Abstract Favorable weather conditions prevailing on most South American Pampas allows to grow more than one crop per year. Indeed, increasing crop intensity per unit area has been highlighted as an opportunity to increase crop production in a high food demanding world scenario. Previous studies have analyzed cropping-system yield gap by aggregating crop yields either as total amount of grain or as unit of energy. However, few cropping-system yield gap analysis have made a distinction between single (i.e., soybean sown as a single crop per year) and double-cropped soybean (i.e., soybean sown immediately after harvest of a winter cereal crop), and none of them at a country level. This article focuses on the estimation of cropping system-imposed yield gap (CSIYg), which is defined as the difference of seed yield between single soybean and double-cropped soybean. The aims of the present study were: (i) to analyze yield potential (Yp), water-limited (Yw) and yield gap (Yg) spatial and interannual variability; (ii) to investigate the concept of CSIYg for soybean using cropping systems in Uruguay as a proof of concept; and (iii) to assess differences on yield variability between single and double-cropped soybean. Yp and Yw were estimated for single and double-cropped soybean in specific locations within the major soybean crop producing areas using CROPGROW model coupled with long-term good quality weather data, soil types and dominant management practices. Estimations were scaled up following the protocols of the Global Yield Gap Atlas project. We applied a boundary function analysis to assess the differences on Yw variability between single and double-cropped soybean. At country level Yp was estimated on 6.6 and 5.7 Mg ha−1 for single and double-cropped soybean, respectively. However, we found lower differences on Yw between single and double-cropped soybean (3.6 and 3.4 Mg ha−1, respectively). We estimated CSIYg due to combined effect of weather condition and water regime on 3.2 Mg ha−1. The CSIYg representing the combined effect of weather condition, water regime and management was estimated on 1.6 Mg ha−1. Double-cropped and single soybean showed the same Yw response to precipitations and a similar Yw variability (t-test P = 0.55). Our results highlight double-cropped soybean cropping systems as an alternative for increasing grain production in this main agricultural region of the world.

中文翻译：

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种植制度造成的产量差距：乌拉圭大豆种植制度的概念证明

摘要 大多数南美潘帕斯草原的有利天气条件允许每年种植不止一种作物。事实上，在高粮食需求的世界情景中，增加单位面积的作物密度已被强调为增加作物产量的机会。先前的研究通过将作物产量作为粮食总量或能量单位进行汇总来分析耕作系统产量差距。然而，很少有种植系统产量差距分析区分单季大豆（即每年作为单一作物播种）和双季大豆（即冬季谷物作物收获后立即播种的大豆）。他们在国家层面。本文重点介绍种植制度造成的产量差距（CSIYg）的估计，定义为单季大豆与双季大豆种子产量的差异。本研究的目的是： (i) 分析产量潜力 (Yp)、限水 (Yw) 和产量差距 (Yg) 空间和年际变化；(ii) 使用乌拉圭的种植系统研究大豆的 CSIYg 概念作为概念证明；(iii) 评估单季和双季大豆产量变异性的差异。使用 CROPGROW 模型结合长期优质天气数据、土壤类型和主要管理实践，估计了主要大豆作物产区特定地点的单季和双季大豆的 Yp 和 Yw。按照全球产量差距图集项目的协议扩大了估计值。我们应用边界函数分析来评估单季和双季大豆之间 Yw 变异性的差异。在国家层面，单季和双季大豆的 Yp 估计分别为 6.6 和 5.7 Mg ha-1。然而，我们发现单季和双季大豆之间的 Yw 差异较小（分别为 3.6 和 3.4 Mg ha-1）。由于天气条件和水情对 3.2 Mg ha-1 的综合影响，我们估计了 CSIYg。代表天气条件、水情和管理的综合影响的 CSIYg 估计为 1.6 Mg ha-1。双季和单季大豆对降水表现出相同的 Yw 响应和类似的 Yw 变异性（t 检验 P = 0.55）。