Rain Erosion Hazard Evaluated from Microtopographic Erosion Features on Arable Fields and Forest: A Case Study in Nepal

Authors: Kunwar L.B.; Bergsma E.; Shrestha u.P.

Source: Geografiska Annaler: Series A, Physical Geography, Volume 85, Numbers 3-4, October 2003 , pp. 313-321(9)

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Abstract:

Erosion hazard has been studied under existing conditions in 12 sites, representative of physiographic landscape units in the Likhu Khola watershed which is located 50 km northwest of Katmandu, Nepal. For this purpose the accumulated effect of erosion has been recorded as expressed by microtopographic erosion features formed in a rainy period. Seven types of micro-topographic features are used: resistant clods, eroding clods, flow paths, prerills, rills, depressions and basal plant cover.

As a measure of erosion hazard, the observed erosion intensity was expressed by an indicator using the percentage of shallow flow features and the more heavily weighted features of incision.

Soil erosion hazard on the maize-wheat sites was found to be various, partly due to different soil surface texture of the sites. The hazard was lower on sites of dense sal forest. Crown canopy, a seasonal litter layer and a good permeability limit the erosion. The erosion hazard is lower still on sites with degraded Sal forest. These sites have a substantial basal plant cover.

The erosion intensity derived from microtopographic features did not correlate with results of the Bouyoucos test, but had a good correlation with the crusting index.

Keywords: erosion hazard; soil conservation; microtopographic erosion features

Document Type: Research article

DOI: http://dx.doi.org/10.1111/j.0435-3676.2003.00208.x

Affiliations: 1: Soil Science Division, ITC, International Institute for Geo-information Science and Earth Observation, The Netherlands

Publication date: 2003-10-01