Winans Eric T, Beyrer Tryston A, Below Frederick E
Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States.
Front Plant Sci. 2021 Dec 15;12:767465. doi: 10.3389/fpls.2021.767465. eCollection 2021.
Continued yield increases of maize ( L.) will require higher planting populations, and enhancement of other agronomic inputs could alleviate density-induced stress. Row spacing, plant population, P-S-Zn fertility, K-B fertility, N fertility, and foliar protection were evaluated for their individual and cumulative impacts on the productivity of maize in a maize-soybean [ (L.) Merr.] rotation. An incomplete factorial design with these agronomic factors in both 0.76 and 0.51 m row widths was implemented for 13 trials in Illinois, United States, from 2014 to 2018. The agronomic treatments were compared to two controls: enhanced and standard, comprising all the factors applied at the enhanced or standard level, respectively. The 0.51 m enhanced management control yielded 3.3 Mg ha (1.8-4.6 Mg ha across the environments) more grain (25%) than the 0.76 m standard management control, demonstrating the apparent yield gap between traditional farm practices and attainable yield through enhanced agronomic management. Narrow rows and the combination of P-S-Zn and K-B fertility were the factors that provided the most significant yield increases over the standard control. Increasing plant population from 79,000 to 109,000 plants ha reduced the yield gap when all other inputs were applied at the enhanced level. However, increasing plant population alone did not increase yield when no other factors were enhanced. Some agronomic factors, such as narrow rows and availability of plant nutrition, become more critical with increasing plant population when density-induced stress is more significant. Changes in yield were dependent upon changes in kernel number. Kernel weight was the heaviest when all the management factors were applied at the enhanced level while only planting 79,000 plants ha. Conversely, kernel weight was the lightest when increasing population to 109,000 plants ha while all other factors were applied at the standard level. The yield contribution of each factor was generally greater when applied in combination with all other enhanced factors than when added individually to the standard input system. Additionally, the full value of high-input agronomic management was only realized when matched with greater plant density.
玉米（L.）持续增产需要更高的种植密度，增加其他农艺投入可以缓解密度胁迫。在玉米 - 大豆[（L.）Merr.]轮作中，评估了行距、种植密度、磷 - 硫 - 锌肥力、钾 - 硼肥力、氮肥肥力和叶面保护对玉米生产力的单独和累积影响。2014年至2018年在美国伊利诺伊州进行了13次试验，采用不完全析因设计，在0.76米和0.51米两种行距下设置这些农艺因素。将农艺处理与两个对照进行比较：强化对照和标准对照，分别包括以强化水平或标准水平应用的所有因素。0.51米强化管理对照比0.76米标准管理对照多产3.3公吨/公顷（各环境下为1.8 - 4.6公吨/公顷）的籽粒（增产25%），这表明传统农场做法与通过强化农艺管理可实现的产量之间存在明显的产量差距。窄行以及磷 - 硫 - 锌和钾 - 硼肥力的组合是比标准对照增产最显著的因素。当所有其他投入以强化水平施用时，将种植密度从79,000株/公顷增加到109,000株/公顷可缩小产量差距。然而，当不增强其他因素时，仅增加种植密度并不会提高产量。当密度胁迫更显著时，一些农艺因素，如窄行和植物养分供应，随着种植密度的增加变得更为关键。产量变化取决于籽粒数量的变化。当所有管理因素以强化水平施用而种植密度仅为79,000株/公顷时，籽粒重量最重。相反，当种植密度增加到109,000株/公顷而所有其他因素以标准水平施用时，籽粒重量最轻。与单独添加到标准投入系统相比，各因素与所有其他强化因素组合施用时的产量贡献通常更大。此外，只有与更高的种植密度相匹配时，高投入农艺管理的全部价值才能实现。
