scholarly journals Spatial Downscaling of AMSR2 Soil Moisture Content using Soil Texture and Field Measurements

2015 ◽  
Vol 48 (6) ◽  
pp. 571-581
Author(s):  
Sangil Na ◽  
Kyoungdo Lee ◽  
Shinchul Baek ◽  
Sukyoung Hong
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Texture ◽  
Soil Moisture Content ◽  
Field Measurements ◽  
Spatial Downscaling

TIME OF SAMPLING AFTER AN IRRIGATION TO DETERMINE FIELD CAPACITY OF SOIL

1965 ◽  
Vol 45 (2) ◽  
pp. 171-176 ◽  
Author(s):  
J. C. Wilcox
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Texture ◽  
Soil Moisture Content ◽  
Field Capacity ◽  
Percentage Error ◽  
High Positive Correlation ◽  
Positive Correlation

Drainage curves following irrigation were determined at six depths in eight soils having unrestricted drainage but varying widely in soil texture. The field capacities were determined under relatively high rates of evapotranspiration. The time after irrigation that it was necessary to wait before sampling the soil, to determine field capacity, was also determined. A high positive correlation was obtained between the log of field capacity in inches and the log of time after irrigation at which to sample the soil. The time varied from about 0.5 day with 1.5 in. field capacity to 4.0 days with 35 in. From the curves of soil moisture content versus time, the errors caused by sampling too soon or too late were determined. The percentage error (i.e. percent of field capacity) increased with an increase in the error in time of sampling; it decreased with an increase in field capacity in inches; and it was greater when sampling was too soon than when it was too late.

Thermal properties of Antarctic soils: wetting controls subsurface thermal state

2016 ◽  
Vol 28 (5) ◽  
pp. 361-370 ◽  
Author(s):  
Joseph S. Levy ◽  
Logan M. Schmidt
Keyword(s):  
Soil Moisture ◽  
Thermal Diffusivity ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Thermal State ◽  
Thermal Characteristics ◽  
Field Measurements ◽  
Dry Valleys ◽  
Ground Ice ◽  
Mineral Soils

AbstractMineral soils in the McMurdo Dry Valleys (MDV), Antarctica, are commonly considered to be dry, and therefore to be good insulators with low thermal diffusivity values (~0.2 mm2s-1). However, field measurements of soil moisture profiles with depth, coupled with observations of rapid ground ice melt, suggest that the thermal characteristics of MDV soils, and thus their resistance to thaw, may be spatially variable and strongly controlled by soil moisture content. The thermal conductivity, heat capacity and thermal diffusivity of 17 MDV soils were measured over a range of soil moisture conditions from dry to saturated. We found that thermal diffusivity varied by a factor of eight for these soils, despite the fact that they consist of members of only two soil groups. The thermal diffusivity of the soils increased in all cases with increasing soil moisture content, suggesting that permafrost and ground ice thaw in mineral soils may generate a positive thawing feedback in which wet soils conduct additional heat to depth, enhancing rates of permafrost thaw and thermokarst formation.

scholarly journals Investigation of the Effect of Soil Moisture Content, Contact Surface Material and Soil Texture on Soil Friction and Soil Adhesion Coefficients

2018 ◽  
Vol 21 (2) ◽  
pp. 44-50 ◽  
Author(s):  
Yousef Abbaspour-Gilandeh ◽  
Fereshteh Hasankhani-Ghavam ◽  
Gholamhosein Shahgoli ◽  
Vali Rasooli Shrabian ◽  
Mohammadreza Abbaspour-Gilandeh
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Contact Surface ◽  
Soil Texture ◽  
Soil Moisture Content ◽  
Fluid Phase ◽  
Surface Material ◽  
Mean Values ◽  
Contact Materials ◽  
Draft Force

