International Journal of
Water Resources and Environmental Engineering

  • Abbreviation: Int. J. Water Res. Environ. Eng.
  • Language: English
  • ISSN: 2141-6613
  • DOI: 10.5897/IJWREE
  • Start Year: 2009
  • Published Articles: 281

Full Length Research Paper

Comparative assessment of soil and nutrient losses from three land uses in the central highlands of Ethiopia

Daniel Jaleta*
  • Daniel Jaleta*
  • Department of Engineering Sciences and Technology, Sokoine University of Agriculture, P. O. Box 3003, Morogoro, Tanzania.
  • Google Scholar
Boniface P. Mbilinyi
  • Boniface P. Mbilinyi
  • Department of Engineering Sciences and Technology, Sokoine University of Agriculture, P. O. Box 3003, Morogoro, Tanzania.
  • Google Scholar
Henry F. Mahoo
  • Henry F. Mahoo
  • Department of Engineering Sciences and Technology, Sokoine University of Agriculture, P. O. Box 3003, Morogoro, Tanzania.
  • Google Scholar
Mulugeta Lemenih
  • Mulugeta Lemenih
  • Department of Forestry and Natural Resource, Farm Africa, P. O. Box 5746, Addis Ababa, Ethiopia.
  • Google Scholar


  •  Received: 14 October 2016
  •  Accepted: 22 November 2016
  •  Published: 31 January 2017

Abstract

Land use/land cover change drive changes in several ecosystem processes over short and long terms. In Ethiopia, the main land use/land cover change involves conversion of natural ecosystem into cultivated land. However, a recent change also involves conversion of cultivated and grazing land into Eucalyptus woodlots. This study was conducted to analyse the effects of such land use/land cover change on soil and nutrient losses. Three land use/ land cover types (cultivated land, grassland and Eucalyptus woodlot) were selected for a comparative assessment. A total of twelve runoff plots, each with 43.3 m2 area and with four replications, were installed. Rainfall depth, runoff volume and sediment samples (500 ml) were collected from each plots every morning and evening for 91 days (from 4th July to 2nd October, 2015) in the main rainy season. The sediment samples for ten consecutive days were stored in separate containers and composite sediment concentration samples were weighed after being filtered and oven dried for 24 hours at 105oc. From the samples taken at the end of the rainy season, separate composite a sample before filtration of one litre was analysed in the laboratory for nutrient losses. The effect of land use/land cover on soil and nutrients losses was statistically tested using analysis of variance. The study found that soil loss significantly differed between the land use/land cover types. Soil loss from cultivated land (16.8 ton/ha) was significantly higher than loss from grassland (7 ton/ha) and Eucalyptus stand (8.1 ton/ha). The soil and nutrient losses were positively correlated with runoff volume. There was higher nutrient (N and P) loss from cultivated land than grassland and Eucalyptus. From the results, it can be concluded that soil and nutrients losses are above tolerable limit, and perennial land covers including Eucalyptus stand reduce soil and nutrient losses significantly. This re-affirms the multi-purpose nature of Eucalyptus not only for socioeconomic benefit but also for soil erosion control when planted in appropriate locations.

Key words: Cultivated land, grassland, runoff, sediment concentration, runoff plot.