Effects of soil bund age on selected soil physical properties in Chyulu landscape, Kajiado County

Abstract Soil degradation threatens sustainable provision of ecosystem services and adversely affects the livelihoods in Kenya, especially in arid and semi-arid areas. To mitigate the impacts of soil degradation, soil conservation measures such as terraces, retention ditches, cut-off drains, and soil bunds have been adopted. In Chyulu landscape, soil bunds have been adopted over the last eight years. However, their impacts on soil physical properties have not been well understood. Thus, this study evaluated effects of soil bunds on soil physical properties in Chyulu landscape, Kajiado County. Soil samples were collected from the sites with 7–8 years (old), 4–5 years (medium), 2–3 years (new) soil bunds, and unbunded area along soil profile at depths of 0–10, 10–20, 20–30, 30–40 cm. Standard laboratory methods were used to determine bulk density, moisture content, porosity, infiltration rate, saturated hydraulic conductivity, and proportions of sand, silt, and clay. From Analysis of variance (ANOVA), it was observed that there was significant difference (p < 0.05) in mean bulk density at different sites and soil depths while infiltration rate showed significant difference at different sites. The mean bulk density was significantly higher in unbunded area (1.46 g cm −3 ) compared to old (1.25 g cm −3 ), medium (1.33 g cm −3 ), and new bunds (1.38 g cm −3 ). Bulk density had negative correlation with porosity, saturated hydraulic conductivity, moisture content, %silt, and %clay. Thus, this study concludes that soil bunds had significant effects on soil physical properties and that despite the age, the bunds had positive impacts towards restoration of degraded soil.