Knowledge Base
 

Identification code

PP00081

Project title

Strongly saline soils water-salt regime study in Karshi Steppe Charachyl sink

Project location:

The Republic of Uzbekistan, Kashkadarya oblast (Karshi Steppe), state farm ¹ 11

Rubric

70.03.21

Rubric (SIC ICWC)

01.20.01.15

Project duration

1974 - 1976

Project Manager

Gulchekhra Khasankhanova, Uzmeliovodkhoz (Sredazgiprovodkhlopok)

Summary

Investigations, directed on improvement of water-salt regime management of irrigated saline soils, were carried out on basis of  moisture availability assessment  criteria improvement for soils of different mechanical composition. Climate is characterized by high temperatures all year around Soils are meadow-desert, meadow-takir, etc. Setting up water and salt regime field studies, capillary-sorption potential of soil moisture, mineralization of soils and ground waters were implemented on 2 plots with area 25 ha. Plots were equipped by registration and observation means.Estimations of summarized potential of soil moisture show that during all period of  study it is found in easily available form in root layer shortly only during irrigations. During  3 – 10 days moisture remains at a depth of 25-75 m medium-available, then, in process of  dehydration, turns into category of hardly available and non-available form for plants. Actually, irrigation intervals of 20-30 days are overestimated. They should be reduced down to 10, maximum 15 days. Observed irrigation depths (800 -2300 m3/ha) under annual irrigation norm during vegetation  about 4000-5000 m3/ha are insufficient. Existing ground water regime (below  2.0 -2.5 m) allows  water supply increase for desalination speed by 1.5-2 times. Data analysis allowed to conclude that the conditions formed in root layer (characterized by soil moisture potential values) are very dynamic and vary in a greater degree than moisture both during of non-irrigations period and during the year.

Analysis of field and laboratory study allows to determine bounding empiric relations between salt composition and osmotic pressure of soil solution as well as distinguished graphs of capillary-sorption pressure from moisture for soils of different mechanical composition, that allows to carry out the assessment of soil moisture availability through  data of usual analysis of soil extract and soil structure.

Key words

irrigation regime; salt regime; soil salinization; soil moisture

Bibliography

1. Authors: A.N.Morozov, A.I. Artyukhova, V.N. IgnatikovTitle: Estimation of soil solution osmotic pressure on specific electric conductivity of soil extract. The collection of works of "Sredazgiprovodkhlopok" Institute and SANIIRI, Tashkent, 1978Comparison of specific conductance values and easily soluble salts in soil  extracts is given in 1:5, 1:1 and soil solutions extracted under "soil-water"  ratio of 1:0,4 - 0,3 that enable  to find the dependence, allowing by chemical analysis data to estimate specific conductance of soil solutions and their osmotic pressure.2. Authors - M. Kh. Kondrakov, F.V. Serebrennikov, A.N. MorozovTitle: Research studies under development of projects on irrigation and new lands reclamation. The collection of works of "Sredazgiprovodkhlopok" Institute and SANIIRI, Tashkent, 1979

The achievements of "Sredazgiprovodkhlopok" Institute were represented for  the last years in the field of research studies and their role in irrigation system improvement on large reclamation objects- Golodnaya, Karshi Steppes, etc. Materials on developments efficiency in the field of irrigation regimes, drainage, irrigations technology and saline lands are given.