Effect of soil water repellency on soil hydraulic properties estimated under dynamic conditions

2013 ◽  
Vol 486 ◽  
pp. 175-186 ◽  
Author(s):  
E. Diamantopoulos ◽  
W. Durner ◽  
A. Reszkowska ◽  
J. Bachmann
Keyword(s):  
Soil Water ◽  
Hydraulic Properties ◽  
Water Repellency ◽  
Soil Hydraulic Properties ◽  
Soil Water Repellency ◽  
Dynamic Conditions ◽  
Soil Hydraulic

scholarly journals Inverse estimation of soil hydraulic properties and water repellency following artificially induced drought stress

2018 ◽  
Vol 66 (2) ◽  
pp. 170-180 ◽  
Author(s):  
Vilim Filipović ◽  
Thomas Weninger ◽  
Lana Filipović ◽  
Andreas Schwen ◽  
Keith L. Bristow ◽  
...  
Keyword(s):  
Soil Water ◽  
Inverse Modeling ◽  
Hydraulic Properties ◽  
Global Climate ◽  
Water Repellency ◽  
Irrigation Event ◽  
Water Infiltration ◽  
Soil Hydraulic Properties ◽  
Soil Water Repellency ◽  
Soil Hydraulic

AbstractGlobal climate change is projected to continue and result in prolonged and more intense droughts, which can increase soil water repellency (SWR). To be able to estimate the consequences of SWR on vadose zone hydrology, it is important to determine soil hydraulic properties (SHP). Sequential modeling using HYDRUS (2D/3D) was performed on an experimental field site with artificially imposed drought scenarios (moderately M and severely S stressed) and a control plot. First, inverse modeling was performed for SHP estimation based on water and ethanol infiltration experimental data, followed by model validation on one selected irrigation event. Finally, hillslope modeling was performed to assess water balance for 2014. Results suggest that prolonged dry periods can increase soil water repellency. Inverse modeling was successfully performed for infiltrating liquids, water and ethanol, withR2and model efficiency (E) values both > 0.9. SHP derived from the ethanol measurements showed large differences in van Genuchten-Mualem (VGM) parameters for the M and S plots compared to water infiltration experiments. SWR resulted in large saturated hydraulic conductivity (Ks) decrease on the M and S scenarios. After validation of SHP on water content measurements during a selected irrigation event, one year simulations (2014) showed that water repellency increases surface runoff in non-structured soils at hillslopes.

Root effects on soil water and hydraulic properties

Biologia ◽  
2007 ◽  
Vol 62 (5) ◽  
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.

Resistance to water uptake by irrigated potatoes on a duplex soil

Soil Research ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 487 ◽  
Author(s):  
MA Rab ◽  
KA Olsson ◽  
ST Willatt
Keyword(s):  
Root System ◽  
Soil Water ◽  
Plant Resistance ◽  
Root Length ◽  
Hydraulic Properties ◽  
Potato Crop ◽  
Soil Resistance ◽  
Soil Hydraulic Properties ◽  
Matric Potential ◽  
Soil Hydraulic

Resistances to water flow were analysed for the soil-root system of a potato crop growing on a duplex soil-where soil hydraulic properties varied with depth-under two irrigation regimes: 'wet' (irrigated weekly) and 'dry' (irrigated twice only during the growing season). The relative magnitudes of the soil and plant resistances controlling root water uptake were evaluated over depth and time using field-measured soil hydraulic properties and root length densities in successive soil layers. Resistance to water flow in the root system is likely to be the dominant resistance in the liquid phase, although soil resistance increased more rapidly than plant resistance with decreasing soil-water matric potential and root length density. Soil resistance reached similar values to plant resistance only when the soil-water matric potential was in the range -900 kPa to -1500 kPa (corresponding soil hydraulic conductivities of 10-7 and 10-8 m day-1 respectively), depending on the root length beneath unit ground area in the soil layer, La. Poor utilization of water from depth of this soil was attributed to resistance in the root system (possibly radial) associated with low La. Practical considerations for improved water management of the potato crop on clay soils are discussed.

From soil degradation to restoration via soil microorganisms

2020 ◽  
Author(s):  
Oksana Coban ◽  
Gerlinde de Deyn ◽  
Martine van der Ploeg
Keyword(s):  
Soil Water ◽  
Soil Degradation ◽  
Hydraulic Properties ◽  
Anthropogenic Factors ◽  
Soil Hydrology ◽  
Soil Physics ◽  
Soil Hydraulic Properties ◽  
Water Conductivity ◽  
Soil Hydraulic ◽  
Water Holding

<p>Soil, the living skin of the Earth, provides ecosystem services critical for life: soil acts as a water filter and a growing medium, offers habitat for billions of organisms, and supplies most of the antibiotics. In places, it may take a hundred years to form one cm of soil, but it can be degraded only in a few years or less by a number of natural and anthropogenic factors, including climate change. Presently, one third of all land is degraded to some extent, and fertile soil is lost every year. Droughts are becoming more common, also in humid climates, and the combination of erratic weather patterns with an increased pressure on land by human activities leads to soil degradation. Soil degradation results in a loss of fertile topsoil, thereby altering the soil hydrology completely. As the consequences, soil water holding capacity decreases, hydrophobicity increases, and more runoff is observed, that leads to further soil degradation. Thus, soil hydrology is the key for a healthy functioning topsoil/soil ecosystem. We are in urgent need for novel solutions for improving soil hydraulic properties that will lead to restoration of degraded soils.</p><p>In this study we investigate a possibility of restoring degraded soil using microorganisms. The hypothesis is that microorganisms can improve soil hydraulic properties such as infiltration and water retention, and reduce hydrophobicity that will facilitate further ecosystem restoration. Such strategy is based on combining the research fields of microbiology and soil physics that to date have hardly been combined. To test this hypothesis, we have inoculated sandy soil with a bacterium Bacillus mycoides and then measured its hydraulic properties using evaporation and pressure plate methods. We have also made efforts of standardizing this methodology by testing incubation time and inoculum concentrations on the hydraulic properties of the soil. Evaluation of an effect of bacteria addition on the soil water holding capacities and unsaturated water conductivity have been conducted as a comparison between inoculated soil and uninoculated (control). Results of this ongoing study will be presented here.</p>

Does water repellency of pyrochars and hydrochars counter their positive effects on soil hydraulic properties?

Geoderma ◽  
2015 ◽  
Vol 245-246 ◽  
pp. 31-39 ◽  
Author(s):  
Nina Eibisch ◽  
Wolfgang Durner ◽  
Michel Bechtold ◽  
Roland Fuß ◽  
Robert Mikutta ◽  
...  
Keyword(s):  
Hydraulic Properties ◽  
Water Repellency ◽  
Soil Hydraulic Properties ◽  
Positive Effects ◽  
Soil Hydraulic
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