Revealing the relative influence of soil and topographic properties on soil water content distribution at the watershed scale in two sites

2014 ◽  
Vol 516 ◽  
pp. 107-118 ◽  
Author(s):  
Wei Hu ◽  
Bing Cheng Si
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Content Distribution ◽  
Relative Influence ◽  
Watershed Scale

scholarly journals Estimating spatially distributed soil water content at small watershed scales based on decomposition of temporal anomaly and time stability analysis

2016 ◽  
Vol 20 (1) ◽  
pp. 571-587 ◽  
Author(s):  
W. Hu ◽  
B. C. Si
Keyword(s):  
Stability Analysis ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Spatial Patterns ◽  
Watershed Scale ◽  
Small Watershed ◽  
Time Stability ◽  
Spatially Distributed ◽  
Space Variant

Abstract. Soil water content (SWC) is crucial to rainfall-runoff response at the watershed scale. A model was used to decompose the spatiotemporal SWC into a time-stable pattern (i.e., temporal mean), a space-invariant temporal anomaly, and a space-variant temporal anomaly. The space-variant temporal anomaly was further decomposed using the empirical orthogonal function (EOF) for estimating spatially distributed SWC. This model was compared to a previous model that decomposes the spatiotemporal SWC into a spatial mean and a spatial anomaly, with the latter being further decomposed using the EOF. These two models are termed the temporal anomaly (TA) model and spatial anomaly (SA) model, respectively. We aimed to test the hypothesis that underlying (i.e., time-invariant) spatial patterns exist in the space-variant temporal anomaly at the small watershed scale, and to examine the advantages of the TA model over the SA model in terms of the estimation of spatially distributed SWC. For this purpose, a data set of near surface (0–0.2 m) and root zone (0–1.0 m) SWC, at a small watershed scale in the Canadian Prairies, was analyzed. Results showed that underlying spatial patterns exist in the space-variant temporal anomaly because of the permanent controls of static factors such as depth to the CaCO3 layer and organic carbon content. Combined with time stability analysis, the TA model improved the estimation of spatially distributed SWC over the SA model, especially for dry conditions. Further application of these two models demonstrated that the TA model outperformed the SA model at a hillslope in the Chinese Loess Plateau, but the performance of these two models in the GENCAI network (∼  250 km2) in Italy was equivalent. The TA model can be used to construct a high-resolution distribution of SWC at small watershed scales from coarse-resolution remotely sensed SWC products.

scholarly journals Overstory–Understory Vegetation Cover and Soil Water Content Observations in Western Juniper Woodlands: A Paired Watershed Study in Central Oregon, USA

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 151 ◽  
Author(s):  
Grace Ray ◽  
Carlos G. Ochoa ◽  
Tim Deboodt ◽  
Ricardo Mata-Gonzalez
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Canopy Cover ◽  
Understory Vegetation ◽  
Watershed Scale ◽  
Shrub Cover ◽  
Western Juniper ◽  
Tree Canopy Cover

The effects of western juniper (Juniperus occidentalis) control on understory vegetation and soil water content were studied at the watershed-scale. Seasonal differences in topsoil (12 cm) water content, as affected by vegetation structure and soil texture, were evaluated in a 96-ha untreated watershed and in a 116-ha watershed where 90% juniper was removed in 2005. A watershed-scale characterization of vegetation canopy cover and soil texture was completed to determine some of the potential driving factors influencing topsoil water content fluctuations throughout dry and wet seasons for approximately one year (2014–2015). We found greater perennial grass, annual grass, and shrub cover in the treated watershed. Forb cover was no different between watersheds, and as expected, tree canopy cover was greater in the untreated watershed. Results also show that on average, topsoil water content was 1% to 3% greater in the treated watershed. The exception was during one of the wettest months (March) evaluated, when soil water content in the untreated watershed exceeded that of the treated by <2%. It was noted that soil water content levels that accumulated in areas near valley bottoms and streams were greater in the treated watershed than in the untreated toward the end of the study in late spring. This is consistent with results obtained from a more recent study where we documented an increase in subsurface flow residence time in the treated watershed. Overall, even though average soil water content differences between watersheds were not starkly different, the fact that more herbaceous vegetation and shrub cover were found in the treated watershed led us to conclude that the long-term effects of juniper removal on soil water content redistribution throughout the landscape may be beneficial towards restoring important ecohydrologic connections in these semiarid ecosystems of central Oregon.

Watershed scale temporal stability of soil water content

Geoderma ◽  
2010 ◽  
Vol 158 (3-4) ◽  
pp. 181-198 ◽  
Author(s):  
Wei Hu ◽  
Mingan Shao ◽  
Fengpeng Han ◽  
Klaus Reichardt ◽  
Jing Tan
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Temporal Stability ◽  
Watershed Scale

scholarly journals Estimating spatially distributed soil water content at small watershed scales based on decomposition of temporal anomaly and time stability analysis

2015 ◽  
Vol 12 (7) ◽  
pp. 6467-6503 ◽  
Author(s):  
W. Hu ◽  
B. C. Si
Keyword(s):  
Stability Analysis ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Spatial Patterns ◽  
Watershed Scale ◽  
Small Watershed ◽  
Time Stability ◽  
Spatially Distributed ◽  
Space Variant

