Transmission of vertical stress in a real soil profile. Part III: Effect of soil water content

2011 ◽  
Vol 114 (2) ◽  
pp. 78-85 ◽  
Author(s):  
Mathieu Lamandé ◽  
Per Schjønning
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Vertical Stress

scholarly journals Monitoring water content changes in a soil profile with TDR-probes at just three depths - How well does it work?

RBRH ◽  
2020 ◽  
Vol 25 ◽  
Author(s):  
Jens Hagenau ◽  
Vander Kaufmann ◽  
Heinz Borg
Keyword(s):  
Time Delay ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
High Precision ◽  
Soil Profile ◽  
Reliable Data ◽  
Short Term ◽  
True Values ◽  
Daily Changes

ABSTRACT TDR-probes are widely used to monitor water content changes in a soil profile (ΔW). Frequently, probes are placed at just three depths. This raises the question how well such a setup can trace the true ΔW. To answer it we used a 2 m deep high precision weighing lysimeter in which TDR-probes are installed horizontally at 20, 60 and 120 cm depth (one per depth). ΔW-data collected by weighing the lysimeter vessel were taken as the true values to which ΔW-data determined with the TDR-probes were compared. We obtained the following results: There is a time delay in the response of the TDR-probes to precipitation, evaporation, transpiration or drainage, because a wetting or drying front must first reach them. Also, the TDR-data are more or less point measurements which are then extrapolated to a larger soil volume. This frequently leads to errors. For these reasons TDR-probes at just three depths cannot provide reliable data on short term (e.g. daily) changes in soil water content due to the above processes. For longer periods (e.g. a week) the data are better, but still not accurate enough for serious scientific studies.

Modelling leaching and recharge in a bare transitional red-brown earth ponded with low salinity water in summer

1994 ◽  
Vol 34 (7) ◽  
pp. 1085 ◽  
Author(s):  
L Cai ◽  
SA Prathapar ◽  
HG Beecher
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Soil Surface ◽  
Saturated Hydraulic Conductivity ◽  
Rate Dependent ◽  
Water And Salt Movement ◽  
Winter Fallow

A modelling study was conducted to evaluate water and salt movement within a transitional red-brown earth with saline B horizon soil when such waters are used for ponding in summer. The model was calibrated using previously published experimental data. The calibrated model was used to evaluate the effect of depth to watertable, saturated hydraulic conductivity, and ponding water salinity on infiltration, water and salt movement within the soil profile, and recharge. The study showed that when initial soil water content and the saturated hydraulic conductivity (Ks) are low, infiltrating water will be stored within the soil profile even in the absence of a shallow watertable. Once the soil water content is high, however, recharge will be significant in winter, even if there is no net infiltration at the soil surface. Infiltration rates depend more on Ks than the depth to watertable if it is at, or below, 1.5 m from the soil surface. When Ks is high, recharge under ponding will be higher than that under winter fallow. Subsequent ponding in summer and fallow in winter tend to leach salts from the soil profile, the leaching rate dependent on Ks. During winter fallow, due to net evaporation, salts tend to move upwards and concentrate near the soil surface. In the presence of shallow watertables, leached salts tend to concentrate at, or near, the watertable.

The impact of ski slopes management on Krvavec ski resort (Slovenia) on hydrological functions of soils

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Marina Pintar ◽  
Bostjan Mali ◽  
Hojka Kraigher
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Ski Resort ◽  
Ski Resorts ◽  
Upper Timberline ◽  
Profile Characteristics ◽  
Summer Time ◽  
The Impact

AbstractThe study was performed on the ski resort Krvavec, which is one of the most frequented ski resorts in Slovenia. The ski slopes serve as pastures for cattle during summer time and range from 1500 to 2000 m a.s.l., which is at or above the upper timberline. To offer a longer ski season and to profit snow better (either natural or artificial one) the slopes have been levelled and consequently the soil profile has been changed. Such altered soil profile characteristics strongly impact hydrological functions of soils.To study these impacts, five plots (20 × 20 m) have been chosen on the slopes with a different history: pasture without any amelioration work, a patch of forest in the ski resort without any ameliorations, and three plots with different intensity of amelioration.Dynamics of soil water content on each plot has been determined by measuring soil water content in-situ with portable TDR system during several days after long lasting heavy rains. Statistically significant differences were shown in soil water content between the plots after the rain, although some differences between plots have disappeared in the following days.

scholarly journals Impacts of grass removal on wetting and actual water repellency in a sandy soil

