Little is known about the relationships between soybean [Glycine max (L.) Merr.] maturity grouping and the yield-limiting factors in the subtropics. This information can be used to estimate soybean potential yield (Yp) and the water-limited yield (Yw) and to optimize current soybean management practices to improve yield and resource use efficiency. The objectives were (a) to estimate the Yp, Yw, and yield gaps (YGs) of soybean in subtropical Brazil and (b) to identify the biophysical and management factors which potentially explain the YG. The CSM CROPGRO model that was calibrated with data collected between 2011 and 2019 was used to estimate the influence of sowing date and maturity group (MG) on yield potentials and water efficiencies. Yield varied from 6.1 to 7.2 Mg ha⁻¹ and from 2.5 to 5.1 Mg ha⁻¹ between buffer zones (BZs) for Yp and Yw, respectively. The YG caused by water deficit (YGw) ranged from 26% (1.8 Mg ha⁻¹) to 62% (4.1 Mg ha⁻¹) of the Yp and the YG caused by management (e.g., sowing date, MG, final density) ranged from 9% (0.6 Mg ha⁻¹) to 39% (2.7 Mg ha⁻¹) of the Yp. The main management factor of the YG was sowing date. The potential yield was higher in the early MGs, showing greater water use efficiency in MG ≤ 5.5 (9.6 kg ha⁻¹ mm⁻¹) than in high MGs (MG ≥ 5.6). Findings from this study can be used by agronomists in subtropical regions to optimize soybean yields.

中文翻译：

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造成巴西亚热带地区大豆产量缺口的生物物理和管理因素

关于亚热带地区的大豆[ Glycine max（L.）Merr。]成熟度分组与产量限制因素之间的关系知之甚少。该信息可用于估计大豆的潜在单产（Yp）和限水单产（Yw），以及优化当前的大豆管理实践以提高产量和资源利用效率。目标是（a）估计亚热带巴西大豆的Yp，Yw和产量缺口（YGs），以及（b）识别可能解释YG的生物物理和管理因素。使用2011年至2019年收集的数据进行校准的CSM CROPGRO模型用于估算播种日期和成熟度组（MG）对单产潜力和水分利用效率的影响。产量从6.1 Mg ha ^-1变化到7.2 Mg ha ^-1在Yp和Yw的缓冲区（BZs）之间分别为2.5至5.1 Mg ha ^-1。水分亏缺（YGw）引起的YG介于Yp和管理引起的YG的26％（1.8 Mg ha ^-1）至62％（4.1 Mg ha ^-1）之间（例如播种日期，MG，最终密度）Yp的范围从9％（0.6 Mg ha ^-1）到39％（2.7 Mg ha ^-1）。YG的主要管理因素是播种期。早期MGs的潜在产量更高，表明MG≤5.5（9.6 kg ha ^-1  mm ^-1）的水分利用效率高于高MGs（MG≥5.6）。亚热带地区的农学家可以利用这项研究的结果来优化大豆产量。