1Department of Agricultural Science and Technology, School of Agriculture and Environmental Sciences, Kenyatta University, Nairobi, Kenya
2Department of Environmental Studies, College of Natural Resources and Environmental Studies, University of Juba, University Road, Juba, South Sudan
3Kenya Wildlife Services, Nairobi Center, Nairobi, Kenya
4Department of Agronomy and Agroforestry, M.S. Swaminathan School of Agriculture, Centurion University of Technology and Management, Paralakhemundi, Odisha, India
*Corresponding author: maloguna@yahoo.com, (ORCID ID: 0000-0002-5453-9170)
Online Published on 17 April, 2025.
The composition of soil organic carbon (SOC) and soil organic nitrogen (SON) is imperative to soil health in different agroecological zones globally. The proliferation of anthropogenic activities triggers the nitrogen and carbon stocks in soils. This study presents the spatial distribution of SOC and SON in six counties in Central Equatoria State, South Sudan counties. This study sought to determine the effect of pastoral activities on SOC and SON. We collected the soil samples within a 12–14 km radius from specific areas including congregation, grazing, degraded, water points, and agricultural land. The soil was collected at depths of 0–10 cm, 10–20 cm, and 20–30 cm respectively. The results indicate that land use activities had varied impacts on SOC and SON at different depths. The results showed that the interactive effects of the three sites and land uses differed in soil organic carbon (SOC) under different soil depths, which varied from 0.3 to 5.3%. The grazing area also recorded a higher SOC than the other land use types under 0–10 cm soil depth. The means showed that the SOC in the deep soils (20-30 cm) was lower than the surface soils in all the areas and land uses. The interactive effects of the districts and land uses differed in soil organic carbon (SOC) under different soil depths, which varied from 0.3 to 5.3%. The highest mean SOC of 5.73% was recorded in 0–10 depth in Kajokeji in the grazing area. The grazing area also recorded a higher SOC than the other land use types under 0–10 cm soil depth. The means showed that the SOC in the deep soils 20–30 cm was lower than the surface soils in all the areas and land uses. The results thus underscore that study areas and land use activity could impact the SOC and SON directly or indirectly.
Soil organic content and soil organic nitrogen concentrations decreased with the increase of soil depth in most land uses, implying that management of topsoil is paramount.
The grazing area exhibited higher soil organic carbon and soil organic nitrogen concentrations than other areas, which may be related to manure and urine deposits and trades-off the losses from plant tissues.
Land use types have far-reaching changes in soil organic carbon and nitrogen as shown by variation in different districts.
Soil Organic Carbon, Soil Organic Nitrogen, Carbon Stocks, Nitrogen, Grazing Intensity