Abstract Soil friction and soil adhesion increase the implement draft force and energy consumption particularly in the tools that have larger contact area with soil. The main ways of lowering the total draft force of the tillage tools include the use of proper materials in tools structures as well as application of the tools in appropriate soil moisture content condition. This paper investigates the effects of soil moisture content, contact surface material and soil texture on soil friction and soil adhesion coefficients. To measure the coefficients of soil friction and soil adhesion, a measurement system was developed at the University of Mohaghegh Ardabili. Experiments for each soil texture were performed at five levels of soil moisture content and four contact materials of steel, cast iron, rubber, and teflon with three replications. Results have shown that in all soil types, the effects of soil moisture content and contact materials had a significant effect on the coefficient of both soil friction and soil adhesion at the probability level of 1%. The coefficient of friction increased with soil moisture content increment and reached its maximum and then had a drop in the fluid phase. Results have shown that the mean values of soil friction and soil adhesion coefficients were significantly different from the studied soils.

scholarly journals SHORT TDR PROBES TO MEASURE WATER AND FERTILIZER ION GRADIENTS IN CONTAINER MEDIA

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 742c-742
Author(s):  
Shaun F. Kelly ◽  
J.L Green ◽  
John S. Selker
Keyword(s):  
Porous Media ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Steel Wire ◽  
Field Measurements ◽  
Time Domain Reflectometry ◽  
Ion Concentrations ◽  
High Bandwidth ◽  
High Concentrations

Time Domain Reflectometry (TDR) is used to measure in situ soil moisture content and salinity of porous media. Commercially available TDR systems used for field measurements have limited use in laboratory scale experiments where short high resolution probes are needed. A short TDR probe was designed for use with high bandwidth TDR instruments currently available. The probes are designed from SMA bulkhead connectors using gold-plated stainless steel wire 0.035 inches in diameter. A 20.GHz digital sampling oscilloscope (11801; Tektronix, Beaverton, Ore.) with an SD-24 TDR sampling head is used with the probes to determine water content and ion concentrations in porous media. The 7.5- and 3.0-cm-long probes were used to measure soil moisture content and ion concentrations in laboratory columns. Fertilizer and water gradients were observed by using bromide salts brought into contact with the top of laboratory columns, 7.6 cm in diameter and 18 cm long, packed with container media [1 peat: 1 vermiculite v/v)]. Soil moisture measurements in the presence of high concentrations of salts were made by insulating the probes with Teflon heat-shrinkable tubing to minimize conductivity losses.

Estimating extractable soil moisture content for Australian soils from field measurements

Soil Research ◽  
2006 ◽  
Vol 44 (5) ◽  
pp. 531 ◽  
Author(s):  
A. R. Ladson ◽  
J. R. Lander ◽  
A. W. Western ◽  
R. B. Grayson ◽  
Lu Zhang
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Transfer Functions ◽  
Vegetation Type ◽  
Field Measurements ◽  
Pasture Production ◽  
Soil Moisture Storage ◽  
Moisture Storage ◽  
Extractable Soil

The amount of water that can be stored in soil and evaporated or actively used by plants is a key parameter in hydrologic models and is important for crop and pasture production. Often, the active soil moisture store is estimated from laboratory measurements of soil properties. An alternative approach, described in this paper, is to estimate the extractable soil moisture capacity from direct measurements of soil moisture content in the field. A time series of soil moisture values, over the depth of the soil, shows the actual changes in water content. The difference between the wettest and driest profiles is an estimate of the extractable soil moisture storage. We have gathered data on extractable soil water capacity for 180 locations over Australia and have compared our values with published results from the Atlas of Australian Soils (AAS), derived from profile descriptions and pedo-transfer functions. Our results show that data from the AAS provide a useful lower bound for measured extractable soil moisture storage, but of the sites examined, 42% had values >2 times those in the AAS. In part, this was because total soil depths were underestimated in the AAS results compared with the active depths from the measured data. Active depths are strongly related to vegetation type.

