Comparing anhydrous ammonia (Big N) with urea in rice (August 2001)

Dang, Y  Walker, C  Kirkby, C

Incitec Fertilizers, Griffith
Incitec Fertilizers, Geelong
CSIRO, Grifftih


Big N for pre-plant nitrogen boosted rice yield by 1 t/ha over urea. Big N offers greater opportunity to apply nitrogen 3-4 weeks before flooding. Big N and urea have similar effects on Microbes.  Studies reported by Heenan and Bacon (NSW Agriculture) in 1989 showed that urea nitrogen applied two weeks or more before permanent flooding of aerial sown rice significantly decreased the grain yields, which may be due to loss of nitrogen through volatilisation and denitrification, depending on soil type, soil moisture and weather conditions.