Groundwater table and salinity: Spatial and temporal distribution and influence on soil salinization in Khorezm region (Uzbekistan, Aral Sea Basin)

Abstract

Groundwater (GW) management is an essential element in irrigated agriculture. This paper analyzes the temporal dynamics of GW table and salinity in Khorezm, a region of Uzbekistan which is situated on the lower Amu Darya River in the Aral Sea Basin and suffering from severe soil salinization. We furthermore identify the critical areas for potential soil salinization by examining GW table and salinity measured during 1990-2000 in 1,972 wells, covering the entire region. Additionally, case studies were performed to assess the contribution of the GW to the soil salinization on a field scale. Over the entire area, GW was only moderately saline averaging 1.75±0.99 g l −1 However, GW levels were generally very shallow averaging 148±57 cm below the ground surface and thus likely to prompt secondary soil salinization. Three case studies where GW table, soil and GW salinity were closely monitored at the field scale, suggested that the elevated GW levels forced soil salinization by annually adding 3.5-14 t ha −1 of salts depending on the position and salinity of the GW table. Maps interpolated from the regional dataset revealed that GW was significantly shallower and more saline in the western and southern parts of Khorezm despite the presence of a drainage network which is rather uniformly distributed throughout the region. The results of the current study will assist the development of an improved drainage management in Khorezm.

Per-Field Irrigated Crop Classification in Arid Central Asia Using SPOT and ASTER Data

“…Since the independency of Uzbekistan 1991, demand on the scarce water resources has been increasing due to the introduction of winter-wheat for self-sufficiency. Soil quality in the region is low, shallow and saline groundwater in combination with inappropriate management practices, formerly described by [23], further increase the soil salinity [24] throughout the region. Furthermore, Khorezm is strongly affected by periodic droughts and resulting shortages in irrigation water supply.…”

Variations on Soil Salinity and Sodicity and Its Driving Factors Analysis under Microtopography in Different Hydrological Conditions

“…Salt-affected area covers about 1ˆ10 9 ha in the world [1]. Soil salinization is an increasing environmental problem because of adverse effects of soil salinity and sodicity on soil properties and behavior [2,3].…”

“…Saline-affected soil formation was correlated with critical depth of shallow groundwater (GW) level, except when controlled by arid climate [7]. Salinization occurred when GW depth was less than 2.0 m with salinity higher than 0.48 dS/m [8,9]. For the GW with lower salinity, the GW table should not be shallower than 1.5 m [10].…”

The role of Remote Sensing in land degradation assessments: opportunities and challenges

“…The study was conducted within the irrigated croplands of Khorezm region and southern Karkalpakstan Republic of Uzbekistan where ongoing LD in the form of secondary soil salinization is an acute problem, triggered by unsustainable irrigation and land management practices (Ibrakhimov et al, 2007). This study demonstrates the use of multi-temporal and multi-scale satellite images for assessment of vegetation dynamics and degradation.…”