Untitled

et al. 2019

Remote Sensing

The spectral features of soils are a comprehensive representation of their physicochemical parameters, surface states, and internal structures. To date, spectral measurements have been mostly performed for powdered soils and smooth aggregate soils, but rarely for cracked soils; a common state of soda-saline soils. In this study, we measured the spectral features of 57 saline soil samples in powdered, aggregate, and cracked states for comparison. We then explored in depth the factors governing soil spectral features to build up simple and multiple linear regression models between the spectral features and physicochemical parameters (salt content, Na+, pH, and electronic conductivity (EC)) of saline soils in different states. We randomly selected 40 samples to construct the models, and used the remaining 17 samples for validation. Our results indicated that the regression models worked more effectively in predicting physicochemical parameters for cracked soils than for other soils. Subsequently, the crack ratio (CR) was introduced into the regression models to modify the spectra of soils in powdered and aggregate states. The accuracy of prediction was improved, evidenced by a 2–11% decrease in the parameters mean absolute error (MAE).

Section: Discussionmentioning

confidence: 99%

Correlation between Spectral Characteristics and Physicochemical Parameters of Soda-Saline Soils in Different States

Ren

et al. 2019

Remote Sensing

“…The formed water films dispersed the cementation and increased the spacing of soil particles，which reduced the tensile strength and the shear strength between soil colloidal particles (Zhang et al, 2008). Furthermore, the lubrication of salt solution also decreased the shear strength among soil particles (Aksenov et al, 2003;Jeong et al, 2012). Table 3 indicates Na + is highly correlated to the crack characteristics; this is because Na + is the main component of combined water films between soil particles, in addition, Na + has a very large hydrolytic radius and the content of Na + is far greater than the other cations in the soil solution.…”

Section: Discussionmentioning

confidence: 99%

Quantitative analysis of relationships between crack characteristics and properties of soda-saline soils in Songnen Plain, China

Ren

2015

Chin. Geogr. Sci.

The Songnen Plain has a typical soda-saline soil, which often shrinks and cracks under natural conditions during water evaporation. This study aims to analyze the relationships between the crack characteristics and the soil properties of soda-saline soils quantitatively, and attempts to establish prediction models for the main soil properties of soda-saline soils based on the results. In order to achieve these objectives, a desiccation cracking test was conducted using 17 soil specimens with different salinity levels under controlled laboratory conditions. Correlation analysis was then performed between the crack characteristics and the soil properties. The results indicate that the crack characteristics can well represent the surface appearances of cracked soils, they also can well distinguish the salinity levels of soda-saline soils while the clay contents and mineralogical compositions of soils are stable. Among the crack characteristics, crack length has the best relationships with the salinity levels of soda-saline soils. Specifically, the crack length has high correlation (R 2 > 0.87) with the electrical conductivity (EC), Na + , CO 3 2and the salinity, it also has reasonable relationship (R 2 > 0.68) with HCO 3 -, this indicates crack length can be well used for the prediction of these properties of soda-saline soils.

“…This kind of water film always in turn reduces the cohesion between soil particles and then results in a decrease in the soil strength [ 55 ]. Aksenov et al [ 56 ] also found that the combined water film generated among soil particles could reduce the internal friction angle and shear strength of salinized soil samples, thus making the surface of saline–alkali soils more prone to shrinkage and cracking. Moreover, many studies have indicated that the diffuse double layer (DDL) also plays an important role in determining the shrinking and cracking processes of saline soils during water evaporation [ 57 , 58 ].…”

Section: Discussionmentioning

confidence: 99%

Quantitative Response of Gray-Level Co-Occurrence Matrix Texture Features to the Salinity of Cracked Soda Saline–Alkali Soil

Zhang

Zhu

et al. 2022

IJERPH

Desiccation cracking during water evaporation is a common phenomenon in soda saline–alkali soils and is mainly determined by soil salinity. Therefore, quantitative measurement of the surface cracking status of soda saline–alkali soils is highly significant in different applications. Texture features can help to determine the mechanical properties of soda saline–alkali soils, thus improving the understanding of the mechanism of desiccation cracking in saline–alkali soils. This study aims to provide a new standard describing the surface cracking conditions of soda saline–alkali soil on the basis of gray-level co-occurrence matrix (GLCM) texture analysis and to quantitatively study the responses of GLCM texture features to soil salinity. To achieve this, images of 200 field soil samples with different surface cracks were processed and calculated for GLCMs under different parameters, including directions, gray levels, and step sizes. Subsequently, correlation analysis was then conducted between texture features and electrical conductivity (EC) values. The results indicated that direction had little effect on the GLCM texture features, and that four selected texture features, contrast (CON), angular second moment (ASM), entropy (ENT), and homogeneity (HOM), were the most correlated with EC under a gray level of 2 and step size of 1 pixel. The results also showed that logarithmic models can be used to accurately describe the relationships between EC values and GLCM texture features of soda saline–alkali soils in the Songnen Plain of China, with calibration R2 ranging from 0.88 to 0.92, and RMSE from 2.12 × 10−4 to 9.68 × 10−3, respectively. This study can therefore enhance the understanding of desiccation cracking of salt-affected soil to a certain extent and can also help to improve the detection accuracy of soil salinity.