Numerical investigation of wetting front migration and soil water distribution under vertical line source irrigation with different influencing factors

Abstract Vertical line source irrigation (VLSI) is an underground irrigation method suitable for deep-rooted plants. Understanding the characteristics of the soil wetting body of the VLSI was the key to designing this irrigation system. On the basis of experimental verification of the reliability of the HYDRUS simulation results of VLSI under the conditions of soil texture (ST), initial water content (θi), line source buried depth (B), line source diameter (D) and line source length (L), numerical studies of the migration law of the wetting front of VLSI and the distribution characteristics of soil moisture were performed. The wetting front migration (WFM) was mainly influenced by ST, θi, D and L (P < 0.05), while B had little effect on WFM (P > 0.05). The shape of the soil wetting body changed little under different influencing factors. The water content contour was approximately ‘ellipsoidal’ around the line source. The soil moisture near the line source was close to the saturated moisture content. The moisture content around the line source gradually decreased outward, and the contour lines gradually became dense. According to the simulation results, a prediction model of multiple factors influencing the migration process of the VLSI wetting front was established. The predicted value was in good agreement with the measured value. The results of this research could provide a theoretical basis for further optimizing the combination of VLSI and irrigation elements.

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Root effects on soil water and hydraulic properties

Biologia ◽

10.2478/s11756-007-0110-8 ◽

2007 ◽

Vol 62 (5) ◽

Cited By ~ 8

Author(s):

Horst Gerke ◽

Rolf Kuchenbuch

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Water Content ◽

Bulk Density ◽

Soil Water ◽

Soil Water Content ◽

Hydraulic Properties ◽

Soil Hydraulic Properties ◽

Soil Hydraulic ◽

Root Effects

AbstractPlants can affect soil moisture and the soil hydraulic properties both directly by root water uptake and indirectly by modifying the soil structure. Furthermore, water in plant roots is mostly neglected when studying soil hydraulic properties. In this contribution, we analyze effects of the moisture content inside roots as compared to bulk soil moisture contents and speculate on implications of non-capillary-bound root water for determination of soil moisture and calibration of soil hydraulic properties.In a field crop of maize (Zea mays) of 75 cm row spacing, we sampled the total soil volumes of 0.7 m × 0.4 m and 0.3 m deep plots at the time of tasseling. For each of the 84 soil cubes of 10 cm edge length, root mass and length as well as moisture content and soil bulk density were determined. Roots were separated in 3 size classes for which a mean root porosity of 0.82 was obtained from the relation between root dry mass density and root bulk density using pycnometers. The spatially distributed fractions of root water contents were compared with those of the water in capillary pores of the soil matrix.Water inside roots was mostly below 2–5% of total soil water content; however, locally near the plant rows it was up to 20%. The results suggest that soil moisture in roots should be separately considered. Upon drying, the relation between the soil and root water may change towards water remaining in roots. Relations depend especially on soil water retention properties, growth stages, and root distributions. Gravimetric soil water content measurement could be misleading and TDR probes providing an integrated signal are difficult to interpret. Root effects should be more intensively studied for improved field soil water balance calculations.

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Temperature and seed moisture content affect electrical conductivity test in pea seeds

Journal of Seed Science ◽

10.1590/2317-1545v39n4181021 ◽

2017 ◽

Vol 39 (4) ◽

pp. 410-416 ◽

Cited By ~ 1

Author(s):

Lara Bernardes da Silva Ferreira ◽

Nayara Alves Fernandes ◽

Luan Costa de Aquino ◽

Anderson Rodrigo da Silva ◽

Warley Marcos Nascimento ◽

...

Keyword(s):

Electrical Conductivity ◽

Moisture Content ◽

Water Content ◽

Initial Water Content ◽

Seed Moisture Content ◽

Initial Water ◽

Test Efficiency ◽

Seed Moisture ◽

Pea Seeds ◽

Initial Seed

Abstract: Several factors affect the electrical conductivity test efficiency, with emphasis given to the initial water content and the temperature during imbibition. This study aimed to evaluate the effect of the initial water content of pea seeds and the temperature on the electrical conductivity test efficiency. Six lots of ‘Mikado’ pea were used, which were previously tested for initial characterization. In the first trial, based on the initial value of the samples, the seed moisture content was adjusted to 9, 11, 13 and 15% and then the seeds were submitted to the electrical conductivity test. In the second trial, the water for seed imbibition was kept for 24 hours at 10, 15, 20, 25 and 30 ºC, and after that time the seeds were added and soaked for other 24 hours at the temperatures already mentioned. It was observed that initial seed moisture content and water temperature during imbibition influenced the results of the electrical conductivity test. This test should be carried out with distilled water, previously maintained for 24 hours at 25 °C for temperature stabilization. Then, the seeds with seed moisture content between 11 and 15% should be put to soak at 25 °C, and maintained at this temperature for 24 hours.

