施氮时期对夏玉米生长、干物质转运与产量的影响

为探索不同施氮时期对陕西关中地区夏玉米生长和产量的影响,通过桶栽施氮试验,研究了施氮总量相同的情况下,不同施氮时期对夏玉米的生长、产量和干物质分配转运的影响。试验设置7个施氮处理:N0不施氮(对照);N1拔节期一次性施入;N2大喇叭口期一次性施入;N3吐丝期一次性施入;N4拔节期、大喇叭口期分次施入;N5拔节期和吐丝期分次施入;N6拔节期、大喇叭口期和吐丝期分三次施入。结果表明:N4处理植株的产量显著高于其它处理,相对于拔节期一次施肥的N1处理增加了5.56%;N4处理的叶面积、成熟期干物质较其它处理高,相对于N1处理分别增长了8.03%和8.29%;N2、N5和N6处理的产量和干物质量无显著性差异,相对于N1处理产量分别增长了4.0%、4.7%和4.1%,N1、N3处理的产量和干物质量较其它处理低,说明分次施肥可以提高玉米的产量和干物质量,最佳施肥方案为拔节期、大喇叭口期分次施入;N3、N5处理的干物质转运率相对较低,相对于产量较高的N4处理转运率分别降低5.5%和8.6%,但其花后同化物累积量相对于N4处理分别提高4.1%和7.8%,绿叶面积相对于其它处理较高,表明吐丝期追施氮肥可以延缓叶片衰老,从而提高玉米的产量。

Effects of nitrogen application at different stages on growth, yield, and dry matter transportation of summer maize

Under the same nitrogen application amount, the effects of nitrogen application at different growth stages on growth, yield and dry matter transportation of summer maize in Guanzhong District of Shaanxi Province were explored. There were seven nitrogen treatments with the same nitrogen application amount: zero nitrogen application (N0, as control); all nitrogen application at elongation stage (N1); all nitrogen application at bell stage (N2); all nitrogen application at silking stage (N3); separate nitrogen application at elongation stage and bell stage (N4); separate nitrogen application at elongation stage and silking stage (N5); separate nitrogen application at elongation stage, bell stage and silking stage (N6). The results showed that the N4 significantly improved the yield and dry matter accumulation compared with the other treatments. Compare to N1, the yield of N4 was increased by 5.56%, the leaf area was increased by 8.03%, and the dry matter was increased by 8.29%. There were no significant difference between the yield and dry matter accumulation of N2, N5 and N6, whose average yield and dry matter accumulation increased were increased 4.0%, 4.7% and 4.1% compare to N1, respectively. The yield and dry matter accumulation of N1 and N3 were much lower than those of the other treatments, which indicate that separate nitrogen application could improve the yield and dry matter accumulation compared with all nitrogen application at a single growth stage. Nitrogen split application at elongation stage and bell stage was considered as the optimum nitrogen application mode. The dry matter translocation efficiency of N3, N5 were lower than the other treatments, but they maintained much more green leaf area at mature stage. The dry matter translocation efficiency of N3 was 5.5% less than that of N4, while the accumulation of dry matter after silking stage was increased by 4.1% compared with N4. The dry matter translocation efficiency of N5 was 8.6% less than that of N4, while the accumulation of dry matter after silking stage was increased by 7.8% compared with N4. The results indicate that nitrogen application at silking stage can help retarded the senescence of leaves, which can raise the yield of summer maize by maintaining higher photosynthetic rates.