See more from this Session: Management Practices Impact On Soil Carbon and Nitrogen Cycling in Agricultural Ecosystems: Greenhouse Gas Emissions
Monday, November 1, 2010: 2:50 PM
Hyatt Regency Long Beach, Shoreline A, First Floor
This study examined carbon dioxide (CO2) emission from a tropical soil (Waialua clay variant: Isohyperthermic Pachic Haplustolls) amended with organic compost (CP) and chicken manure (CM [Gallus domesticus]) under conventional (CT), residual (RT), and no tillage (NT). Measurements of CO2 emission were made with CIRAS-1 Infrared Gas Analyzer during three growing seasons of a sweet corn (Zea mays L.) on a weekly or biweekly basis. The CO2 flux data were analyzed using repeated measures of a split-plot design considering amendment type as the main plot and date of CO2 measurement as sub-plot. Organic compost and CM amendments resulted in significantly high CO2 emission compared with control treatments. Time after tillage significantly affected CO2 emission, especially during warmer growing seasons, in interaction with amendment type. Soil surface disturbance during initial stage of growing season resulted in lesser CO2 emission than continuous and frequent disturbances across the growing season. Therefore, CO2 emission from soils under RT should be carefully assessed because the emission is correlated with the intensity and timing of soil surface disturbance. Maximum cumulative CO2 emission (Cmax), calculated from the Lineweaver–Burk transformation of the Michaelis–Menten equation, for NT was 81 and 41% less than those in CT and RT, respectively. Maximum cumulative CO2 emission for RT was 68% less than that for CT (101 Mg CO2 ha–1). Carbon dioxide emission from Waialua soil tilled with ripper plow is in agreement with that from soils in the continental US tilled with chisel plow.