Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, New Delhi 110012.
A field experiment was conducted to study the effect of greenmanure incorporation and urea application on flood water properties under lowland rice cultivation. From the data on ammoniacal N concentration, temperature and pH of flood water, the partial pressure of ammonia (PNH3 was calculated. PNH3 was significantly higher in plots receiving urea alone than with Sesbania alone or combined with urea. This was probably due to high pH and high NH/content of flood water in urea plots. The higher the substitution of urea by Sesbania, the lower was the PNH3 of floodwater and, hence, the possibility of lower NH3 volatilization loss.
Flood water, greenmanure, NH3 loss, partial pressure, volatilization loss
