Effects of Different Land Use Systems on Selected Physico-Chemical Properties of Soils in Northwestern Ethiopia

Abstract

Information about effects of different land use systems on soil physico-chemical properties is crucial for best land management practices. This study was, therefore, conducted to evaluate the same on Nitosols of Achefer District, Northwestern Ethiopia. The landuse systems studied included grassland, cultivated land, plantation forest and natural forest. The research was superimposed on land use systems that were located nearby on similar soil, contour line and slope classes. Undisturbed core and disturbed composite soil samples were collected randomly from two sites with three replications for each landuse system at two varying depths (0-15 cm and 15-30 cm). The undisturbed soil samples were analysed for bulk density, particle density, porosity and moisture content at different pressures; while the composite soil samples were analyzed for pH, organic carbon, total N and available P. Results of the study indicated that the lowest bulk and particle densities, the highest total porosity, and higher moisture content at both field capacity and permanent wilting percentage were found under natural forest land use system. In contrast, the highest bulk and particle densities, the lowest total porosity and lower water contents at both field capacity and permanent wilting percentage were obtained under the cultivated landuse system. Soil pH was moderately acidic under all landuse systems. The lowest organic carbon, total N, and C:N ratio were recorded under cultivated land; whereas the highest values of the same parameters were found under natural forest. In all landuse systems, organic carbon and total N decreased with soil depth. The highest and lowest available P contents were recorded under natural forest and grassland, respectively. From the results of the study it was possible to conclude that conversion of forest lands to cultivated and grasslands had detrimental effects on the soil physico-chemical properties under subsistance farming systems of the study area. It is, therefore, recommended that appropriate and integrated land management options for different land use syetems are required to sustain agricultural productivity while protecting the environment.

Conversion of natural forest results in a significant degradation of soil hydraulic properties in the highlands of Kenya

“…Our results are thus consistent with previous studies that reported higher bulk densities for pastures or croplands compared to native or forest plantations in Argentina (Cisneros et al, 1999), the north-eastern USA (Zhou et al, 2008), Costa Rica (Reiners et al, 1994), Iraq (Emadi et al, 2008) and Ethiopia (Selassie and Ayanna, 2013).…”

Rethinking Eucalyptus globulus Labill. Based Land Use Systems in Smallholder Farmers Livelihoods: A Case of Kolobo Watershed, West Shewa, Ethiopia

“…This is probably attributed to short rotation age of E. globulus (4 years). These findings are in agreement with similar study report by Selassie and Ayanna (2013), Getachew et al (2012) and Haile et al (2014) who had reported no significant difference on the same between E. globulus and cultivated land.…”

“…The finding agrees with Haile et al (2014) who had reported lower pH value under Eucalyptus woodlots compared to other land use types. However, the pH value (5.55) of this study is greater than that previous report by Selassie and Ayanna (2013) who reported pH values of 5.06 and 5.01 under the E. globulus at Abechikeli Mariam and Aferfida Georgis sites, respectively. Duguma et al (2010) also reported a lower pH value (5.06) under E. globulus compared to homestead, croplands and grazing lands at central highlands of Ethiopia.…”

Expansion of Eucalyptus Woodlots in the Fertile Soils of the Highlands of Ethiopia: Could It Be a Treat on Future Cropland Use?

“…Our result is in line with the findings of different authors; Lalisa et al (2010) and Yihenew and Getachew (2013) reported that in Ethiopian central highlands that soil pH is lower in wood lots/eucalyptus plantation as compared to homestead, croplands and grazing lands. Zerfu (2002) also noted that eucalyptus globulus plantation sites showed high level of active acidity or low pH as compared to agricultural lands.…”

“…Again Tilashwork et al (2012) also found that in Koga irrigation watershed, soils bulk densities at all depths and distances from Eucalyptus camaldulensis and Croton macrostachyus stands are low and ranged from 1.0 to 1.1 g cm -3 . The lower bulk density in crop lands as compared to eucalyptus plantation also reported by (Yihenew & Getachew, 2013). The lower bulk density under eucalyptus may be due to organic matter accumulation and les trampling by livestock.…”