In the face of climate change, quantification of the emission of nitrous oxide from soils in relation to sufficient N availability for crop uptake has assumed much significance. This study used the 15N stable isotope technique, under controlled laboratory conditions, to quantify the interactive effect on and relative contributions of the component species to N2O emission and mineral N dynamics in a tropical luvisol incorporated with different rates of cowpea-maize residue mixtures. The results show that increasing the maize residue proportion in the mixture significantly decreases N2O emission compared to the sole cowpea incorporation but increases mineral N concentration compared to sole maize residue incorporation. It is concluded that mixing low C:N ratio cowpea residue with high C:N ratio maize residue has potential for N management in tropical legume-cereal intercropping systems with the view to minimizing N2O emission while making N available for crop uptake.
Keywords Nitrous oxide emission – Mineral N – Cowpea-maize residue – 15N stable isotope