Soil moisture content estimation using water absorption bands

GEOMATICA ◽  
2019 ◽  
Vol 73 (3) ◽  
pp. 63-73 ◽  
Author(s):  
Mohammad Reza Mobasheri ◽  
Meisam Amani ◽  
Mahin Beikpour ◽  
Sahel Mahdavi
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Absorption ◽  
Soil Moisture Content ◽  
Mean Squared Error ◽  
Sandy Loam ◽  
Soil Types ◽  
Accurate Estimation ◽  
Absorption Bands ◽  
New Models

Soil moisture content (SMC) is a crucial component in various environmental studies. Although many models have been proposed for SMC estimation, developing new models for accurate estimation of SMC is still an interesting subject. This study aimed to develop new models for SMC estimation using the water absorption bands in the spectral signatures of three different soil types: loam, silty loam, and sandy loam. Based on the three absorption bands (i.e., 1400, 1900, and 2200 nm) and regression analyses, six approaches were considered. These scenarios were generally based on the reflectance value and its logarithm, as well as the difference between the wet and dry reflectance values for the absorption bands. Finally, 24 models were developed for SMC estimation from the three different soil types, as well as the entire soil samples. The most accurate SMC, as indicated by the lowest root mean squared error (RMSE) and the highest correlation coefficient (r), was obtained from the model developed using the logarithm of the average values reflectance in the three water absorption bands for sandy loam (RMSE = 0.31 g/kg, r = 0.99). Overall, using the spectrometry data derived in the lab, the results of the proposed models were promising and demonstrate great potential for SMC estimation using spectral data collected by satellites in the future studies.

scholarly journals Field Calibration of TDR to Assess the Soil Moisture of Drained Peatland Surface Layers

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1842 ◽  
Author(s):  
Tomasz Gnatowski ◽  
Jan Szatyłowicz ◽  
Bogumiła Pawluśkiewicz ◽  
Ryszard Oleszczuk ◽  
Maria Janicka ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Mean Squared Error ◽  
Time Domain Reflectometry ◽  
Calibration Model ◽  
Surface Layers ◽  
Calibration Equation ◽  
North East

The proper monitoring of soil moisture content is important to understand water-related processes in peatland ecosystems. Time domain reflectometry (TDR) is a popular method used for soil moisture content measurements, the applicability of which is still challenging in field studies due to requirements regarding the calibration curve which converts the dielectric constant into the soil moisture content. The main objective of this study was to develop a general calibration equation for the TDR method based on simultaneous field measurements of the dielectric constant and gravimetric water content in the surface layers of degraded peatlands. Data were collected during field campaigns conducted temporarily between the years 2006 and 2016 at the drained peatland Kuwasy located in the north-east area of Poland. Based on the data analysis, a two-slopes linear calibration equation was developed as a general broken-line model (GBLM). A site-specific calibration model (SSM-D) for the TDR method was obtained in the form of a two-slopes equation describing the relationship between the soil moisture content and the dielectric constant and introducing the bioindices as covariates relating to plant species biodiversity and the state of the habitats. The root mean squared error for the GBLM and SSM-D models were equal, respectively, at 0.04 and 0.035 cm3 cm−3.

Evaluation of Various Soil Moisture Sensors in Four Different Soil Types

2018 ◽  
Vol 34 (6) ◽  
pp. 963-971 ◽  
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.

scholarly journals Effects of Rain Intensity and Initial Soil Moisture on Hydrological Responses in Laboratory Conditions

2015 ◽  
Vol 29 (2) ◽  
pp. 165-173 ◽  
Author(s):  
Abdulvahed Khaledi Darvishan ◽  
Kazimierz Banasik ◽  
Seyed Hamidreza Sadeghi ◽  
Leila Gholami ◽  
Leszek Hejduk
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Initial Moisture Content ◽  
Hydrological Responses ◽  
Laboratory Conditions ◽  
Initial Soil Moisture ◽  
Erosion Processes ◽  
Initial Soil

Abstract Although the possibility of measuring and analysing all parts of the rainfall, infiltration, runoff, and erosion process as a natural hydrologic cycle in field conditions is still one of the more unattainable goals in the hydrological sciences, it can be accomplished in laboratory conditions as a way to understand the whole process. The initial moisture content is one of the most effective factors on soil infiltration, runoff, and erosion responses. The present research was conducted on a 2 m2 laboratory plot at a slope of 9% on a typical sandy-loam soil. The effects of the initial soil moisture content on the infiltration, runoff, and erosion processes were studied at four levels of initial soil moisture content (12, 25, 33, and 40 volumetric percentage) and two rainfall intensities (60 and 120 mm h-1). The results showed a significant (p ≤ 0.05) correlation between rainfall intensity and downstream splash, with r = 0.87. The results reflected the theory of hydrological responses, showing significant (p ≤ 0.05) correlations with r =-0.93, 0.98, -0.83, 0.88, and 0.73 between the initial soil moisture content and the time-to-runoff, runoff coefficient, drainage as a part of the infiltrated water, downstream splash, and total outflow sediment, respectively.

