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Table 5
Chemism of soil salinity
According to anion
According to cation
1
2
3
4
5
6
7
8
Cl
SO
4
SO
4
Cl
HCO
3
SO
4
Salinity type
Na
Mg
Na
Ca
Mg
Ca
Salinity type
>2,5
<0,5
Chloride
>1
>1
-
Sodium
2,5-
1,0
0,5-
1,0
Sulphate-chloride
>1
>1
>1
Magnesium-
sodium
<0,2
>5
Sulphate
<1
<1
>1
Calcium-
magnesium
1
2
3
4
5
6
7
8
<0,2
>5
>1
Hydrocarbonate-
sulphate
<1
>1
>1
Sodium-
magnesium
<1
>1
>1
Sulphate-sodium
>1
<1
<1
Sodium-calcium
<1
<1
<1
Magnesium-
calcium
<1
-
>1
Magnesium
Grouping salinity types on soil salinity level was conducted in accordance to the following
perfection scale.
Table 6
Salinity level
Sulphate
Chloride sulphate
Sulphate-chloride
Chloride
Dry
residue
Dry
residue
Cl
-
Dry
residue
Cl
-
Cl
-
Non-salinated
>0,3
<0,1
<0,01
<0,1
<0,01
<0,01
Weakly
salinated
0,3-1,0
0,1-0,3
0,01-0,05
0,1-0,3
0,01-0,04
0,01-0,03
Medium
salinated
1,0-2,0
0,3-1,0
0,05-0,2
0,3-0,6
0,04-0,2
0,03-0,1
Strongly
salinated
2,0-3,0
1,0-2,0
0,2-0,3
0,6-1,0
0,2-0,3
0,1-0,2
Very strongly
salinated
>3,0
>2,0
>0,3
>1,0
>0,3
>0,2
The amount of toxic salts was determined by binding the ions to the hypothetical salts on
an aqueous solution. This is the sum of toxic salts and the percentage of sodium, magnesium,
chlorine ions in the acetic anhydrous ions of the aqueous solution.
Evaluation of the one-meter layer of soil on toxic salts was determined by the scale
developed and recommended by O.K. Komilov, A.U. Akhmedov and M.I. Ruzmetov in 1998
(table 7).
142
Table - 7
Evaluation scale on toxic salt reserve of soil salinity
Salinity level
Oscillating amount of
salt reserve, t/ha
Amount of salt
according to dry
residue, %
Quantitative
evaluation
Non-salinated
<18
<0,13
Very low
Weakly salinated
18-42
0,13-0,31
Low
Medium salinated
42-90
0,31-0,66
Medium
Strongly salinated
90-150
0,66-1,11
High
Very strongly
salinated
>150
>1,11
Very high
The level of mineralization of groundwater is determined by the classification proposed
by the Institute of “Central Asian hydro supply system of cotton” (Table 8).
Table 8
Classification of the level of mineralization of groundwaters
No.
Level of mineralization
Dry residue, gr/l
1
Fresh
0-1
2
Very weakly mineralized
1-3
3
Weakly mineralized
3-5
4
Medium mineralized
5-10
5
Strongly mineralized
10-25
6
Very strongly mineralized
25-50
7
Alkaline
>50
There are three large groups associated with the hydro-geological, climatic and
lithologic-geomorphologic conditions of Mirzachul area soils: the first one is zonal soils, the
second is hydromorphic moisture-free soils, and the third is a complex of irrigated soils of
farming lands.Gray soils are one of the most easily digested and fertile soils of Mirzachul and
nowadays the complexity of these soils is decreasing. Most of them are already cultivated in
irrigated agriculture, and in time they have become aphid soil, while others are used in dry
farming on the edges of irrigated areas.The key farms we have studied are formerly and newly
irrigated gray grassland and grassland soils of varying degrees of salinity, which are
characterized by alluvial and alluvial-proluvial deposits of origin.Newly irrigated soils in
Gulistan farmers; association of Mirzachul district in Syrdarya region were distributed in the
open pit areas of Bobur Farmers’ Association of AkAltyn district in Syrdarya region.The
complex geomorphological structure of the studied territory, along with complexity of
hydrogeological, climatic and soil-ameliorative conditions, has a significant impact on the soil
layer as a result of human’s economic activities in the area, and the specific soil-specific lands
are formed.However, these soils and ground waters are strongly salinatedand highly mineralized,
sometimes with aqueous suspension alkalinity. Sulfate-chloride and chloride-sulphate type
mineralized and diverse watersheds constitute the majority of fields and they have different
characteristics depending on the level of mineralization and quality of salts. Generally, all the
studied farming associations have a very high mineralization level, which is one of the main
reasons for the poor work of the drainage collector networks.As natural and irrigation-economic
conditions of the territory differ, they also determine the quantity and quality of salts and their
accumulation in soil, degree of salinity and alkaline and general direction of salinity. Salinity at
different levels is observed both on soil layers and through distant spaces, where little
salinatedsoils are found at different levels of salinizedsoils. On the studied soils there are
different variants of salinity and type of salinity and the location of salinatedhorizons.In the
samples of the studied soil sections there is occurrence of lowland soils, their absorption capacity
is lower than usual soil. Such soils occupy a leading position in the absorption complex (41-
143
60%), fewer magnesium (31-46%), slightly sodium (5-17%), absorbed in potassium content of
about 1-4%.
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