The influence of stoniness and canopy properties on soil water content distribution: simulation of water movement in forest stony soil

The Tempe cell, modified by others to determine saturated hydraulic conductivity (K), was further modified to restrain swelling of the soil and to facilitate air and water movement across the top and bottom of the sample. An apparatus was developed whereby K and water content (θ) could be determined for several soil samples concurrently and suction levels could be varied without disturbing the sample. K and θ were determined for several prepared soil samples by the constant head permeameter method and by the Tempe cell with and without swelling restrained, and for soil cores by the Tempe cell with swelling restrained. With swelling restrained, the K results from the prepared samples did not differ significantly from those of the core samples. For the sandy to silty loam soils at suction levels 0, 10, and 20 kPa, θ of the core sample was less than that from the other samples, whereas for the clay loam soils, θ of the core sample was less than that from the others at suction levels of 0 and 10 kPa. For all methods, θ was correlated to clay content of the soil. These results indicate that the Tempe cell, as finally modified with swelling restraints, can be used to determine K and θ for characterizing the drainability of a nonstructured to weakly structured soil, using either prepared samples or cores. Key words: Hydraulic conductivity, pore volume, soil water content, Tempe cell

Download Full-text

Using the sensitivity of biomass production to soil water for physiological drought evaluation

Soil and Water Research ◽

10.17221/1411-swr ◽

2008 ◽

Vol 3 (Special Issue No. 1) ◽

pp. S116-S122 ◽

Cited By ~ 1

Author(s):

V. Novák

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Biomass Production ◽

Transpiration Rate ◽

Water Movement ◽

Root Zone ◽

Vegetation Period ◽

Plant Production ◽

Potential Transpiration

The analysis of drought as a phenomenon and the proposal of how to define and quantify the deficiency of water in soil for plants, so called physiological drought, are described. The presented approach is based on the theoretical considerations supported by empirically estimated relationships between the biomass production of a particular plant and the transpiration total of this plant during its vegetation period. This relationship is linear and is valid for particular plant and environmental conditions (nutrition, agrotechnics). Optimal plant production can be reached for maximum seasonal transpiration total, therefore the potential transpiration total corresponds to the maximum possible yield. The transpiration rate lower than the potential one leads to a biomass production decrease. This phenomenon can be used to define the physiological drought, under which the soil water content in the root zone decreases below the so called critical soil water content of limited availability for plants, under which the transpiration rate drops below its potential transpiration rate. Methodology is illustrated on the basis of the results of mathematical modelling of soil water movement in Soil – Plant – Atmosphere system, with loamy soil and maize canopy.

Download Full-text

Multiscale Influences of Soil Properties on Soil Water Content Distribution in a Watershed on the Chinese Loess Plateau

Soil Science ◽

10.1097/ss.0000000000000021 ◽

2013 ◽

Vol 178 (10) ◽

pp. 530-539 ◽

Cited By ~ 14

Author(s):

Dongli She ◽

Dongdong Liu ◽

Shizhang Peng ◽

Ming’an Shao

Keyword(s):

Soil Properties ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Loess Plateau ◽

Content Distribution ◽

Chinese Loess Plateau ◽

Chinese Loess ◽

The Chinese Loess Plateau

Download Full-text

Factors influencing salt and water movement near crystalline salts in relatively dry soil

Soil Research ◽

10.1071/sr9740077 ◽

1974 ◽

Vol 12 (2) ◽

pp. 77 ◽

Cited By ~ 3

Author(s):

DR Scotter

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Soil Texture ◽

Water Movement ◽

Factors Influencing ◽

Initial Soil ◽

Crystalline Salt ◽

Water Accumulation ◽

Dry Soil

Crystalline salts were placed at one end of sealed tubes of initially uniformly wet soil. The effect of soil texture, the initial soil water content, temperature, and the particular salt used on the resulting water and salt distributions in the soil was studied. In all experiments using relatively dry soil a zone of water accumulation adjacent to the salt, and a zone of water depletion further away from the salt, developed. Dissolved salt moved into the wetter zone next to the salt. The rate at which salt dissolved and moved out into the soil was found to depend very strongly on the solubility and saturated solution vapour pressure of the salt used, and the initial soil water content. Soil temperature and texture were less important factors. In some experiments quite large amounts of water accumulated in the crystalline salt, apparently when adequate contact was not maintained between the salt and the soil as the salt dissolved.

