Retrieving Photometric Properties and Soil Moisture Content of Tidal Flats Using Bidirectional Spectral Reflectance

Moisture content in tidal flats changes frequently and spatially on account of tidal fluctuations, which greatly influence the reflectance of the tidal flat surface. Precise prediction of the spatial-temporal variation of tidal flats’ moisture content is an important foundation of surface bio-geophysical information research by remote sensing. In this paper, we first measured the multi-angle reflectance of soil samples obtained from tidal flats in the northeastern Dongtai, Jiangsu Province, China, in the laboratory. Then, based on the particle swarm optimization (PSO) algorithm, we retrieved the photometric characteristics of the soil surface by employing the SOILSPECT bidirectional reflectance model. Finally, the soil moisture content was retrieved by introducing the equivalent water thickness of the soil. The results showed that: (i) A significant correlation existed between the retrieved equivalent water thickness and the measured soil moisture content. The SOILSPECT model is capable of estimating soil moisture with high precision by using multi-angle reflectance. (ii) Retrieved values of single scattering albedo (ω) were consistent with the variation of soil moisture content. The roughness parameter (h) and the asymmetry factor (Θ) were consistent with the structure and particle composition of the soil surface in dry soil samples. (iii) When the soil samples were soaked with water, the roughness parameter (h) and the type of scattering on the soil surface both showed irregular changes. These results support the importance of using the measured soil particle size as one of the parameters for the retrieval of soil moisture content, which is a method that should be used cautiously, especially in tidal flats.

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Draft Requirement of Two Animal - Drawn Institute for Agricultural Research (IAR) Weeders

Journal of Engineering Research and Reports ◽

10.9734/jerr/2020/v10i317039 ◽

2020 ◽

pp. 14-20

Author(s):

Y. A. Unguwanrimi ◽

A. M. Sada ◽

G. N. Ugama ◽

H. S. Garuba ◽

A. Ugoani

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Bulk Density ◽

Soil Moisture Content ◽

Agricultural Research ◽

Soil Samples ◽

Soil Conditions ◽

Experimental Plot ◽

Moisture Contents ◽

Loam Soil

Draft requirements of two animal – drawn (IAR) weeders operating on loam soil were determined in the study. The implements include a straddle row weeder and an emcot attached rotary weeder evaluated under the same soil conditions, using a pair of white Fulani breed of oxen. The animal draft requirement was first estimated from the animal ergonomics measurements. Using area of 0.054 hectare as experimental plot for each implement the draft requirement of each implement was investigated after taking soil samples for soil moisture content and bulk density determinations. The implements tested showed variation in their average draft requirement. The straddle row weeder had the highest value of 338.15 N respectively while the emcot attached rotary weeder had the lowest value of 188.12 N with 47.03%, respectively. The average soil moisture contents and bulk density were 13.0% and 1.46%/cm3, respectively.

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Evaluation of Various Soil Moisture Sensors in Four Different Soil Types

Applied Engineering in Agriculture ◽

10.13031/aea.12712 ◽

2018 ◽

Vol 34 (6) ◽

pp. 963-971 ◽

Cited By ~ 1

Author(s):

Tonny José Araújo da Silva ◽

Edna Maria Bonfim-Silva ◽

Adriano Bicioni Pacheco ◽

Thiago Franco Duarte ◽

Helon Hébano de Freitas Sousa ◽

...

