Nutrient Management Research Database

The use of organic residues as soil additives is increasing, but, depending on their composition and application methods, these organic amendments can stimulate the emissions of CO(2) and N(2)O. The objective of this study was to quantify the effects of management practices in irrigated sweet corn (Zea mays L.) on CO(2) and N(2)O emissions and to relate emissions to environmental factors. In a 3-yr study, corn residues (CR) and pasteurized chicken manure (PCM) were used as soil amendments compared with no residue (NR) under three management practices: shallow tillage (ST) and no tillage (NT) under consecutive corn crops and ST without crop. Tillage significantly increased (P < 0.05) CO(2) and N(2)O fluxes in residue-amended plots and in NR plots. Carbon dioxide and N(2)O fluxes were correlated with soil NH(4) concentrations and with days since tillage and days since seeding. Fluxes of CO(2) were correlated with soil water content, whereas N(2)O fluxes had higher correlation with air temperature. Annual CO(2) emissions were higher with PCM than with CR and NR (9.7, 2.9, and 2.3 Mg C ha(-1), respectively). Fluxes of N(2)O were 34.4, 0.94, and 0.77 kg N ha(-1) yr(-1) with PCM, CR, and NR, respectively. Annual amounts of CO(2)-C and N(2)O-N emissions from the PCM treatments were 64 and 3% of the applied C and N, respectively. Regardless of cultivation practices, elevated N(2)O emissions were recorded in the PCM treatment. These emissions could negate some of the beneficial effects of PCM on soil properties.

• This three year study in a sweet corn system investigated the effects of corn residue and pasteurized chicken manure incorporation on CO2 and N2O emissions.
• The study was conducted in a Mediterranean climate similar to that in California.
• Shallow tillage and no tillage systems were also analyzed.
• Soil moisture and nitrogen levels were also tracked over the course of the experiment.

• Tillage increased both N2O and CO2 emissions.
• CO2 and N2O emissions were highest from the poultry manure.
• Both poultry manure and corn residue incorporation increased soil moisture.
• Soil plant available N levels were highest in the poultry manure amended soil, though this also was likely the cause of the increased N2O emissions.
• This study shows that careful management of soil amendments is needed to limit greenhouse emissions resulting from their application.