Study of Holocene Soil Erosion on Agricultural Loess Slope using luminescence in conjunction with fallout radioisotopes 137Cs and 210Pbex.

Soil erosion and associated sediment accumulation could be a serious problem, especially in agricultural loess areas. Polish loess areas have been used for agriculture since the beginning of the Neolithic era and are particularly vulnerable to soil erosion that began during that period due to deforestation for agricultural purposes. Mechanical denudation increased in the Middle Ages and was intensive for a period of up to 200 years. The main problem in interpreting the effects of agricultural use on the environment is the precise determination of the age of the sediments corresponding to the phases of increased anthropogenic soil erosion. The answer to the question of the intensity of soil erosion and land use change during periods of prehistoric and historic settlements is a key environmental problem in the archaeology and paleogeography of the Holocene. In this work, to study soil erosion and accumulation and to determine the age of colluvial sediments and the rate of soil erosion, we have used optically stimulated luminescence (OSL) in conjunction with fallout radionuclides 137Cs and 210Pbex which are often used to study soil erosion. Their use overcomes many of the limitations associated with traditional methods. We present a study of the intensity of soil erosion and sediment accumulation during the last 100 years. For this purpose, 30 field soil cores were collected from an agricultural field. This was supplemented by 10 soil cores from undisturbed sites to obtain reference values of the radionuclide fallout. In addition to these soil cores, three soil cores from the top, middle, and base of the soil were collected for OSL dating. In addition, five sediment traps were located on the slope to collect moving sediments and investigate the fractionation of fallout radionuclides, as well as residual luminescence. For detailed sediment characterisation, detailed soil physicochemical properties, i.e., pH, OM, N-tot, Fedith, Feox, and grain size, were studied. The results obtained from the isotope and luminescence analysis confirmed that the soil cover in this area has strongly eroded. The intensity of modern soil erosion is high and clearly increased after World War II. This is probably related to the establishment of a state-owned farm in this area. It is also visible that the OSL ages of the mobilised sediments are almost independent of the distance travelled on the slope. Almost all previous luminescence signals from sediment samples are bleached before the quartz grains start to be transported down the slope and are bleached again before burial at the deposition site. [ABSTRACT FROM AUTHOR]