Quantification of the Temporal Variability of N and Available P Loss in the Eroded Sediment the Case of Mana Watershed Goro District, South Eastern Ethiopia

Abstract

Human induced changes in the Ethiopian highlands aggravate runoff, sediment and nutrient losses compromising ecosystem services. Soil erosion damages capital that supports economic development and improvements in quality of life. Most studies conducted in Ethiopia are focused on quantification of soil loss in terms of spaces. But this study aims to quantify the temporal variability of N and available P loss in the eroded sediment of Mana Watershed Goro District, South Eastern Ethiopia. The Mana watershed is located in the northeastern part of the Genale Dawa Basin, southeastern Ethiopia. To achieve the identified objective, sampling station was selected at the outlet of the watershed. Depth integrated runoff samples were collected during the Belg season in 2019. Daily runoff samples were collected and filtered to separate the sediment from the water. The result revealed that both N and P concentrations were highly variable in time; in which lower concentration occurred towards the end of the rainy season than at the beginning. The average TN lost associated with the sediment in the rainy season was 584.47 gram per kilogram. From the sample analyzed an average of 369.98 gram of P per kilogram associated with sediment was lost in runoff only during the spring season from the watershed. In addition to the long-term deterioration of land quality, the annual financial loss suffered by farmers is substantial. Therefore, linking traditional and modern SWC measures in the study area is crucial in order to mitigate soil erosion and associated nutrient loss.

Keywords: Mana watershed, nutrient loss, soil erosion

DOI: 10.7176/CER/11-12-02

Publication date: December 31^st 2019