CHEMICAL PROPERTIES OF SOIL IN UZBEKISTAN

Abstract

The chemical properties of soil are crucial for ensuring sustainable agriculture, plant growth and fertility. This study aims to investigate variations in chemical indicators in irrigated and saline soils in Uzbekistan, mainly sieroze and grey soils. The study aimed to determine the relationships between soil pH, cation exchange capacity (CEC), organic matter content, and the presence of macroelements (N, P, K) and micronutrients in their available forms, and to assess their impact on agricultural productivity.

Samples were collected from 45 typical and saline soil profiles in the Tashkent and Fergana Valley regions between 2022 and 2025. Standard agrichemical methods (pH-metry, titrimetry, spectrophotometry and atomic absorption spectrometry) were employed. The results showed that most soils had a pH between 7.8 and 8.6, exhibiting carbonate and alkaline properties. The CEC was found to be between 12 and 28 meq/100 g and the organic matter content was found to be between 0.6 and 1.8%. The available forms of phosphorus were sharply reduced by carbonates (often <15 mg/kg P₂O₅), while potassium remained at medium-to-high levels.

High salinity (EC > 4 dS/m) and pH limit the uptake of micronutrients such as Fe, Mn, and Zn by plants. These results confirm the importance of applying organic fertilisers, gypsum and phosphatic fertilisers in a sustainable way to improve soil fertility in Uzbekistan. This information can be used to develop sustainable soil management strategies.