The publication of this Handbook was supported by the Russian Federation

Fig. 3.2
A nomogram for calculating changes in the mean content of  salts within a layer 0 < x ≤ L, %;;
; O
p
 and O
c
 – the total of  water inputs; E – the total 
evaporation; х and m0 – the thickness and porosity of  the specified layer of  soil; the numbers on the curves show the values of  non-dimentional parameter Pe = x/m0
λ
The distribution of  salts within a soil profile is estimated using the following equations [1]:
with c
1
 = 0
(3.4)
with c
1
> 0 (3.5)
where: c, c
1
 and c
2
 – calculated mineralization, mineralization of  irrigation and ground waters, g/l; 
 - ratio of  upward and downward fluxes of  moisture in soil; x and x
1
 - the;  
specified 
layer of  soil and groundwater depth, m.
The dynamics of  salt regime in soils can be predicted upon 2-3 trial crop rotations. Calculations are 
carried out for certain periods of  each year: the growing season, the autumn-winter season and the 
spring season. If  a soil undergoes freezing, then the autumn-winter season can be excluded from 
calculations. The value   is determined on the basis of  the results of  water regime predictions for 
the same periods of  the year.

---

34
Soil salinity manаgement manual | Part I.Soil salinity management in the Eurasian Region 
(3.6)
where: E + T
p
 – the total evaporation, mm; O
c
 + O
p
 – the atmospheric precipitation and the 
irrigation  norm, mm.
If  the required salt regime is disrupted, then the O
n
 value increases due to the percolative regime.