Assessing soil fertility influenced by land use in Moche, Gurage Zone, Ethiopia

Abstract

One of the main reasons for Ethiopia’s declining agricultural production is land use change under poor soil management practices. Hence, in order to evaluate the effects of various land use types on certain soil qualities, research was done on the soils of Cheha district, Gurage zone in Ethiopia’s central highlands. Four different land use types (LUTs) (cultivated, enset, eucalyptus, and wild forest) were used for this study to assess and analyze their response to soil fertility. A total of 48 soil samples (24 undisturbed and 24 disturbed) was collected from the selected LUTs and two different soil depths (SDs) (0-20 and 20-40 cm) with three replications for the laboratory analysis. The results showed that most of the properties of soil physicochemical properties of soil were significantly affected by LUTs, SD, and the interactions. The result showed that the highest sand (43%), silt (46.5%), and clay (30.30%) fractions were observed under forest land (FL), enset farmland (ENFL), and cultivated land (CUL), respectively. Concerning the SD, higher silt (40.9%) and clay (28.3%) were found in the subsurface soils. Except for CUL, textural classes of all LUTs were loamy. The highest (1.37 g cm-3) bulk density was observed under the subsurface soils of CUL and the lowest (1.06 g cm-3) was in the surface soils of FL and ENFL. In contrast to bulk density, total porosity was highest (60.1%) under surface soils of FL and ENFL and the lowest (48.3%) value was observed under subsurface soils of CUL. The combination of two factors influenced the soil pH. The highest value (6.54) and lowermost (4.82) values were found under the surface soils of ENFL and subsoils of EUCL, respectively. Comparatively, the uppermost (7.48%) and lowermost (3.55%) values of organic matter were recorded under the surface soils of FL and subsoils of EUCL. The uppermost (0.37%) and lowermost (0.17%) values of total nitrogen were registered under surface soil and subsoils of FL and EUCL, respectively. The uppermost (22.69 mg kg-1) value of Av.P was registered under superficial soils of ENFL and the lowermost (5.02 mg kg-1) was obtained under a subsurface layer of EUCL. The uppermost (37.96 cmol(+) kg-1) and lowermost (11.90 cmol(+) kg-1) of CEC values were observed under the surface soils of FL and subsoils of EUCL. The uppermost value of exchangeable acidity (1.85 cmol(+) kg-1) was recorded under soils of EUCL. This study showed that different LUTs and SDs have substantial impacts on the status of soil fertility. Soils of FL and ENFLs were relatively more fertile. Increasing eucalyptus tree cover on arable land and intensive farming severely impacted soil fertility which may have increased soil acidity. Appropriate land use and a variety of soil fertility management practices are crucial to address soil fertility loss and acidity issues