the scatterometer ASCAT/MetOp in the microwave range when simulating soil water content was also revealed. These estimates may use to set initial conditions for the vertical soil water transfer equation, as well as for calculating evaporation from the soil surface and the subsequent formation of the upper boundary condition for this equation.As a summary, the described approach can be considered as a method for assessing the water availability for agricultural arid region.

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