CO₂ enrichment in greenhouse production: Towards a sustainable approach

As the unique source of carbon in the atmosphere, carbon dioxide (CO₂) exerts a strong impact on crop yield and quality. However, CO₂ deficiency in greenhouses during the daytime often limits crop productivity. Crucially, climate warming, caused by increased atmospheric CO₂, urges global efforts to implement carbon reduction and neutrality, which also bring challenges to current CO₂ enrichment systems applied in greenhouses. Thus, there is a timely need to develop cost-effective and environmentally friendly CO₂ enrichment technologies as a sustainable approach to promoting agricultural production and alleviating environmental burdens simultaneously. Here we review several common technologies of CO₂ enrichment in greenhouse production, and their characteristics and limitations. Some control strategies of CO₂ enrichment in distribution, period, and concentration are also discussed. We further introduce promising directions for future CO₂ enrichment including 1) agro-industrial symbiosis system (AIS); 2) interdisciplinary application of carbon capture and utilization (CCU); and 3) optimization of CO₂ assimilation in C₃ crops via biotechnologies. This review aims to provide perspectives on efficient CO₂ utilization in greenhouse production.