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Moisture Content ◽

Soil Samples ◽

Soil Types ◽

Coefficient Of Determination ◽

Regression Analyses ◽

Drying Method ◽

Soil Moisture Sensors ◽

Calibration Equations

Abstract.Accurate measurements of soil moisture content can contribute to resource conservation in irrigated systems. The objective of this study was to evaluate various soil moisture sensors (a porous cup tensiometer, Diviner 2000, PR2, XH300, PM100, and ML3; the mention of model names does not constitute an implied endorsement) used in four different soil types. The experiment was conducted inside a greenhouse using a specially constructed box that contained the soil samples. The soil samples were first saturated and subsequently drained before starting the measurements. The soil moisture content was determined by the oven-drying method. Using the standard deviation of the sensor readings, regression analyses were performed, resulting in calibration equations and coefficient of determination (R2) values for each sensor and soil type combination. The porous cup tensiometer, Diviner 2000, PR2, and ML3 measurements resulted in excellent R2 values that exceeded 0.95 for the four soils. However, measurements with the XH300 and PM100 sensors resulted in R2 values of 0.37 to 0.86 and 0.61 to 0.94, respectively, limiting their scientific applicability for the studied soils. Therefore, the porous cup tensiometer, Diviner 2000, PR2, and ML3 estimated the soil moisture content with greater confidence than did the other sensors and with an error of less than 5%. Keywords: Calibration, Tensiometer, Volumetric water content.

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Heat-Transfer in the Soil During Very Low-Intensity Experimental Fires - the Role of Duff and Soil-Moisture Content

International Journal of Wildland Fire ◽

10.1071/wf9940225 ◽

1994 ◽

Vol 4 (4) ◽

pp. 225 ◽

Cited By ~ 55

Author(s):

JC Valette ◽

V Gomendy ◽

J Marechal ◽

C Houssard ◽

D Gillon

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Temperature Rise ◽

Soil Moisture Content ◽

Soil Surface ◽

Dry Weight ◽

Prescribed Burns ◽

Low Intensity ◽

Lethal Temperatures ◽

Maximum Temperatures

The aim of this study was to analyse the effects of duff thickness and moisture content, and of soil moisture content on the transfer of heat in the soil. The experimental design used intact soil blocks with their duff layer, subjected to controlled fires of variable very low intensities of up to 100 kW m-1. The fuel on the surface was composed of needles and twigs of Pinus pinaster. The maximum temperatures measured within the fuel were of the order of 650 degrees C and were independent of the fireline intensities. For fires with fireline intensity of the order of 30 kW m-1, the presence of the duff layer reduced from 330 degrees C the temperature rise at the soil surface. Duff thickness played only a secondary role, but increasing moisture content reinforced its insulating effect, so that the temperature rise was 2.5 times less at 1 cm depth in the duff when the moisture content exceeded 70% dry weight, than when the moisture content was less than 30%. For more intense fires (> 50 kW m-1) that produced longer-lasting surface heating, duff thickness and moisture content played an important role in significantly reducing the temperature rise at the soil surface (range 140 degrees C to 28 degrees C). Because of low soil thermal conductivity, temperature attenuation with increasing depth was noticed. In the case of low intensity fires (< 30 kW m-1) in the absence of a duff layer, the maximum temperatures were reduced from 350 degrees C at the surface to 7 degrees C at 3.5 cm. The temperature rise in the soil decreased with depth according to a negative exponential relation. The rate constant of this relation was greater when the initial surface temperature and the soil moisture content were higher. For the soil studied, and under the moisture conditions encountered (between 7 and 19% of dry weight), the rate constant could be predicted with acceptable precision (r2 = 0.67), if the surface soil temperature rise and the soil moisture content were known. In these experimental fires, which were carried out when the air temperature did not exceed 20 degrees C, lethal temperatures (> 60 degrees C) were measured in the upper few centimetres of the duff layer in very low-intensity fires, and in the upper few centimetres of the soil (where nutrients are most concentrated and biological activity most intense) in the slightly more intense fires. The fire intensities were always very moderate, and of the order of magnitude df those encountered in the prescribed burns conducted on fuel-breaks of the french Mediterranean area. Their impact on the surface of the forest soil, in terms of lethal temperatures transmitted to the horizon rich in organic matter, are not negligible. In contrast, below 3 to 5 cm depth, prescribed burns, conducted under the conditions of the experiments, would not lead to significant change to nutrients or microfaunal or microfloral activity; in particular, root tips would not be subjected to heat stress sufficient to kill them.

