Soil-specific calibration of capacitance sensors considering clay content and bulk density

Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 111 ◽  
Author(s):  
Nargish Parvin ◽  
Aurore Degré
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Bulk Density ◽  
Precise Measurement ◽  
Clay Content ◽  
Limited Range ◽  
Soil Profiles ◽  
Soil Hydrology ◽  
Soil Columns ◽  
Different Depths

Soil hydrology research requires the accurate measurement of soil water content. Recently, less expensive capacitance sensors (CS) have become popular for the measurement of soil moisture across soil profiles, but these sensors need to be calibrated for precise results. The purpose of the present study was to determine the effect of clay content and bulk density (ρb) on the calibration of CS. Two different CS (10HS and 5TM) were considered for the study. Clay content and ρb of the soils were determined from two different sites and from three different depths (0–5, 25–30 and 50–60 cm) of an experimental field in Gembloux, Belgium. Custom calibration (CC) equations were developed using packed soil columns following the same ρb at sequential volumetric water content (θ) levels. The factory-supplied calibration (FSC) showed an overestimation of θ (0.04–0.07 m3 m–3) with the 10HS sensor, and an underestimation of θ (0.06–0.077 m3 m–3) with the 5TM sensor for the entire calibration range. The variance in raw sensor outputs for different ρb and clay content of soil depths was not highly significant because the soil had limited range of variability in ρb and clay content. However, the CC is recommended in parallel with FSC for the precise measurement of soil moisture with CS.

scholarly journals Characterizing Soil Physical Properties for Soil Moisture Monitoring with the North Carolina Environment and Climate Observing Network

2012 ◽  
Vol 29 (7) ◽  
pp. 933-943 ◽  
Author(s):  
Weinan Pan ◽  
R. P. Boyles ◽  
J. G. White ◽  
J. L. Heitman
Keyword(s):  
North Carolina ◽  
Soil Moisture ◽  
Physical Properties ◽  
Soil Properties ◽  
Water Content ◽  
Bulk Density ◽  
Soil Physical Properties ◽  
The North ◽  
Wide Range ◽  
Soil Moisture Monitoring

Abstract Soil moisture has important implications for meteorology, climatology, hydrology, and agriculture. This has led to growing interest in development of in situ soil moisture monitoring networks. Measurement interpretation is severely limited without soil property data. In North Carolina, soil moisture has been monitored since 1999 as a routine parameter in the statewide Environment and Climate Observing Network (ECONet), but with little soils information available for ECONet sites. The objective of this paper is to provide soils data for ECONet development. The authors studied soil physical properties at 27 ECONet sites and generated a database with 13 soil physical parameters, including sand, silt, and clay contents; bulk density; total porosity; saturated hydraulic conductivity; air-dried water content; and water retention at six pressures. Soil properties were highly variable among individual ECONet sites [coefficients of variation (CVs) ranging from 12% to 80%]. This wide range of properties suggests very different behavior among sites with respect to soil moisture. A principal component analysis indicated parameter groupings associated primarily with soil texture, bulk density, and air-dried water content accounted for 80% of the total variance in the dataset. These results suggested that a few specific soil properties could be measured to provide an understanding of differences in sites with respect to major soil properties. The authors also illustrate how the measured soil properties have been used to develop new soil moisture products and data screening for the North Carolina ECONet. The methods, analysis, and results presented here have applications to North Carolina and for other regions with heterogeneous soils where soil moisture monitoring is valuable.

