Which form of nitrogen is most suitable for rice cultivation in waterlogged soil conditions?

Explanation

In flooded or submerged soils common to rice fields, oxygen availability is limited, creating anaerobic conditions. Under these circumstances, ammonium (NH4+) remains more stable and accessible to rice plants compared to nitrate (NO3-) and nitrite (NO2-), which tend to be less stable and can be lost through denitrification. Therefore, ammonium is the preferred nitrogen form for rice grown in submerged soils.