Assessment of efficiency of vegetative barriers as soil conservation systems on steep lands.
Soil conservation trials were conducted on an Aquic Paleudult soil at Bajo Seco, Distrito Federal, Venezuela, to examine the effectiveness of different vegetation barriers on slopes of 15-20% cultivated with carrot. Barrier plant species included: vetiver grass (Vetiveria zizanioides), Guatemala grass (Tripsacum laxum), fern (Nephrolepis sp.), African lily (Agapanthus africanus) and lemon grass (Cymbopogon citratus). Soil, water, nutrient and organic matter losses were determined as well as soil water content, crop yields and universal soil loss equation (USLE) parameters. It was found that rainfall erosivity and soil erodability were low during the evaluation period. Soil and water losses increased as the slope increased. Carrot offered very poor protection against soil erosion. The most efficient barrier to reduce soil, nutrients, organic matter and water losses and maintain good water availability in the soil was 10-year-old vetiver. The highest yields were obtained 1 m above the vegetation barriers. From authors' summary. KEYWORDS: TROPAG | Daucus carota | Vetiveria zizanioides | Tripsacum laxum | Cymbopogon citratus | soil conservation | Daucus carota | sloping land | hedges | erosion control plants | Cymbopogon citratus | Tripsacum laxum | Vetiveria zizanioides | VENEZ | Distrito Federal.