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Development of calibration algorithms for selected water content reflectometry probes for burned and non-burned organic soils of Alaska

International Journal of Wildland Fire ◽

10.1071/wf07175 ◽

2010 ◽

Vol 19 (7) ◽

pp. 961 ◽

Cited By ~ 8

Author(s):

Laura L. Bourgeau-Chavez ◽

Gordon C. Garwood ◽

Kevin Riordan ◽

Benjamin W. Koziol ◽

James Slawski

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Water Content ◽

Soil Profile ◽

Soil Moisture Content ◽

Mineral Soil ◽

Organic Soil ◽

Organic Content ◽

Organic Soils ◽

Probe Type

Water content reflectometry is a method used by many commercial manufacturers of affordable sensors to electronically estimate soil moisture content. Field‐deployable and handheld water content reflectometry probes were used in a variety of organic soil‐profile types in Alaska. These probes were calibrated using 65 organic soil samples harvested from these burned and unburned, primarily moss‐dominated sites in the boreal forest. Probe output was compared with gravimetrically measured volumetric moisture content, to produce calibration algorithms for surface‐down‐inserted handheld probes in specific soil‐profile types, as well as field‐deployable horizontally inserted probes in specific organic soil horizons. General organic algorithms for each probe type were also developed. Calibrations are statistically compared to determine their suitability. The resulting calibrations showed good agreement with in situ validation and varied from the default mineral‐soil‐based calibrations by 20% or more. These results are of particular interest to researchers measuring soil moisture content with water content reflectometry probes in soils with high organic content.

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Geostatistical analysis for soil moisture content under the no tillage cropping system

Scientia Agricola ◽

10.1590/s0103-90162006000400005 ◽

2006 ◽

Vol 63 (4) ◽

pp. 341-350 ◽

Cited By ~ 25

Author(s):

Célia Regina Grego ◽

Sidney Rosa Vieira ◽

Aline Maria Antonio ◽

Simone Cristina Della Rosa

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Spatial Variability ◽

Water Content ◽

Spatial Dependence ◽

Soil Moisture Content ◽

No Tillage ◽

Moisture Contents ◽

Classical Statistics ◽

Evaluation Point

Experiments in agriculture usually consider the topsoil properties to be uniform in space and, for this reason, often make inadequate use of the results. The objective of this study was to assess the variability for soil moisture content using geostatistical techniques. The experiment was carried out on a Rhodic Ferralsol (typic Haplorthox) in Campinas, SP, Brazil, in an area of 3.42 ha cultivated under the no tillage system, and the sampling was made in a grid of 102 points spaced 10 m x 20 m. Access tubes were inserted down to one meter at each evaluation point in order to measure soil moisture contents (cm³ cm-3) at depths of 30, 60 and 90 cm with a neutron moisture gauge. Samplings were made between the months of August and September of 2003 and in January 2004. The soil moisture content for each sampling date was analyzed using classical statistics in order to appropriately describe the central tendency and dispersion on the data and then using geostatistics to describe the spatial variability. The comparison between the spatial variability for different samplings was made examining scaled semivariograms. Water content was mapped using interpolated values with punctual kriging. The semivariograms showed that, at the 60 cm depth, soil water content had moderate spatial dependence with ranges between 90 and 110 m. However, no spatial dependence was found for 30 and 90 cm depths in 2003. Sampling density was insufficient for an adequate characterization of the spatial variability of soil moisture contents at the 30 and 90 cm depths.

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

Canadian Journal of Soil Science ◽

10.4141/cjss82-044 ◽

1982 ◽

Vol 62 (2) ◽

pp. 407-413 ◽

Cited By ~ 3

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.

