Coating of prilled urea with neem (Azadirachta indica) for efficient nitrogen use in lowland transplanted rice (Oryza sativa)

A field experiment was conducted during 1995–96 at New Delhi, to study the efficiency of modified forms of urea materials, viz. prilled urea (PU), neem cake-coated urea (NCU), 0.5% of 10% neem oil emulsion-coated urea and 0.5% of 20% neem oil emulsion-coated urea at varying N rates (0, 60 and 120 kg/ha) on the productivity of lowland transplanted rice [Oryza sativa L.). Each incremental N level recorded significantly higher growth parameters, yield attributes, grain and straw yields and also N uptake over its preceding level. However, apparent N recovery decreased with increasing N levels. Neem cake-coated urea and neem oil emulsion-coated urea irrespective of the concentration improved rice growth, yield attributes and resulted in more grain and straw yields, N uptake and also higher apparent N recovery than did commercial prilled urea.