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Pedotransfer functions (PTFs) based on the van Genuchten–Mualem (VGM) model have shown great value in the widespread application of water flow and solute transport models at the field and larger scales. We reviewed the state of the art with respect to using the VGM model to describe hydraulic properties and to develop PTFs.

Vadose Zone Journal November 01, 2010, Vol.9, 795-820. doi:https://doi.org/10.2136/vzj2010.0045

This paper introduces the special section on Patterns in Soil–Vegetation–Atmosphere Systems: Monitoring, Modeling, and Data Assimilation. It briefly presents three key topics: (i) the development measurement techniques, (ii) the development and improvement of coupled numerical models, and (iii) the long-term monitoring of key state variables and fluxes.

Vadose Zone Journal November 01, 2010, Vol.9, 821-827. doi:https://doi.org/10.2136/vzj2010.0122

Nuclear magnetic resonance has become an increasingly important technique for characterization of porous materials, in particular for petroleum exploration. Such advanced techniques have been accepted as one of the most valuable logging services. This development, although originally for rocks, could be applicable to partially saturated formations such as the vadose zone.

Vadose Zone Journal November 01, 2010, Vol.9, 828-834. doi:https://doi.org/10.2136/vzj2009.0171

Flow processes in soils are generally too slow to be monitored directly by magnetic resonance flow velocity imaging. This study showed the convenience of Gd-diethylenetriaminepentaacetate as a conservative tracer in soil cores and validates the results with a numerical, three-dimensional, forward simulation. The method allows direct observation of different flow patterns such as matrix and preferential flow.

Vadose Zone Journal November 01, 2010, Vol.9, 835-845. doi:https://doi.org/10.2136/vzj2009.0177

To advance the fundamental understanding necessary to translate measured nuclear magnetic resonance (NMR) relaxometry data into pore-space properties, NMR signals were simulated at the microscale using a finite element analysis. Subjects studied were a pore-size- and frequency-dependent ratio of transverse and longitudinal relaxation times, coupling, and heterogeneity of surface relaxivity.

Vadose Zone Journal November 01, 2010, Vol.9, 846-857. doi:https://doi.org/10.2136/vzj2009.0161

The influence of pore structure and water salinity on the frequency-dependent electrical properties (i.e., the spectral induced polarization response) of simple water-saturated pore systems was studied by simulating the underlying ion transport processes, diffusion and migration, at the microscale.

Vadose Zone Journal November 01, 2010, Vol.9, 858-870. doi:https://doi.org/10.2136/vzj2009.0162

Spatiotemporal variability of apparent electrical conductivity measured in a clay soil with various soil management systems, is explained in terms of soil moisture, topography, and tillage patterns. Time-lapse images of apparent electrical conductivity show the field response to the interplay between rainfall, soil surface state, and soil profile properties.

Vadose Zone Journal November 01, 2010, Vol.9, 871-881. doi:https://doi.org/10.2136/vzj2009.0160

The capacitively coupled resistivity (CR) technique can outpace direct current (DC) methods in terms of measurement speed and data density but still lacks interpretation programs. We investigated the possibility of using established DC resistivity inversion programs on CR data to obtain more reliable subsurface resistivity models.

Vadose Zone Journal November 01, 2010, Vol.9, 882-892. doi:https://doi.org/10.2136/vzj2009.0164

Nuclear magnetic resonance (NMR) relaxometry is particularly suitable for the study of water dynamics in natural porous media like soils. Two-dimensional NMR transverse relaxation-relaxation exchange experiments were performed on water-saturated soil samples at low magnetic fields. Exchange of water molecules between the different pore classes could be observed.

Vadose Zone Journal November 01, 2010, Vol.9, 893-897. doi:https://doi.org/10.2136/vzj2009.0179

Evapotranspiration cover systems over hazardous mine waste should hold and evaporate all precipitation. Analysis of replicates of two cover designs showed heterogeneity in cover materials and hence water flow, which resulted in seepage into the hazardous material below, challenging the common assumption of hydrologic uniformity within covers.

Vadose Zone Journal November 01, 2010, Vol.9, 898-909. doi:https://doi.org/10.2136/vzj2009.0172

An 11-d field experiment was performed to estimate van Genuchten–Mualem hydraulic parameters from infrared (IR)-measured soil surface temperatures and water contents measured by time domain reflectometry (TDR). Either IR data or IR and TDR data were used for optimization. Uncertainties in the parameters estimated from both approaches were characterized with a global optimizer.

Vadose Zone Journal November 01, 2010, Vol.9, 910-924. doi:https://doi.org/10.2136/vzj2009.0176

For analyzing hydrological time series data we employ the technique recently developed called the Hilbert-Huang Transform (HHT). We provide a comparison of the Hilbert spectra with Fourier and wavelet spectra to demonstrate a better localization of the energy components which also exhibit strong seasonal components.

Vadose Zone Journal November 01, 2010, Vol.9, 925-942. doi:https://doi.org/10.2136/vzj2009.0163

Through a combination of eddy covariance measurements with a footprint model and potential and actual evapotranspiration calculations, the spatial variability of bare soil evaporation at the field scale was observed. Using soil water flow modeling, this variability was linked to variations in the depth of the water table from the soil surface in the sloping field plot.

Vadose Zone Journal November 01, 2010, Vol.9, 943-954. doi:https://doi.org/10.2136/vzj2009.0159

Hydrologic modeling at the catchment scale shows a strong scale dependency. The discharge dynamics and spatial patterns of soil moisture were studied using a fully coupled three-dimensional model. The impact of the spatial discretization on the water fluxes highlights the need for a more sophisticated description of the evapotranspiration process.