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RELATIONSHIP BETWEEN SOIL MOISTURE CONTENT AND SOIL SURFACE REFLECTANCE

Transactions of the ASAE ◽

10.13031/2013.19990 ◽

2005 ◽

Vol 48 (5) ◽

pp. 1979-1986 ◽

Cited By ~ 51

Author(s):

A. L. Kaleita ◽

L. F. Tian ◽

M. C. Hirschi

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Moisture Content ◽

Soil Surface ◽

Surface Reflectance

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The Influence of a Water Absorbing Geocomposite on Soil Water Retention and Soil Matric Potential

Water ◽

10.3390/w11081731 ◽

2019 ◽

Vol 11 (8) ◽

pp. 1731 ◽

Cited By ~ 2

Author(s):

Michał Śpitalniak ◽

Krzysztof Lejcuś ◽

Jolanta Dąbrowska ◽

Daniel Garlikowski ◽

Adam Bogacz

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Water ◽

Water Retention ◽

Soil Moisture Content ◽

Soil Surface ◽

Soil Matric Potential ◽

Soil Water Retention ◽

Matric Potential ◽

Control Samples

Climate change induces droughts that are becoming more intensive and more frequent than ever before. Most of the available forecast tools predict a further significant increase in the risk of drought, which indicates the need to prepare solutions to mitigate its effects. Growing water scarcity is now one of the world’s leading challenges. In agriculture and environmental engineering, in order to increase soil water retention, soil additives are used. In this study, the influence of a newly developed water absorbing geocomposite (WAG) on soil water retention and soil matric potential was analyzed. WAG is a special element made from geotextile which is wrapped around a synthetic skeleton with a superabsorbent polymer placed inside. To describe WAG’s influence on soil water retention and soil matric potential, coarse sand, loamy sand, and sandy loam soils were used. WAG in the form of a mat was used in the study as a treatment. Three kinds of samples were prepared for every soil type. Control samples and samples with WAG treatment placed at depths of 10 cm and 20 cm were examined in a test container of 105 × 70 × 50 cm dimensions. The samples had been watered and drained, and afterwards, the soil surface was heated by lamps of 1100 W total power constantly for 72 h. Soil matric potential was measured by Irrometer field tensiometers at three depths. Soil moisture content was recorded at six depths: of 5, 9, 15, 19, 25, and 30 cm under the top of the soil surface with time-domain reflectometry (TDR) measurement devices. The values of soil moisture content and soil matric potential were collected in one-minute steps, and analyzed in 24-h-long time steps: 24, 48, and 72 h. The samples with the WAG treatment lost more water than the control samples. Similarly, lower soil matric potential was noted in the samples with the WAG than in the control samples. However, after taking into account the water retained in the WAG, it appeared that the samples with the WAG had more water easily available for plants than the control samples. It was found that the mechanism of a capillary barrier affected higher water loss from soil layers above those where the WAG had been placed. The obtained results of water loss depend on the soil type used in the profile.

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Microenvironment of Lake Huron sand dunes

Canadian Journal of Botany ◽

10.1139/b83-028 ◽

1983 ◽

Vol 61 (1) ◽

pp. 241-255 ◽

Cited By ~ 51

Author(s):

K. A. Baldwin ◽

M. A. Maun

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Transition Zone ◽

Soil Moisture Content ◽

Sand Dunes ◽

Organic Matter Content ◽

Soil Surface ◽

Matter Content ◽

Lake Huron ◽

Canonical Variate

Measurements were obtained of relative abundance of vegetation, edaphic properties, and microclimate characteristics of some initial stages of the Lake Huron sand-dune sequence at Pinery Provincial Park, Ont. Of the five dune habitats sampled, the oldest (transition zone) was distinguishable from the rest on the basis of greater diversity and abundance of vegetation, higher organic matter content, higher moisture-retaining capacity, enhanced concentrations of available K+ and Mg2+, depleted levels of Ca2+ in the surface soil, reduced air turbulence, and slightly higher air temperatures. The midsummer microclimate of the open dune habitat was characterized by extremely high day temperatures at the soil surface (5 cm) with large diurnal temperature fluctuations. Soil moisture content was generally low in the surface layers of the soil, but at depths greater than 10 cm, it was always plentiful (> 2.5% of soil by weight). Canonical variates analysis showed that the transition zone habitat (800 years old) was separated from younger ones (first dune ridge, slack, high beach) on the first canonical variate (V1), which accounted for about 50% of the total dispersion in the data. The discrimination of the transition zone microclimate on V1 was best characterized by difference in soil moisture content at shallow depths (5 and 10 cm) and wind velocity at 50 and 150 cm above the soil surface.

