Huang et al. 2004

Huang Y, Zou J, Zheng X, Wang Y, Xu X. 2004. Nitrous oxide emissions as influenced by amendment of plant residues with different C:N ratios. Soil Biology & Biochemistry 36: 973-981.

These authors examined the role of residue quality, in the form of C:N ratio and a range of crop residues, on N2O emissions from soils. They also measured CO2 emissions, and found strong correlations between organic-matter decomposition and respiration, and nitrogen cycling.

Gas fluxes of CO2 and N2O were highly correlated across all incubations. To ensure only respiration-derived CO2 was measured, the CO2 released by urea breakdown in urea-treated treatments was calculated and subtracted; respiration in the urea-only treatment was similar to that in the untreated controls. Both gas emissions were negatively correlated with residue C:N ratios. Finally, residue C:N ratios were negatively correlated with dissolved organic carbon concentrations.

Overall, higher C:N ratios in residues seem to result in slow decomposition of mainly recalcitrant organic matter, and low CO2 and N2O emissions. Addition of urea in conjunction with crop residues produces a range of N2O emissions depending on the C:N ratio of the residues.

This short paper may serve as a model for the work I will be doing in the special topics class in soil science, fall 2010.