Estimating soil water fluxes from soil water records obtained using dielectric sensors

2007 ◽  
Vol 21 (20) ◽  
pp. 2785-2793 ◽  
Author(s):  
J. Fernández-Gálvez ◽  
A. Verhoef ◽  
E. Barahona
Keyword(s):  
Soil Water ◽  
Water Fluxes ◽  
Dielectric Sensors

Characterization of hydraulic properties in the upper vadose zone for two aquifers in Slovenia

2021 ◽  
Author(s):  
Vesna Zupanc ◽  
Matjaž Glavan ◽  
Miha Curk ◽  
Urša Pečan ◽  
Michael Stockinger ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Soil Water ◽  
Water Flow ◽  
Vadose Zone ◽  
Hydraulic Properties ◽  
Isotope Composition ◽  
Transport Processes ◽  
Precipitation Event ◽  
Water Fluxes ◽  
Flow And Transport

<p>Environmental tracers, present in the environment and provided by nature, provide integrative information about both water flow and transport. For studying water flow and solute transport, the hydrogen and oxygen isotopes are of special interest, as their ratios provide a tracer signal with every precipitation event and are seasonally distributed. In order to follow the seasonal distribution of stable isotopes in the soil water and use this information for identifying hydrological processes and hydraulic properties, soil was sampled three times in three profiles, two on Krško polje aquifer in SE Slovenia and one on Ljubljansko polje in central Slovenia. Isotope composition of soil water was measured with the water-vapor-equilibration method. Based on the isotope composition of soil water integrative information about water flow and transport processes with time and depth below ground were assessed. Porewater isotopes were in similar range as precipitation for all three profiles.  Variable isotope ratios in the upper 60 cm for the different sampling times indicated dynamic water fluxes in this upper part of the vadose zone. Results also showed more evaporation at one sampling location, Brege. The information from stable isotopes will be of importance for further analyzing the water fluxes in the vadose zone of the study sties. <br>This research was financed by the ARRS BIAT 20-21-32 and IAEA CRP 1.50.18 Multiple isotope fingerprints to identify sources and transport of agro-contaminants.  </p>

scholarly journals Dissolved organic carbon mobilized from organic horizons of mature and harvested black spruce plots in a mesic boreal region

2020 ◽  
Vol 17 (3) ◽  
pp. 581-595
Author(s):  
Keri L. Bowering ◽  
Kate A. Edwards ◽  
Karen Prestegaard ◽  
Xinbiao Zhu ◽  
Susan E. Ziegler
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Soil Temperature ◽  
Soil Water ◽  
Boreal Forests ◽  
Temporal Variations ◽  
Forest Harvesting ◽  
Water Fluxes ◽  
Wide Range ◽  
Doc Flux

Abstract. Boreal forests are subject to a wide range of temporally and spatially variable environmental conditions driven by season, climate, and disturbances such as forest harvesting and climate change. We captured dissolved organic carbon (DOC) from surface organic (O) horizons in a boreal forest hillslope using passive pan lysimeters in order to identify controls and hot moments of DOC mobilization from this key C source. We specifically addressed (1) how DOC fluxes from O horizons vary on a weekly to seasonal basis in forest and paired harvested plots and (2) how soil temperature, soil moisture, and water input relate to DOC flux trends in these plots over time. The total annual DOC flux from O horizons contain contributions from both vertical and lateral flow and was 30 % greater in the harvested plots than in the forest plots (54 g C m−2 vs. 38 g C m−2, respectively; p=0.008). This was despite smaller aboveground C inputs and smaller soil organic carbon stocks in the harvested plots but analogous to larger annual O horizon water fluxes measured in the harvested plots. Water input, measured as rain, throughfall, and/or snowmelt depending on season and plot type, was positively correlated to variations in O horizon water fluxes and DOC fluxes within the study year. Soil temperature was positively correlated to temporal variations of DOC concentration ([DOC]) of soil water and negatively correlated with water fluxes, but no relationship existed between soil temperature and DOC fluxes at the weekly to monthly scale. The relationship between water input to soil and DOC fluxes was seasonally dependent in both plot types. In summer, a water limitation on DOC flux existed where weekly periods of no flux alternated with periods of large fluxes at high DOC concentrations. This suggests that DOC fluxes were water-limited and that increased water fluxes over this period result in proportional increases in DOC fluxes. In contrast, a flushing of DOC from O horizons (observed as decreasing DOC concentrations) occurred during increasing water input and decreasing soil temperature in autumn, prior to snowpack development. Soils of both plot types remained snow-covered all winter, which protected soils from frost and limited percolation. The largest water input and soil water fluxes occurred during spring snowmelt but did not result in the largest fluxes of DOC, suggesting a production limitation on DOC fluxes over both the wet autumn and snowmelt periods. While future increases in annual precipitation could lead to increased DOC fluxes, the magnitude of this response will be dependent on the type and intra-annual distribution of this increased precipitation.

