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participation of  soda
Total alkalinity < Cl
-
 
and < SO
4
2-
, SO
4
2- 
> Cl
-
Sulphate
Cl
-
/SO
4
2- 
< 0,5 Soda- chloride Total alkalinity < Cl
-
, SO
4
2- 
< 
20% of  the ∑ of  anions
Sulphate 
(gypsum)
Cl
-
/SO
4
2- 
< 0,5
SO
4
2-
³ Ca
2+
Ca
2+
>8-12 
Soda- sulphate Total alkalinity < SO
4
2-
, Cl
-
< 
200% of  the ∑ of  anions
Table A.2. Soil salinity chemistry: the balance of cations (cmol(eq.)/kg)
The chemical type of  salinity
The balance of  cations
Sodium 
Na
+
>Ca
2+
, Na
+
>Mg
2+
, Ca
2+
<20%Sк*, Mg
++
<20%Σк 
Magnesium 
Mg
2+
>Ca
2+
, Mg
2+
>Na
+
, Na
+
<20%Sк, Ca
2+
<20%Σк 
Calcium 
Ca
2+
>Na
+
, Ca
2+
>Mg
2+
, Na
+
<20%Sк, Mg
2+
<20%Σк
Magnesium-sodium 
Na
+
>Mg
2+
, Ca
2+
<20%Σк
Calcium-sodium 
Na
+
>Ca
2+
, Mg
2+
<20%Σк
Calcium-magnesium
Mg
2+
>Ca
2+
, Na
+
< 20%Σк 
Sodium-magnesium
Mg
2+
>Na
+
, Ca
2+
<20%Σк 
Sodium-calcium
Ca
2+
>Na
+
, Mg
2+
<20%Σк
Magnesium-calcium
Ca
2+
>Mg
2+
, Na
+
< 20%Σк 
Note: 
Σк
 – the sum of  cations, mmol(eq.)/100 g of  soil 

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89
Annex A.Classifications, assessment criteria and distribution of salt-affected soils 
Table А.3. Relationships between soil alkalinity and fertility [12]
Parameters
Values of  parameters
Exchangeable sodium, % of  the cation exchange capacity
<5
10-15
25-30
>50
Total alkalinity (%), in water extract 
0,02 -0,04
0,05 -0,06
0,07-0,08
0,1- 0,2
pH of  soil paste and water suspension 
7,5-8,4
8,5-9,0
9,0-9,5
9,5-10
Relative fertility, %
100
75-60
30-20
0
Table A.4. The characteristics of saline and alkaline soils [20]
Parameter
Saline soils
Alkaline soils
pH
< 8,3
>8,5 within the profile and (or) ESP*>15 in the B horizon
Chemical type of  salinity
Dominant ions are SO
4 
2-
 and Cl
-
Dominant ions are HCO
3
- or CO
3
2- 
or both
Influence of  electrolytes on soil
Coagulation of  colloids
Peptization, dispergation
Toxic impact on plants
High osmotic pressure of  soil solution
Alkalinity of  soil solution
Main purpose of  amelioration
Removal of  electrolyte excess by washing 
(leaching)
Lowering the high pH, neutralizing the alkalinity via 
chemical amelioration
Note: 
ESP* - exchangeable sodium percentage expressed as a % of  the total cation exchange capacity (CEC).
A2. Diagnostics of solonetz and solonetzized soils
Solonetz (alkaline or sodic) and solonetzized soils (undergoing alkalization) are characterized by a 
profile with differentiated clay distribution, consisting of  the Natric (eluvial) and Solonetzic (clay-
illuvial) horizons with specific properties and saline C horizons [6, 10, 13].
Table А.5. Soil grouping by the degree of solonetzization (alkalization) - by sodium percentage (%)