Soil organic carbon spatial and temporal variability influenced by cultivation in the Miombo woodland of central Africa
(2025)
Files
proof_clean_Xiaojing_PhD_thesis_Oct2025.pdf
Restricted Access - Adobe PDF
- 5.64 MB
Details
- Authors
- Supervisors
- Van Oost, Kristof
- Abstract
- Soil organic carbon (SOC) underpins soil health, agricultural productivity, and is essential in the global carbon cycle. In tropical Africa, land pressure is rising with population growth and the associated increase in food demand, yet SOC responses to cultivation remain poorly quantified. This thesis examines how farming practices and cultivation history control cropland SOC content under the two farm types (i.e., smallholder vs. commercial agriculture) in the Copperbelt region of the Democratic Republic of the Congo (DRC). We combine farm-scale soil sampling with region-scale satellite mapping. First, a pilot study on a commercial farm shows that mechanical levelling of termite mounds during land preparation quickly dilutes surface SOC and restructures SOC in space. Older and larger mounds contain more low-SOC material, and their levelling causes larger SOC reductions. This reduction does not recover within about a decade, despite the mound material’s beneficial chemical properties. Second, at the regional scale, using a mapping approach that explicitly accounts for model uncertainty and the spatial autocorrelation of errors, we find that cultivation duration alone has a limited effect on SOC in both smallholder and commercial farms. In contrast, the two farm types show detectable SOC differences, but the direction and magnitude of these differences vary with environment. Taken together, we show that SOC variation in tropical cropland is controlled primarily by local land preparation and farming systems, with clear regional differences and little influence of cultivation duration. Future studies should combine more detailed management data and repeated soil observations to track SOC change over time and relate it to agronomic performance and productivity.
- Affiliations
Citations
Ou, X. (2025). Soil organic carbon spatial and temporal variability influenced by cultivation in the Miombo woodland of central Africa. https://hdl.handle.net/2078.5/266372