Optimizing Energetics in Aerobic Rice: Comparative Analysis of Tillage Practices and Nitrogen Fertilizer Schedules

A field experiment conducted at the Indian Institute of Rice Research, Hyderabad, Telanagana, India, during the rabi season (November—April) of 2022 and 2023 assessed the impact of tillage practices and nitrogen fertilizer schedules on aerobic rice energetics. Ths study employed three tillage treatments (T) and five nitrogen fertilizer schedules (N) in a strip plot design with three replications. The data were analyzed using two-way ANOVA with R software. The Bartlett test was performed to assess homogeneity before conducting the combined (pooled) analysis. The results revealed that conventional tillage (T1) showed higher energy input (53899 MJ ha^-1), whereas zero tillage (T3) showed lower energy input (51846 MJ ha^-1). Higher gross energy output (GEO), net energy output (NEU) (143114, 89257 MJ ha^-1), energy use efficiency (EUE) (2.65%), and energy productivity (EP) (0.0832 kg MJ^-1) obtained under T1, which is statistically comparable with minimum tillage with residue retention (T2), and significantly higher over T3. Treatment T3 resulted in the highest physical energy intensity (EIP) (5.89 MJ kg^-1). Energy intensity in economic terms (EIE) was not significantly influenced by tillage practices. Among nitrogen fertilizer treatments, the treatment 100% RDN + foliar spray of 2.5 ml l^-1 nano urea at tillering and before the panicle initiation stage (N2) generally yielded the highest energy metrics, including GEO and NEO (144278, 90759 MJ ha^-1), EUE (2.69%), EP (0.0841 kg MJ^-1) and EIP (3.55 MJ kg^-1). The treatment involving 75% RDN + foliar spray of 2.5 ml l^-1 nano DAP at tillering and before panicle initiation stage (N5) showed a higher EIE (6.11 MJ kg^-1) with the lowest energy input (51728 MJ ha^-1). Treatments T1 and N2 demonstrated superior performance across various energetics, emphasizing their effectiveness in enhancing the energetic efficiency of aerobic rice cultivation. Treatment T2 showed comparable results with T1, so conservation tillage was performed similarly with conventional tillage.