Grass hedges to reduce overland flow and soil erosion

Abstract

Overland flow and the consequent soil erosion are worldwide problems that are particularly acute in the Chinese Loess Plateau. Negative consequences are in situ erosion and land impoverishment, and even more serious damage such as physical and chemical pollution in downstream areas. Land impoverishment is due to the loss of fertile topsoil with its load of organic matter and nutrients. Nonetheless, the overland flowing water could be beneficial by helping to reduce the drought risk, if it could be controlled and encouraged to infiltrate the soil. Grass hedges are a cheap and effective structure for controlling overland flow and for filtering nutrients and pollutants, but research has mainly focused on their use in tropical, subtropical and Mediterranean environments. Here, two grass species were tested for their ability to reduce overland flow and soil erosion. Simulated rainfall was applied during sets of three 1-h runs to evaluate the effects of protective grass hedges. We tested two different grasses, Pennisetum alopecuroide and Arundinella hirta, under three rain intensities of 14, 22 and 36 mm h −1 , and 5-20% slope gradients on overland flow and soil loss. Plots without grass hedges were used as control. Our results show that grass hedges reduced overland flow by 72% for Pennisetum and by 36% for Arundinella on average. Such native, non-invasive, perennial grasses proved to be very promising for use in conservation practices.filter strips/ soil erosion/ rain simulator/ overland flow/ natural engineering

The geomorphic signature of bare-nosed wombats (Vombatus ursinus) and cattle (Bos taurus) in an agricultural riparian ecosystem

“…we were confident that rainsplash, rather than overland flow (sensu Wu et al, 2010), was the predominant soil transport mechanism. Wombat-induced soil displacement is not short-lived, as indicated by the consistent quantities of soil collected over the course of a year.…”

Modelling soil erosion reduction by Mahonia aquifolium on hillslopes in Hungary: The impact of soil stabilization by roots

“…Durán Zuazo et al, 2008;Wu et al, 2010). Besides its sediment trapping capacity vegetative strips could filter over 90% of the chemicals onsite due to increased infiltration and temporary storage in the surface layer (Fogle et al, 1994) thereby reducing the amount of contaminants carried off-site.…”

“…Most studies on permanent vegetative strips focused on warmseason grasses in tropical, subtropical and Mediteranean areas (Sudhishri et al, 2008;Thierfelder et al, 2005;Wu et al, 2010) and rarely focused on species which have the ability to perform successively under not only dry but cold conditions (Wu et al, 2010). Due to the high abiotic tolerance of M. aquifolium (Hudek et al, 2010) it has the advantage of being able to be used under various climatic conditions.…”

Soil and water conservation effects of contour grass hedges on sloping croplands

“…An initial one hour rainfall simulation at low soil moisture condition ("dry run") was followed by a second rainfall approximately 24 hours later ("wet run") and a third rainfall later ("very wet run"), all the rainfall duration was one hour [7]. After each simulated rainfall, the volume of runoff in the barrels was measured and transferred into runoff, and about 1000 mL runoff was sampled after thoroughly stirred.…”