How can the grasslands under rainfall events modify water balance in drought conditions

Abstract

Taking into account the well-established influence of hillslopes grasslands on runoff processes, the purpose of this study was to investigate how grasslands can affect the water flow pathways on hillslopes, in drought conditions. This study was performed in experimental grassland at plot-scale (e.g., Festuca pratensis), in temperate humid continental climatic conditions of Curvature Subcarpathians, Romania. The rainfall, evapotranspiration, and soil moisture daily data, respectively 208 rainfall and 16 rainfall-runoff events data measured in grassland hills during the growing season (1 April up to 30 September 2015 and 2016) were used. Our results suggest that a runoff event response in extreme drought conditions occurs on grasslands only if precipitation exceeds the threshold of 31 mm Hortonian overland flow (HOF), while this threshold drops to 17 mm during moderate droughts and up to 8 mm for wet conditions. The rainfall events up to 16 mm proved to be insufficient to completely saturate the soil. Therefore, HOF has only a minor contribution in drought conditions, on grassland and light on bare soil. A complementary and negative effect of grasslands in drought conditions is the water resources suppressing on hillslopes.

Journal of Water and Land Development

“…The current study observed the growth and development of plants according to the method of [BEIDEMAN 1974;MINEA et al 2018;NORELDIN et al 2015] using "Recommendations for the study of the ontogenesis of introduced plants in the botanical gardens of the USSR" [SYKURA, SYRYTSA 1990]. The current study determined the productivity of raw material and seeds according to "Research methodology for the introduction of medicinal plants"; the current study also used methods adopted in other botanical gardens [KIRICHENKO et al 2019;KLUBNIKIN et al 2000;MININA 2020], with slight modifications appropriate for the local conditions.…”

The dominant runoff processes on grassland versus bare soil hillslopes in a temperate environment - An experimental study

“…(i) grasslands -corresponding to secondary perennial grass ( Figure 1); this plot was never grazed, but herbage was cut in June, according to traditional practices in the region; the average height of grass species surrounding the plot was about 40 cm and an abundant superficial network of grass roots dominated in the top ~ 20 cm of the soil (see Minea et al, 2018);…”

“…In Romania, regarding the hydrological influence of vegetation on runoff generation, few field investigations at microscale were initiated within the Curvature Subcarpathians (e.g., Stanciu and Zlate-Podani, 1987;Minea et al, 2018), and different results on runoff processes such as runoff coefficients, overland flow volume, and discharge or infiltration rates were found. These hydrologic experimental studies on hillslopes were marked by the pioneering work of Blidaru (1965).…”