Influence of selected factors on erodibility in catchment scale on the basis of field investigation

Abstract

Drying of soil surface can affect the soil water repellency and reduce the infiltration, it may have impact on runoff and erosion. The aim of the research was to determine the effect of soil surface drying on its repellency and erosion, and the dependence of these values from the land use on the changing weather conditions background during the year. The research was conducted on Zagozdzonka river catchment, six times during the period of July 2014-September 2015, at five measuring points characterized by different land use. The irrigation of soil was carried out using rainfall simulator made by Eijkelkamp company. The intensity of the rain during the first 3 minutes of precipitation was 6 mm / min, the kinetic energy of rain was 72 J·m-2. The surface runoff was collected into containers placed in the bottom of the rainfall simulator. Water Drop Penetration Time test was used to determine soil surface wettability. WET-2 probe was used to measure the moisture and soil temperature. Sediment concentration in the effluent was determined by weight method on filters. Variability of soil wettability was observed in different dates of measurements. Increasing repellency was recorded during the dry periods. The highest class of repellency was found in the forest and wild meadow areas. There was no direct correlation between the soil moisture, soil temperature and runoff. Both, sediment concentrations and sediment grain size, varied in the collected samples, depending on measurement time. The highest sediment concentrations were found in runoff from agricultural land use.