PROCESS OF DENITRIFICATION IN FLOODED RICE SOILS

Abstract

Denitrification, which converts soil nitrogen to nitrogen gas, involves a great loss of nitrogen fertilizer. Controlling the process of denitrification rate could help reducing the losses of applied nitrogen fertilizer in crop fields. Fertilizer nitrogen is one of the major concerns due to the high energy demand for its production. Since flooded rice soils are known to have strong denitrifying activity, innovative techniques are emerging as needs to improve nitrogen fertilizer retention efficiency in flooded rice soils. Nitrous oxide (N₂O) emissions are not considered as significant, compared to that of methane (CH₄) emissions from flooded rice soils, most probably due to its complete denitrification process with prolonged submergence that favors the production of nitrogen (N₂) gas. This is due to a further reduction of N₂O to N₂. However, efficient use of nitrogen in the rice soils could have the benefits of saving energy costs that are being spent on nitrogen fertilizers in many developing countries. While conventional approaches are less efficient in controlling denitrification, technical solutions are emerging to solve this need. Technical solutions based on soil redox potential (Eh) for the control of denitrification have not been adequately covered. We propose that applicability of microbial fuel cell based on soil redox chemistry would be more promising for the control of denitrification in flooded rice soils.