Analysis of spatial variability of soil water retention using the cumulative distribution function matching

2020 ◽  
pp. 1-7
Author(s):  
Nizami Gummatov ◽  
Yakov A. Pachepsky
Keyword(s):  
Spatial Variability ◽  
Soil Water ◽  
Water Retention ◽  
Distribution Functions ◽  
Cumulative Distribution ◽  
Cumulative Probability ◽  
Soil Matric Potential ◽  
Soil Water Retention ◽  
Matric Potential ◽  
Water Contents

The importance of modeling dependencies of spatial variability of soil water content on soil matric potential grows due to the proliferation of ensemble modeling, data assimilations, and other soil water modeling applications. The objective of this work was to investigate conversions between cumulative distribution functions of water contents at different matric potentials. In total, 80 samples were taken in the nodes of the grid to measure soil water retention using sand and sand–kaolin capillarimeters at absolute values of soil matric potential of 0.001, 0.003, 0.010, 0.020, and 0.050 MPa, and with the water vapor desorption method at 3, 21, 39, 82, and 142 MPa. The probabilities of distributions of both non-transformed and log-transformed soil water contents being normal appeared to be larger than 0.05 in most cases. Using the probit function to represent the observed variability allowed us to match cumulative probability distributions at different soil water potentials. Slopes of dependencies of probits on non-transformed and log-transformed water contents had one-parametric linear dependencies on the logarithms of the absolute value of soil matric potential in capillary and adsorptive potential ranges.

scholarly journals The Influence of a Water Absorbing Geocomposite on Soil Water Retention and Soil Matric Potential

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1731 ◽  
Author(s):  
Michał Śpitalniak ◽  
Krzysztof Lejcuś ◽  
Jolanta Dąbrowska ◽  
Daniel Garlikowski ◽  
Adam Bogacz
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Water Retention ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Soil Matric Potential ◽  
Soil Water Retention ◽  
Matric Potential ◽  
Control Samples

Climate change induces droughts that are becoming more intensive and more frequent than ever before. Most of the available forecast tools predict a further significant increase in the risk of drought, which indicates the need to prepare solutions to mitigate its effects. Growing water scarcity is now one of the world’s leading challenges. In agriculture and environmental engineering, in order to increase soil water retention, soil additives are used. In this study, the influence of a newly developed water absorbing geocomposite (WAG) on soil water retention and soil matric potential was analyzed. WAG is a special element made from geotextile which is wrapped around a synthetic skeleton with a superabsorbent polymer placed inside. To describe WAG’s influence on soil water retention and soil matric potential, coarse sand, loamy sand, and sandy loam soils were used. WAG in the form of a mat was used in the study as a treatment. Three kinds of samples were prepared for every soil type. Control samples and samples with WAG treatment placed at depths of 10 cm and 20 cm were examined in a test container of 105 × 70 × 50 cm dimensions. The samples had been watered and drained, and afterwards, the soil surface was heated by lamps of 1100 W total power constantly for 72 h. Soil matric potential was measured by Irrometer field tensiometers at three depths. Soil moisture content was recorded at six depths: of 5, 9, 15, 19, 25, and 30 cm under the top of the soil surface with time-domain reflectometry (TDR) measurement devices. The values of soil moisture content and soil matric potential were collected in one-minute steps, and analyzed in 24-h-long time steps: 24, 48, and 72 h. The samples with the WAG treatment lost more water than the control samples. Similarly, lower soil matric potential was noted in the samples with the WAG than in the control samples. However, after taking into account the water retained in the WAG, it appeared that the samples with the WAG had more water easily available for plants than the control samples. It was found that the mechanism of a capillary barrier affected higher water loss from soil layers above those where the WAG had been placed. The obtained results of water loss depend on the soil type used in the profile.

scholarly journals Pedotransfer functions related to spatial variability of water retention attributes for lowland soils

2010 ◽  
Vol 34 (3) ◽  
pp. 669-680 ◽  
Author(s):  
Álvaro Luiz Carvalho Nebel ◽  
Luís Carlos Timm ◽  
Wim Cornelis ◽  
Donald Gabriels ◽  
Klaus Reichardt ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Soil Water ◽  
Water Retention ◽  
Pedotransfer Functions ◽  
Predictive Values ◽  
Soil Variables ◽  
Mean And Variance ◽  
Different Characteristics ◽  
Water Contents ◽  
Soil Water Contents

