Suše i proces aridizacije kao faktor degradacije zemljišta na području Deliblatske peščare

In this doctoral dissertation, the research of the influences of droughts and the process of aridification have been conducted on Deliblato Sands area’s sensitivity, as a Special nature reserve, especially from the aspect of land degradation, the condition of vegetation cover and sustainable management of these ecosystems. Research included two groups: climatological studies (for the period 1980-2010) and the studies of soil. Within climatological studies, the focus was on climate factors most often used in the research of land degradation. This primarily refers to precipitation (P), temperature (T), wind (W) and their extremes, potential evapotranspiration (PET), standardized precipitation index (SPI for 1. 2. 3. 6 and 12 monts ) and aridity indices (AI and BGI). Soil studies (31 pedological profiles) comprised of field and laboratory research that defined morphological, physical and chemical properties. Based on these researches, described and selected soils were grouped into four categories, according to WRB classification: group I – Protic Arenosol (Calcaric), group II – Arenosol (Haplic, Calcaric), group III – Chernozem (Arenic), group IV – Glaysol (Calcaric, Arenic). The results of soil degradation of Deliblato Sands, amongst other, have enabled the marking off of three texture classes which belong to different categories of erodibility: highly erodible soils with 56.17% (sand), medium erodible soils with 41.27% (clay sand) and low erodible soils with 36.62% (sandy clay). Soil sensitivity to the process of wind erosion, in model RWEQ, is defined by the participation of erodible fraction (EF) that contains soil particles <0.84 mm. The erodible fraction depends on physical and chemical soil properties, including the contents of sand, dust and clay, the contents of organic matter and CaCO3 in surface level 0-25 mm. Using the same model, the soil crust factor (SCF) is determined which reflects the changes of abrasive surface resistance, when the surface is modifie