Ammonia Volatalization Losses from Integrated Nutrient Management in Rice Fields of Alkali Soils

In a field experiment conducted during the wet season of 1997 and 1998 at the Central Soil Salinity Research Institute, Karnal, the effect of integrated use of fertilizer N and green manuring or FYM was evaluated on ammonia volatilization losses in an alkali soil (pH 8.7; ESP 18). Ammonia volatilization losses decreased significantly with FYM or green manure combined with urea-N application compared with urea-N application alone. The losses of ammonia volatilization were 1.23, 23.46 and 32.20 kg ha⁻¹ following application of 0, 120 and 180 kg N ha⁻¹, respectively while 120 kg N ha⁻¹ combined with green manuring or FYM resulted in ammonia volatilization loss of 16.08 or 17.75 kg N ha⁻¹ respectively. Ammonia volatilization losses were more up to 24 hours of urea application and sharply declined during the next 48 hours. Addition of second and third split of N as urea-N gave significantly lower ammonia losses than the basal application before rice transplanting.