Root effects on soil water and hydraulic properties

Biologia ◽  
2007 ◽  
Vol 62 (5) ◽  
Author(s):  
Horst Gerke ◽  
Rolf Kuchenbuch
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic ◽  
Root Effects

AbstractPlants can affect soil moisture and the soil hydraulic properties both directly by root water uptake and indirectly by modifying the soil structure. Furthermore, water in plant roots is mostly neglected when studying soil hydraulic properties. In this contribution, we analyze effects of the moisture content inside roots as compared to bulk soil moisture contents and speculate on implications of non-capillary-bound root water for determination of soil moisture and calibration of soil hydraulic properties.In a field crop of maize (Zea mays) of 75 cm row spacing, we sampled the total soil volumes of 0.7 m × 0.4 m and 0.3 m deep plots at the time of tasseling. For each of the 84 soil cubes of 10 cm edge length, root mass and length as well as moisture content and soil bulk density were determined. Roots were separated in 3 size classes for which a mean root porosity of 0.82 was obtained from the relation between root dry mass density and root bulk density using pycnometers. The spatially distributed fractions of root water contents were compared with those of the water in capillary pores of the soil matrix.Water inside roots was mostly below 2–5% of total soil water content; however, locally near the plant rows it was up to 20%. The results suggest that soil moisture in roots should be separately considered. Upon drying, the relation between the soil and root water may change towards water remaining in roots. Relations depend especially on soil water retention properties, growth stages, and root distributions. Gravimetric soil water content measurement could be misleading and TDR probes providing an integrated signal are difficult to interpret. Root effects should be more intensively studied for improved field soil water balance calculations.

Soil water contents and displacements monitoring, integrated into a Hydrological-Geotechnical Model for the evaluation of large-scale susceptibility to landslides triggered by rainfalls

2020 ◽  
Author(s):  
Roberto Passalacqua ◽  
Rossella Bovolenta ◽  
Bianca Federici ◽  
Alessandro Iacopino
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Ground Level ◽  
Water Infiltration ◽  
Landslide Monitoring ◽  
Simple Relationship ◽  
Capacitive Sensors ◽  
Different Depths

<p>Soil water content is often a landslide’s trigger factor, in particular the shallow ones. Although there is no simple relationship between the water content into the soil and the hydraulic conditions of the slopes at the depths at which the landslides develop, the knowledge of the actual soil moisture is fundamental for the study of landslides, thus, it should be monitored.<br>The LAMP (LAndslide Monitoring and Predicting) system is employed in the INTERREG-ALCOTRA project called AD-VITAM. LAMP (Bovolenta et al., 2016) was yet formulated for the analysis and forecasting of landslides triggered by rain. It adopts a physically based Integrated Hydrological Geotechnical (IHG) model (Passalacqua et al., 2016) and is implemented in GIS. In this Project, the IHG model is fed by data measured using a Wireless Sensor Network (WSN), this formed by low-cost and self-sufficient sensors. The WSN may gather rainfall, temperature, surface’s displacement data (these by mass-market GNSS receivers in RTK) and, in this case, soil water content (by capacitive sensors).<br>The WaterScout SM100 capacitive sensors were lab-analyzed then, recognized as satisfactory, installed on-site together with their related equipment. These sensors connect to a “Sensor Pup”, which has four available channels; therefore, four sensors are installed at each node, at different depths from ground-level, in order to achieve a vertical soil-moisture profile and the rate of infiltration.<br>The selection of the most suitable spots for the water content soil-sensors’ installations depends on the presence of shallow soil layers and of the radio signal emission-reception’s too.<br>The sensors may be set up both in vertical or horizontal direction. In general, the vertical installation is preferable. This implies the creation of small adjacent vertical holes, each one reaching a different depth, where the sensors are singularly pushed. Alternatively, the horizontal one may be adopted, by the opening of a small trench where the sensors are manually inserted at different depths, along a quasi-vertical vertical line. The full contact between the soil and the sensors is always verified, immediately after the installation, using a directly connected FieldScout reader to any single sensor. Furthermore, it is necessary to protect the emerging cables and to avoid preferential ways for water infiltration along the wiring lines.<br>The monitoring networks, installed at the two Italian sites of Mendatica and Ceriana, are currently providing informations in real-time. The data acquired at five nodes, distributed at each of these two sites (40 sensors in total), are currently relayed on a specific web-portal by a GSM connected Retriever-Modem, marking the evolutions of soil moisture profiles at depths between 10 and 85 cm from ground level: these continuous data allow the analysis of the infiltration and evapotranspiration phenomena. Moreover, a correlation between the soil moisture contents and the local displacements is made possible. Finally, a specific calibration of the SM100 sensors’ in relation to the on-site soil types is in progress.</p>

