Revegetation of Decomposed Granite Roadcuts in Korea: Developing Digger, Evaluating Cost Effectiveness, and Determining Dimensions of Drilling Holes, Revegetation Species, and Mulching Treatment

Abstract

Decomposed granite roadcuts are difficult to revegetate after losing the topsoil and vegetation cover. We developed a new drilling machine, Digger, to efficiently drill six holes simultaneously on decomposed granite roadcuts to facilitate revegetation. The Digger consists of a base machine (0.7 m3‐level excavator) and a mounting body with six hydraulic motors instead of a bucket. We tested its performance on two roadcuts in southwest Korea using time‐motion studies, which showed that the Digger can drill 240 m2 of decomposed granite roadcuts daily. The unit cost of the Digger was less than a half of other roadcut stabilization and revegetation techniques in Korea, making the Digger a cost‐effective revegetation technology. Field germination and growth tests were also conducted to identify appropriate diameter and depth of drilling holes, suitable revegetation species, and mulching treatment. We drilled holes with three different diameters and depths, filled the holes with a mixture of plant seeds and cultivated soil, applied mulching treatments (coir geotextile, shade net, and no mulching), and measured the germination and growth results at two field plots after 1 month and 1 year. The results showed that drilling diameter 10 cm and depth 10 cm were large enough to result in better plant germination and growth. Erosion control species, Poa pratensis L. and Eragrostis curvula (Schrad.) Nees, survived and grew better than native woody species. Coir geotextile improved the plant germination and growth. The time‐motion and revegetation results show that the Digger can be a promising technology to restore decomposed granite roadcuts. Copyright © 2013 John Wiley & Sons, Ltd.

Effects of wood chip amendments on the revegetation performance of plant species on eroded marly terrains in a Mediterranean mountainous climate (Southern Alps, France)

“…Most plant mortalities occurred during the first summer, which was the driest of the 3 years, and occurred very little during the following summer droughts. Another approach could be to associate seeding with drilling holes, as was experimented by Lee et al (2013).…”

“…Planting and seedling methods for installing vegetation on slopes are therefore required. Such methods have already been tested on several other eroded lands (Reubens et al, 2009;Bochet et al, 2010;Fernández et al, 2012;Commander et al, 2013;Lee et al, 2013), but these studies did not apply to our climatic, topographic and pedological conditions, and the studied plant species are not appropriate or currently available. Therefore, the main issue for practitioners is to find the adequate solution to develop vegetation cover on gully slopes.…”

Characterization and interaction of driving factors in karst rocky desertification: a case study from Changshun, China

“…On the other hand, however, when roads penetrate into (or are improved in) areas, they may intensify efforts to exploit resources (Deng et al, 2011) and therefore cause KRD deterioration (Mick, 2010;Yang et al, 2013). Road construction can create numerous roadcuts and embankments that can contribute to increased sediment production and further cause land degradation (Lee et al, 2013). Serious soil erosion can occur on bare road embankments (especially those under construction) (Cerdà, 2007) and on unpaved roads (Cao et al, 2013b).…”

“…Serious soil erosion can occur on bare road embankments (especially those under construction) (Cerdà, 2007) and on unpaved roads (Cao et al, 2013b). Restoration efforts should be directed to guarantee key ecological processes and support soil formation for roadcuts and embankments (Jimenez et al, 2013;Lee et al, 2013). New strategies should emphasize the need to decrease the impact of road construction on plant and animal habitats and the benefits of using local species for the re-vegetation of land surrounding the roads (Cheng et al, 2013).…”

The immediate effectiveness of barley straw mulch in reducing soil erodibility and surface runoff generation in Mediterranean vineyards

“…In these cases, straw mulch was confirmed to have a positive effect on water quality (Faucette et al, 2007) and the mitigation of wind-induced soil erosion (Nelson, 2002). Low mulch cover was also found to be efficient by researchers who dealt with road embankments protection (Lee et al, 2013), afforested land (Jiménez et al, 2013) and agricultural soils (Jordán et al, 2010). In addition, García-Moreno et al (2013) reported that excessive mulch rates (9-12 Mg ha −1 yr.…”