Variations in Greenhouse Gas Fluxes in Response to Short-Term Changes in Weather Variables at Three Elevation Ranges, Wakiso District, Uganda

Abstract

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.

Nitrous Oxide Emissions from Smallholders’ Cropping Systems in Sub-Saharan Africa

“…Soil temperature significantly influences soil N 2 O fluxes by increasing microbial activities responsible for N 2 O emissions in soil [27]. Nitrous oxide emissions increase with an increase in soil temperature due to advanced decomposition rates of organic matter [58]. An increase in N 2 O emissions with rising temperature can be associated with increased nitrogen mineralization, hence higher availability of nitrogen lost as N 2 O fluxes [27].…”

“…Atmospheric temperature also influences N 2 O emissions. For instance, Fatumah et al [58] reported higher N 2 O emissions in higher altitudes (1200-1300 m above sea level (asl)) characterized with low temperatures as compared to low altitudes (1100 to 1200 m and 900 to 1100 m asl) with higher temperature in Uganda. Further, in Kenya, higher soil N 2 O emissions were observed in Kaptumo with an elevation of 2000 m asl than Kolero with an elevation of 1250 m asl [42].…”

“…Soil moisture is a crucial driver of N 2 O fluxes as it determines oxygen and organic substrates' availability [24]. Several studies have shown that increased soil moisture content, especially at the onset of a season, results in increased microbial activities causing enhanced soil N 2 O emissions [28,43,44,58,64]. Increased N 2 O emissions following the beginning of precipitation can be attributed to improved soil CN mineralization and decomposition due to Birch's birch effect [75].…”

“…Soil N 2 O emissions can significantly be influenced by soil C, N, and C/N ratio [58]. e C/N ratio can predict whether mineralization or immobilization takes place.…”

Assessing the Influence Factors of Agricultural Soils’ CH4/N2O Emissions Based on the Revised EDGAR Datasets over Hainan Island in China

“…GHGe from agricultural soil are strongly correlated with temperature and precipitation [17,18]. Soil microorganisms play a critical role in driving biochemical processes that lead to GHGe and are sensitive to temperature changes [19,20].…”