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Methodology adaptation and development to assess salt content dynamics and salt balance of soils under secondary salinization

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/1/8326 ◽

2021 ◽

pp. 199-206

Author(s):

Arzu Rivera Garcia ◽

Géza Tuba ◽

Györgyi Kovács ◽

Lúcia Sinka ◽

József Zsembeli

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Moisture Content ◽

Saline Water ◽

Salt Content ◽

Soil Layer ◽

Soil Samples ◽

Irrigation Season ◽

Salt Balance ◽

Secondary Salinization

The effect of irrigation with saline water (above 500 mg L-1) is considered a problem of small-scale farmers growing vegetable crops with high water demand in the hobby gardens characteristic of the Hungarian Great Plain. In order to simulate the circumstances of such hobby garden, we set up an experiment including five simple drainage lysimeters irrigated with saline water in the Research Institute of Karcag IAREF UD in 2019. We regularly measured the electric conductivity (EC) of the soil referring to its salt content and the soil moisture content with mobile sensors. Before and after the irrigation season, soil samples from the upper soil layer (0-0.6 m) were taken for laboratory analysis and the soil salt balance (SB) was calculated. The actual salt balance (SBact) was calculated of the upper soil layer (0-0.6 m) based on the salt content of the obtained soil samples. The theoretical salt balance (SBth) was calculated by the total soluble salt content of the irrigation water and leachates. During the irrigation season, we experienced fluctuating EC in the topsoil in close correlation with the soil moisture content. Based on the performed in-situ EC measurements, salts were leached from the upper soil layer resulting in a negative SB. Combining SBact and SBth of the soil columns of the lysimeters, we estimated the SB of the deeper (0.6-1.0 m) soil layer. We quantified 12% increase of the initial salt mass due to accumulation. We consider this methodology to be suitable for deeper understanding secondary salinization, which can contribute to mitigating its harmful effect. By repeating our measurements, we expect similar results proving that saline irrigation waters gained from the aquifers through drilled wells in Karcag are potentially suitable for irrigation if proper irrigation and soil management are applied.

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The influence of the initial soil moisture content on the degree of water stable aggregation as determined by wet sieving

Agricultural and Food Science ◽

10.23986/afsci.71490 ◽

1959 ◽

Vol 31 (1) ◽

pp. 233-239

Author(s):

Mikko Sillanpää

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Moisture Content ◽

Soil Samples ◽

Moisture Condition ◽

Initial Soil Moisture ◽

Initial Soil ◽

Pre Treatment ◽

A Minor ◽

Wet Sieving

The effect of the soil moisture content (varying from the field-moist to air-dry before re-wetting the muddy clay soil samples for aggregate analysis) on aggregation was studied. Two wetting procedures were used and compared: They were spraying samples with a fine mist and wetting them by immersion; aggregate analyses were made by wet sieving method. The results of the aggregate analyses proved to be practically independent of the initial moisture condition of the soil samples when the samples were wetted slowly with a spray. When wetting the samples by direct immersion the mean weight diameters of aggregates decrease with decreasing initial soil moisture content to values of less than half of those obtained from samples in their original field-moist condition (34.6—36.7 % dry wt.) or of those wetted with a spray. Air-drying seems to be a minor factor affecting the destruction of aggregates but the destruction effect of the sample pre-treatment may be very harmful if immersion wetting is used. This, however, can be eliminated almost completely if wetting with a fine mist is used.

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Effect of Biochar on Soil Temperature under High Soil Surface Temperature in Coal Mined Arid and Semiarid Regions

Sustainability ◽

10.3390/su12198238 ◽

2020 ◽

Vol 12 (19) ◽

pp. 8238

Author(s):

Jibing Xiong ◽

Runhua Yu ◽

Ejazul Islam ◽

Fuhai Zhu ◽

Jianfeng Zha ◽

...