scholarly journals Drought stress tolerance of two wheat genotypes

2008 ◽  
Vol 3 (Special Issue No. 1) ◽  
pp. S95-S104 ◽  
Author(s):  
A. Lukács ◽  
G. Pártay ◽  
T. Németh ◽  
S. Csorba ◽  
C. Farkas
Keyword(s):  
Soil Moisture ◽  
Drought Stress ◽  
Water Balance ◽  
Water Content ◽  
Stress Tolerance ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Columns ◽  
Undisturbed Soil ◽  
Wheat Genotypes

Biotic and abiotic stress effects can limit the productivity of plants to great extent. In Hungary, drought is one of the most important constrains of biomass production, even at the present climatic conditions. The climate change scenarios, developed for the Carpathian basin for the nearest future predict further decrease in surface water resources. Consequently, it is essential to develop drought stress tolerant wheat genotypes to ensure sustainable and productive wheat production under changed climate conditions. The aim of the present study was to compare the stress tolerance of two winter wheat genotypes at two different scales. Soil water regime and development of plants, grown in a pot experiment and in large undisturbed soil columns were evaluated. The pot experiments were carried out in a climatic room in three replicates. GK Élet wheat genotype was planted in six, and Mv Emese in other six pots. Two pots were left without plant for evaporation studies. Based on the mass of the soil columns without plant the evaporation from the bare soil surface was calculated in order to distinguish the evaporation and the transpiration with appropriate precision. A complex stress diagnosis system was developed to monitor the water balance elements. ECH<sub>2</sub>O type capacitive soil moisture probes were installed in each of the pots to perform soil water content measurements four times a day. The irrigation demand was determined according to the hydrolimits, derived from soil hydrophysical properties. In case of both genotypes three plants were provided with the optimum water supply, while the other three ones were drought-stressed. In the undisturbed soil columns, the same wheat genotypes were sawn in one replicate. Similar watering strategy was applied. TDR soil moisture probes were installed in the soil at various depths to monitor changes in soil water content. In order to study the drought stress reaction of the wheat plants, microsensors of 1.6 mm diameter were implanted into the stems and connected to a quadrupole mass spectrometer for gas analysis. The stress status was indicated in the plants grown on partly non-irrigated soil columns by the lower CO<sub>2</sub> level at both genotypes. It was concluded that the developed stress diagnosis system could be used for soil water balance elements calculations. This enables more precise estimation of plant water consumption in order to evaluate the drought sensitivity of different wheat genotypes.

Laboratory calibration of different soil moisture sensors in various soil types

2020 ◽  
Author(s):  
Urša Pečan ◽  
Damijana Kastelec ◽  
Marina Pintar
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Bulk Density ◽  
Soil Samples ◽  
Soil Types ◽  
Soil Moisture Sensors ◽  
Dry Soil

&lt;p&gt;Measurements of soil water content are particularly useful for irrigation scheduling. In optimal conditions, field data are obtained through a dense grid of soil moisture sensors. Most of the currently used sensors for soil water content measurements, measure relative permittivity, a variable which is mostly dependant on water content in the soil. Spatial variability of soil characteristics, such as soil texture and mineralogy, organic matter content, dry soil bulk density and electric conductivity can also alter measurements with dielectric sensors. So the question arises, whether there is a need for a soil specific calibration of such sensors and is it dependant on the type of sensor? This study evaluated the performance of three soil water content sensors (SM150T, Delta-T Devices Ltd, UK; TRIME-Pico 32, IMKO micromodultechnik GmbH, DE; MVZ 100, Eltratec trade, production and services d.o.o., SI) in nine different soil types in laboratory conditions. Our calibration approach was based on calibration procedure developed for undisturbed soil samples (Holzman et al., 2017). Due to possible micro location variability of soil properties, we used disturbed and homogenized soil samples, which were packed to its original dry soil bulk density. We developed soil specific calibration functions for each sensor and soil type. They ranged from linear to 5&lt;sup&gt;th&lt;/sup&gt; order polynomial. We calculated relative and actual differences in sensor derived and gravimetrically determined volumetric soil water content, to evaluate the errors of soil water content measured by sensors which were not calibrated for soil specific characteristics. We observed differences in performance of different sensor types in various soil types. Our results showed measurements conducted with SM150T sensors were within the range of manufacturer specified measuring error in three soil types for which calibration is not necessary but still advisable for improving data quality. In all other cases, soil specific calibration is required to obtain relevant soil moisture data in the field.&lt;/p&gt;

