Assessing Bacterial and Fungal Contribution to N2O Production in Soils Under Different Tillage Practices.

Nitrous oxide (N₂O) is an atmospheric constituent that has been implicated in climate warming and stratospheric ozone depletion. Among anthropogenic activities, agriculture is the largest N₂O producer contributing about 62% of total N₂O emission. Therefore, agricultural land management decisions could influence atmospheric N₂O burden. During the last several decades, no-till (NT) farming has been widely adopted as a better tillage practice compared to conventional plowing (PT). However, the net effect of NT on N₂O emission and the factors involved are not well understood. In this study, we investigated the N₂O production potential of soils under long-term NT (10 to 48 years) relative to PT and forest soils. A selective inhibition technique using different biocides has been used to determine the relative contribution of fungi and bacteria to the denitrification process in various types of soils. Additional experiments are underway to optimize the selective inhibition assays. Results will help clarify some of the controversies surrounding NT farming.