A LABORATORY STUDY ON THE EFFECTS OF SOIL MOISTURE CONTENT, TEXTURE, AND TIMING OF LEACHING ON N LOSS FROM TWO SOUTHERN ALBERTA SOILS

1982 ◽  
Vol 62 (2) ◽  
pp. 407-413 ◽  
Author(s):  
T. G. SOMMERFELDT ◽  
C. CHANG ◽  
J. M. CAREFOOT
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Wetting Front ◽  
N Losses ◽  
Initial Soil Moisture ◽  
N Removal ◽  
Southern Alberta ◽  
Initial Soil

A column study was conducted to determine the effects of soil texture, initial soil moisture content and timing of leaching on N removal from two irrigated soils of southern Alberta. Pelleted NH4NO3 fertilizer (0.639 g N per column = 336 kg∙ha−1) was applied to Lethbridge loam (Leth L) and Cavendish fine sandy loam (CV FSL) at three initial levels of soil moisture: air dry (AD), 0.5 field capacity (0.5 FC), and wet (W, 25 cm suction). Leaching began immediately after the fertilizer application or was delayed 1 wk. Water was applied in 1400-mL (7.6 cm depth) increments every 2nd day for a total of 33 600 mL (175 cm depth). The leachate was collected, measured, and analyzed for NH4-N and NO3-N. The soil was analyzed for N content before and after leaching. More N was leached from CV FSL (0.600 g) than from Leth L (0.521 g). Responses to initial soil moisture were similar for both soils; the NO3-N concentration peak followed the advancing wetting front more closely in the AD than in the W systems and leaching losses were greatest from the 0.5 FC treatment. Delayed leaching did not significantly affect the amount of N leached. N losses, other than from leaching, were greatest in the W and AD treatments, in the AD treatment these losses were attributed to volatilization and, in the W soils, to denitrification.

EFFECTS OF IRRIGATION AND NITROGEN ON A NATURAL PASTURE SWARD

1978 ◽  
Vol 58 (2) ◽  
pp. 347-356
Author(s):  
W. N. BLACK
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Field Capacity ◽  
Early Spring ◽  
Naturally Occurring ◽  
Natural Pasture ◽  
Loam Soil ◽  
Grazing Period

Irrigation and nitrogen (N) requirements of a natural pasture sward were studied on a Charlottetown sandy loam soil over a 5-yr period. The soil moisture content at the 0-to 15- and 15- to 30-cm depths was determined at from 7- to 10-day intervals, while irrometer soil moisture readings at 15-, 30-, and 45-cm depths were recorded more frequently during the grazing seasons. Soil moisture content in irrigated plots averaged 92 and 94% of field capacity, respectively, at 0- to 15- and 15- to 30-cm sampling depths. In non-irrigated plots, corresponding values were 77 and 82%. N treatments resulted in significant dry matter (DM) increases over untreated plots. Yield differences among plots receiving 56, 84, and 112 kg of N/ha in mid-June and again in mid-August were not significant. Early spring and September applications of N at 56 kg/ha, combined with mid-June and early August supplements of N at 84 kg/ha were superior to all other treatments in prolonging the grazing period. Neither irrigation nor N affected the characteristic yield decline of naturally occurring forage species in mid- and late-season. Mean DM production for the 5-yr period, and for years, showed no significant N treatment × moisture level interaction. While irrigation failed to increase yields significantly, livestock preferred to graze the irrigated plots. As a result of less competition from grasses, volunteer white clover became better established, and constituted a larger percentage of the sward than on non-irrigated plots.

Measurement and prediction of permethrin persistence in six Malaysian agricultural soils

Soil Research ◽  
2002 ◽  
Vol 40 (5) ◽  
pp. 817 ◽  
Author(s):  
B. S. Ismail ◽  
Kalithasan Kailasam
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Half Life ◽  
Dissipation Rate ◽  
Degradation Rate ◽  
Soil Moisture Content ◽  
Rate Coefficient ◽  
Agricultural Soils ◽  
Field Capacity ◽  
Soil Types

The effect of soil types, soil temperature, and soil moisture content on the degradation of permethrin was studied under controlled greenhouse conditions. Six soils were used in the study: Soil 1 (Teringkap series), Soil 2 (Ringlet series), Soil 3 (Teringkap 2), Soil 4 (Teringkap 3), Soil 5 (Gunung Berinchang), and Soil 6 (Lating series). Observed data showed that permethrin was more persistent in Soil 1 (23.3 days) and less persistent in Soil 5 (16.7 days). Similarly, the degradation rate coefficient (k) was greater in Soil 5 than Soil 1. The half-life and the dissipation patterns of permethrin between the observed and predicted data were not much different in all 6 soils studied, even though the predicted data were slightly higher. The half-life of permethrin in Soil 6 decreased as the temperature increased from 20°C (36.1 days) to 35°C (13.9 days). The degradation rate coefficient increased as the temperature increased. The predicted data derived from the model showed greater values than the observed data. The half-life of permethrin in Soil 6 decreased as the soil moisture increased from 30% (26.8 days) to 80% (20.1 days). The dissipation rate was not very different between the predicted and the observed data at 80% field capacity and at the temperature of 35°C, and it consequently became closer when the incubation period was prolonged.