Abstract. Soil water content (SWC) at watershed scales is crucial to rainfall–runoff response. A model was used to decompose spatiotemporal SWC into time-stable pattern (i.e., temporal mean), space-invariant temporal anomaly, and space-variant temporal anomaly. This model was compared with a previous model that decomposes spatiotemporal SWC into spatial mean and spatial anomaly. The space-variant temporal anomaly or spatial anomaly was further decomposed using the empirical orthogonal function for estimating spatially distributed SWC. These two models are termed temporal anomaly (TA) model and spatial anomaly (SA) model, respectively. We aimed to test the hypothesis that underlying (i.e., time-invariant) spatial patterns exist in the space-variant temporal anomaly at the small watershed scale, and to examine the advantages of the TA model over the SA model in terms of estimation of spatially distributed SWC. For this purpose, a SWC dataset of near surface (0–0.2 m) and root zone (0–1.0 m) from a small watershed scale in the Canadian prairies was analyzed. Results showed that underlying spatial patterns exist in the space-variant temporal anomaly because of the permanent controls of "static" factors such as depth to the CaCO3 layer and organic carbon content. Combined with time stability analysis, the TA model improved estimation of spatially distributed SWC over the SA model because the latter failed to capture the space-variant temporal anomaly which accounted for non-negligible amounts of spatial variance in SWC. The outperformance was greater when SWC deviated from intermediate conditions, especially for dry conditions. Therefore, the TA model has potential to construct a spatially distributed SWC at watershed scales from remote sensed SWC.

scholarly journals Application of Electrical Resistivity Imaging for MeasuringWater Content Distribution on Hillslopes

2013 ◽  
Vol 8 (1) ◽  
pp. 81-89
Author(s):  
Yosuke Yamakawa ◽  
◽  
Naoya Masaoka ◽  
Ken’ichirou Kosugi ◽  
Yasuyuki Tada ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Content Distribution ◽  
Electrical Resistivity Imaging ◽  
Resistivity Imaging ◽  
Weathered Granite ◽  
Invasive Method ◽  
Water Catchment

Electrical resistivity imaging (ERI) as a method for effectively evaluating soil water content distribution on natural hillslopes was validated by combining ERI technique with the invasive measurement of volumetric water content (θ) using a combined penetrometermoisture probe (CPMP) on a hillslope in a head-water catchment underlain by weathered granite porphyry. There was a reasonable correlation (R2= 0.54) between θ and electrical resistivity (ρ). The correlation between (θ and ρ measured on two natural hillslopes in a head-water catchment underlain by weathered granite in our previous studies was also analyzed, and there was some reasonable correlation (R2= 0.33 to 0.53) between θ and ρ within each slope, indicating the potential of ERI for quantitatively evaluating moisture conditions within soil layers of natural hillslopes based on field-scale calibrations with invasive methods. These θ-ρ datasets were roughly consistent with a common fitted functionalmodel (Archie’s equation) (R2= 0.37), indicating the possibility of quantitatively evaluating θ of soil layer on natural hillslopes using ERI without directly measuring θ using any invasive method, although results still showed the importance of combining invasive methods with ERI and obtaining sitespecified θ-ρ correlation models for providing a more accurate spatial distribution of θ within the soil mantle. Inconsistencies between θ and ρ within datasets may be significantly attributable to not only limitations on spatial resolution of ERI technique related to the issue of representative volumes of the technique and inversion analysis to obtain ρ profiles but also the assumption that soil properties and pore-water resistivity of the entire slope are homogeneous. Using a CPMP as invasive method, detecting heterogeneous θ distribution more accurately than ERI technique, together with ERI is one of the most reasonable ways of effectively quantifying soil water content distribution on natural hillslopes.

SOIL WATER CONTENT AFFECTS THE AVAILABILITY OF PHOSPHATE

1985 ◽  
pp. 185-189
Author(s):  
M.C.H.Mouat Pieter Nes
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Solution ◽  
Equivalent Reduction

Reduction in water content of a soil increased the concentration of ammonium and nitrate in solution, but had no effect on the concentration of phosphate. The corresponding reduction in the quantity of phosphate in solution caused an equivalent reduction in the response of ryegrass to applied phosphate. Keywords: soil solution, soil water content, phosphate, ryegrass, nutrition.

Effect of inter-row cultivation on soil carbon dioxide emission in a peach plantation

2010 ◽  
Vol 59 (1) ◽  
pp. 157-164 ◽  
Author(s):  
E. Tóth ◽  
Cs. Farkas
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Carbon Dioxide Emission ◽  
Nutrient Content ◽  
Soil Disturbance ◽  
Biological Properties ◽  
Soil Tillage ◽  
Favourable Effect ◽  
Volumetric Soil Water Content

Soil biological properties and CO2emission were compared in undisturbed grass and regularly disked rows of a peach plantation. Higher nutrient content and biological activity were found in the undisturbed, grass-covered rows. Significantly higher CO2fluxes were measured in this treatment at almost all the measurement times, in all the soil water content ranges, except the one in which the volumetric soil water content was higher than 45%. The obtained results indicated that in addition to the favourable effect of soil tillage on soil aeration, regular soil disturbance reduces soil microbial activity and soil CO2emission.

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