Browsing by Author "Mukiibi Jackson"

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    Impact of wetland conversion to cropland on soil organic carbon and greenhouse gas emissions in yala wetland, kenya
    (Egerton University, 2025) Mukiibi Jackson
    Climate change is one of the major global concems, with scientific evidence linking it to the rising emissions of greenhouse gases (GHGs), particularly carbon dioxide (CO2), methane (CH4) and nitrous oxide (N20) in the atmosphere. Wetlands provide an optimum natural environment for mitigation of climate change through carbon sequestration. Converting wetlands to cropland is well known to reduce soil carbon storage and increase emissions of GHGs. However, there is limited data on how different wetland plants and conversion of wetlands to cropland influence carbon and GHG fluxes. This study aimed to fill the gap in understanding how different wetland plant communities and land conversion affect carbon and nitrogen fluxes. This study was conducted during a dry season i.e. from December 2024 to March 2025 in Kadenge and Usonga sections of Yala wetland. The sampling design was stratified and included four sampling sites that is, wetland areas converted to sugarcane and those dominated by Cyperus alopecuroides, T ypha latzfolia, and Cyperus papyrus. Each site had three sub-sampling sites (replicates), each with three chambers to cater for spatial heterogeneity. Sampling of gases was carried out twice a month using the closed static chamber method. The gas samples were analysed using the SRI GHG gas chromatograph. Soil samples were collected during each sampling session and analysed for NO;-N, NH4-N, soil organic carbon (SOC), total phosphorus, and total nitrogen. The Kruskal—Walli’s test was used to examine the differences in the medians of SOC and GHGs under the different wetland plant dominance and cropland. The results showed that SOC was significantly lower in areas converted to sugarcane (1.73%) than areas dominated by either Cyperus alopecuroides (2.98 %), Typha latzfolia (3.50%) or Cyperus papyrus (3.09 %) (adj. p < 0.05). There were no significant differences in the proportion of SOC among the plant communities (adj. p > 0.05). Both CO2 and NZO did not show significant differences in their emissions among the sites (adj p > 0.05). Significantly higher CH4 emissions were observed in Cyperus alopecuroides (27.19 mg m’ 2 h") compared to Cyperus papyrus (0.09 mg m’ 2 h’l) and sugarcane areas (0.31 mg m’ 2 h’l). In this study, conversion of a wetland area to a sugarcane farm significantly reduced the SOC but had no significant effect on GHG emissions except for CH4 which was significantly higher in Cyperus alopecuroides. Therefore, this necessitates sustainable use of wetlands to minimize SOC loss and consequently GHG emissions