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Soil moisture monitoring at the field scale using neutron probe

Canadian Geotechnical Journal ◽

10.1139/cgj-2012-0113 ◽

2014 ◽

Vol 51 (3) ◽

pp. 332-345 ◽

Cited By ~ 22

Author(s):

J. Kodikara ◽

P. Rajeev ◽

D. Chan ◽

C. Gallage

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Layer ◽

Calibration Method ◽

Flow Equation ◽

Wetting Front ◽

Wet Season ◽

Buried Structures ◽

Neutron Probe ◽

Moisture Variation

Measurement of the moisture variation in soils is required for geotechnical design and research because soil properties and behavior can vary as moisture content changes. The neutron probe, which was developed more than 40 years ago, is commonly used to monitor soil moisture variation in the field. This study reports a full-scale field monitoring of soil moisture using a neutron moisture probe for a period of more than 2 years in the Melbourne (Australia) region. On the basis of soil types available in the Melbourne region, 23 sites were chosen for moisture monitoring down to a depth of 1500 mm. The field calibration method was used to develop correlations relating the volumetric moisture content and neutron counts. Observed results showed that the deepest “wetting front” during the wet season was limited to the top 800 to 1000 mm of soil whilst the top soil layer down to about 550 mm responded almost immediately to the rainfall events. At greater depths (550 to 800 mm and below 800 mm), the moisture variations were relatively low and displayed predominantly periodic fluctuations. This periodic nature was captured with Fourier analysis to develop a cyclic moisture model on the basis of an analytical solution of a one-dimensional moisture flow equation for homogeneous soils. It is argued that the model developed can be used to predict the soil moisture variations as applicable to buried structures such as pipes.

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EFFECTS OF HYDROPHILIC POLYMERS AND ORGANIC AMENDMENTS ON ESTABLISHMENT OF KENTUCKY BLUEGRASS.

HortScience ◽

10.21273/hortsci.27.6.588a ◽

1992 ◽

Vol 27 (6) ◽

pp. 588a-588

Author(s):

A. James Downer ◽

Ben Faber ◽

Richard White

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Water Content ◽

Soil Moisture Content ◽

Organic Amendments ◽

Kentucky Bluegrass ◽

Soil Bulk Density ◽

Time Domain Reflectometry ◽

Peat Moss ◽

Turf Quality

Three polymers (a polyacrylamide, polyacrylate and a propenoate-propenamide copolymer) and three organic amendments (peat moss, wood shavings, and composted yardwaste) were incorporated at five rates in a sandy soil to 15cm depth. Soil moisture content was determined by time domain reflectometry and gravimetrically. Only the highest polymer rates (2928kg/ha [60#/1000sq.ft.]) produced significant increases in soil moisture content and reductions of soil bulk density. Peat moss and yardwaste increased soil water content while shavings decreased water content. Turf quality scores were not affected by polymers but were initially reduced by yardwaste and shavings.

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Effect of soil moisture content on the bearing capacity of small bored piles in the unsaturated soil of Maringá, Paraná, Brazil

MATEC Web of Conferences ◽

10.1051/matecconf/202133703006 ◽

2021 ◽

Vol 337 ◽

pp. 03006

Author(s):

Verônica Ricken Marques ◽

Antonio Belincanta ◽

Mary-Antonette Beroya-Eitner ◽

Jorge Luis Almada Augusto ◽

Ewerton Guelssi ◽

...

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Bearing Capacity ◽

Water Content ◽

Unsaturated Soil ◽

Soil Layer ◽

Matric Suction ◽

Load Test ◽

Degree Of Saturation ◽

Static Load Test

In this study, the influence of soil moisture on the bearing capacity of piles founded in an unsaturated clay soil was investigated. The soil studied, composing the upper soil layer in Maringá, Brazil, is lateritic, has degree of saturation between 37% and 70% and has collapsible behaviour when wet. The bearing capacity was determined by full-scale load tests following the Brazilian Standard for Static Load Test. Two pile lengths, 4 m and 8 m, were considered. To analyse the influence of soil moisture, two tests were performed for each pile length: one in soil in its natural moisture content and another in pre-moistened soil. Results show that for both pile lengths, an increase in water content caused a significant reduction in bearing capacity, which is attributed to the decrease in the matric suction of the soil. This is confirmed by the results of the initial evaluation made on the variation of matric suction and its contribution to the bearing capacity with changes in water content. In summary, this study confirms that the pile bearing capacity in unsaturated soil is dependent on soil water content, highlighting the fact that the approach of assuming full saturation condition in the evaluation of the pile bearing capacity in such soil may give erroneous results. Moreover, this study demonstrate that the empirical methods most commonly used in Brazil for pile bearing capacity determination, the Décourt & Quaresma and Aoki & Velloso methods, are overly conservative when applied to the Maringá soil.

