See more from this Session: Agricultural Practices to Increase Nitrogen-Use Efficiency, Carbon Sequestration, and Greenhouse Gas Mitigation: I
Monday, October 17, 2011: 11:00 AM
Henry Gonzalez Convention Center, Room 218, Concourse Level
Abstract: The reuse of treated wastewater in agricultural systems could partially help alleviate water resource shortages in developing countries. Treated wastewater differs from fresh water in that it has higher concentrations of salts, E. coli and presence of dissolved organic matter and inorganic N after secondary treatment, among others. Its application could thus cause environmental consequences such as soil salinization, ammonia volatilization and greenhouse gas emissions. However, the effect of irrigation with treated wastewater on N2O and CO2 emissions is not well known. In an incubation experiment, we evaluated the characteristics and effects of water filled pore space and N inputs on greenhouse gas emissions from silt loam soil receiving treated wastewater. Irrigation with treated wastewater (vs. fresh water) significantly increased cumulative N2O emission in unamended soil (32.5 μg N kg-1 dry soil). N2O emissions caused by irrigation with treated wastewater combined with urea fertilization did not simply add linearly, but significant interaction (P<0.01) caused lower emissions than the additive effects of the two treatments alone. However, no significant impact on cumulative CO2 emission and emission rate was measured in soil irrigated with treated wastewater. Significant interaction between water filled pore space and N inputs was shown in soil to which treated wastewater was applied. Cumulative N2O emissions showed an exponential relationship with increasing water content.