Numerical Simulation of Terrestrial Radiation over a Snow Cover

2015 ◽  
Vol 32 (8) ◽  
pp. 1478-1485 ◽  
Author(s):  
P. Ducharme ◽  
A. Houdayer ◽  
Y. Choquette ◽  
B. Kapfer ◽  
J. P. Martin
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Snow Water Equivalent ◽  
Field Measurements ◽  
Radioactive Material ◽  
Gamma Detector ◽  
Content Type ◽  
Basic Assumptions ◽  
Snow Water

AbstractThe intensity of terrestrial gamma radiation is a function of a number of parameters: emissivity and spatial distribution of the radioactive material in the soil, snow/water cover above ground, soil moisture content, type, and height above ground of the detector. Thus, the conversion of gamma measurements into reliable information must be based on a solid knowledge of the behavior of the gamma detector under different conditions. Such a detector, using a cylindrical NaI(Tl) crystal, was developed to remotely and automatically provide information on snow water equivalent (SWE) and soil moisture content (M). It became rapidly obvious that the behavior of the detector [gamma monitor (GMON)] over an infinite source could not be exactly reproduced in a laboratory. Therefore, a relatively simple model to simulate the behavior of GMON and to establish the relevant data analysis algorithms was conceived. This paper presents the basic assumptions for developing the model, the resulting algorithms, a comparison with field measurements, and some useful information on how GMON reacts to various field conditions.

scholarly journals Effect of Biomimetic Surface Geometry, Soil Texture, and Soil Moisture Content on the Drag Force of Soil-Touching Parts

2021 ◽  
Vol 11 (19) ◽  
pp. 8927
Author(s):  
Abouelnadar El. Salem ◽  
Hongchang Wang ◽  
Yuan Gao ◽  
Xiantao Zha ◽  
Mohamed Anwer Abdeen ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Drag Force ◽  
Soil Texture ◽  
Soil Moisture Content ◽  
Dome Height ◽  
Soil Conditions ◽  
Surface Geometry ◽  
Base Diameter ◽  
Coverage Ratio

Soil adhesion is a major problem for agricultural machinery, especially in sticky soils within the plastic range. One promising and practical way to minimize soil–tool adhesion is to modify the surface geometry to one inspired by soil-burrowing animals. In this study, 27 domed discs were fabricated according to an L27 (33) Taguchi orthogonal array and tested to determine the optimal dimensions of domed surfaces to reduce drag force. The optimized domed disc was tested in a soil bin under different soil conditions (soil texture: silty loam and sandy clay loam; soil moisture content: 23%, 30%, and 37%). All trials included a flat disc (without a dome pattern) as a control. The optimal dimensions of domed surfaces to generate the lowest possible drag force under the present experimental conditions were explored based on signal-to-noise ratio analysis. The optimal levels of control parameters were found at a surface coverage ratio of 60%, dome height of 5 mm, and dome base diameter of 20 mm. Statistics revealed that the dome height-to-diameter ratio and disc coverage ratio are crucial factors that influence the drag force of domed surfaces. In contrast, the dome base diameter had a limited influence on drag force. In all treatments, the drag force of the optimized domed disc was less than that of the flat disc (by about 9% to 25%, according to soil conditions). Accordingly, it can be concluded that adequately designed domed surfaces could significantly reduce the drag force in sticky soil compared to their flat counterparts.

FIELD CALIBRATION OF A NEUTRON PROBE

1986 ◽  
Vol 66 (1) ◽  
pp. 173-176 ◽  
Author(s):  
D. S. CHANASYK ◽  
R. H. McKENZIE
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Bulk Density ◽  
Soil Texture ◽  
Calibration Curve ◽  
Soil Moisture Content ◽  
Field Calibration ◽  
Neutron Probe ◽  
Probe Calibration

A study near Lethbridge, Alberta examined the effect of soil texture and bulk density on the calibration of a neutron probe and explored the feasibility of using only one calibration curve for measuring soil moisture. The effect of soil texture was found to be negligible. Bulk density did affect calibration, but not enough to warrant calibration based on bulk density. A calibration curve derived using all data was adequate for estimating soil moisture content and moisture changes, but the manufacturer’s curve was highly inappropriate for determination of either. Key words: Neutron probe, calibration, texture, bulk density

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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