In Vietnam soil erosion is a major environmental problem with respect to soil fertility, water quality and downstream property damages and involves 40% of total land surface. Due to a continuous and persistent decrease of soil quality under annual crops, farmers gradually convert their fields to grazing lands and their crops to fodder cultures or tree plantations. Experimental 1-m(2) field plots with three replicates each were monitored for two years (2006-2007) to evaluate the impact of three different fodder treatments (Paspalum atratum, Panicum maximum and Stylosanthes guianensis) on runoff and soil detachment in a cultivated catchment of North Vietnam. These experiments were designed to monitor at local scale the protective effect of vegetation cover against splash and rain-impacted erosion. The lowest runoffs (ca. 3.0-4.4%), sediment yields (ca. 14-19 g m(-2) yr(-1)) and soil organic carbon losses (ca. 0.7 g C m(-2) a(-1)) were obtained for P. maximum that provided the best soil protection with respect to the two other treatments. These values were low as compared to cultivated crops (cassava and rainfed rice). Soil surface characteristics (mainly biological activity and crusting) did apparently not play a key role, most likely because each plant cover provided, with its own efficiency, protection against rainfall erosivity and rapid plant regrowth wiped out traces of flow detachment. The extent of soil detachment and sediment export, mainly controlled by cut and carry operations of fodder management, was reduced by increasing slope length from 1 to 5 m. The choice of dense fodders such as P. maximum appears to be, in terms of improved livelihood and environment sustainability, an interesting issue for uplands farmers. (C) 2012 Elsevier B.V. All rights reserved.
