Irrigation practices are important agronomic measures that influence maize yield and lodging resistance. However, the impact of irrigation practices on the spatial distribution of maize roots and stem traits, as well as their interaction with nitrogen application, remains unclear. This study examined the combined and single-factor effects of irrigation and nitrogen fertilizer on the root distribution, stem traits, and grain yield of different lodging-resistant maize hybrids. Three irrigation practices, drip irrigation (DI), flood irrigation (FI), and rainfed (RF), along with three nitrogen application rates, 0 (N0), 180 (N180), and 360 kg hm (N360), were employed. Irrigation and nitrogen optimized maize root distribution, leaf productivity, and grain biomass allocation, leading to increased maize yield. Irrigation and nitrogen increased root length density (RLD) and the proportion of coarse root length (CRP). Compared with FI and RF, DI enlarged the difference in RLD among nitrogen application rates. N180 and N360 did not differ in RLD regardless of irrigation practice except in interplant. The difference in RLD of interplant across treatments was smaller than that of interrow, especially at the 20–60 cm soil depth. Irrigation and nitrogen increased dry matter accumulation and yield by increasing leaf area and chlorophyll content. However, excessive nitrogen reduced the remobilization of nitrogen and dry matter to the grains. DI and FI increased grain yield by 70.9 % and 55.0 % in ZD958, and by 33.8 % and 20.3 % in FM985 regardless of nitrogen application rate, respectively, compared to RF. Consequently, the combination of DI and N180 significantly increased RLD, stem puncture strength, dry matter accumulation, and yield of maize. Moreover, root length at different soil layers was closely related to yield, while the proportion of coarse roots at the surface layer contributing the most to yield.

中文翻译：

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滴灌与适当的氮输入相结合，通过优化根和茎性状提高玉米 (Zea mays L.) 产量和抗倒伏性


灌溉措施是影响玉米产量和抗倒伏性的重要农艺措施。然而，灌溉措施对玉米根和茎性状空间分布的影响以及它们与施氮的相互作用仍不清楚。本研究探讨了灌溉和氮肥对不同抗倒伏玉米杂交种根系分布、茎性状和籽粒产量的联合和单因素影响。采用滴灌（DI）、漫灌（FI）和雨养（RF）三种灌溉方式，以及三种施氮量：0（N0）、180（N180）和360 kg·hm（N360）。灌溉和施氮优化了玉米根系分布、叶片生产力和谷物生物量分配，从而提高了玉米产量。灌溉和施氮增加了根长密度（RLD）和粗根长比例（CRP）。与FI和RF相比，DI扩大了施氮量间RLD的差异。无论灌溉方式如何，N180 和 N360 的 RLD 均无差异（间种除外）。间作各处理的 RLD 差异小于行间，特别是在 20-60 cm 土层深度。灌溉和施氮通过增加叶面积和叶绿素含量来增加干物质积累和产量。然而，过量的氮减少了氮和干物质向谷物的再利用。与 RF 相比，无论施氮量如何，DI 和 FI 使 ZD958 的籽粒产量分别提高了 70.9% 和 55.0%，FM985 的籽粒产量提高了 33.8% 和 20.3%。因此，DI 和 N180 的组合显着提高了玉米的 RLD、茎穿刺强度、干物质积累和产量。 此外，不同土层的根系长度与产量密切相关，而表层粗根的比例对产量的贡献最大。