2017 ◽  
Vol 65 (1) ◽  
pp. 88-98 ◽  
Author(s):  
Klaas Oostindie ◽  
Louis W. Dekker ◽  
Jan G. Wesseling ◽  
Violette Geissen ◽  
Coen J. Ritsema
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Water Repellency ◽  
Bare Soil ◽  
Soil Profiles ◽  
The Impact ◽  
Water Contents ◽  
Soil Water Contents

Abstract Soil water content and actual water repellency were assessed for soil profiles at two sites in a bare and grasscovered plot of a sand pasture, to investigate the impact of the grass removal on both properties. The soil of the plots was sampled six times in vertical transects to a depth of 33 cm between 23 May and 7 October 2002. On each sampling date the soil water contents were measured and the persistence of actual water repellency was determined of field-moist samples. Considerably higher soil water contents were found in the bare versus the grass-covered plots. These alterations are caused by differences between evaporation and transpiration rates across the plots. Noteworthy are the often excessive differences in soil water content at depths of 10 to 30 cm between the bare and grass-covered plots. These differences are a consequence of water uptake by the roots in the grass-covered plots. The water storage in the upper 19 cm of the bare soil was at least two times greater than in the grass-covered soil during dry periods. A major part of the soil profile in the grass-covered plots exhibited extreme water repellency to a depth of 19 cm on all sampling dates, while the soil profile of the bare plots was completely wettable on eight of the twelve sampling dates. Significant differences in persistence of actual water repellency were found between the grass-covered and bare plots.

scholarly journals Changes to soil water content and biomass yield under combined maize and maize-weed vegetation with different fertilization treatments in loam soil

2016 ◽  
Vol 64 (2) ◽  
pp. 150-159 ◽  
Author(s):  
Éva Lehoczky ◽  
Mariann Kamuti ◽  
Nikolett Mazsu ◽  
Renáta Sándor
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Field Experiments ◽  
Developmental Stages ◽  
Early Stage ◽  
Crop Growth ◽  
Long Term Study ◽  
Loam Soil

AbstractEspecially during early developmental stages, competition with weeds can reduce crop growth and have a serious effect on productivity. Here, the effects of interactions between soil water content (SWC), nutrient availability, and competition from weeds on early stage crop growth were investigated, to better understand this problem. Field experiments were conducted in 2013 and 2014 using long-term study plots on loam soil in Hungary. Plots of maize (Zea maysL.) and a weed-maize combination were exposed to five fertilization treatments. SWC was observed along the 0–80 cm depth soil profile and harvested aboveground biomass (HAB) was measured.Significant differences were found between SWC in maize and maize-weed plots. In all treatments, measured SWC was most variable in soil depths of up to 50 cm, and at the 8–10 leaves (BBCH19) growth stage of the crop. The greatest depletion of SWC was detected within PK treatments across the entire soil profile and under both vegetation types, with depletion also considerable under NPK and NP treatments. Biomass growth was significantly influenced by weeds in treated plots between the BBCH 13 and 19 phenological stages, but water availability did not hamper growth rates in non-fertilized conditions. These findings suggest that, at early stages of crop growth, SWC model simulations need to include better characterisation of depth- and structure-dependent soil water uptake by vegetation.

scholarly journals Optimizing the Positioning of Soil Moisture Monitoring Sensors in Winter Wheat Fields

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1707
Author(s):  
Xiaojun Shen ◽  
Jing Liang ◽  
Ketema Zeleke ◽  
Yueping Liang ◽  
Guangshuai Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Winter Wheat ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Root Distribution ◽  
Soil Surface ◽  
Soil Moisture Sensors ◽  
Total Average

Collecting accurate real-time soil moisture data in crop root zones is the foundation of automated precision irrigation systems. Soil moisture sensors (SMSs) have been used to monitor soil water content (SWC) in crop fields for a long time; however, there is no generally accepted guideline for determining optimal number and placement of soil moisture sensors in the soil profile. In order to study adequate positioning for the installation of soil moisture sensors in the soil profile, six years of field experiments were carried out in North China Plain (NCP). Soil water content was measured using the gravimetric method every 7 to 10 days during six growing seasons of winter wheat (Triticum aestivum L), and root distribution was measured using a soil core method during the key periods of winter wheat growth. The results from the experimental data analysis show that SWC at different depths had a high linear correlation. In addition, the values of correlation coefficients decreased with increasing soil depth; the coefficient of variation (CV) of SWC was higher in the surface layers than in the deeper layers (depths were 0–40 cm, 0–60 cm, and 0–100 cm during the early, middle, and last stages of winter wheat, respectively); wheat roots were mainly distributed in the surface layer. According to an analysis of CV for SWC and root distribution, the depths of planned wetted layers were determined to be 0–40 cm, 0–60 cm, and 0–100 cm during the sowing to reviving stages (the early stage of winter wheat), returning green and jointing stages (the middle stage of winter wheat), and heading to maturity stage (the last stage of winter wheat), respectively. The correlation and R-cluster analyses of SWC at different layers in the soil profile showed that SMSs should be installed 10 and 30 cm below the soil surface during the winter wheat growing season. The linear regression model can be built using SWC at depths of 10 and 30 cm to predict total average SWC in the soil profile. The results of validation showed that the developed model provided reliable estimates of total average SWC in the planned wetted layer. In brief, this study suggests that suitable positioning of soil moisture sensors is at depths of 10 and 30 cm below the soil surface.