INTERMITTENT INFILTRATION AND EVAPORATION FROM SOIL COLUMNS

1983 ◽  
Vol 63 (2) ◽  
pp. 303-314 ◽  
Author(s):  
M. A. MUSTAFA ◽  
R. DE JONG ◽  
H. N. HAYHOE ◽  
G. C. TOPP
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Clay Soil ◽  
Field Capacity ◽  
Richards Equation ◽  
Soil Columns ◽  
Successful Prediction ◽  
Deep Distribution ◽  
Satisfactory Prediction

Varying total amounts of water (160 and 320 mm) were infiltrated into 60-cm columns of air-dry saline sodic clay soil. The intervals between irrigation applications were varied from 5 to 20 days. The soil columns were subjected to a potential evaporation rate of 4.8 mm∙day−1 in a growth room. The cumulative evaporation followed a square root of time response, similar to that found by others for non-saline soils of coarser texture. An analytical solution of the Richards’ equation gave satisfactory (± 10%) prediction of cumulative evaporation at the end of the experiment as long as water was added in amounts of 40 mm or more per irrigation. The numerical solution to the Richards’ equation gave satisfactory estimates of evaporation for the latter stages of the experiment, but in the earlier stages it underestimated evaporation because of the too deep distribution of water in the soil given by this model. The neglect of hysteresis was invoked to explain the discrepancy between observed and predicted soil water content profiles. The "versatile soil moisture budget" empirical model also gave satisfactory prediction of evaporation but the successful prediction of water content profiles depended on "field capacity" values measured in situ. Key words: Soil moisture, modelling, water budgets, Richards’ equation

scholarly journals Environmental effectiveness of GAEC cross-compliance Standard 3.1 ‘Ploughing in good soil moisture conditions’ and economic evaluation of the competitiveness gap for farmers

2015 ◽  
Vol 10 (1s) ◽  
Author(s):  
Rosa Francaviglia ◽  
Antonio Melchiorre Carroni ◽  
Paola Ruda ◽  
Mauro Salis ◽  
Paolo Bazzoffi ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Economic Evaluation ◽  
Water Content ◽  
Bulk Density ◽  
Packing Density ◽  
Soil Tillage ◽  
Structure Degradation ◽  
Environmental Effectiveness ◽  
Moisture Conditions ◽  
Cross Compliance

<p>Within the MO.NA.CO. Project<em> </em>the environmental effectiveness of GAEC cross-compliance Standard 3.1 ‘Ploughing in good soil moisture conditions’ was evaluated, as well as the economic evaluation of the competitiveness gap for farmers which conform or do not conform to cross-compliance. The monitoring has been carried out at nine experimental farms with different pedoclimatic characteristics, where some indicators of soil structure degradation have been evaluated, such as bulk density, packing density and surface roughness of the seedbed, and the crop productive and qualitative parameters. In each monitoring farm two experimental plots have been set up: factual with soil tillage at proper water content (tilth), counterfactual with soil tillage at inadequate water content (no tilth). The monitoring did not exhibit univocal results for the different parameters, thus the effectiveness of the Standard 3.1 is ‘contrasting’ (class of merit B), and there was an evident practical problem to till the soil at optimum water content, even in controlled experimental condition. Bulk density was significantly lower in the factual treatment although in soils with very different textures (sandy-loam and clayey). Packing density (PD) showed a high susceptibility to compaction in soils with low PD and medium texture. The tortuosity index, indicating the roughness of the seedbed, was lower and generally significantly different in the factual treatment. Results showed that the ploughing done in excessive soil moisture conditions is more expensive due to the increased force of traction of the tractor, which causes an increase in slip of the tractor wheels, with a speed reduction and increase in the working times and fuel consumption. Moreover, the crop yield is also reduced considerably according to the cultivated species.</p>

