Assessment of soil water repellency as a function of soil moisture with mixed modelling

2015 ◽  
Vol 66 (5) ◽  
pp. 910-920 ◽  
Author(s):  
O. Fishkis ◽  
M. Wachten ◽  
R. Hable
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Mixed Modelling

scholarly journals Spatially variable soil water repellency enhances soil respiration rates (CO<sub>2</sub> efflux)

2017 ◽  
Author(s):  
Emilia Urbanek ◽  
Stefan H. Doerr
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Water ◽  
Water Distribution ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Water Repellency

Abstract. Soil CO2 emissions are strongly dependent on water distribution in soil pores, which in turn can be affected by soil water repellency (SWR; hydrophobicity). SWR restricts infiltration and movement of water, affecting soil hydrology as well as biological and chemical processes. Effects of SWR on soil carbon dynamics and specifically on soil respiration (CO2 efflux) have been studied in a few laboratory experiments but they remain poorly understood. Existing studies suggest that soil respiration is reduced in water repellent soils, but the responses of soil CO2 efflux to varying water distribution created by SWR are not yet known. Here we report on the first field-based study that tests whether soil water repellency indeed reduces soil respiration, based on in situ field measurements carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. CO2 efflux was reduced on occasions when soil exhibited consistently high SWR and low soil moisture following long dry spells. However, the highest respiration rates occurred not when SWR was absent, but when SWR, and thus soil moisture, was spatially patchy, a pattern observed for the majority of the measurement period. This somewhat surprising phenomenon can be explained by SWR-induced preferential flow, directing water and nutrients to microorganisms decomposing organic matter concentrated in hot spots near preferential flow paths. Water repellent zones provide air-filled pathways through the soil, which facilitate soil-atmosphere O2 and CO2 exchanges. This study demonstrates that SWR have contrasting effects on CO2 fluxes and, when spatially-variable, can enhance CO2 efflux. Spatial variability in SWR and associated soil moisture distribution needs to be considered when evaluating the effects of SWR on soil carbon dynamics under current and predicted future climatic conditions.

Soil Water Repellency: A Method of Soil Moisture Sequestration in Pinyon-Juniper Woodland

2010 ◽  
Vol 74 (2) ◽  
pp. 624-634 ◽  
Author(s):  
David A. Robinson ◽  
Inma Lebron ◽  
Ronald J. Ryel ◽  
Scott B. Jones
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Juniper Woodland

Temporal fluctuations in soil water repellency following wildfire in chaparral steeplands, southern California

2005 ◽  
Vol 14 (4) ◽  
pp. 439 ◽  
Author(s):  
K. R. Hubbert ◽  
V. Oriol
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Repellency ◽  
Weather Conditions ◽  
Antecedent Rainfall ◽  
Soil Water Repellency ◽  
Soil Wetness ◽  
Moisture Conditions ◽  
East West ◽  
Seasonal Weather

Soil water repellency is particularly common in unburned chaparral, and its degree and duration can be influenced by seasonal weather conditions. Water repellency tends to increase in dry soils, while it decreases or vanishes following precipitation or extended periods of soil moisture. The 15 426 ha Williams Fire provided an opportunity to investigate post-fire fluctuations in water repellency over a 1-year period. Soil water repellency was measured at the surface, and at 2-cm and 4-cm depths along six east–west-positioned transects located within the chaparral-dominated San Dimas Experimental Forest. During the winter and spring, seasonal variation in the degree of surface water repellency appeared to be inversely proportional to antecedent rainfall and soil moisture conditions. Precipitation through December reduced the proportion of surface ‘moderate or higher repellency’ from 49 to 4% as soil wetness increased to 12%. Throughout the summer, soil wetness remained below 2%; however, surface soils remained ‘wettable’, with the proportion of surface ‘moderate or higher repellency’ never returning to the early post-fire amount of 47%. Interestingly, at the 4-cm depth, the proportion of ‘moderate or higher repellency’ remained at levels >25% throughout the summer dry season.

