Does incorporation of cowpea-maize residue mixes influence nitrous oxide emission and mineral nitrogen release in a tropical luvisol?

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 N-15 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.