Influence of soil properties on N2O emissions

Observations on nitrous oxide (N2O) from urine and dung patches deposited by grazing cattle in sub-Saharan Africa (SSA) are scarce. Moreover, the effects of soil properties (e.g. pH or texture) on N2O emissions from excreta patches have hardly been studied. Here, we investigated the importance of soil properties on N2O emissions from cattle excreta (dung, urine) for five typical tropical soils in Kenya using intact soil cores in both dry and rainy seasons.

The emission factor (EF) during the rainy season were higher for both dung (0.08%) and urine (0.50%) compared to the dry season EF (0.02% and 0.07% for dung and urine respectively). Soil type had no measurable effect on dung EF while urine EF was significantly correlated with soil clay content (negatively) and pH (positively). Assuming an excreta-N ratio of dung to urine of 66:34 for SSA, we calculated a cattle excreta N2O EF of 0.13%, which is still lower than the default value of 0.20% for dry climate from IPCC 2019 refinement.