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

scholarly journals Field and laboratory ad hoc calibrations of Virrib and ThetaProbe dielectric sensors for soil moisture measurements

2008 ◽  
Vol 3 (No. 4) ◽  
pp. 199-214 ◽  
Author(s):  
F. Doležal ◽  
T. Litschmann ◽  
J. Kučera ◽  
J. Peterková ◽  
J. Zavadil ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Calibration Curve ◽  
Ad Hoc ◽  
Soil Moisture Content ◽  
Seasonal Pattern ◽  
Repeated Measurements ◽  
Field Calibration ◽  
Moisture Contents ◽  
Moisture Variation

For the research of irrigation optimization and nitrate leaching it is important to know the short-term soil moisture variation during percolation episodes as well as its seasonal pattern. Dielectric soil moisture sensors Virrib (AMET – Consortium) and ThetaProbe ML2x (Delta-T) were used for this purpose over several years for measuring soil moisture content at hourly intervals in Valečov (49°38’40” N, 14°30’25” E, 461 m a.s.l.), Czech Republic, in a deep loamy Stagnosol soil underlain by weathered paragneiss. One-point field calibration was made each spring at the time of sensor installation over three (for Virribs) or two (for ThetaProbes) consecutive years by taking sensor readings and soil samples (at least one 100 cm3 core sample near to each sensor) in parallel. A supplementary check was then made in the laboratory by taking readings of individual sensors, inserted into pre-made loamy-sand mixtures with various moisture contents. During both the field calibration and the laboratory check, the readings were taken manually, using either the AMET hand-held meter or the EMS ModuLog datalogger. The results suggest that the average slope of the secondary Virrib calibration curve (defined as the plot of y = sensor readings in terms of moisture content vs. x = soil moisture content determined gravimetrically) is near to unity, but the offsets are quite large and vary from probe to probe. The axial zone of influence of the Virrib sensors is up to about 30 cm, as it follows from both laboratory and field observations. The results of the laboratory check of Virribs were biased, because the volume of the soil was not large enough and the soil had different dry bulk densities at different moisture contents. The field secondary calibration curve of ThetaProbes appears to be roughly linear, in contrast to the laboratory calibration curve, because of absence of very low moisture contents in the field. If the same calibration line is applied to several different depths, then its slope is statistically significantly lower then unity, due to the dependence of ThetaProbe readings on the soil bulk density. The overall accuracy of the sensors and its components due to different factors is estimated from the statistics of repeated measurements.

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.

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.

scholarly journals Predicting rut depth induced by an 8-wheeled forwarder in fine-grained boreal forest soils

2020 ◽  
Vol 77 (2) ◽  
Author(s):  
Jori Uusitalo ◽  
Jari Ala-Ilomäki ◽  
Harri Lindeman ◽  
Jenny Toivio ◽  
Matti Siren
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Bulk Density ◽  
Soil Moisture Content ◽  
Mineral Soil ◽  
Coarse Grained ◽  
Forest Operations ◽  
Fine Grained ◽  
Humus Layer ◽  
Cumulative Mass

Abstract Key message Rut depth in fine-grained boreal soils induced by an 8-wheeled forwarder is best predicted with soil moisture content, cumulative mass of machine passes, bulk density and thickness of the humus layer. Context Forest machines are today very heavy and will cause serious damage to soil and prevent future growth if forest operations are carried out at the wrong time of the year. Forest operations performed during the wettest season should therefore be directed at coarse-grained soils that are not as prone to soil damage. Aims The study aimed at investigating the significance of the most important soil characteristics on rutting and developing models that can be utilized in predicting rutting prior to forest operations. Methods A set of wheeling tests on two fine-grained mineral soil stands in Southern Finland were performed. The wheeling experiments were conducted in three different periods of autumn in order to get the largest possible variation in moisture content. The test drives were carried out with an 8-wheeled forwarder. Results Soil moisture content is the most important factor affecting rut depth. Rut depth of an 8-wheeled forwarder in fine-grained boreal soil is best predicted with soil moisture content, cumulative mass of machine passes, bulk density and thickness of the humus layer. Conclusion The results emphasize the importance of moisture content on the risk of rutting in fine-grained mineral soils, especially with high moisture content values when soil saturation reaches 80%. The results indicate that it is of high importance that soil type and soil wetness can be predicted prior to forest operations.

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 Soil compaction of various Central European forest soils caused by traffic of forestry machines with various chassis

2015 ◽  
Vol 24 (3) ◽  
pp. e038 ◽  
Author(s):  
Michal Allman ◽  
Martin Jankovský ◽  
Valéria Messingerová ◽  
Zuzana Allmanová ◽  
Michal Ferenčík
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Bulk Density ◽  
Soil Compaction ◽  
Soil Moisture Content ◽  
Standard Test ◽  
Primary Objective ◽  
Climatic Conditions ◽  
Moisture Content Level ◽  
European Forest

<p><em>Aim of study: </em>The primary objective of this paper was to compare the effects of different types of forestry machine chassis on the compaction of the top layers of soil and to define the soil moisture content level, at which machine traffic results in maximum compaction.</p><p><em>Area of study:</em> Measurements were conducted in eight forest stands located in Slovakia and the Czech Republic. The soil types in the stands subjected to the study were luvisols, stagnosols, cambisols, and rendzinas.</p><p><em>Material and Methods:</em> The measurements were focused on tracked and wheeled (equipped with low pressure tyres) cut-to-length machines, and skidders equipped with wide and standard tyres. The bulk density of soil was determined from soil samples extracted from the ruts, the centre of the skid trail, and the undisturbed stand. To determine soil moisture content, at which the soil is the most susceptible to compaction, the Proctor standard test was employed.</p><p><em>Main results:</em> The moisture content for maximal compaction fluctuated from 12% to 34.06%. Wheeled machines compacted the soil to 1.24 – 1.36 g.cm<sup>-3</sup> (30.3 – 35.4 % compaction) in dried state. Bulk density of soil in stands where tracked machine operated was lower, ranging from 1.02 to 1.06 g.cm<sup>-3</sup> (25.3 % compaction).</p><p><em>Research highlights:</em> All wheeled machines caused the same amount of soil compaction in the ruts, despite differences in tyres, machine weight, etc. Maximum compaction caused by forestry machines occurred at minimal moisture contents, easily achievable in European climatic conditions.  </p><p><strong>Keywords:</strong> soil compaction; bulk density; soil moisture content limits; cut-to-length machines; skidders.</p>

Sign in / Sign up

Export Citation Format

Share Document