scholarly journals The Relationship between Soil Moisture and Soil Water Repellency Persistence in Hydrophobic Soils

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2322 ◽  
Author(s):  
Mohamed Bayad ◽  
Henry Wai Chau ◽  
Stephen Trolove ◽  
Jim Moir ◽  
Leo Condron ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Drop ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Sigmoidal Curve ◽  
New Equation ◽  
Two Parameters ◽  
The Relationship ◽  
Penetration Time

In this work, we modelled the response of soil water repellency (SWR) persistence to the decrease in moisture in drying soils, and we explored the implication of soil particle size distribution and specific surface area on the SWR severity and persistence. A new equation for the relationship between SWR persistence and soil moisture (θ) is described in this paper. The persistence of SWR was measured on ten different hydrophobic soils using water drop penetration time (WDPT) at decreasing levels of gravimetric water content. The actual repellency persistence showed a sigmoidal response to soil moisture decrease, where Ra(θ)=Rp/1+eδ(θ−θc). The suggested equation enables one to model the actual SWR persistence (Ra) using θ, the potential repellency (Rp) and two characteristic parameters related to the shape of the response curve. The two parameters are the critical soil moisture θc, where the Ra increase rate reaches its maximum, and the parameter δ affecting the steepness of the curve at the inflexion point of the sigmoidal curve. Data shows that both soil carbon and texture are controlling the potential SWR in New Zealand pastures.

Soil water repellency in sandy soil depends on the soil drying method, incubation temperature and specific surface area

Geoderma ◽  
2021 ◽  
Vol 402 ◽  
pp. 115264
Author(s):  
Enoch V.S. Wong ◽  
Philip R. Ward ◽  
Daniel V. Murphy ◽  
Matthias Leopold ◽  
Louise Barton
Keyword(s):  
Specific Surface ◽  
Soil Water ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sandy Soil ◽  
Incubation Temperature ◽  
Water Repellency ◽  
Soil Drying ◽  
Drying Method ◽  
Soil Water Repellency

The use of visible and near-infrared spectroscopy for the analysis of soil water repellency

2014 ◽  
Vol 65 (3) ◽  
pp. 360-368 ◽  
Author(s):  
I. Kim ◽  
R. R. Pullanagari ◽  
M. Deurer ◽  
R. Singh ◽  
K. Y. Huh ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Soil Water ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Water Repellency ◽  
Soil Water Repellency

Soil water repellency persistence after recurrent forest fires on Mount Carmel, Israel

2013 ◽  
Vol 22 (4) ◽  
pp. 515 ◽  
Author(s):  
Naama Tessler ◽  
Lea Wittenberg ◽  
Noam Greenbaum
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Forest Fires ◽  
Water Drop ◽  
Chemical Properties ◽  
Water Repellency ◽  
Mediterranean Ecosystem ◽  
Long Term Effects ◽  
Soil Water Repellency ◽  
Chemical Properties Of Soils

Variations in forest fires regime affect: (1) the natural patterns of community structure and vegetation; (2) the physico-chemical properties of soils and consequently (3) runoff, erosion and sediment yield. In recent decades the Mediterranean ecosystem of Mount Carmel, north-western Israel, is subjected to an increasing number of forest fires, thus, the objectives of the study were to evaluate the long-term effects of single and recurrent fires on soil water repellency (WR) and organic matter (OM) content. Water repellency was studied by applying water drop penetration time (WDPT) tests at sites burnt by single-fire, two fires, three fires and unburnt control sites. Water repellency in the burnt sites was significantly lower than in the unburnt control sites, and the soil maintained its wettability for more than 2 decades, whereas after recurrent fires, the rehabilitation was more complicated and protracted. The OM content was significantly lower after recurrent than after a single fire, causing a clear proportional decrease in WR. The rehabilitation of WR to natural values is highly dependent on restoration of organic matter and revegetation. Recurrent fires may cause a delay in recovery and reduced productivity of the soil for a long period.

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