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Mechanical Dewatering and Thermal Drying Characteristics of Pulp Mill Sludge Cake

10.31224/osf.io/9mhxg ◽

2020 ◽

Author(s):

Kevin Prawiranto ◽

Syamsudin ◽

Herri Susanto

Keyword(s):

Energy Consumption ◽

Moisture Content ◽

Water Content ◽

Calorific Value ◽

High Water Content ◽

Initial Water Content ◽

Main Concern ◽

Coal Powder ◽

Thermal Drying ◽

Sludge Cake

Sludge cake is a type of solid waste in pulp and paper mills which may harm the environment if disposed without treatment. Its proximate analysis (adb) are: ash 26.74%; volatile matter 59.09%; fixed carbon 11.04%; moisture 3.13%, while its ultimate analysis (adb) are: C 33.46%; H 4.5%; N 1.14%; S 0.35%; O 33.81%. Having a calorific value of 3000 cal/g (adb), sludge cake may be used as renewable fuel. Unfortunately it has a high water content, so reduction of water content become a main concern in utilizing sludge cake. A combination of mechanical dewatering and thermal drying has been considered for water removal with a minimum energy consumption. Moreover, the application of pressurized mechanical dewatering may also play a role in formation of briquettes.Experiments on mechanical dewatering and thermal drying were carried out using 50 g sludge cake with initial water content 73%. With a pressure of 400 kg/cm2 for compression, water content at the end of mechanical dewatering was 57%. This dewatered slugde was subsequently treated using thermal drying to a moisture content of 15%. Calculated total energy for this combination of mechanical dewatering and thermal drying was about 1080 J/g. This value was lower than the energy consumption of 1520 J/g required for direct thermal drying from its moisture content of 73% down to 15%. Experiments on the use of coal powder as compression aid were also trial to improve sludge dewaterability and briquettes calorific value. Mechanical dewatering of slugde with addition of 20%-w/w coal powder resulting a briquette with moisture content of 38% at compression pressure of 400 kg/cm2. The drying curves of briquette did not affected with its size if its diameter was less than 0.5 cm. Briquette with 1 cm thickness took significantly more time to remove its water content.

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Initial Moisture Content of Corncobs Plays an Important Role in Maintaining its Quality during Storage

Jurnal Agritech ◽

10.22146/agritech.26663 ◽

2018 ◽

Vol 38 (2) ◽

pp. 167

Author(s):

Lince Mukkun ◽

Herianus J.D. Lalel ◽

Yuliana Tandirubak

Keyword(s):

Moisture Content ◽

Water Content ◽

Insect Pests ◽

Initial Moisture Content ◽

High Water ◽

High Water Content ◽

Initial Water Content ◽

Initial Water ◽

Plant Materials ◽

Randomized Design

Maize is one of the important staple foods for people in Timor, East Nusa Tenggara Province, Indonesia. Subsistent farmers store the maize for their own consumption until the next harvest season, for seed and feed. However, high initial water content of the kernel due to improper drying prior storage initiate serious damage and losses during the maize storage. High water content promotes the growth of fungi and insects, and increase respiration rate, resulting in rapid deterioration of maize. The purpose of this study was to determine the initial moisture content that might minimize damage and losses of maize in the farmers’ storage, and to study the effects of some plant materials that are used to smoke corns before storage. The experiment was initiated by sun-drying the harvested corncobs for 0, 2, 4, 6, 8, and 10 days (6 hours a day). This experiment was designed using Completely Randomized Design with 6 treatments and 3 replications. Dried corncobs were stored in the farmer’s storage for 4 months. The effects of maize kernels’ initial water content on the development of water content in kernels; the percentage of damaged kernels; and the species of pathogen and insects were investigated during storage with 2-week intervals. The results demonstrated that drying the corncobs prior storage for 10 days, resulting in 12.96% of water content, significantly decreased the percentage of seed damage to 6.5%, as compared to without drying process which resulted in 63%. Aspergillus flavus, Fusarium sp., and Penicillium sp were found to be the main pathogen during storage. There are no insect pests found during the storage.

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