Vadose Zone Journal November 01, 2010, Vol.9, 955-969. doi:https://doi.org/10.2136/vzj2009.0166

Detailed geostatistical models of alluvial and fracture permeability and an integrated hydrologic model were used to demonstrate focused recharge and spatial correlation of land-energy fluxes in an arid mountain system

Vadose Zone Journal November 01, 2010, Vol.9, 970-983. doi:https://doi.org/10.2136/vzj2010.0014

Many data assimilation algorithms rely on linearized models. The questions arise whether the inherent assumptions are viable for land surface data assimilation and which model parameters have a large impact on latent heat fluxes. These questions were addressed using a linearized version of the Community Land Model.

Vadose Zone Journal November 01, 2010, Vol.9, 984-1001. doi:https://doi.org/10.2136/vzj2009.0190

Wireless sensor networks are an exciting new technology for near-real-time monitoring of soil water content (SWC). In this study, we developed the SoilNet technology and analysed six million SWC measurements from a 4-mo period to explore SWC variability at the headwater catchment scale.

Vadose Zone Journal November 01, 2010, Vol.9, 1002-1013. doi:https://doi.org/10.2136/vzj2009.0173

The relationship between the spatial variability of surface soil moisture and the mean surface moisture content is investigated at different scales (field to catchment scale) using in situ measurements and synthetic aperture radar retrievals. We show that the spatial variability strongly depends on scale as well as on soil moisture status.

Vadose Zone Journal November 01, 2010, Vol.9, 1014-1024. doi:https://doi.org/10.2136/vzj2009.0165

Independent measurements of grassland evapotranspiration (ET) are compared against the eddy covariance (EC) method and used for inferring how to best close the energy imbalance commonly encountered with this method. To force energy balance closure, and thereby correct EC estimates of ET, adjustment with the average energy balance ratio is recommended.

Vadose Zone Journal November 01, 2010, Vol.9, 1025-1033. doi:https://doi.org/10.2136/vzj2009.0158

Temperature measurements in the topsoil revealed an unexpected heat sink at 4 cm. We explored relevant explanations for this sink, the prime candidate being evaporation, yet water vapor diffusion is one order of magnitude too small to account for the heat sink. The findings have direct importance for satellite observations and soil distributed temperature sensing.

Vadose Zone Journal November 01, 2010, Vol.9, 1034-1045. doi:https://doi.org/10.2136/vzj2009.0174

Water repellency index measurements were conducted using the water/ethanol sorptivity ratio method and the molarity of ethanol droplet (MED) method on sand samples manifesting various degrees of water repellency. A significant linear regression model capable of predicting the water/ethanol sorptivity ratio, or repellency index, from more easily measured MED values was developed.

Vadose Zone Journal November 01, 2010, Vol.9, 1046-1051. doi:https://doi.org/10.2136/vzj2009.0119

We evaluated a modified version of the gas push–pull test for the quantification of microbial gas turnover in near-surface soil. The modified test allows higher gas recovery and was successfully applied to estimate in situ first-order rate coefficients of methane oxidation. Values agreed well with the literature and methane concentration profile estimates.

Vadose Zone Journal November 01, 2010, Vol.9, 1052-1062. doi:https://doi.org/10.2136/vzj2009.0192

An electromagnetic model was developed for frequency domain reflectometry (FDR) based on the characterization of the FDR probe by transfer functions and on the decoupling of the probe signals from the ground signals. Inverse modeling of the FDR waveforms permits accurate retrieval of the frequency-dependent soil electrical properties.

Vadose Zone Journal November 01, 2010, Vol.9, 1063-1072. doi:https://doi.org/10.2136/vzj2010.0004

Two 6.5-m-long soil profiles drained by subsurface tile were irrigated with dyed water. Dye staining revealed that the number of biopores taking part in water transport varied considerably. The findings suggest that the connectivity of biopores to fractures and the drain pipe has an important impact on the observed staining patterns at the site.

Vadose Zone Journal November 01, 2010, Vol.9, 1073-1079. doi:https://doi.org/10.2136/vzj2010.0013.

Soil hydraulic properties obtained by multistep-outflow and evaporation experiments were compared for two different soil types. Parametric functions and a free-form approach were used to get an optimal parameterization of the properties. Agreement was good, but the measurement ranges for reliable results were notably different.

Vadose Zone Journal November 01, 2010, Vol.9, 1080-1091. doi:https://doi.org/10.2136/vzj2010.0050

Tension ceramic lysimeters may bias the concentration of P in the sampled soil water. To give authenticity to the data being reported, a procedure to determine the efficiency of commercially available ceramic lysimeters to sample a leachate containing P was proposed.

Vadose Zone Journal November 01, 2010, Vol.9, 1092-1099. doi:https://doi.org/10.2136/vzj2010.0052
Vadose Zone Journal November 01, 2010, Vol.9, 1100-1101. doi:https://doi.org/10.2136/vzj2010.0072
Vadose Zone Journal November 01, 2010, Vol.9, 1102-1104. doi:https://doi.org/10.2136/vzj2010.0088

Book Reviews

Vadose Zone Journal November 01, 2010, Vol.9, 1105-1106. doi:https://doi.org/10.2136/vzj2010.0067br
Vadose Zone Journal November 01, 2010, Vol.9, 1107-1108. doi:https://doi.org/10.2136/vzj2010.0084br
Vadose Zone Journal November 01, 2010, Vol.9, 1109. doi:https://doi.org/10.2136/vzj2010.0097br
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