Tuesday, 11 July 2006
28-7

A Compendium of Data on Salt-Affected Soils of Russia: New Monograph and Maps.

Ye.I. Pankova, A.F. Novikova, G.I. Chernousenko, I.A. Yamnova, and Maria V. Gabchenko. Dokuchaev Soil Science Institute, Pyzhevskii per. 7, Moscow, Russia

In the monograph "Salt-Affected Soils of Russia" published in 2005, complete information about the diagnostics, geography and peculiar features of salt-affected soils in Russia is given. For the first time in the last 50 years the bulk of original and literature sources, including the cartographic and analytical data, was summarized and generalized with the aim at characterizing the salt-affected soils in different regions of Russia. The book consists of 3 parts. Part 1 describes the most important methods and criteria to estimate the soil salinity. In Russia the analysis of water extracts is predominantly employed to obtain the data about the total content of water soluble salts in the soil, whereas in the other countries the measurement is made on filtrates from a soil paste to determine the salt concentration in soil solutions. In the monograph, the soils are grouped according to their chemistry, salinity degree, the salt horizon thickness and the form of the salt profile. The total content of toxic salts, the ions ratio, soil-pH and the ratio between the total alkalinity and the sum of Ca and Mg are taken as indices and criteria for estimating the soil salinity. According to their chemistry, the soils are distinguished as saline with neutral (NaCl, Na2SO4, etc.) and alkali salts (Na2CO3, NaHCO3). Under consideration is also the character of alkalinity. Based upon the method elaborated by L.A. Vorobieva (the method of direct and inverse potentiometric titration) it has been experimentally established that calcareous ions (CO32- and HCO3-), anions of organic acids and borate-ions are responsible for the formation of alkalinity in soils of Russia. Part 2 provides the information on geography, properties and genesis of the salt-affected soils at regional level. The characteristics of soil salinity are given for economic regions of Russia, where the salt-affected soils are widely or locally spread. For every region, geographical position, natural conditions and the distribution of salt-affected soils are described. Analytical data and maps illustrate the characteristics of salt-affected soils in different regions. For every economic region, 3 maps and data on chemical composition of salts and other analyses are given; the three maps are as follows: (1) the soil map showing the percent of salt-affected soils in the soil cover; (2) the map of salt-affected soils with information about the depth of upper boundary of saline horizon and the percent of soils containing the salts within the upper one-meter layer of the soil profile; (3) the map of the chemical composition of salts in soils. The scale of the maps is 1:2 500 000. These maps are the fragments from the Map of Soil Salinity in Russia of 1: 2 500 000 scale, compiled by specialists of the department for genesis and amelioration of salt-affected soils at the V.V. Dokuchaev Soil Science Institute in 2003. This map has been digitized and it is provided with databases. The analysis of the data given in the chapter 2 allows us to summarize: 1. Salt-affected and solonetzic soils are expanded in agricultural areas of 42 (among 89) states of Russia, mainly concentrating in southern regions of the country within the semi-desert, dry steppe, and steppe zones and in the forest steppe zone to a lesser extent. In the northern regions they are locally distributed. 2. Salt-affected soils dominate in the south of European Russia and West Siberia. They occupy small areas in the soil cover of East Siberia and Far East. 3. In Russia the soils differ depending on the chemistry of salinization. Dominant are soils with sulfate salinity. The soils with chloride and sodium composition of salts occur to a lesser extent. 4. In Russia, the majority of salt-affected soils reveal the features of solonetzicity, however, not all the solonetzes and solonetzic soils can be referred to the category of alkali soils according to the salt composition. Vast areas are covered by solonetzic soils with neutral salts what is considered as a specific of these soils in Russia to be a distinctive feature from alkali soils in the other regions of Eurasia (Szabolcs, 1989). Part 3 is devoted to some general questions regarding the salt-affected soils in the country. There is a short review of existing small-scale and schematic maps. The literature data are summarized to show the areas covered by salt-affected soils in the land fund of the country. Under discussion are some problems relating to genesis and geography of salt-affected soils. The areas occupied by salt-affected soils have been first calculated for several economic regions and the country on the whole, including those subdivided into different genetic types and subtypes. We hope that this monograph will be used as a basis for further studies of salt-affected soils in Russia and in the world. The publication of the monograph was supported by the Russian Foundation for Basic Research, project nos. 04-04-62015, 04-04-48197 and 01-04-48093.

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