Rice yield development and the shrinking yield gaps in China, 1981-2008

摘要

Increasing population, limited land resources, and the demand for environmental protection highlight the urgency of improving crop yield on the limited cultivated land. To identify a possible food supply under a sustainable intensification of agricultural production, it is necessary to accurately estimate yield potentials and yield gaps. Here, we used a well-validated, large-scale process-based crop model, Model to capture the Crop-weather relationship over a Large Area for rice, and an ensemble model simulation method to estimate the yield potential across the rice planting area of China. We further evaluated the spatiotemporal patterns of actual yield, yield potential, and yield gap over the past three decades. Rice yield showed an increasing trend in more than 95% of the studied counties. However, 48.3% of the counties were already experiencing yield stagnation. The yield potential in northeast China had increased over the past three decades by 20-40 kg/ha per year because of the increase in temperature, while the increased temperature and decreased solar radiation reduced the yield potentials in other regions by 10-30 kg/ha per year. Because of changes in the actual yield and yield potential, the yield gap decreased in 93.4% of the counties by an average of 0.5-2% per year, resulting in less room for yield improvement. Additionally, 65.9% of the counties had nearly approached their yield ceilings (> 70% of the yield potential). Our study highlights that popularizing advanced management technologies to close yield gaps and breeding climate-resilient cultivars to expand yield potentials should be of equal importance for the sustainable development of agricultural production and food security.