Soil organic carbon and total nitrogen stocks as a function of land use and land cover in the drylands of Kibwezi West, Eastern Kenya

Abstract

Abstract Soil organic carbon (SOC) and total nitrogen (TN) are critical indicators of soil health, yet research on their distribution across different land use and land cover (LULC) types in Kenyan drylands remains limited. The study assessed the impact of LULC on SOC and TN in Kibwezi West dryland, Eastern Kenya. A completely randomized design was used, with LULC types (cropland, forested land, grassland and shrubland) as treatment groups. Each treatment had three sampling points, with five replicates per point. SOC was analyzed using the Walkley Black method, while TN was analyzed using the Kjeldahl method. Significant (p < 0.05) variations in concentrations of SOC and TN were observed across the LULC types and soil depths. Additionally, concentrations of SOC and TN decreased with increasing soil depth in all LULC types. The SOC and TN stocks were 62.13 t C ha−1 and 5.95 t N ha−1 in forested land, 53.03 t C ha−1 and 4.34 t N ha−1 in grassland, 30.80 t C ha−1 and 4.20 t N ha−1 in shrubland and 20.21 t C ha−1 and 4.11 t N ha−1 in in cropland. The study highlighted the potential of forested areas to serve as critical carbon sinks and underscores the necessity of sustainable management for croplands to enhance SOC and nitrogen retention. This study contributes to the body of knowledge on the effects of LULC types on SOC and TN in drylands. The resulting information can be used to inform the development of sustainable land management strategies in drylands.

Keywords

• Soil organic carbon stocks
• Drylands
• Total nitrogen stocks
• Sustainable land management