Comparative assessment of soil and nutrient losses from three land uses in the central highlands of Ethiopia
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Academic journals
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 gra zing 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 cove r 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 105o
c. 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
Description
International Journal of Water Resources and
Environmental Engineering,Vol. 9(1), pp. 1-7, 2017
Keywords
Cultivated land., Grassland., Runoff., Sediment concentration., Runoff plot.