تلخیص
Two independent experiments were conducted to assess neem oil coated urea (NOCU), as a natural nitrification inhibitor and
to improve nitrogen use efficiency in maize. In first experiment, soil incubation with increasing levels (i.e. 1%, 2% and 3%
w/v) of neem oil coating was done for 28 days to monitor the release of NH4
+
and NO3
-
contents. Neem oil coated urea slowed
down the release of mineral N with maximum nitrification inhibition (40%) at 3% level of neem coating as compared to 2%
and 1%, hence selected for next study. In the subsequent pot study, NOCU was applied according to recommended dose (250
kg ha-1
) of urea at three different levels (50%, 75% and 100%) for maize crop. There was a significant increase in N contents
of shoot and grains that ultimately provoked high protein contents in maize grains. Application of NOCU enhanced the N
uptake due to its increased availability for longer period of time, resulting in higher grain yield. Maximum agronomic efficiency
(24.38 g g-1
) of applied N was observed with 75% dose of NOCU, while maximum recovery efficiency (0.44 g g-1
) was recorded
with 100% dose of NOCU. Conclusively, application of NOCU saves 25% N application compared to ordinary urea.