Changes in the land cover of Absheron and southeastern Gobustan under the influence of desertification processes

Original Paper

Abstract

The relevance of the study is driven by the need to assess land degradation on the Absheron Peninsula and  southeastern Gobustan under conditions of global climate change and intensive technogenic impact. The complex ecological background of the region, shaped by long-term oil extraction and urbanization, significantly accelerates desertification processes. The main objective of the work is to analyze the spatial-temporal dynamics of the region's land cover. The research tasks include the calculation of vegetation indices, diagnostics of the state of gray-brown soils (Calcisols), and identification of factors causing their degradation. Material and methods. Remote sensing data (Landsat) were used to calculate the Normalized Difference Vegetation Index (NDVI). Field studies included semi-stationary observations at 16 plots. Laboratory analyses were conducted using the Tyurin method (organic matter) and the Kachinsky method (particle size distribution). Soil classification is based on the works of V.R. Volobuev (1966) and M.E. Salaev (1991) and is brought into line with the international WRB system. It was established that the soil cover in areas of long-term oil production has undergone severe degradation. Based on field and laboratory studies, precise quantitative parameters for four stages of gray-brown soil degradation were determined: humus content in the "A" horizon decreases from the initial 1.3-1.5% to critical values of <0.5%, absorption capacity drops from 18.5-21.5 to 15.0-17.5 meq/100g, and the soil pH shifts from weakly alkaline (7.8-8.0) to strongly alkaline (>9.0). Soil bulk density increases from 0.9-1.1 to >1.6 g/cm³, while the physical clay fraction expands from 48.0-52.5% to 76.5-78.0%. The average soil surface temperature during the 2024 growing season rises across the degradation stages from 19.4-23.1°C to 31.4-35.2°C, correlating with a decline in projective vegetation cover from 55-60% to 0-5%. The analysis showed that on the Absheron Peninsula, technogenic factors prevail over natural ones. However, sustainable anthropogenic measures (the development of almond and olive plantations) demonstrate high potential for soil fertility restoration during the initial stages.