Soil properties classification

Fig. 4 Soil types classification adopted in the present study, based on soil information provided by CHE aggregated into 23 main classes, which soil properties are then assigned by comparison with similar soils of the SWAT database...

Soil classification has been oriented to soil properties in recent years, but still is tempered with concepts of soil genesis, with external associations, and with the use of the soil. The first systematic classification was by Dokuchaiev in Russia in 1882, Based upon field and laboratory characteristics, soils were grouped into three categories—normal soils of the dry-land vegetative zones and moors, transitional soils of washed or dry land sediments and abnormal soils. The system involved properties of the soil with external associations of climate and vegetation. Later, an associate (Sibirtsev) renamed the highest classes zonal intrazonal, and azonal. 

Soil samples were taken from the experimental field in which spinach is cultivated at the National Institute for Agro-environmental Sciences, Tsukuba, Japan. The top 10 cm of soil was collected from 15 points and then mixed, air-dried, and passed through a 2-mm sieve. For comparison, surface soil was also taken from the adjacent non-cultivated land. The soil classification based on the world reference base for soil resources is Andosols. Relevant soil properties are shown in Table 1. A distinctive feature of this soil is a high amount of organic matter and a higher capacity for phosphate adsorption due to the presence of non-crystalline minerals. 

Table II. Classification of Some Macro Soil Properties...

Polypedon. A group of pedons closely associated in the field and having similar soil properties. They are used to serve as the basic classification unit or soil individual. 

We will exemplify the result of lag-dependent transition probability by employing data on the variability of the contamination level as found at the Testfeld Siid. Figure 1.4 shows the observed frequencies of the contamination levels. As was seen for the variability of other soil properties (Fig. 1.2), the contamination level was also found to be highly variable in space. Classification of the contamination was based on the... 

Particle size analysis is the determination of the particle size distribution of a soil sample. It is one of the most important physical characteristics of soil since classification of soils is based on that and many geotechnical and geohydrological properties of soil are related to the particle size distribution. 

The values of these limits are used in various aspects. There is a close relationship between the limits and properties of a soil sueh as eompressibility, permeability and strength. Thus the Atterberg limits are not only used to identify the soil s classification, but it also allows for the use of empirieal correlations for some other engineering properties. Liquid limit test is to elassify soils and to find the plasticity index of soil because different soils have various plastie limits. The shrinkage limit is much less commonly used than the liquid and plastic limits. 

Identification and classification is usually taught at the very beginning of most Soil Mechanics courses, but it is believed that the subject becomes more relevant before the eyes of the students when they are faced with the real problem of estimating relevant soil properties on the basis of classification and a boring log, which is a common situation in practice. For this approach to be possible, it is essential that students... 

For SMI, Project 1 includes carrying out identification and characterisation laboratory tests on soil samples and deriving the main physical properties of, for example. Soils 1 and 2 (Figure 1). The calculations are done using spreadsheets and include relationships between soil properties, in order to students to become more familiarised with them. Those results are also used to classify the soil samples using three different systems (Unified Classification system, AASHTO and LCPC-SETRA). Students have to prepare spreadsheets which, besides the calculation of the main physical properties, include, for example, the implementation of the plasticity chart of the Unified Classification system for soils. 

Atterberg (liquid and plastic) limit tests on cohesive soils for classification and correlation studies. Significant insight relative to strength and compressibility properties can be inferred from the natural water content and Atterberg limit test results. 

The only measures of soil properties used in the NCEER method are geological classifications, fines content (the fraction passing the 200 sieve) and the Atterberg limits. In one version of this method, these geological classification parameters have been correlated to the soil behaviour type indicated by the CRT this allows direct use of the method based on CPT data alone. 

Based on their molecular properties as well as the properties of the solvent, each inorganic or organic contaminant exhibits an adsorption isotherm that corresponds to one of the isotherm classifications just described. Figure 5.1 illustrates these isotherms for different organic contaminants, adsorbed either from water or hexane solution on kaolinite, attapulgite, montmorillonite, and a red Mediterranean soil (Yaron et al. 1996). These isotherms may be used to deduce the adsorption mechanism. 

Illume, H.-R, and Leinweber, P. (2004). Plaggen soils Landscape history, properties, and classification. J. Plant Nutr. Soil Sci. 167,319-327. 

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