Complex Dielectric Permittivity of Sandy Loam as a Function of Salinity and Biomass at Microwaves

2013 ◽  
Vol 209 ◽  
pp. 116-120 ◽  
Author(s):  
Arun Sharma ◽  
K.C. Pancholi ◽  
S.P. Bhatnagar
Keyword(s):  
Soil Moisture ◽  
Dielectric Permittivity ◽  
Sandy Loam ◽  
Strong Dependence ◽  
Normal Incidence ◽  
Complex Dielectric Permittivity ◽  
Network Analyzer ◽  
Frequency Range ◽  
Moisture Contents ◽  
Loam Soil

Real and Imaginary parts of Complex Dielectric Permittivity (ε’ and ε” ) of Sandy Loam soil have been measured in the frequency range 150 MHz – 2.4 GHz using a Vector Network Analyzer at varied Moisture contents, Salinity and Biomass. The Emissivity of the soil for normal incidence was also calculated from measured values of Complex Permittivity. The measured permittivity data show strong dependence on moisture content. Salinity causes higher permittivity and dielectric loss. Biomass appears to enhance the permittivity data due to increase in porosity of the soil. The emissivity of the soil was observed to decrease with increasing soil moisture and soil salinity, but it increases with biomass.

Combined vector network analyzer and impedance analyzer for broadband determination of complex permittivity spectrum of glass beads with talc

2020 ◽  
Author(s):  
Justyna Szerement ◽  
Hironobu Saito ◽  
Kahori Furuhata ◽  
Shin Yagihara ◽  
Agnieszka Szypłowska ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Moisture ◽  
Dielectric Permittivity ◽  
Glass Beads ◽  
Vector Network Analyzer ◽  
Complex Dielectric Permittivity ◽  
Network Analyzer ◽  
Frequency Range ◽  
Impedance Analyzer ◽  
Permittivity Spectrum

<p>Soil complex dielectric permittivity is frequency dependent. At low frequencies soil dielectric spectrum exhibits relaxation effects mainly due to interfacial phenomena caused by water strongly bounded to solid phase particles surfaces, double-layer effects and Maxwell-Wagner effect. At frequencies of several GHz and above, the influence of dielectric dispersion of free water dipoles can be observed.  Since dielectric soil moisture meters operate at frequencies from kHz up to several GHz, their output can be affected by these phenomena.</p><p>Currently, there is a variety of commercial sensors that operate at various frequencies from kHz up to several GHz. Most popular are TDR sensors with frequency band up to 1-2 GHz and capacitance/impedance sensors that operate at a single frequency usually from the range <br>1-150 MHz. Therefore, the knowledge of the broadband complex dielectric permittivity spectrum can help to improve the existing and develop new methods and devices for soil moisture and salinity estimation. Also, accurate characterization of complex dielectric permittivity spectrum of porous materials in the broadband frequency range is required for modeling of dielectric properties of materials in terms of moisture, salinity, density, mineralogy etc.</p><p>The aim of the study was to measure the complex dielectric permittivity of glass beads with 5% talc moistened with distilled water and saline water (electrical conductivity of 500, 1000, 1500 mS/m). The experiment was carried out using a seven-rod probe connected to an impedance analyzer (IA) and a vector network analyzer (VNA) using a multiplexer in the frequency range from 40Hz to 110MHz (IA) and 10MHz to 500MHz (VNA). The glass beads (90-106 µm, Fuji Manufacturing Industries, Japan) with 5% talc (Sigma Aldrich) in 4 different moisture and 4 different salinity values were examined. The results obtained from the IA and the VNA were combined and modeled with complex conductivity and dielectric permittivity model. The influence of water content and electrical conductivity on broadband complex dielectric spectra and the fitted model parameters was examined.</p><p> </p><p>The work has been supported by the National Centre for Research and Development, Poland, BIOSTRATEG3/343547/8/NCBR/2017.</p>

scholarly journals Effects of Variable Angular Velocities and Soil Moisture Contents on Undrained Shear Strength in a Sandy Loam Soil (Eutric Leptosol)

