Several decision support tools have been proposed for precision nitrogen (N) fertilizer application in rice (Oryza sativa L.) to increase nitrogen use efficiency (NUE) and grain yields. However, a comparison of their effectiveness has not been well documented. A field experiment was conducted in western Terai of Nepal during 2017–2018 to identify the appropriate decision support tool for improving NUE and grain yields. Nine N fertilizer management treatments were laid out in a randomized complete block design with three replications. The treatments included a GreenSeeker (GS) optical sensor, soil plant analysis development (SPAD) meter, leaf color chart (LCC), each of these treatments with basal application of N at 25 kg ha⁻¹, urea briquette deep placement (UDP), and the existing government-recommended practice (RP, 100 kg N ha⁻¹). N fertilizer application guided by decision support tools had a significant (p < 0.05) effect on grain yields. UDP produced the highest grain yield (6.80 Mg ha⁻¹) among the treatments. Grain yields were not significantly different among GS, LCC (in combination with basal 25 kg N ha⁻¹), RP, and UDP treatments. However, GS, UDP, and LCC saved N input by 54%, 22%, and 21%, respectively, compared to RP. In addition, GS produced a significantly higher agronomic N use efficiency (ANUE), partial factor productivity of N (PFPN), apparent N recovery (ANR), and utilization efficiency of N (UEN) compared to RP. These results suggest that application of N fertilizer guided by the GS decision support tool can save significant amount of N fertilizer compared to the current RP without compromising grain yield.

已经提出了几种决策支持工具，用于水稻（Oryza sativa L.）的精确氮（N）肥施用，以提高氮的利用效率（NUE）和谷物产量。但是，其有效性的比较尚未有充分的文献记载。在2017-2018年期间，在尼泊尔西部的特赖进行了一次野外试验，以确定适当的决策支持工具，以提高NUE和谷物单产。九种氮肥管理处理方法以随机完整区组设计的形式进行，一式三份。这些处理包括GreenSeeker（GS）光学传感器，土壤植物分析开发（SPAD）仪，叶色表（LCC），这些处理均在25 kg ha ^-1的基础上施氮，尿素团块深铺（UDP）和现有的政府建议措施（RP，100 kg N ha ^-1）。决策支持工具指导下的氮肥施用 对谷物单产有显着影响（p <0.05）。在所有处理中，UDP的籽粒产量最高（6.80 Mg ha ^-1）。GS，LCC（与基础25 kg N ha ^-1结合使用）之间的谷物产量没有显着差异），RP和UDP处理。但是，与RP相比，GS，UDP和LCC分别节省了54％，22％和21％的N输入。此外，与RP相比，GS产生了显着更高的农艺氮利用效率（ANUE），氮的部分因子生产率（PFPN），表观氮回收率（ANR）和氮的利用效率（UEN）。这些结果表明，与当前的RP相比，由GS决策支持工具指导的N肥料的应用可以节省大量N肥料。