Effect of soil moisture levels on nitrification

1968 ◽  
Vol 14 (12) ◽  
pp. 1348-1350 ◽  
Author(s):  
H. D. Dubey
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Nitrification Rate ◽  
Flooded Soils ◽  
Cold Room ◽  
Release Curve ◽  
Humidified Air ◽  
Crushed Ice

Nitrification of 100 p.p.m. added NH4-N was studied in two soils of Georgia. Moisture levels tried were equivalent to those equilibrated at soil tension of 15, 8, 4, 2, 0.3, 0.0 bars on the release curve and a flooded condition. Moisture was applied as crushed ice in a cold room at −5 °C. Samples were incubated at 25 °C with a constant stream of humidified air passing over them. Nitrification rate in Cecil sandy loam increased as the soil moisture content increased from 15 to 2 bars and decreased thereafter. Marked nitrification occurred even under flooded conditions. Unaccounted-for nitrogen amounted to 30% under flooded condition. Nitrification in Norfolk loamy sand was exceptionally high, nitrification being 73% complete within 2 weeks at 15 bars. There was practically no difference in nitrification at 15 to 0.3 bar. Unaccounted-for nitrogen amounted to over 60% in flooded soils.

Modification on optical trapezoid model for accurate estimation of soil moisture content in a maize growing field

2020 ◽  
Vol 14 (03) ◽  
Author(s):  
Reza Hassanpour ◽  
Davoud Zarehaghi ◽  
Mohammad Reza Neyshabouri ◽  
Bakhtiar Feizizadeh ◽  
Mehdi Rahmati
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Accurate Estimation

Some effects of urea and of soil moisture on solute translocation

1975 ◽  
Vol 53 (8) ◽  
pp. 756-763 ◽  
Author(s):  
Wm. Harold Minshall
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Water Control ◽  
Tomato Plants ◽  
Soil Mixture ◽  
Solute Uptake ◽  
Before And After ◽  
Loam Soil

In detopped plants, stump exudation resulting from root pressure provides a measure of the quantity of solutes and of water being transferred to the xylem. In dry soil the transfer of water to the xylem stops when the force required to remove the water from the soil is equal to the osmotic pull of the solutes in the xylem. In a sandy loam soil mixture, detopped tomato plants (Lycopersicon esculentum Mill.) treated with urea maintained stump exudation to a soil moisture content as low as 12.1% while water-control plants ceased exudation at 15.0% soil moisture. By maintaining the transfer of solutes to the xylem, the application of urea enhanced the ability of the detopped root system to remove water from the dry soil.By watering plants to pot capacity at different times before and after detopping, a series of soil moisture levels were obtained with detopped roots of tomato. In this clay loam soil mixture stump exudation started at 10% soil moisture (about −3.0 bars potential). With increasing moisture the rate of exudation increased rapidly to reach a maximum exceeding 5 ml per hour at soil moisture contents between 20 and 25% (about −0.05 bars potential). The rate then decreased gradually to 2.5 ml per hour as the soil moisture content increased from 25 to 45%. Starting at 10% soil moisture and continuing up to 25%, solute uptake increased proportionately with increasing moisture content, and at these dry and medium soil moisture levels, the supply of water to the root determined the quantity of solutes being translocated to the stump. The depletion of oxygen and accumulation of carbon dioxide in soils containing more than 25% moisture reduced the translocation of solutes in the plants.

Influence of Soil Texture on Soil-Water Characteristic Curves of Different Sandy Loam Layers

2014 ◽  
Vol 955-959 ◽  
pp. 3607-3610
Author(s):  
Li Zhu Hou ◽  
Jochen Wenninger ◽  
Xu Jie Li
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Soil Water Storage ◽  
Characteristic Curves ◽  
Van Genuchten Model ◽  
Soil Water Characteristic Curves ◽  
Matrix Suction

Characteristic curves of soil moisture, between water content and matrix suction, are the basis for solving the problems of water flow and solute movement in soils. The soil–water characteristics of five layers of depths, 0–12 cm, 12–24 cm, 24–36 cm, 36–48 cm, and 48–60 cm, were measured for a sandy loam soil from Daxing District of Beijing in the northern part of the North China Plain by a pressure membrane apparatus. Curves were fitted using the Van Genuchten model. The fit between measured data and modeled results was excellent. The soil-water characteristic curves showed the typical Sshape of the Van Genuchten model. Matrix suction decreased with an increase in soil moisture; at low suctions, soil moisture content changed to a greater extent with suction, but at high suction, changes in soil moisture content with changes in suction were small. Clay content was proportional to soil water storage capacity and was inversely related to the speed of dehydration.

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