Gully erosion on the Tetves catchment

Abstract

Soil erosion has primary importance in soil degradation processes. Its role is considerable not only from the point of view of crop production, but also of nature protection. Both the total volume of soil loss and the ratio of gully-originated sediment were measured at the outlet of the Tetves catchment (approx. 120 km2) next to Lake Balaton. With the investigation of the sediment from the sediment reservoir at the outlet of the catchment it was concluded that during the lifetime of the reservoir (1970–2000) ~4000 t sediment were delivered out of the catchment. This volume of soil loss divided by the area of agricultural land on the catchment is 0.8 t ha-1 year-1. According to the results of the sediment analysis approximately half of the soil loss arrived from deeper horizons of the original soil profile. These particles were probably eroded due to linear erosion. This type of erosion is also a very effective link between slopes and the stream from the point of view of sediment delivery. Therefore in case of the Tetves catchment gully erosion plays an important role in recent soil degradation. In order to find more details of linear erosion in the Tetves catchment 140 gullies were surveyed. The most important parameters of each gully were determined in three years 1968, 1984 and 2004. To compare the results of these surveys with the data of the sediment reservoir analysis the following statements can be made. The maximum activity of gully erosion was between 1884 and 1995 in the investigated catchment. In this period in Hungary the disintegration of the collective farms happened and total anarchy in land property could be observed. In this case the change in economical and social factors indicated the increase of gully erosion.