Relative Performance of Neem Coated Urea Viz-a-Viz Ordinary Urea Applied to Rice-Wheat Cropping in Sub-Tropical Soils

On-farm trials (OFTs) at eighteen different farmer field locations varying in soil fertility were conducted (2006-08) to assess the relative performance of different nitrogen sources viz., neem coated urea (NCU) and ordinary urea (OU). The treatments thus compared consisted of 96 and 120 kg N ha^-1 through NCU and OU, thus, constituting T₁=80% NCU, T₂=80% OU, T₃=100% NCU and T₄=100% OU. The grain yield for wheat and rice in T₃/T₄ was significant (p<0.05) (6.9% and 13.8%, respectively) higher than T₁/T₂, however, the grain yield among equivalently applied N treatments was statistically at par. The results revealed no significant differences in agronomic efficiency of N (AEN) applied through different sources at equal applied level. However, there was significantly higher AEN for T₁/T₂ than T₃/T₄ in both wheat and rice. The total energy productivity for wheat in T₃/T₄ was 6.87 per cent higher, with a decrease in energy productivity by 0.11 MJ ha^-1 than T₁/T₂. However, in rice the total energy productivity was 14.9 per cent higher in T₃/T₄ with 0.16 MJ ha^-1 over T₁/T₂. Thus, it can be concluded that the two N sources are equally effective for rice-wheat cropping in sub-tropical soils.