Gaseous emissions and soil fertility of homegardens in the Nuba Mountains, Sudan

Abstract

AbstractIntensification of homegardens in the Nuba Mountains may lead to increases in C and nutrient losses from these small‐scale land‐use systems and potentially threaten their sustainability. This study, therefore, aimed at determining gaseous C and N fluxes from homegarden soils of different soil moisture, temperature, and C and N status. Emissions of CO2, NH3, and N2O from soils of two traditional and two intensified homegardens and an uncultivated control were recorded bi‐weekly during the rainy season in 2010. Flux rates were determined with a portable dynamic closed chamber system consisting of a photo‐acoustic multi‐gas field monitor connected to a PTFE coated chamber. Topsoil moisture and temperature were recorded simultaneously to the gas measurements. Across all homegardens emissions averaged 4,527 kg CO2‐C ha−1, 22 kg NH3‐N ha−1, and 11 kg N2O‐N ha−1 for the observation period from June to December. Flux rates were largely positively correlated with soil moisture and predominantly negatively with soil temperature. Significant positive, but weak (rs < 0.34) correlations between increasing management intensity and emissions were noted for CO2‐C. Similarly, morning emissions of NH3 and increasing management intensity were weakly correlated (rs = 0.17). The relatively high gaseous C and N losses in the studied homegardens call for effective management practices to secure the soil organic C status of these traditional land‐use systems.