Indicators of humus state of virgin and irigated gray-brown soils of khorezm vilayat of Uzbekistan

Abstract

The humus content, elemental composition and optical density of humic acids in virgin and irrigated soils of the Tashsakinsky massif of the Khorezm region of Uzbekistan were estimated. The studied desert virgin and irrigated soils have characterized by light and medium loamy granulometric composition, dusty-granular structure and slightly alkaline reaction. Carbonates present in small quantities - 3.10-10.60%. The total humus content in the upper horizons varies from 0.19% to 0.76%. In virgin grey-brown soils the humus type is humate-fulvate, agriculture soils are humate. The degree of humification of organic matter in newly irrigated gray-brown-meadow and meadow-marsh soils is higher than in virgin gray-brown soils and decreases down the profile. It was revealed that the optical density of humic acids of virgin gray-brown, irrigated meadow and meadow-marsh soils is characterized by high values. The percentage of the sum of humic acid elements differs little from virgin soils to old-irrigated meadow soils. In the lower horizons, oxidation increases by 1.02 times compared to other studied soils. For the first time, the elemental composition of humic acids in virgin and irrigated soils of the desert zone of the Tashsakinsky massif of the Khorezm region was determined. The elemental composition of humic acids showed the oxidizability of humic acids, which decreases from top to bottom along the profile, which is associated with the features of the genesis of the studied soils, the age of irrigation and the degree of cultivation of these soils.