scholarly journals Spatial Heterogeneity and Driving Factors of Soil Moisture in Alpine Desert Using the Geographical Detector Method

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2652
Author(s):  
Zhiwei Zhang ◽  
Huiyan Yin ◽  
Ying Zhao ◽  
Shaoping Wang ◽  
Jiahua Han ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Spatial Heterogeneity ◽  
Water Content ◽  
Driving Factors ◽  
Tibet Plateau ◽  
Interaction Detection ◽  
Geographical Detector ◽  
Detector Method ◽  
Different Depths ◽  
Gravimetric Water Content

Soil moisture is a vital factor affecting the hydrological cycle and the evolution of soil and geomorphology, determining the formation and development of the vegetation ecosystem. The previous studies mainly focused on the effects of different land use patterns and vegetation types on soil hydrological changes worldwide. However, the spatial heterogeneity and driving factors of soil gravimetric water content in alpine regions are seldom studied. On the basis of soil sample collection, combined with geostatistical analysis and the geographical detector method, this study examines the spatial heterogeneity and driving factors of soil gravimetric water content in the typical alpine valley desert of the Qinghai–Tibet Plateau. Results show that the average value of soil gravimetric water content at different depths ranges from 3.68% to 7.84%. The optimal theoretical models of soil gravimetric water content in 0–50 cm layers of the dune are different. The nugget coefficient shows that the soil gravimetric water content in the dune has a strong spatial correlation at different depths, and the range of the optimal theoretical model of semi-variance function is 31.23–63.38 m, which is much larger than the 15 m spacing used for sampling. The ranking of the influence of each evaluation factor on the alpine dune is elevation > slope > location > vegetation > aspect. The interaction detection of factors indicates that an interaction exists among evaluation factors, and no factors are independent of one another. In each soil layer of 0–50 cm, the interaction among evaluation factors has a two-factor enhancement and a nonlinear enhancement effect on soil gravimetric water content. This study contributes to the understanding of spatial heterogeneity and driving factors of soil moisture in alpine deserts, and guidance of artificial vegetation restoration and soil structure analysis of different desert types in alpine cold desert regions.

scholarly journals CALIBRAÇÃO DE UM SENSOR CAPACITIVO PARA ESTIMATIVA DA UMIDADE EM TRÊS CLASSES DE SOLOS

Irriga ◽  
2017 ◽  
Vol 22 (3) ◽  
pp. 458-468 ◽  
Author(s):  
SAMUEL COLA PIZETTA ◽  
ROGÉRIO RANGEL RODRIGUES ◽  
GERALDO MAGELA PEREIRA ◽  
FABIÁN ENRIQUE DÍAZ PACHECO ◽  
MARCELO RIBEIRO VIOLA ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Precise Measurement ◽  
Minas Gerais ◽  
Moisture Determination ◽  
Capacitance Sensor ◽  
Soil Moisture Sensors ◽  
Constant Content ◽  
Hydraulics Laboratory ◽  
Moisture Estimation

