DENITRIFICATION AND GAS EMISSIONS FROM ORGANIC SOILS UNDER DIFFERENT WATER TABLE AND FLOODING MANAGEMENT

作者：Miller J O^*; Hunt P G; Ducey T F; Glaz B S

来源：Transactions of the ASABE, 2012, 55(5): 1793-1800.

• Denitrification
• N2O
• Organic soils

Draining the Florida Everglades for agricultural use has led to land subsidence and increased phosphorus (P) loads to the southern Everglades, environmental concerns that can be limited by controlling water table depth. The resulting anaerobic conditions in saturated soils may lead to increased denitrification and gaseous N2O release. Sugarcane was grown in lysimeters using four water table treatments, ranging from 40 to 16 cm in depth. Gas emissions were measured in April, July, and September using a photoacoustic gas analyzer Denitrification enzyme activity (DEA) was performed on soil samples from the upper 15 cm, including non-limiting carbon and nitrogen conditions. No differences in N2O emissions or DEA were observed between water table treatments. However; emissions of N2O were higher in the spring, and CO2 emissions were greater in the late summer Overall, incomplete DEA was very low in the soil samples, indicating that shallow water tables will not increase N2O emissions in these organic soils. Additions of C versus NO3 increased DEA, indicating that these organic soils are carbon limited. Neither the amoA nor nosZ genes were affected by water table management, but the abundance of the nosZ gene increased from April to September, while amoA gene abundance decreased.

• 出版日期2012-10