Response of maize biomass and soil water fluxes on elevated CO 2 and drought—From field experiments to process‐based simulations

2019 ◽  
Vol 25 (9) ◽  
pp. 2947-2957 ◽  
Author(s):  
Juliane Kellner ◽  
Tobias Houska ◽  
Remy Manderscheid ◽  
Hans‐Joachim Weigel ◽  
Lutz Breuer ◽  
...  
Keyword(s):  
Soil Water ◽  
Field Experiments ◽  
Water Fluxes

Estimating water fluxes in Douglas-fir plantations

1985 ◽  
Vol 15 (4) ◽  
pp. 701-707 ◽  
Author(s):  
Susan J. Riha ◽  
Gaylon S. Campbell
Keyword(s):  
Soil Water ◽  
Root Zone ◽  
Potential Evapotranspiration ◽  
Field Measurements ◽  
Douglas Fir ◽  
Root Uptake ◽  
Richards Equation ◽  
Water Fluxes ◽  
Air Temperatures ◽  
Dimensional Finite Element

A model was developed to estimate water fluxes in Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantations using daily measurements of precipitation and maximum and minimum air temperatures. Soil water flow was modeled using a one-dimensional finite element solution to the Richards equation, with precipitation and root uptake of water included as source and sink terms. Soil hydraulic properties varied as a function of depth. Root uptake of water was based on an analog water uptake model modified to include root resistance and cylindrical flow of water. Potential evapotranspiration was calculated assuming leaf and air temperature did not differ and assuming stomatal conductance was dependent on the vapor density deficit of the air. Model validity was tested by comparing predictions with field measurements of soil water content made in the summer of 1978 at two locations in western Washington. In general, the model predicted the observed drying of the soil. Aspects of the simulated water budget for these Douglas-fir stands considered most significant were (i) the use of soil-stored water for transpiration in the summer, (ii) the net flux of water into the root zone from deeper in the soil during the summer, (iii) the dependence of water reaching the soil in the summer on the intensity of rainfall, (iv) the large percentage of the total transpiration that occurred in spring and fall, and (v) the large amount of water moving out of the soil profile in the winter.

scholarly journals Processes of bedrock groundwater seepage and their effects on soil water fluxes in a foot slope area

2016 ◽  
Vol 535 ◽  
pp. 160-172 ◽  
Author(s):  
Naoya Masaoka ◽  
Ken’ichirou Kosugi ◽  
Yosuke Yamakawa ◽  
Daizo Tsutsumi
Keyword(s):  
Soil Water ◽  
Water Fluxes ◽  
Groundwater Seepage

Crop growth and soil water fluxes at erosion-affected arable sites: A model inter-comparison based on weighing-lysimeter observations

2020 ◽  
Author(s):  
Jannis Groh ◽  
Keyword(s):  
Soil Water ◽  
Crop Growth ◽  
Water Dynamics ◽  
Water Fluxes ◽  
Ecosystem Models ◽  
Phenological Stages ◽  
Soil System ◽  
Area Index ◽  
Individual Model ◽  
Crop Development

