Effectiveness of vegetative buffer strips at reducing runoff, soil erosion, and nitrate transport during degraded hillslope restoration in northern Iran
2018
Kavian, Ataollah | Saleh, Iman | Habibnejad, Mahmoud | Brevik, Eric C. | Jafarian, Zeinab | Rodrigo‐Comino, Jesús
Soil and water conservation in natural and cultivated areas is a major concern for humankind. However, there are severe problems with degraded hillslopes due to bare soils in northern Iran, which are one of the most important factors driving land degradation processes. Subsequently, soil erosion, pollutant transport, and/or nutrient impoverishment are affecting large territories; therefore, rapid and inexpensive soil conservation measures need to be implemented. The use of vegetative buffer strips could be an effective strategy to reduce pollutant transport as well as soil erosion. Thus, this research aimed to investigate the possible efficiency of two different vegetative buffer strips composed of vetiver‐grass (Chrysopogon zizanioides) and native turf‐grass (Festuca arundinacea) at reducing runoff and soil losses as well as nitrate transport on a representative degraded hillslope with bare soils in Mazandaran, Iran. Twelve 10 m² experimental plots were tested over 1 year using a runoff simulator that produced overland flow that corresponded to the 25‐ and 100‐year return period rainfall events. The plots with bare soils had the highest runoff volumes (30.5 and 55.4 L m⁻²), sediment concentrations (101.2 and 430.6 g L⁻¹), and nitrate concentrations (10.4 and 37.6 mg L⁻¹). Vetiver was the most useful tool to reduce runoff, soil loss, and nitrate concentration, with values of 13.4 and 28.6 L m⁻², 13.4 and 90.9 g L⁻¹, and 2.9 and 16.4 mg L⁻¹, respectively. Of the treatments investigated, vetiver provided the most rapid cover and was the most efficient at preventing soil erosion and nitrate transport directly after plantation.
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