Effects of soil moisture content on CO2 triggered soil physicochemical properties in a near-surface environment

2020 ◽  
Vol 20 (4) ◽  
pp. 2107-2120 ◽  
Author(s):  
Zahra Derakhshan-Nejad ◽  
Woojin Lee ◽  
Seunghee Han ◽  
Jaeyoung Choi ◽  
Seong-Taek Yun ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Physicochemical Properties ◽  
Soil Moisture Content ◽  
Soil Physicochemical Properties ◽  
Near Surface ◽  
Surface Environment

scholarly journals Effects of soil‐moisture content on shallow‐seismic data

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1357-1362 ◽  
Author(s):  
Robert D. Jefferson ◽  
Don W. Steeples ◽  
Ross A. Black ◽  
Tim Carr
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Seismic Data ◽  
Soil Moisture Content ◽  
Soil Conditions ◽  
Near Surface ◽  
Surface Moisture ◽  
Shallow Seismic ◽  
Unconsolidated Material ◽  
Moisture Conditions

Repeated shallow‐seismic experiments were conducted at a site on days with different near‐surface moisture conditions in unconsolidated material. Experimental field parameters remained constant to ensure comparability of results. Variations in the seismic data are attributed to the changes in soil‐moisture content of the unconsolidated material. Higher amplitudes of reflections and refractions were obtained under wetter near‐surface conditions. An increase in amplitude of 21 dB in the 100–300 Hz frequency range was observed when the moisture content increased from 18% to 36% in the upper 0.15 m (0.5 ft) of the subsurface. In the time‐domain records, highly saturated soil conditions caused large‐amplitude ringy wavelets that interfered with and degraded the appearance of some of the reflection information in the raw field data. This may indicate that an intermediate near‐surface moisture content is most conducive to the recording of high‐quality shallow‐seismic reflection data at this site. This study illustrates the drastic changes that can occur in shallow‐seismic data due to variations in near‐surface moisture conditions. These conditions may need to be considered to optimize the acquisition timing and parameters prior to collection of data.

scholarly journals Prediction of Soil Moisture-Holding Capacity with Support Vector Machines in Dry Subhumid Tropics

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jacob Kaingo ◽  
Siza D. Tumbo ◽  
Nganga I. Kihupi ◽  
Boniface P. Mbilinyi
Keyword(s):  
Soil Moisture ◽  
Support Vector Machines ◽  
Moisture Content ◽  
Physicochemical Properties ◽  
Support Vector ◽  
Attractive Alternative ◽  
Linear Regression Method ◽  
Soil Physicochemical Properties ◽  
Vector Machines ◽  
Subhumid Tropics

Soil moisture-holding capacity data are required in modelling agrohydrological functions of dry subhumid environments for sustainable crop yields. However, they are hardly sufficient and costly to measure. Mathematical models called pedotransfer functions (PTFs) that use soil physicochemical properties as inputs to estimate soil moisture-holding capacity are an attractive alternative but limited by specificity to pedoenvironments and regression methods. This study explored the support vector machines method in the development of PTFs (SVR-PTFs) for dry subhumid tropics. Comparison with the multiple linear regression method (MLR-PTFs) was done using a soil dataset containing 296 samples of measured moisture content and soil physicochemical properties. Developed SVR-PTFs have a tendency to underestimate moisture content with the root-mean-square error between 0.037 and 0.042 cm3·cm−3 and coefficients of determination (R2) between 56.2% and 67.9%. The SVR-PTFs were marginally better than MLR-PTFs and had better accuracy than published SVR-PTFs. It is held that the adoption of the linear kernel in the calibration process of SVR-PTFs influenced their performance.

GPS Multipath and Its Relation to Near-Surface Soil Moisture Content

2010 ◽  
Vol 3 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Kristine M. Larson ◽  
John J. Braun ◽  
Eric E. Small ◽  
Valery U. Zavorotny ◽  
Ethan D. Gutmann ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Surface Soil ◽  
Surface Soil Moisture ◽  
Near Surface

scholarly journals Aspect and soil textural controls on snowmelt runoff on forested Boreal Plain hillslopes

2011 ◽  
Vol 42 (4) ◽  
pp. 250-267 ◽  
Author(s):  
Todd Redding ◽  
Kevin Devito
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Surface Runoff ◽  
Soil Moisture Content ◽  
Mineral Soil ◽  
Sandy Soils ◽  
Slope Aspect ◽  
Snowmelt Runoff ◽  
Near Surface ◽  
Spring Snowmelt

