In order to improve the grain yield of food crops, which is necessary to ensure food security, it is crucial to narrow existing yield gaps. Quantitative analyses of crop yield gaps can provide theoretical support for ascertaining the primary cause of these yield gaps, and then it can be used to increase the grain yield. We evaluated the size and characteristics of the summer maize yield gap in the North China Plain by combining crop models, farmer surveys, and farm experiments. We simulated the summer maize population of farmers’ yield level, attainable yield level and potential yield level by establishing three cultivation modes: traditional farming practices (FP), established high-yield and high-efficiency practices (HH) and super-high-yield practices (SH), and introduce the cultivation relying solely on the basic soil fertility (BSF) to reveal the impact of environmental and management factors on yield gap. We explored the driving factors causing observed variations of yield gaps through a quantitative analysis of several additional parameters that are commonly used to characterize the efficiency of the maize production process, including the contribution rates of dry matter and harvest index to grain yield, the radiation interception rate and the radiation conversion efficiency. Our results show that the total yield gap based on farmer surveys and crop models was 4.9 t ha^-1, accounting for 37% of the potential yield, of which 46% was exploitable. The total yield gap based on the farm experiments was 3.9 t ha^-1, accounting for 30% of the potential yield, of which 69% was exploitable. The grain yield of FP significantly positively correlated with the grain yield of BSF, HH and SH. The contribution rates of dry matter and harvest index to grain yield of FP treatment were 45.7% and 54.3%, respectively. With the increase of yield level, the contribution rate of dry matter increased and the contribution rate of harvest index decreased. In summary, we found a sizeable total yield gap in summer maize in the North China Plain, and a considerable part is exploitable. Optimizing integrated agronomic management has a great potential for closing the exploitable yield gap. Narrowing the yield gap requires a synergistic increase in the contribution rate of dry matter and harvest index to grain yield, but a substantial increase in dry matter is more important. At present, narrowing the exploitable yield gap requires synergistic improvement of radiation interception rate and radiation conversion efficiency to increase the dry matter of maize population. In the future, the regulation measures aiming at narrowing the unexploitable yield gap should further focus on improving the radiation conversion efficiency.

为了提高粮食作物的粮食产量，这是确保粮食安全所必需的，缩小现有的产量差距至关重要。作物单产差距的定量分析可以为查明造成这些单产差距的主要原因提供理论支持，进而用于提高粮食产量。我们通过结合作物模型、农民调查和农场试验评估了华北平原夏玉米单产差距的大小和特征。我们通过建立传统耕作模式（FP）、成熟高产高效模式（HH）和超高产三种栽培模式，模拟农户产量水平、可达到产量水平和潜在产量水平的夏玉米种群实践（SH），并引入单纯依靠基本土壤肥力（BSF）的栽培，揭示环境和管理因素对产量差距的影响。我们通过对通常用于表征玉米生产过程效率的几个附加参数进行定量分析，探索了导致观察到的产量差距变化的驱动因素，这些参数包括干物质和收获指数对谷物产量的贡献率、辐射拦截率和辐射转换效率。我们的结果表明，基于农民调查和作物模型的总产量差距为 4.9 吨公顷 我们通过对通常用于表征玉米生产过程效率的几个附加参数进行定量分析，探索了导致观察到的产量差距变化的驱动因素，这些参数包括干物质和收获指数对谷物产量的贡献率、辐射拦截率和辐射转换效率。我们的结果表明，基于农民调查和作物模型的总产量差距为 4.9 吨公顷 我们通过对通常用于表征玉米生产过程效率的几个附加参数进行定量分析，探索了导致观察到的产量差距变化的驱动因素，这些参数包括干物质和收获指数对谷物产量的贡献率、辐射拦截率和辐射转换效率。我们的结果表明，基于农民调查和作物模型的总产量差距为 4.9 吨公顷^-1，占潜在产量的37%，其中46%可开发利用。基于农场试验的总产量差距为 3.9 t ha ^-1，占潜在产量的30%，其中69%可开发利用。FP的籽粒产量与BSF、HH和SH的籽粒产量呈显着正相关。FP处理干物质和收获指数对籽粒产量的贡献率分别为45.7%和54.3%。随着产量水平的提高，干物质贡献率增加，收获指数贡献率降低。综上所述，华北平原夏玉米总产缺口较大，且有相当一部分可开发利用。优化综合农艺管理具有缩小可开发产量差距的巨大潜力。缩小产量差距需要干物质和收获指数对粮食产量的贡献率协同提高，但干物质的大幅增加更为重要。目前，缩小可利用产量差距需要协同提高辐射拦截率和辐射转化效率，以增加玉米群体的干物质。未来，旨在缩小未开发产量差距的调控措施应进一步着眼于提高辐射转换效率。