2016 ◽  
Vol 11 (2) ◽  
pp. 49-60
Author(s):  
David Lomeling ◽  
Juma L.L. Yieb ◽  
Modi A. Lodiong ◽  
Mandlena C. Kenyi ◽  
Moti S. Kenyi ◽  
...  
Keyword(s):  
Shear Strength ◽  
Soil Moisture ◽  
Sandy Loam ◽  
Undrained Shear Strength ◽  
Sandy Loam Soil ◽  
Moisture Contents ◽  
Angular Velocities ◽  
Loam Soil ◽  
Undrained Shear

Dielectric Properties of Clay Loam Soil at Lower Microwave Frequencies

2013 ◽  
Vol 209 ◽  
pp. 229-232
Author(s):  
Asha Buliya ◽  
K.C. Pancholi ◽  
R.K. Paliwal ◽  
S.P. Bhatnagar
Keyword(s):  
Remote Sensing ◽  
Network Analyzer ◽  
Clay Loam ◽  
Frequency Range ◽  
Clay Loam Soil ◽  
Microwave Frequencies ◽  
Moisture Contents ◽  
Salinity Levels ◽  
Microwave Signals ◽  
Loam Soil

Real and Imaginary parts ( ) of the Complex Dielectric Permittivity (ε*) of Clay Loam soil collected from Nanta Farm, CAD, Kota, Rajasthan have been measured using a Vector Network Analyzer with varied Moisture contents and Salinity levels in the frequency range 150 MHz to 2.2 GHz. Both and are observed to be strongly dependent on moisture content. The Reflection coefficient(R) , Emissivity(e) and Brightness temperature(T_B) of Microwaves for the soil sample were also calculated from the measured permittivity data. These parameters have their own importance in remote sensing of soil moisture using Microwave signals and show expected variations with soil salinity and Microwave frequencies used.

Evaluation of Presswheels and Seed Coverers for Direct Seeding of Brassica

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 599E-600
Author(s):  
Regina P. Bracy ◽  
Richard L. Parish
Keyword(s):  
Soil Moisture ◽  
Sandy Loam ◽  
Visual Observation ◽  
Mustard Seed ◽  
High Soil Moisture ◽  
Loam Soil ◽  
Direct Seeded ◽  
Plant Emergence ◽  
Moisture Conditions ◽  
Determine Effect

Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.

scholarly journals Effect of Ploughing Depth, Tractor Forward Speed, and Plough Types on the Fuel Consumption and Tractor Performance

2019 ◽  
Vol 9 (1) ◽  
pp. 43-49
Author(s):  
Kareem Ibrahim kareem ◽  
P. Sven
Keyword(s):  
Soil Moisture ◽  
Fuel Consumption ◽  
Agricultural Production ◽  
Soil Moisture Content ◽  
Sandy Loam ◽  
Forward Speed ◽  
Power Requirement ◽  
Primary Tillage ◽  
Loam Soil ◽  
Ploughing Depth

Cost of fuel has a significant impact on the input costs of agricultural production, especially during primary tillage. It is affected by several parameters including tractor forward speed, depths of ploughing, and plough types. The experiment was performed in a Soil Hall at Harper Adams University, United Kingdom, in April 2015. A Massey Ferguson 8480 4WD tractor was used for investigating objectives of this study. The experiment was performed in a sandy loam soil texture at 11.73% soil moisture content and 1.35 (g/cm3) dry bulk density to study the amount of fuel consumption (l/ha) and the performance of tractor with effect of moldboard and disc ploughs as ploughs type, 15 and 20 cm as ploughing depth and 5 and 7 km/h as tractor forward speeds. The results showed that fuel consumption with a disc plough 5% was higher compared to the moldboard. Fuel consumption decreased approximately 8% when tractor at 7 km/h. Fuel consumption significantly decreased about 34% when ploughing depth increased from 15 to 20 cm. The power requirement to operate moldboard plough was higher by about 14% than a disc. The power requirement at speeds of 7 km/h was higher compared to the speeds of 5 km/h by about 27%. When the depth of ploughing increased from 15 to 20 cm, the power requirement increased by about 1.5%.