Effect of variability in soil properties plus model complexity on predicting topsoil water content and nitrous oxide emissions

Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 810 ◽  
Author(s):  
Iris Vogeler ◽  
Rogerio Cichota
Keyword(s):  
Nitrous Oxide ◽  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Nitrous Oxide Emissions ◽  
Soil Types ◽  
N2o Emissions ◽  
Silt Loam

Despite the importance of soil physical properties on water infiltration and redistribution, little is known about the effect of variability in soil properties and its consequent effect on contaminant loss pathways. To investigate the effects of uncertainty and heterogeneity in measured soil physical parameters on the simulated movement of water and the prediction of nitrous oxide (N2O) emissions, we set up the Agricultural Production Systems sIMulator (APSIM) for different soil types in three different regions of New Zealand: the Te Kowhai silt loam and the Horotiu silt loam in the Waikato region, and the Templeton silt loam in the Canterbury region, and the Otokia silt loam and the Wingatui silt loam in the Otago region. For each of the soil types, various measured soil profile descriptions, as well as those from a national soils database (S-map) were used when available. In addition, three different soil water models in APSIM with different complexities (SWIM2, SWIM3, and SoilWat) were evaluated. Model outputs were compared with temporal soil water content measurements within the top 75mm at the various experimental sites. Results show that the profile description, as well as the soil water model used affected the prediction accuracy of soil water content. The smallest difference between soil profile descriptions was found for the Templeton soil series, where the model efficiency (NSE) was positive for all soil profile descriptions, and the RMSE ranged from 0.055 to 0.069m3/m3. The greatest difference was found for the Te Kowhai soil, where only one of the descriptions showed a positive NSE, and the other two profile descriptions overestimated measured topsoil water contents. Furthermore, it was shown that the soil profile description highly affects N2O emissions from urinary N deposited during animal grazing. However, the relative difference between the emissions was not always related to the accuracy of the measured soil water content, with soil organic carbon content also affecting emissions.

scholarly journals Variations in Soil Water Content, Infiltration and Potential Recharge at Three Sites in a Mediterranean Mountainous Region of Baja California, Mexico

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1844 ◽  
Author(s):  
Francisco Del Toro-Guerrero ◽  
Enrique Vivoni ◽  
Thomas Kretzschmar ◽  
Stephen Bullock Runquist ◽  
Rogelio Vázquez-González
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Baja California ◽  
Soil Depth ◽  
Critical Role ◽  
Soil Conditions ◽  
Wet Season ◽  
Potential Recharge

In this research, we examined temporal variations in soil water content (θ), infiltration patterns, and potential recharge at three sites with different mountain block positions in a semiarid Mediterranean climate in Baja California, Mexico: two located on opposing aspects (south- (SFS) and north-facing slopes (NFS)) and one located in a flat valley. At each site, we measured daily θ between 0.1 and 1 m depths from May 2014 to September 2016 in four hydrological seasons: wet season (winter), dry season (summer) and two transition seasons. The temporal evolution of θ and soil water storage (SWS) shows a strong variability that is associated mainly with high precipitation (P) pulses and soil profile depth at hillslope sites. Results shows that during high-intensity P events sites with opposing aspects reveal an increase of θ at the soil–bedrock interface suggesting lateral subsurface fluxes, while vertical soil infiltration decreases noticeably, signifying the production of surface runoff. We found that the dry soil conditions are reset annually at hillslope sites, and water is not available until the next wet season. Potential recharge occurred only in the winter season with P events greater than 50 mm/month at the SFS site and greater than 120 mm/month at the NFS site, indicating that soil depth and lack of vegetation cover play a critical role in the transport water towards the soil–bedrock interface. We also calculate that, on average, around 9.5% (~34.5 mm) of the accumulated precipitation may contribute to the recharge of the aquifer at the hillslope sites. Information about θ in a mountain block is essential for describing the dynamics and movement of water into the thin soil profile and its relation to potential groundwater recharge.

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