Scientific contributions in order to calculate rainfall erosivity factor (R) from revised universal soil loss equation (rusle) for Valea Tata watershed, Dambovita county, Romania

The research studies on the occurrence of complex soil erosion phenomena in the hydrographic basin of the Valea Tata stream, a right bank tributary of the Ialomita river, were carried out in the period 2017-2021 and aimed to quantify the amount of soil that is lost annually from the surface of the analyzed watershed. The main objective of this study was to calculate the rainfall erosivity factor (R) included in the Revised Universal Soil Erosion Equation (RUSLE) based on the records made in the period 2017-2021 on the experimental field as well as the data recorded at the climate monitoring stations in the proximity of the watershed for a period of 30 years for the calculation of soil loss from the Valea Tata watershed depending on the rain aggressiveness. The average value obtained for the Moroeni climate monitoring station was 289.54 MJ mm ha-1 h -1 year-1 with a minimum value of 83.20 MJ mm ha-1 h -1 year-1 and a maximum value of 964.06 MJ mm ha-1 h -1 year-1 while for Fieni climate monitoring station the values obtained were between 60.99 MJ mm ha-1 h -1 year-1 and 537.22 MJ mm ha-1 h -1 year-1 with an average value of 193.38 MJ mm ha-1 h -1 year-1 . For the experimental field, where the rainfall data, rain intensity and duration of the erosive events were more complex, the results obtained for the erosivity factor (R) has values between 149.50 MJ mm ha-1 h -1 year-1 and 800.80 MJ mm ha-1 h -1 year-1 with an average value of 284.91 MJ mm ha-1 h -1 year-1

Research on soil degradation resulting from sheet and gully erosion processes. Case study – the Raul Alb hydrographic basin, Dambovita county, up to the point it meets Barbuletu stream

The research works focused on the upper hydrographic basin of the Raul Alb creek up to the point it meets Barbuletu stream, covering an area of 4 034 ha and aimed at establishing the degree of soil degradation as a result of the complex action of sheet and gully erosion. Following the pedological study, seven soil types have been identified, each with several subtypes, which fall into five large soil classes. Regosols account for 51.00% of the catchment area, followed by eutric cambisols, 18.70%, rendzic leptosols 11.55% and phaeozems 11.00%. The fluvisol, anthrosol and luvisol total 7.75% of the entire basin. The class of Entisols is present in 56.10% of the area, followed by Mollisols 22.55% and Inceptisols 18.70% of the analysed area. The Entisol class (eroded phases) is to be found in 2.26% of the area, whereas the Alfisols account only for 0.39% of the hydrographic basin. In terms of sheet erosion, slightly eroded lands represent 48.26% of the total of 4 034 ha investigated, followed by the moderately eroded ones, 43.97%, whereas 2.27% of soils are strongly and excessively eroded and only 5.50% are not affected by sheet erosion. Deep water erosion is represented by rills, gullies and ravines. Gullies can be found in 35 of the 43 units of identified soils, ravines are present in 2 soil units and only 5 soil units are not affected by gully erosion