Download Full-text

COMPARISON OF TWO SOIL-WATER MODELS UNDER SEMI-ARID GROWING CONDITIONS

Canadian Journal of Soil Science ◽

10.4141/cjss88-002 ◽

1988 ◽

Vol 68 (1) ◽

pp. 17-27 ◽

Cited By ~ 6

Author(s):

R. DE JONG

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Distribution ◽

Water Movement ◽

Arid Zone ◽

Absolute Difference ◽

Long Term Experiment ◽

Growing Conditions ◽

Semi Arid

The Versatile Soil Moisture Budget (VSMB) and the Soil-Plant-Air-Water (SPAW) model were compared and tested against soil-water content data from a long-term experiment in which wheat was grown on fallow land in the semi-arid zone of Saskatchewan. Both models were driven by daily air temperatures and precipitation data. At the expense of requiring more detailed soil and crop information, the SPAW model simulated the water balance and its components in greater detail than the VSMB. Predictions of soil-water contents throughout the growing season with either model corresponded very well with the measured data. The overall mean absolute difference in total soil-water content to a depth of 120 cm was 1.5 cm for the VSMB and 1.2 cm for the SPAW model. Predictions of water distribution in the profile were also satisfactory. A choice between the two models, to be used under semi-arid growing conditions, will depend on the availability of input data and the required level of output. Key words: Soil-water movement, modelling, evapotranspiration

Download Full-text

A bench-scale assessment of the effect of soil temperature on bare soil evaporation in winter

Hydrology Research ◽

10.2166/nh.2020.044 ◽

2020 ◽

Vol 51 (6) ◽

pp. 1349-1357

Author(s):

Peigui Liu ◽

Yan Xia ◽

Manting Shang

Keyword(s):

Soil Temperature ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Water Movement ◽

Bare Soil ◽

Soil Evaporation ◽

Factors Affecting ◽

Bare Soil Evaporation ◽

Soil Water Movement

Abstract To quantitatively evaluate in the laboratory the effect of soil temperature on bare soil evaporation, this study uses two indoor soil columns and homogenized sand as an example to carry out the experimental study of soil temperature on bare soil evaporation in winter. The results show that the soil temperature directly affects the change in bare soil evaporation and that the effect decreases as the soil temperature decreases. Because of the influence of soil temperature, the soil water movement accelerates, and the soil water content increases. At a depth of 50 cm, the average difference in soil water content between groups A and B was 7.61%. The soil evaporation when considering the soil temperature was obviously greater than that without considering the soil temperature. This shows that in a laboratory environment where the soil temperature is higher than the room temperature in winter, the effect of the soil temperature on bare soil evaporation is significant. Soil temperature directly affects soil water movement and distribution, which is one of the important influencing factors affecting bare soil evaporation.

Download Full-text

Effect of Stoniness on the Hydraulic Properties of a Soil from an Evaporation Experiment Using the Wind and Inverse Estimation Methods

Water ◽

10.3390/w11030440 ◽

2019 ◽

Vol 11 (3) ◽

pp. 440

Author(s):

Nerea Arias ◽

Iñigo Virto ◽

Alberto Enrique ◽

Paloma Bescansa ◽

Riley Walton ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Hydraulic Properties ◽

Estimation Methods ◽

Fine Earth ◽

Rock Fragments ◽

Stony Soil ◽

Inverse Estimation

Stony soils are distributed all over the world. The study of their characteristics has gained importance lately due to their increasing use as agricultural soils. The effect that rock fragments exert on the soil hydraulic properties is difficult to measure in situ, and is usually derived from the fine earth properties. However, the corrections used so far do not seem accurate for all types of stony soils. Our objective was to assess the adequacy of estimating the hydraulic properties of a stony soil from the fine earth ones by correcting the latter by the volume occupied by rock fragments. To do that, we first assessed the validity of different approaches for estimating the hydraulic properties of a stone-free and a stony (40% rock fragments) cylinder prepared with samples from the same silt loam soil. The functions relating to the soil hydraulic properties (θ-h, K-h-θ) were estimated by the Wind method and by inverse estimation, using data from an evaporation experiment where the soil water content and pressure head were measured at different soil depths over time. Results from the evaporation experiment were compared to those obtained by applying the equation that corrects fine earth properties by the rock fragments volume. Wind and the Inverse Estimation methods were successfully applied to estimate soil water content and hydraulic conductivity from the stony soil experiment, except for some uncertainties caused by the limited range of suction in which the experiment was conducted. The application of an equation for adjusting the soil water content at different pressure heads (allowing for defining the soil water retention curve, SWRC), and the unsaturated hydraulic conductivity (K) directly from the stone content was not satisfactory. K values obtained from the measured data were higher than those inferred by the correcting equation in the wet range, but decreased much faster with a decreasing pressure head. The use of this equation did therefore not take into account the effect that the creation of lacunar pores by the presence of rock fragments likely exerts on water flow processes. The use of such correction needs therefore to be revised and new approaches are needed for estimating the hydraulic conductivity in stony soils. In relation to SWRC, a new equation to calculate the water content of a stony soil accounting for the influence of possible lacunar pores is proposed.

Download Full-text

Application of Electrical Resistivity Imaging for MeasuringWater Content Distribution on Hillslopes

Journal of Disaster Research ◽

10.20965/jdr.2013.p0081 ◽

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.

Download Full-text