Ratoon rice production in central China: Environmental sustainability and food production

Rice is an important strategic food crop for China concerning food security and environmental sustainability. Ratoon rice (RR) is proposed as a promising rice system to increase grain yield via improving multiple crop index. It is increasingly attractive for farmers due to its high resource efficiency and low labor requirement. Nevertheless, little information is known about the environmental profile of RR production. A comprehensive assessment regarding productivity and sustainability is of urgent importance. This paper aims to investigate the productivity and environmental impact of RR production and to identify its environmental hotspots through life cycle assessment (LCA) methodology. The analysis was conducted based on land-based and yield-based function units (FUs) using on-farm data from 561 RR producers in Hubei Province, China. The results, which were calculated using the land-based FU, showed that the yields for RR production were an average of 25.3% higher than the yields for traditional single rice production. However, the environmental impacts of RR production disproportionally increased, leading to 23.5% to 35.1% higher pollutant emissions. Opposite results were obtained from the comparisons based on the yield-based FU. The worse environmental results per hectare were canceled out because of its higher yields in RR production, leading to lower environmental impacts per ton of rice. If 18% of the current area that should be planted with traditional double rice shifted into RR instead of traditional single rice, a considerable increase in total rice production would be achieved with minimal environmental impacts. The major contributors to pollutions were methane emissions produced from flooded fields, emissions related to fertilizer and pesticide application, and diesel fuel for machinery. Increased environmental burdens in RR compared to the traditional single rice production were mainly attributed to the additional fertilizers and longer growing period. The study's results indicate that RR can be a viable alternative option to increase productivity with minimal environmental impact in rice production.