Interpretation of soil erosion in a Polish loess area using OSL, 137Cs, 210Pbex, dendrochronology and micromorphology – case study: Biedrzykowice site (s Poland)

Abstract Loess areas used for agriculture are susceptible to soil erosion. The intensive process of soil erosion in Polish loess areas began with the onset of the Neolithic and has continued intermittently until today. This work presents the results of soil erosion from simultaneous use of the 137Cs and 210Pbex methods on an agricultural field located on loess slope. Moreover, to establish the age of accumulated sediment connected with water slope erosion, OSL dating, selected physicochemical and micromorphological analyses were applied. The reference values of the 137Cs and 210Pbex fallout for the studied site (Biedrzykowice, the Proszowice Plateau, Małopolska Upland) equal 2627 (45% connected with Chernobyl) and 4835 Bq·m–2, respectively. The results of the 137Cs and 210Pbex inventories measured for the agricultural field range from 730 to 7911 and from 1615 to 11136 Bq·m–2, respectively. The mean soil erosion is about 2.1 kg·m–2·a–1 (about 1.4 mm·a–1). The accumulation of the colluvial sediments started in the Neolithic and drastically increased in the Middle Ages. The examined gully catchment in Biedrzykowice has probably developed quite rapidly as a result of increased erosion. This resulted in the abandonment of this area as farmland and, consequently, in the minimization of water erosion on the slope due to the entrance of woody vegetation in this area. Erosion processes were highly intensified during the last 70 years as a result of deforestation after World War II and intensive agricultural reuse of this area after a break, as indicated by isotope measurements and dendrochronology.