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Surface Temperature ◽

Soil Temperature ◽

Bulk Density ◽

Soil Moisture Content ◽

Soil Surface ◽

Soil Bulk Density ◽

High Soil ◽

Soil Surface Temperature

High soil surface temperature and loosened soil are major limiting factors of plant productivity in arid and semi-arid coal mining areas of China. Moreover, the extensive and illegitimate burning of crop residues is causing environmental pollution; whereas, these residues could be converted to biochar to benefit soil quality. In this study, the effect of wheat straw biochar (WSB) at rates of 0% (control, CK), 1% (low, LB), 2% (medium, MB) and 4% (high, HB) on soil temperature at different depths (5, 10, 15, and 20 cm) and moisture levels (10 and 20%) was investigated under high soil surface temperature of 50 °C and air humidity of 40%. Our data suggested that soil bulk density was inversely, and soil moisture was directly corelated with soil thermal parameters. Moreover, the increasing rate of WSB addition linearly decreased the soil thermal properties. The maximum decrease in soil bulk density at both moisture levels (10% and 20%) was measured in HB treatment compared to respective CKs. The highest decrease in soil thermal conductivity (59.8% and 24.7%) was found under HB treatment in comparison to respective controls (CK10% and CK20% moisture). The soil volumetric heat capacity was also strongly corelated with soil moisture content (r = 0.91). The WSB treatments displayed differential responses to soil temperature. Under 10% soil moisture, temperature of LB, MB and HB treatments was higher as compared to CK at 5–20 cm depth, and MB treated soil had the smallest increase in temperature. At the 15-cm depth, the MB treatment decreased the temperature by 0.93 °C as compared to the CK20%. Therefore, the effect of WSB on soil temperature was influenced by soil moisture content, soil depth and WSB application rates. It suggested that MB treatment could be a useful farming practice for mitigating soil temperature fluctuation.

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Persisting effects of ligneous organic soil amendments on CO2, N2O and CH4 emissions in relation to moisture content in northern agricultural clay soil

10.5194/egusphere-egu2020-7464 ◽

2020 ◽

Author(s):

Kenneth Peltokangas ◽

Jimi Havisalmi ◽

Jussi Heinonsalo ◽

Kristiina Karhu ◽

Liisa Kulmala ◽

...

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Moisture Content ◽

Soil Amendments ◽

Ghg Emissions ◽

Organic Amendments ◽

Organic Soil ◽

Soil Samples ◽

Climate Effect ◽

Organic Soil Amendments

In agriculture, organic soil amendments are envisioned to mitigate climate change through carbon sequestration. However, the full impact of the organic amendments on soil physico-chemical dynamics is still poorly understood. We conducted a laboratory incubation to assess the net climate effect of four ligneous organic amendments: two biochars (willow and spruce) and two fiber byproducts of paper and pulp industry. Soil samples were collected from a soil-amendment field experiment at Qvidja farm, South-West of Finland. Soil samples were sieved, air-dried and adjusted to 30%, 50%, 80% and 110% of water holding capacity (WHC), and incubated for 32 days in standard laboratory conditions. Greenhouse gas (GHG) emissions were measured after 1, 5, 12, 20 and 33 days.&#160;The carbon dioxide (CO2) emissions were highest at 80% WHC, and lowest at severely water stressed conditions at 30% WHC. The organic amendments did not have an observable effect on CO2 dynamics. The CO2 emissions correlated linearly with soil moisture and microbial biomass nitrogen. Nitrous oxide (N2O) emissions were systematically lower in the amended soils compared to the control soil, and independent of soil nitrate concentrations. Without organic amendments, N2O emissions increased exponentially with soil moisture content. Methane (CH4) emissions fluctuated throughout the incubation, exhibiting mostly negative values. Consequently, CH4 emissions played only a minor role in the GHG budget.CO2, N2O and CH4 emissions, calculated as&#160;CO2 equivalent,&#160;exhibited a&#160;linear correlation with the moisture gradient. CO2 dominated the GHG budget up to a moisture of 80% WHC, but was superseded by N2O emissions at 110% WHC. The results indicate that soil moisture content is critically affecting the GHG emissions and that while organic soil amendments may have persisting effects on GHG exchange, they primarily occur through N2O dynamics.

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