Browsing by Author "Fatumah, Nakiguli"

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Comparative assessment of greenhouse gas fluxes and crop yields from various land use systems in Wakiso District, central Uganda
(NM-AIST, 2021-07) Fatumah, Nakiguli
Land use systems, mainly, crop farming is among the leading sources of greenhouse gas emissions into the atmosphere, driving climate variability and global warming. This study aimed to compare greenhouse gas fluxes and crop yields from various land use systems in Wakiso District, Uganda. Specifically, the study; (a) assessed soil physical-chemical properties and greenhouse gas fluxes from land use systems, (b) determined the effect of cropping systems and management practices on greenhouse gas fluxes and crop yields, and (c) assessed the effect of precipitation, soil temperature, and elevation on greenhouse gas fluxes. Greenhouse gas fluxes and crop yields were monitored under split-plot design experiments. Digital gas meters and static chambers were used to measure greenhouse gas fluxes. Carbon dioxide fluxes were highest and lowest in sole cropped sweet potatoes under non-mulched deep tillage (148.12 ± 3.40 µg C m−2 hr−1 ) and grasslands (53.03 ± 1.70 µg C m−2 hr−1 ), respectively. Nitrous oxide fluxes were highest and lowest in sole cropped beans under non-mulched reduced tillage (14.21 ± 0.40 µg N m−2 hr−1 ) and banana-coffee intercrops under compost - reduced tillage (3.76 ± 0.20 µg N m−2 hr−1 ), respectively. Methane uptake was highest and lowest in banana-coffee intercrops under mulched - no-tillage (-0.57 ± 0.00 µg C m−2 hr−1 ) and sole cropped sweet potatoes under mulched - no-tillage (0.3 ± 0.01 µg C m−2 hr−1 ), respectively. Crop yields were slightly higher in intercropped than sole cropped systems. Carbon dioxide fluxes were highest and lowest at 1200 - 1340 m (87.42 ± 5.60 µg C m −2 hr −1 ) and 900 - 1000 m (52.41 ± 3.90 µg C m−2 hr −1 ), respectively. Nitrous oxide fluxes were highest and lowest at 1200 - 1340 m (6.82 ± 0.80 µg N m −2 hr −1 ) and 900 - 1000 m (3.65 ± 0.60 µg N m −2 hr −1 ), respectively. Methane flux was highest at 1200 - 1340 m (0.31 ± 0.01 µg C m−2 hr −1 ) and lowest at 900 - 1000 m (0.04 ± 0.00 µg C m−2 hr −1 ). The results are vital in understanding greenhouse gas fluxes and crop yields from various land use systems in Uganda
The effect of land-use systems on greenhouse gas production and crop yields in Wakiso District, Uganda
(Elsevier B.V., 2020-12-16) Fatumah, Nakiguli; Munishi, Linus; Ndakidemi, Patrick
Land-use systems are among the leading sources of anthropogenic GHG into the atmosphere; driving global warming, climate change, and associated extreme weather events. To estimate GHGs from the land-use systems, we measured fluxes (positive/negative emissions per unit of time) of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) from the cropping and adjacent non-cropping systems in Wakiso District, Uganda. The study comprised of 9 treatments with 2 inter-cropping systems (banana-coffee and maize-beans), 4 sole-cropped systems (banana, maize, beans, and sweet potato), and 3 non-cropping systems (fallow lands, pasture lands, and grasslands). Four management practices: mulching with no-tillage (mulched-NT); non-mulching with reduced-tillage (non-mulched-RT); non-mulching with deep-tillage (non-mulched-DT); compositing with reduced-tillage (compost-RT) were embedded in the cropping systems. The study also assessed the effect of the cropping systems and their management practices on crop yields. The GHG fluxes were monitored using the static chamber technique and analysed using a gas chromatography (G.C.). The results showed that all the land-use systems were sources of CO2 flux with sole-cropped sweet potato under non-mulched-DT (148.12 ± 3.4 μg C m−2 h−1) as the most substantial source, and the grasslands (33.03 ± 1.7 μg C m−2 h−1) as the weakest source. Similarly, all the land-use systems were sources of N2O flux with sole-cropped beans under non-mulched-RT (14.21 ± 0.4 μg N m−2 h−1) as the strongest source, and grasslands (3.43 ± 0.4 μg N m−2 h−1) as the weakest source. The management practices were sinks (any system that absorbs more GHGs than it releases) of CH4 except mulched-NT in the maize-beans intercrop, sole-cropped beans, and sole-cropped maize. The sole-cropped sweet potato under mulched-RT (0.3 ± 0.01 μg C m−2 h−1) was the strongest source of CH4, while the grasslands (−0.67 ± 0.01 μg C m−2 h−1) were the strongest sink. The intercropped systems significantly reduced GHG fluxes and had a yield advantage relative to the sole-cropped systems. Our results suggested that intercropping in central Uganda could be a more sustainable and eco-friendly approach concerning GHG fluxes.
Variations in Greenhouse Gas Fluxes in Response to Short-Term Changes in Weather Variables at Three Elevation Ranges, Wakiso District, Uganda
(MDPI, 2019-11-14) Fatumah, Nakiguli; Munishi, Linus; Ndakidemi, Patrick
Weather conditions are among the major factors leading to the increasing greenhouse gas (GHG) fluxes from the agricultural soils. In this study, variations in the soil GHG fluxes with precipitation and soil temperatures at different elevation ranges in banana–coffee farms, in the Wakiso District, Uganda, were evaluated. The soil GHG fluxes were collected weekly, using the chamber method, and analyzed by using gas chromatography. Parallel soil temperature samples were collected by using a REOTEMP soil thermometer. Daily precipitation was measured with an automated weather station instrument installed on-site. The results showed that CO2, N2O, and CH4 fluxes were significantly different between the sites at different elevation ranges. Daily precipitation and soil temperatures significantly (p < 0.05) affected the soil GHG fluxes. Along an elevation gradient, daily precipitation and soil temperatures positively associated with the soil GHG fluxes. The combined factors of daily precipitation and soil temperatures also influence the soil GHG fluxes, but their effect was less than that of the single effects. Overall, daily precipitation and soil temperatures are key weather factors driving the soil GHG fluxes in time and space. This particular study suggests that agriculture at lower elevation levels would help reduce the magnitudes of the soil GHG fluxes. However, this study did not measure the soil GHG fluxes from the non-cultivated ecosystems. Therefore, future studies should focus on assessing the variations in the soil GHG fluxes from non-cultivated ecosystems relative to agriculture systems, at varying elevation ranges.