Assessing sediment enrichment ratio in Mai-Negus catchment, northern Ethiopia

Abstract

Soil degradation is a threat to sustainable development in Ethiopia. However, degradation indicators, such as sediment enrichment ratio (SER), are not adequately documented in literature. This study aims to investigate the SER of different erosion-status sites (aggrading, stable, eroded) in various landforms in Mai-Negus catchment, northern Ethiopia. The erosion-status sites in the landforms were identified using field indicators, and soil samples were collected for analysis of selected soil parameters. In this study, due to the ratio of aggrading to eroded or stable sites at catchment and landform levels, the SER of soil nutrients and fine soil particles was > 1. But due to the ratio of aggrading to eroded sites in the landforms the average SER of the soils were higher (1.42–7.22) as compared to the ratios of aggrading to stable sites (1.10–3.66). The SER significantly (P ≤ 0.05) differed among the landforms, which indicated differences in the effect of erosion. The relationships between the SER of fine soil particles and soil nutrients were strong. Thus, priority for introducing appropriate anti-erosion measures should be given to sources of high SER sites such as the mountainous and central ridge landforms in the catchment using the limited resources available.