<p>Agro-ecosystem models have been developed to study effects of agricultural management on crop production, mostly from an agronomic point of view. Based on a biophysical process representation, their most prominent advantage is the coupled modelling of crop development and yield formation, as well as water and nutrients fluxes in the plant-soil system. Crop models have previously been calibrated based on experimental data with a focus on plant observations. Less attention has been given to soil water and solute dynamics despite the importance of plant nutrient availability and chemical leaching, particularly for arable soils often affected by erosion. The question was whether the description of soil processes and properties play an important role in the crop simulations.</p><p>The aim of this study was to compare the ability of agro-ecosystem models to predict crop development and water fluxes under changing environmental conditions. Observations on crop growth and soil water dynamics were obtained from four weighable lysimeter of the TERENO-SOILCan lysimeter network in the northeast of Germany (Dedelow). The intact soil monoliths are representative for the spatial soil variability of erosion-affected hummocky agricultural landscape. Twelve agro-ecosystem models (AgroC; DailyDayCent; Daisy; HERMES; MONICA; Theseus, Theseus-HydroGeoSphere; Theseus-Hydrus-1D; Expert-N coupled to CERES, GECROS, SPASS, and SUCROS) were tested. Crop development stages were used to calibrate the agro-ecosystem models. The model performance was tested against observed grain yield, aboveground biomass, leaf area index, actual evapotranspiration, drainage, and soil water content.</p><p>Model descriptions were highly diverse for both crop development and water fluxes. Crop growth and soil water fluxes were better predicted by the Multi Model Mean simulations than by any individual model. Results demonstrate that i) the hydraulic properties of erosion-affected soil profiles controlled the observed interactions between crop yield, plant development, and water fluxes, ii) data on phenological stages contained insufficient information content to calibrated agro-ecosystem models for soils affected by erosion, and iii) neither an individual model nor the Multi Model Mean could describe the observation on crop development and water dynamics, when using phenological stages only for model calibration. The results suggest that soil does matter in agro-ecosystem models and that weighable lysimeter can provide such soil related observation.</p>

scholarly journals Using StorAge Selection functions to quantify ecohydrological controls on the time-variant age of evapotranspiration, soil water, and recharge

2018 ◽  
Author(s):  
Aaron A. Smith ◽  
Doerthe Tetzlaff ◽  
Chris Soulsby
Keyword(s):  
Soil Moisture ◽  
Surface Water ◽  
Soil Water ◽  
Water Uptake ◽  
Root Water Uptake ◽  
Soil Evaporation ◽  
Root Uptake ◽  
Water Fluxes ◽  
Near Surface ◽  
Moisture Conditions

Abstract. Quantifying ecohydrological controls on soil water availability is essential to understand temporal variations in catchment storage. Soil water is subject to numerous time-variable fluxes (evaporation, root-uptake, and recharge), each with different water ages which in turn affect the age of water in storage. Here, we adapt StorAge Selection (SAS) function theory to investigate water flow in soils and identify soil evaporation and root-water uptake sources from depth. We use this to quantify the effects of soil-vegetation interactions on the inter-relationships between water fluxes, storage, and age. The novel modification of the SAS function framework is tested against empirical data from two contrasting soil-vegetation units in the Scottish Highlands; these are characterised by significant preferential flow, transporting younger water through the soil during high soil moisture conditions. Dominant young water fluxes, along with relatively low rainfall intensities, explain relatively stable soil water ages through time and with depth. Soil evaporation sources were more time-invariant with high preference for near-surface water, independent of soil moisture conditions, and resulting in soil evaporation water ages similar to near-surface soil waters (mean age: 50–65 days). Sources of root-water uptake were more variable: preferential near-surface water uptake occurred in wet conditions, with a deeper root-uptake source during dry soil conditions, which resulted in more variable water ages of transpiration (mean age: 56–79 days). The simple model structure provides a parsimonious means of constraining the water age of multiple fluxes from the upper part of the critical zone during time-varying conditions improving our understanding of vegetation influences on catchment scale water fluxes.

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