Variations in Soil Properties Across Land Use Types in the Shemit Watershed, Northern Ethiopian

Abstract

Land use type and soil depth have profound effects on soil physical and chemical properties, influencing soil health, agricultural productivity, and ecological stability. In Shemit watershed, increasing pressure from population growth, deforestation, and unsustainable land management practices has led to land degradation and declining soil fertility. These challenges underline the importance of assessing how various land use types and soil depths affect key soil parameters. Therefore, the study was conducted in the Shemit watershed. The objective was to evaluate the impact of different land use types on soil properties. Four land use types natural forest, cultivated land, grazing land, and plantation forest were selected for analysis. A total of 24 disturbed composite and 24 undisturbed core soil samples were collected from the four land use types at two soil depths, in triplicate. The soil samples were prepared and analyzed in the laboratory using standard procedures. The result revealed that sand, clay, bulk density (BD), pH, organic matter (OM), total nitrogen (TN), available phosphorus (Av.P), exchangeable bases (Ca, Mg, K, and Na), cation exchange capacity (CEC), and percent base saturation (PBS) were significantly (p < 0.05) influenced by land use type. However, silt content and the carbon-to-nitrogen (C:N) ratio were not significantly (p > 0.05) affected. With regard to soil depth, only sand, OM, exchangeable Na, and PBS showed significant variation (p < 0.05). The highest mean values of pH, soil OM (SOM), TN, Av.P, Ca, K, and CEC were recorded under natural forest. In contrast, the lowest values for most of these parameters (except TN, OM, Av.P, and CEC) were observed under plantation forest. The result also indicated as soil depth increased, clay content, BD, pH, exchangeable bases, and PBS also increased, while sand, silt, TN, OM, and CEC decreased. The result showed Natural forest soils had 5.32% OM, while cultivated lands had 2.47%. Similarly natural forest had higher moisture content (33.89%) compared to grazing land (23.05%). The conversion of natural forest to other land use types resulted in a significant reduction in soil fertility. Understanding of how land use and management practices affect soil conditions is essential. Implementing effective land management strategies is vital for assessing the sustainability of current land use systems. Therefore, addressing the declining soil fertility in the Shemit watershed of Northwest Ethiopia, it is crucial to protecting upland natural forests through adopting restoration techniques like compost application, reduced tillage, and contour farming can significantly improve soil health. For example, farmers using contour farming in steep areas have seen reduced erosion and improved crop yields. Moreover, achieving long-term impact requires coordinated efforts from local governments, development partners, and communities to promote sustainable land use and ecological balance in Northwest Ethiopia.