Nitrogen (N) fertilizer is an input that has played an important role in grain yield, N use efficiency (NUE), and agronomic efficiency (AE) that needs to be studied on rainfed wheat grown in permanent beds as a planting system. The objective of this study was to test the effect of N treatments on yield, NUE and AE from 2005 to 2009. The experimental design consisted of three N rates (25, 50 and 75 kg/ha) and four N timing treatments (two single basal applications and two splits), plus a control plot (0 N). Results showed that N rate and N timing treatments had no effect on grain yield, but years, meanwhile Year–N rate interaction affected NUE and AE. Precipitation and post-harvest soil N-NO3 were identified as factors to test the years' effect on yield, NUE and AE. Regression procedures showed that the effect was greater for 25 kg N/ha treatment. The relationships between these variables and precipitation were positive, whereas the opposite occurred with soil N-NO3. NUE and AE, however, showed negative values in crop seasons with moisture constraints from precipitation (<335 mm) and soil N-NO3 (>90 kg N-NO3/ha). This result indicated that N removal and yield in these years were larger in control plots (0 N) than fertilizer application. Precipitation and soil N-NO3, rather than N treatments, explained most of the yield, NUE and AE variation over years. Therefore, to enhance that effect of weather and soil, further research on alternate N sources is needed.

中文翻译：

---

受氮肥、降水和土壤硝酸盐影响的永久床中雨育小麦的氮利用和农艺效率

氮 (N) 肥料是一种对粮食产量、氮利用效率 (NUE) 和农艺效率 (AE) 发挥重要作用的投入，需要对作为种植系统的永久床中种植的雨养小麦进行研究。本研究的目的是测试 2005 年至 2009 年 N 处理对产量、NUE 和 AE 的影响。实验设计包括三个 N 施用量（25、50 和 75 kg/ha）和四个 N 定时处理（两个单一的基础应用和两个拆分），加上一个控制图（0 N）。结果表明，施氮量和施氮时间处理对籽粒产量没有影响，但年份，同时年施氮量交互作用影响了NUE和AE。降水和收获后土壤 N-NO3被确定为测试年份对产量、NUE 和 AE 影响的因素。回归程序表明，25 kg N/ha 处理的效果更大。这些变量与降水之间的关系是正的，而土壤 N-NO 则相反。3. 然而，NUE 和 AE 在受降水（<335 毫米）和土壤 N-NO 的水分限制的作物季节显示为负值3(>90 公斤 N-NO3/哈）。这一结果表明，这些年份的 N 去除和产量在对照地块（0 N）中大于施肥。降水与土壤 N-NO3，而不是 N 处理，解释了多年来的大部分产量、NUE 和 AE 变化。因此，为了增强天气和土壤的影响，需要进一步研究替代氮源。