The estimation of non available soil variables through the knowledge of other related measured variables can be achieved through pedotransfer functions (PTF) mainly saving time and reducing cost. Great differences among soils, however, can yield non desirable results when applying this method. This study discusses the application of developed PTFs by several authors using a variety of soils of different characteristics, to evaluate soil water contents of two Brazilian lowland soils. Comparisons are made between PTF evaluated data and field measured data, using statistical and geostatistical tools, like mean error, root mean square error, semivariogram, cross-validation, and regression coefficient. The eight tested PTFs to evaluate gravimetric soil water contents (Ug) at the tensions of 33 kPa and 1,500 kPa presented a tendency to overestimate Ug 33 kPa and underestimate Ug1,500 kPa. The PTFs were ranked according to their performance and also with respect to their potential in describing the structure of the spatial variability of the set of measured values. Although none of the PTFs have changed the distribution pattern of the data, all resulted in mean and variance statistically different from those observed for all measured values. The PTFs that presented the best predictive values of Ug33 kPa and Ug1,500 kPa were not the same that had the best performance to reproduce the structure of spatial variability of these variables.

scholarly journals Measurement systems of soil water matric potential and evaluation of soil moisture under different irrigation depths

2012 ◽  
Vol 32 (3) ◽  
pp. 467-478 ◽  
Author(s):  
José M. G. Beraldo ◽  
José E. Cora ◽  
Edemo J. Fernandes
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Retention Curve ◽  
Soil Matric Potential ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Matric Potential ◽  
Measurement Systems ◽  
Neutron Attenuation ◽  
New Methodologies

The development of new methodologies and tools that enable to determine the water content in soil is of fundamental importance to the practice of irrigation. The objective of this study was to evaluate soil matric potential using mercury tensiometer and puncture digital tensiometer, and to compare the gravimetric soil moisture values obtained by tensiometric system with gravimetric soil moisture obtained by neutron attenuation technique. Four experimental plots were maintained with different soil moisture by irrigation. Three repetitions of each type of tensiometer were installed at 0.20 m depth. Based on the soil matric potential and the soil water retention curve, the corresponding gravimetric soil moisture was determined. The data was then compared to those obtained by neutron attenuation technique. The results showed that both tensiometric methods showed no difference under soil matric potential higher than -40 kPa. However, under drier soil, when the water was replaced by irrigation, the soil matric potential of the puncture digital tensiometer was less than those of the mercury tensiometer.

SPATIAL VARIABILITY OF SOIL WATER RETENTION FUNCTIONS IN A SILT LOAM SOIL

Soil Science ◽  
1995 ◽  
Vol 159 (1) ◽  
pp. 1-12 ◽  
Author(s):  
P. J. SHOUSE ◽  
W. B. RUSSELL ◽  
D. S. BURDEN ◽  
H. M. SELIM ◽  
J. B. SISSON ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Soil Water ◽  
Water Retention ◽  
Silt Loam ◽  
Soil Water Retention ◽  
Silt Loam Soil ◽  
Loam Soil

Influence of active aluminium oxides on water movement in soils

Soil Research ◽  
1969 ◽  
Vol 7 (3) ◽  
pp. 325 ◽  
Author(s):  
CK Tweneboah ◽  
JW Kijne ◽  
DJ Greenland
Keyword(s):  
Sodium Chloride ◽  
Soil Water ◽  
Water Retention ◽  
Water Movement ◽  
Soil Water Retention ◽  
Water Diffusivity ◽  
The Stability ◽  
Soil Pores ◽  
Water Contents ◽  
Soil Water Contents

Active aluminium oxides were removed from several soils by treatment with 0.5M calcium chloride or lM sodium chloride at pH 1.5. Soil-water retention and soil-water diffusivity were determined and contrasted with the values for these properties obtained after treatment with neutral salts. The changes resulting from the removal of aluminium oxides were relatively small in calcium saturated systems, but in sodium saturated systems soil-water diffusivity was drastically reduced by the prior removal of aluminium oxides. The results are discussed in terms of the influence of aluminium oxides on the stability of soil pores at different soil-water contents.