CALIBRAÇÃO DE UM SENSOR CAPACITIVO PARA ESTIMATIVA DA UMIDADE EM TRÊS CLASSES DE SOLOS  SAMUEL COLA PIZETTA1; ROGÉRIO RANGEL RODRIGUES2; GERALDO MAGELA PEREIRA3; FABIÁN ENRIQUE DÍAZ PACHECO4, MARCELO RIBEIRO VIOLA5 E LUIZ ANTÔNIO LIMA6 1Doutorando em Recursos Hídricos em Sistemas Agrícolas pela Universidade Federal de Lavras (UFLA)- Campus Universitário, Departamento de Engenharia, C.P. 3037- CEP 37200-000, Lavras-MG, Brasil. [email protected];2 Doutor em Recursos Hídricos em Sistemas Agrícolas pela Universidade Federal de Lavras (UFLA)- Campus Universitário, Departamento de Engenharia, C.P. 3037- CEP 37200-000, Lavras-MG, Brasil., técnico no IFMA, Campus Santarém, Brasil. [email protected];3 Professor Titular da Universidade Federal de Lavras (UFLA) - Campus Universitário, Departamento de Engenharia, C.P. 3037- CEP 37200-000, Lavras-MG, Brasil. [email protected];4 4 Engenheiro Agrícola pela Universidad de Sucre (Unisucre)- Calle  25 # 39-61,  Las Margaritas, Sincelejo-Sucre. Colômbia. fabian_18 hotmail.com;5 Professor Adjunto da Universidade Federal de Lavras (UFLA) – Cam        pus Universitário, Departamento de Engenharia, C.P. 3037- CEP 37200-000, Lavras-MG, Brasil.. [email protected];6 Professor Associado da Universidade Federal de Lavras (UFLA) - Campus Universitário, Departamento de Engenharia, C.P. 3037- CEP 37200-000, Lavras-MG, Brasil.. [email protected]  1 RESUMO Um dos maiores desafios de domínio agrícola atualmente é a mensuração prática, rápida e precisa do teor de água no solo. Dessa forma, o conhecimento acerca dos equipamentos que estimem essa umidade é de fundamental importância. Nesse contexto, objetivou-se com este estudo, efetuar a calibração dos sensores de capacitância Eletrodex por meio do método padrão de estufa em três classes de solo, sendo o Argissolo, Latossolo e Nitossolo. Os solos foram coletados no Campus da Universidade Federal de Lavras (UFLA) e o experimento foi realizado no Laboratório de Hidráulica, no município de Lavras, estado de Minas Gerais. Para a calibração foram utilizados sete níveis de umidade que compreenderam diferentes valores de porcentagens da disponibilidade total de água no solo (DTA). Os resultados demonstraram que a utilização desse sensor não permitiu estimar, de forma satisfatória, a umidade volumétrica do solo, nos intervalos de umidade testados, em nenhum dos solos submetidos à calibração, uma vez que não foi possível obter equações que apresentassem coeficientes de determinação adequados. Palavras-chave: instrumentação, constante dielétrica, teor de água, sensor FDR.  PIZETTA, S. C.; RODRIGUES, R. R.; PEREIRA, G. M. PACHECO, F. E. D; VIOLA, M. R.; LIMA, L. A.CALIBRATION OF A CAPACITANCE SENSOR FOR MOISTURE ESTIMATION IN THREE SOIL CLASSES    2 ABSTRACT One of the largest agricultural challenges has been the practical, quick and precise measurement of water content at soils, thus requiring satisfactory equipment to perform such task. This research investigated capacitive soil moisture sensors defined by the manufacturer as Eletrodex, comparing its measurements to dry oven techniques for soil moisture determination at three soil classes: Argisol, Oxisol, and Nitosol.  Soils were collected at the Campus of the Federal University of Lavras (UFLA), and the experiment was carried out at the Hydraulics Laboratory in Lavras, state of Minas Gerais. For calibration, seven moisture levels were used, which comprised different percentages of total available moisture (TAM).  Results lead to the conclusion that the sensor does not satisfactorily estimate the volumetric water content for any soil class tested.  Such conclusion is based on the fact that no adequate coefficients of determination could be obtained at calibration curves. Keywords: instrumentation, dielectric constant, content of water, FDR sensor.

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