Plot studies were conducted on a jack pine forest with sandy soil and aspen forests with sandy and loam soils to examine the controls of slope aspect, soil texture and fall soil moisture content on near-surface snowmelt runoff and infiltration. It was hypothesized that near-surface runoff would be greater from north-facing slopes on loam soils with increased fall soil moisture content. Fall soil moisture had no measurable effect on spring snowmelt runoff. Infiltration of snowmelt dominated (drainage coefficients 53–100%, median 87%) over near-surface runoff (runoff coefficients 1–65%, median 7%) for most plots. Runoff was related to concrete frost at the mineral soil surface. In contrast to the processes hypothesized, south-facing hillslopes with sandy soils generated greater runoff than north-facing slopes or sites with finer-textured soils. These results were due to greater concrete frost development resulting from periodic spring snowmelt and re-freezing in the upper soil. South-facing hillslopes with sandy soils featured lower canopy cover, allowing greater solar radiation to reach the snow surface which led to the formation of concrete frost and faster melt rates resulting in near-surface runoff. Where hillslopes are connected to receiving surface waters by continuous concrete frost, snowmelt runoff at the watershed scale may be enhanced.

Calibration and modification of impedance probe for near surface soil moisture measurements

2004 ◽  
Vol 84 (2) ◽  
pp. 237-243 ◽  
Author(s):  
T. D. Tsegaye ◽  
W. Tadesse ◽  
T. L. Coleman ◽  
T. J. Jackson ◽  
H. Tewolde
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Agricultural Research ◽  
Soil Depth ◽  
Ground Truth ◽  
Shallow Depth ◽  
Research Station ◽  
Near Surface ◽  
Impedance Probe

A reliable and low cost sensor that can measure soil moisture at or near the soil surface is currently not available. The objectives of this study were: (i) to evaluate the possibility of modifying an impedance probe (IP) to measure soil moisture content at a very shallow depth (2–5 cm); and (ii) to compare the soil moisture values obtained using the IP to the values obtained using the traditional gravimetric method. The research was conducted at the Winfred A. Thomas Agricultural Research Station (WTARS) Hazel Green, Alabama. The standard IP that is capable of measuring soil moisture content at 6-cm soil depth was modified to measure soil moisture at 2-, 3-, and 5-cm depths. Using a site and depth-specific calibration technique it provided results that were comparable to the values that were obtained following the traditional gravimetric water content determination protocol. We found that the instrument was very sensitive to changes in soil moisture content and has great potential as a replacement for the gravimetric technique. It allows repetitive measurements of soil moisture content at a very shallow depth with minimal soil disturbance. Fur thermore, the instrument is particularly valuable for providing ground- truth soil moisture contents to validate remotely sensed data. Key words: Soil moisture, remote sensing, impedance probe, ground-truth, validation

scholarly journals Influence of slope direction on the permafrost degradation: a case study in Qinghai-Tibetan Plateau

2021 ◽  
Author(s):  
Xingwen Fan ◽  
Zhanju Lin ◽  
fujiun niu ◽  
Zeyong Gao ◽  
Jing Luo ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Tibetan Plateau ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Ground Surface ◽  
Thermal Conditions ◽  
Permafrost Region ◽  
Permafrost Degradation ◽  
Near Surface ◽  
Slope Direction

Slope direction affects permafrost degradation because of its influence on the surface energy balance. The ground thermal difference between slopes of differing aspect is known, however there are few detailed reports on differences in soil temperature, humidity, and radiation from slopes in permafrost areas that caused permafrost degradation. In this study variations in air and ground thermal regime were compared at two sloping sites with opposing aspect in a permafrost region of the Qinghai-Tibetan Plateau (QTP). The results indicate that air temperatures (Ta) were similar at both sites in September 2016-19. However, ground temperatures, including the ground surface temperature (Ts), the temperature near the permafrost surface (Tps), and the permafrost temperature at 5.0 m depth (Tg), and soil moisture content within the active layer differed greatly between sites. The mean annual Ts, Tps, and Tg over three years (2016-19) were 1.3-1.4 ℃ higher at the sunny slope than at the shady slope. The near-surface soil moisture content during the thawing season was 10-13% lower at the sunny slope (~22-27%) than the shady slope (~35-38%), and was significantly and negatively correlated with ground temperature. Shortwave downward radiation (DR) at the sunny slope was higher than at the shady slope. However, net radiation (Rn) was lower at the sunny slope due to the greater surface albedo at the site. The results highlight a complex spatial pattern of ground thermal conditions in mountainous permafrost regions, help define the climate-permafrost relation in the region, and for understanding permafrost degradation on a local scale.

Analysis on Soil Moisture Content in the Middle Reaches of the Yellow River

2011 ◽  
Vol 28 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Run-chun LI ◽  
Xiu-zhi ZHANG ◽  
Li-hua WANG ◽  
Xin-yan LV ◽  
Yuan GAO
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Yellow River ◽  
The Yellow River
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