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

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.

scholarly journals Sensitivity of Near-Surface Temperature Forecasts to Soil Properties over a Sparsely Vegetated Dryland Region

2014 ◽  
Vol 53 (8) ◽  
pp. 1976-1995 ◽  
Author(s):  
Jeffrey D. Massey ◽  
W. James Steenburgh ◽  
Sebastian W. Hoch ◽  
Jason C. Knievel
Keyword(s):  
Thermal Conductivity ◽  
Soil Moisture ◽  
Sandy Loam ◽  
Early Morning ◽  
Surface Model ◽  
Silt Loam ◽  
Soil Thermal Conductivity ◽  
Near Surface ◽  
Ground Heat Flux ◽  
Loam Soil

AbstractWeather Research and Forecasting Model forecasts over the Great Salt Lake Desert erroneously underpredict nocturnal cooling over the sparsely vegetated silt loam soil area of Dugway Proving Ground in northern Utah, with a mean positive bias error in temperature at 2 m AGL of 3.4°C in the early morning [1200 UTC (0500 LST)]. Positive early-morning bias errors also exist in nearby sandy loam soil areas. These biases are related to the improper initialization of soil moisture and parameterization of soil thermal conductivity in silt loam and sandy loam soils. Forecasts of 2-m temperature can be improved by initializing with observed soil moisture and by replacing Johansen's 1975 parameterization of soil thermal conductivity in the Noah land surface model with that proposed by McCumber and Pielke in 1981 for silt loam and sandy loam soils. Case studies illustrate that this change can dramatically reduce nighttime warm biases in 2-m temperature over silt loam and sandy loam soils, with the greatest improvement during periods of low soil moisture. Predicted ground heat flux, soil thermal conductivity, near-surface radiative fluxes, and low-level thermal profiles also more closely match observations. Similar results are anticipated in other dryland regions with analogous soil types, sparse vegetation, and low soil moisture.

An empirical model for drainage from soil under rain fed conditions

Soil Research ◽  
1977 ◽  
Vol 15 (3) ◽  
pp. 205 ◽  
Author(s):  
AR Aston ◽  
FX Dunin
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Empirical Model ◽  
Sandy Loam ◽  
Empirical Relationship ◽  
Field Conditions ◽  
Natural Field ◽  
Moisture Contents ◽  
Weighing Lysimeter

An empirical relationship was derived for drainage from a podzolic sandy loam using a weighing lysimeter at Krawarree, N.S.W. The form of the equation was similar to those used to describe drainage following irrigation. The agreement between computed and measured soil moisture contents over a period of five years was good, and indicated the usefulness of such an approach to characterize drainage of soil water under natural field conditions.

scholarly journals Seven-Rod Dielectric Sensor for Determination of Soil Moisture in Small Volumes

Proceedings ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 49
Author(s):  
Justyna Szerement ◽  
Aleksandra Woszczyk ◽  
Agnieszka Szypłowska ◽  
Marcin Kafarski ◽  
Arkadiusz Lewandowski ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Sandy Loam ◽  
Sample Volume ◽  
Small Sample ◽  
Silt Loam ◽  
Frequency Range ◽  
Fem Simulations ◽  
Dielectric Sensor ◽  
Permittivity Spectrum

The paper presents the performance of a seven-rod dielectric probe for determination of soil dielectric permittivity using FEM simulations as well as FDR and TDR measurements. The volume of the sensitivity zone of the tested probe was assessed basing on the simulations and measurement in liquids. The probe was also tested in two soils, sandy loam and silt loam. The obtained results suggested that the seven-rod probe can be used to accurately measure the dielectric permittivity spectrum in a small sample volume of about 8 cm3 in a frequency range from 20 MHz to 200 MHz.

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