Land-Use Driven Variations in Soil Fertility: Evidence from Tiyo District, Central Ethiopia

Soil fertility decline is one of the major challenges to sustainable agriculture in Ethiopia, particularly, where land is continuously cultivated or converted to other uses. To better understand this issue, this study assessed the impact of three predominant land uses, Eucalyptus, cultivated fields, and pastureland, on soil quality in Tiyo District, Central Ethiopia. Ninety soil samples were collected at two depths (0–15 cm and 15–30 cm) in a 300m by 500m plot using systematic sampling. The samples were analyzed for selected soil parameters such as bulk density, pH, organic carbon, total nitrogen, available phosphorus, and exchangeable bases. Statistical tests were utilized to determine differences in land use and soil depth, as well as relations between soil parameters. The results revealed significance variations in soil properties across land use types and soil depths. The surface soil organic carbon was highest in pastureland (6.19) followed by eucalyptus plantation (5.76) and lowest in cultivated fields (2.78). In the subsoil the values were 5.37, 4.81 and 2.02 respectively. Available phosphorous (ppm) followed a similar trend with 14.2, 13.33 and 10.8 in surface soil and 11.73, 10.27 and 7.8 in subsoil for the three land uses respectively. Bulk density was lowest in Pasturelands (0.92 g/cm³), indicating improved soil structure, and highest in cultivated land (1.04/cm3 for g/cm³), suggesting compaction and organic matter depletions. Soil pH ranged from mildly acidic (5.09) in cultivated land to nearly neutral (6.2) under Eucalyptus. Pastureland also had higher level of exchangeable nutrients, while cultivated land exhibited sign of nutrient depletion, particularly as depth increased. In conclusion, Pasturelands are more effective in preserving soil fertility compared to cultivated land or Eucalyptus planting. These findings highlight the need for land management strategies that incorporate pasture – based system to repair and maintain soil health in intensively cultivated areas.