A case study on facing climate change: optimizing planting density and date of summer maize for stable grain yield in the North China Plain

Climate change poses a global threat to agriculture. To mitigate its effects, optimizing the planting density and sowing dates is critical for maintaining stable grain yields. However, research on these adaptive strategies remains limited. This study investigated the impacts of future climate change on summer maize production in the North China Plain (NCP) and explored related mitigation strategies, including planting density and sowing date. This study used the Water-Heat-Carbon-Nitrogen Simulator (WHCNS) model combined with Global Climate Models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6), employing two future Shared Socioeconomic Pathways (SSP): 370 and 585. The results showed that under SSP370 and SSP585 scenarios, the maximum temperatures during the growing season for summer maize were expected to rise by 2.2 degrees C and 3.3 degrees C, leading to projected grain yields of 12.8% and 18.0%, respectively, when compared to historical levels. Solar radiation is projected to increase by 7.0% and 14.4%, respectively. The model simulations of sowing date and density suggest that under future climate conditions, it is recommended to adopt a planting density of 78,000 plants ha-1 as it minimizes yield reductions. From 2030 to 2060, the sowing date in the NCP should be postponed to early July under SSP370, whereas sowing is recommended in early June under SSP585. This study provides scientific evidence for developing climate-adaptive agricultural management strategies.