The publication of this Handbook was supported by the Russian Federation

Konyushkova and I.A.Yamnova (Russia)
1.1. Definitions 
The group of  salt-affected soils includes soils containing soluble salts or their ions in at least one 
of  their horizons in quantities that are above the threshold of  toxicity – the maximal permissible 
concentration of  salts that does not suppress plant growth [10].
According  to  the  USDA  Agriculture  Handbook  [20],  salt-affected  soils  are  characterized  by  a 
specific  electrical  conductivity  (EC)  of   saturated  soil-paste  extracts  above  4  mSm/cm  (t=25˚). 
More recently [4] soils became considered salt-affected starting at a lower EC level of  2 mSm/ sm, 
as several fruit, vegetable and ornamental crops suffer from salinity within the EC interval of  2 to 
4 mSm/cm.
Classifications and groupings of  salt-affected soils within the region under consideration are based 
on  the  Classification  and  Diagnostics  of   Soils  of   the  USSR,  1977[10]  and  analytical  data  on 
saturated extracts (USDA Agriculture Handbook. 1954) [20]. These classifications and groupings 
are presented in Tables 1.1-1.3 and Annex A.
1.2. Soil and water salinity diagnostics and evaluation methods
Soils are regarded as salt-affected, if  they have salt concentrations above the thresholds of  toxicity 
that include the following: 1) a concentration of  salts in the soil solution of  3-5 g/l [11]; 2) a 
sum of  toxic salts measured in water extracts of  0,05-0,15% [1]; 3) specific electrical conductivity 
of  saturated soil-paste extracts of  2-4 mSm/cm (USDA Agriculture Handbook, 1954) [20]. The 
suitability of  such soils for different crops is determined by attributing them to specific soil groups 
differentiated by their salinity levels and respective levels of  the tolerance of  different crops [4].
Salt-affected soils are subdivided into two groups: 1) Saline soils without Natric/Solonetzic/Sodic 
horizon and 2) Alkaline soils with a well-developed Natric/Solonetzic/Sodic horizon, which is 
the diagnostic horizon of  this group. The former group includes Solonchaks and other saline soils 
without the solonetzic horizon, the latter – Solonetz and solonetzized soils.
Solonchaks are soils that contain high concentrations of  toxic (soluble) salts within their surface 
layer: more than 0,5% in the case if  soda-dominated salinity and more than 1% in the case of  
chloride-sulphate salinity. Such concentrations prevent the growth and development of  most 
agricultural crops [9, 10]. The surface layer implies a whole plough layer (15-30 cm) of  arable soils 
and the top 15-cm-thick layer of  virgin soils (Fig. 1.1). The surface salt crust that is usually present 
in Solonchaks has an average salt content of  10 - 20% and often higher.

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Soil salinity manаgement manual | Part I.Soil salinity management in the Eurasian Region