Land and water degradation caused by soil erosion and climate change pose major environmental threats, particularly in agricultural watershed like Kakia-Esamburmbur. Soil erosion in the catchment has led to decreasing crop yields due to a declining soil quality, productivity and sustainability. However, limited studies have been done to assess soil health in Kenya, and none in Narok County. Thus, the aim of this study was to evaluate the soil sustainability status in Kakia-Esamburmbur catchment across three land use types designated as grass land (GL), crop land (CL) and forest land (FL). To achieve the stated objective, two soil quality indexing methods were employed: the Additive Soil Quality Index (A-SQI) using a large data set of 23 selected physical, chemical and biological indicators; and the Weighted Soil Quality Index (W-SQI) using Principal Component Analysis (PCA) as a tool to reduce data to obtain the Identified Key Indicators set (IKI). The results show that at a depth of 20 cm, the catchment’s soils physical, chemical and biological characteristics did not differ significantly. The two methods (A-SQI and W-SQI) resulted in FL having the highest SQI mean values (0.61, 0.57), followed by CL (0.59, 0.55), while the lowest SQI mean value was recorded in GL (0.58, 0.53). Eight Principal Components having eigenvalues 1 explained 81.087% of data variability. Additionally, the sensitivity analysis showed W-SQI as the most sensitive and superior method in the evaluation of SQI changes. This can be attributed to its high sensitivity and coefficient of variation (CV), at 2.25 and 12%, respectively. The results gave ten key indicators (IKI) having the following order of contribution: CEC (18.68%,), BD (15.61%), BIR (14.71%), Mg (14.26%), MBN (8.30%), MBC (8.26%), Sand (6.77%), Moisture (5.75%), TOC (5.16%), and PMN (2.63%). In conclusion, the findings show that the catchment belongs to the "medium" category of SQ. Thus, best sustainable land management strategies such as soil water conservation practices should be implemented and monitored to conserve and improve the quality of degraded soils, using SQI as a decision support tool
