ABSTRACT
Land degradation is related to both natural and human factors. Land degradation processes include soil erosion, acidification, and salinization/alkalization processes as well as physical degradation of soils (compaction, structural damage, degradation processes caused by an extreme soil moisture regime) and biological degradation. The main driving force is in most cases the water regime, or the availability of water (e.g. permeability and water storage capacity influence soil erosion processes, and the groundwater level is of crucial importance for salinization processes, etc.). Some land degradation processes in Hungary can be defined as desertification as a considerable part of Hungary belongs to the dry sub-humid area. Desertification processes in the area can be characterized by the term aridification, which means increasing semi-aridity, manifested by the increase of mean annual temperature and a corresponding decrease of yearly precipitation. According to our results the average warming for the last 110 years is +0.0104°C y−1, and precipitation decrease is 0.917 mm y−1. The physical processes of aridification, including studies on groundwater level change, soil moisture profile dynamics, soil development, and vegetation change were studied in detail in the Danube–Tisza Interfluve. We found a 2–4 m drop in the annual mean groundwater level. With the gradual lowering of the water table in alkali ponds, and with complete desiccation, the direct contact between groundwater and salt-affected soils is interrupted, the Solonchak soil dynamics cease, and heliophyte and hygrophyte plant associations disappear. According to the results of this study, changes in vegetation proved to be an important tool indicating soil changes.
