Nitrogen top-dressing fertilization of maize cultivated in single and twin-row systems

ABSTRACT The aim of this study was to evaluate the effects of cropping systems (single and twin-rows) and N fertilizer rates in the second top-dressing on the agronomic performance and relative economic returns of maize. The experiment was conducted in a randomized block design, with subplots and three repetitions. The plots were composed of two cropping systems: single and twin-rows. The subplots consisted of six rates of N fertilizer, applied in the second top-dressing fertilization in the V8 phenological stage (eight fully developed leaves) of maize: 0, 14, 28, 56, and 70 kg ha-1 of N. The first application of N top-dressing fertilization (rate of 140 kg ha-1 N) was during the V4 phenological stage (four fully developed leaves) in all treatments. The cropping system of twin-rows provides a higher grain yield and relative economic return of maize. The agronomic efficiency of the twin-row cropping system decreases with increasing N rates, but remains higher than that obtained in the single-row system, independent of the N fertilizer top-dressing rate.. The application of the second N top-dressing fertilization in the V8 phenological stage increases linearly with the grain yield and relative economic return of maize, independent of the cropping system.

摘要 本研究旨在评估种植模式（单行、双行种植）与第二次追肥氮肥施用量对玉米农艺表现及相对经济收益的影响。本试验采用带裂区的随机区组设计，设置3次重复。主区划分为两种种植模式：单行种植与双行种植。裂区设置6个氮肥施用量，于玉米V8生育期（8片完全展开叶阶段）进行第二次追肥，施用量分别为0、14、28、56、70 kg·ha⁻¹纯氮。所有处理均在玉米V4生育期（4片完全展开叶阶段）施加第一次氮肥追肥，施用量为140 kg·ha⁻¹纯氮。研究结果表明，双行种植模式可获得更高的玉米籽粒产量与相对经济收益；双行种植模式下的氮肥农艺效率随追肥施用量增加而降低，但无论追肥氮肥施用量如何，其农艺效率均高于单行种植模式。在V8生育期施加第二次氮肥追肥，玉米籽粒产量与相对经济收益均随施用量呈线性增长，且不受种植模式的影响。