Volume No. 13 Issue No.: 03 Page No.: 202-213 January-March 2019

 

TAXONOMIC DISTANCE AS A TOOL FOR FINDING CO-RRELATION BETWEEN SOIL TAXONOMY AND WORLD REFERENCE BASE CLASSIFICATION SYSTEMS, IN CALCAREOUS, GYPSIF -EROUS AND SALINE SOILS

 

Ali Asghar Jafarzadeh*, Vida Montakhabi Kalajahi, Shahin Oustan and Farzin Shahbazi

Soil Science Department, Agriculture Faculty, University of Tabriz, Tabriz (IRAN)

 

Received on : December 29, 2017

 

ABSTRACT

 

Soils with carbonates, gypsum and salts more soluble than gypsum occurs in all continents and under climatic conditions and have distributed relatively more extensive in the arid and semi-arid regions. The nature and properties calcareous, gypsiferous and saline soils are also diverse such that they require specific approaches for their management to maintain their long-term productivity. Therefore, for any long-term solutions, it is necessary to understand the mode of origin of these salt-affected soils and to classify them. For their classification, finding correlation between ST and WRB is important to achieve a comprehensive and universal soil classification system. For this, 40 profiles of calcareous, gypsiferous and saline soils in 10 regions of East and West-Azerbaijan provinces in Iran were selected, described and sampled. In addition, physicochemical and semi-quantitative clay mineralogical analyses (in B-horizons) were carried out. Thereafter, soil classification was performed using ST and WRB systems, and Taxonomic distance between soil units, calculated by concept-based (using dominant identifiers) and centroid-based (using physicochemical characteristics) approaches, to obtain the similarities and differences or general relationships between suborders of Salids, Calcids, Gypsids, Xerolls, Aquolls, Xerepts, xerrerts, and Argids and reference soil groups (RSGs) of Solonchaks, Solonetzs, Calcisols, Gypsisols, Kastanozems, Gleysols, Vertisols, and Luvisols. The foundation of both methods was Mahalanobis distance, calculated by the R software. Remarkably, the concept and centroid-based results showed that Calcids were closest suborder to Kastanozem, Gleysols, Solonetzs and Vertisols RSGs rather than Calcisols, but the first closest group to Gypsids was Gypsisols. In addition, the both methods referred to the closest RSGs of Solonchaks and Solonetzs for Salids. It can be concluded that the expert based, the concept- and the centroid-based methods does not always give the same or predictable results.

 

Keywords : Correlation, Salt affected soils, Soil taxonomy, Taxonomic distance, World Reference Base

 

 

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