Assessing Soil Water Retention Characteristics and Their Spatial Variability Using Pedotransfer Functions

Pedosphere ◽  
2011 ◽  
Vol 21 (4) ◽  
pp. 413-422 ◽  
Author(s):  
Kai-Hua LIAO ◽  
Shao-Hui XU ◽  
Ji-Chun WU ◽  
Shu-Hua JI ◽  
Qing LIN
Keyword(s):  
Spatial Variability ◽  
Soil Water ◽  
Water Retention ◽  
Pedotransfer Functions ◽  
Soil Water Retention ◽  
Retention Characteristics

scholarly journals Topography and spatial variability of soil physical properties

2009 ◽  
Vol 66 (3) ◽  
pp. 338-352 ◽  
Author(s):  
Marcos Bacis Ceddia ◽  
Sidney Rosa Vieira ◽  
André Luis Oliveira Villela ◽  
Lenilson dos Santos Mota ◽  
Lúcia Helena Cunha dos Anjos ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Physical Properties ◽  
Bulk Density ◽  
Soil Water ◽  
Water Retention ◽  
Particle Density ◽  
Soil Physical Properties ◽  
Soil Water Retention ◽  
Soil Attributes ◽  
Physical Attributes

Among the soil formation factors, relief is one of the most used in soil mapping, because of its strong correlation with the spatial variability of soil attributes over a landscape. In this study the relationship between topography and the spatial variability of some soil physical properties was evaluated. The study site, a pasture with 2.84 ha, is located near Seropédica, Rio de Janeiro State, Brazil, where a regular square grid with 20 m spacing was laid out and georreferenced. In each sampling point, altitude was measured and undisturbed soil samples were collected, at 0.0-0.1, 0.1-0.2, and 0.2-0.3 m depths. Organic carbon content, soil texture, bulk density, particle density, and soil water retention at 10 (Field Capacity), 80 (limit of tensiometer reading) and 1500 kPa (Permanent Wilting Point) were determined. Descriptive statistics was used to evaluate central tendency and dispersion parameters of the data. Semivariograms and cross semivariograms were calculated to evaluate the spatial variability of elevation and soil physical attributes, as well as, the relation between elevation and soil physical attributes. Except for silt fraction content (at the three depths), bulk density (at 0.2-0.3 m) and particle density (at 0.0-0.1 m depth), all soil attributes showed a strong spatial dependence. Areas with higher elevation presented higher values of clay content, as well as soil water retention at 10, 80 and 1500 kPa. The correlation between altitude and soil physical attributes decreased as soil depth increased. The cross semivariograms demonstrated the viability in using altitude as an auxiliary variable to improve the interpolation of sand and clay contents at the depth of 0.0-0.3 m, and of water retention at 10, 80 and 1500 kPa at the depth of 0.0-0.2 m.

Multifractal analysis of soil hydraulic properties in arid areas

Soil Research ◽  
2016 ◽  
Vol 54 (8) ◽  
pp. 914 ◽  
Author(s):  
N. Pahlevan ◽  
M. R. Yazdani ◽  
A. A. Zolfaghari ◽  
M. Ghodrati
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Soil Water ◽  
Multifractal Analysis ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Scaling Analysis ◽  
Soil Hydraulic Properties ◽  
Soil Water Retention ◽  
Soil Hydraulic

Physical and hydraulic properties of soil are variable at different spatial scales. This indicates the necessity of understanding spatial patterns of soil properties. Scaling analysis, such as multifractal analysis, has been used to determine the spatial variability of soil properties. There are however limited numbers of studies concerning the applications of multifractal techniques applied to characterise spatial variability of soil properties in arid lands. The objective of this study was to quantify the scaling patterns of soil properties measured across a transect and to apply multifractal analysis in arid land areas. A transect with a length of 4.80km was selected, and soil properties were measured at 0–20cm depth every 145m along the transect. The soil properties analysed were: texture (sand, silt, clay), pH, electrical conductivity (EC), bulk density (BD), soil hydraulic properties (saturated hydraulic conductivity Ks and the van Genuchten soil water-retention equation’s parameters nv and αv), saturated water content (θs), and the slope of the soil water-retention curve at its inflection point (S). Results showed that the variability of pH and BD was characterised by quasi-monofractal behaviour. Results showed that soil hydraulic properties such as Ks, αn, nv, S, and θs were characterised by higher multifractal indices in the transects. EC showed the highest tendency to a multifractal type of scaling or the higher degree of multifractality.

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