An appropriate nitrogen (N) management strategy is required for minimizing the yield loss incurred in aerobic direct-seeded rice (ADR) due to moisture stress. Field experiments for two consecutive years were conducted to evaluate comparative performance of real-time application of neem-coated urea (NCU) and prilled urea (PU) using a customized leaf color chart (CLCC) on growth, yield and N use efficiency of both ADR and puddled transplanted rice (PTR). Six treatments were tested with cultivar ‘Apo’:0 N (T1) as control, 100 kg N ha⁻¹ as prilled urea (PU) applied conventionally (T2), 100 kg N ha⁻¹ as NCU applied conventionally (T3), 100 kg N ha⁻¹ as PU applied on the basis of CLCC recommendation (T4), 100 kg N ha⁻¹ as NCU applied on the basis of CLCC recommendation (T5), and 50 kg N ha⁻¹ as PU and 50 kg N ha⁻¹ as farm yard manure (FYM) (T6). Results of the field experiments showed significant effects (p ≤ 0.05) of both cultivation method and N management on yield. The ADR produced 22.5–46.0% less yield as compared to PTR mainly due to substantial reductions in leaf area, biomass and sink size. As compared to PU, the conventional application of NCU increased yields by 7.1–13.4 % and 6.8–10.0 %,in ADR and PTR, respectively and the differences were significant (p ≤ 0.05). But when applied using CLCC, yield enhancements from PU increased to 21.2–22.9 % and 14.6–15.9 %, respectively. The NCU resulted in 6.6–8.9 and 6.2–6.5 % higher N recovery efficiency as compared to PU, which was further increased to 16.3–18.0 and 11.4–14.6 % in ADR and PTR, respectively when applied using CLCC. Hence, our results indicate that optimization of N application combining both a real-time N management tool (CLCC) and enhanced efficiency N fertilizer (NCU) could help minimize yield losses, which was more visible under ADR by improving growth and yield parameters. The findings of the present study can be proposed as a suitable alternative to the existing N-fertilizer management for rice farmers of both aerobic dry-seeded and puddled transplanted conditions, while more yield advantage was realized in the former.

需要一种适当的氮（N）管理策略，以最大程度减少由于水分胁迫而在需氧直播种子（ADR）中造成的产量损失。连续两年进行了田间试验，以使用定制的叶色图（CLCC）评价印ne包膜尿素（NCU）和造粒尿素（PU）实时施用对两者的生长，产量和氮利用效率的比较性能ADR和混浊的移植大米（PTR）。测试了六种处理方法，以'Apo'：0 N（T1）品种为对照，常规施用（T2）为100千克N ha ^-1作为颗粒尿素（PU），常规施用（T3）为100 kg N ha ^-1作为NCU，百千克ñ公顷^-1应用于CLCC建议的（T4）的基础上PU 100公斤氮公顷^-1根据CLCC建议（T5）应用NCU，将50 kg N ha ^-1作为PU和50 kg N ha ^-1作为农田肥料（FYM）（T6）。田间试验结果表明，栽培方法和氮素管理对产量均具有显着影响（p≤0.05）。与PTR相比，ADR的产量降低了22.5-46.0％，这主要是由于叶片面积，生物量和水槽尺寸的大幅减少。与PU相比，NCU的常规应用分别提高了ADR和PTR的产量，分别为7.1-13.4％和6.8-10.0％，差异显着（p≤0.05）。但是，当使用CLCC施用时，PU的增产分别提高到21.2-22.9％和14.6-15.9％。与PU相比，NCU的N回收效率高出6.6–8.9和6.2–6.5％，当使用CLCC施用时，ADR和PTR的N回收率分别进一步提高到16.3–18.0和11.4–14.6％。因此，我们的结果表明，结合使用实时氮管理工具（CLCC）和提高效率的氮肥（NCU）来优化氮肥施用可以最大程度地减少产量损失，这在ADR下可以通过改善生长和产量参数而更加明显。本研究的结果可作为有氧干播和混栽条件下稻农的现有氮肥管理的合适替代方案，而前者实现了更多的产量优势。