A review of rice‒rapeseed cropping system in China: towards sustainable development

Rice–rapeseed, one of the most important cropping systems in the Yangtze River Valley (YRV), plays a vital role in ensuring both staple food and vegetable oil security in China. Since the 1960s, the system has undergone a rapid area expansion in YRV, with the total area relatively stable in the last two decades while experiencing a spatial shift towards the upper and middle reaches of YRV. Meanwhile, system yield growth has shown a slowing trend, primarily due to the stagnant rice yield and rapid decrease in rapeseed relative yield gain. However, the system production still has considerable room to increase because of the large relative yield gap of more than 50% in rapeseed season and extensive winter fallow fields that can expand rapeseed planting in YRV. To increase system yield, major yield-limiting factors and optimal agronomic management practices were identified, focusing on the aspects of crop establishment, variety selection, fertilizer application, residue return, and water management. We then thoroughly summarized the environmental impacts of carbon footprint and greenhouse gas emissions, as well as possible benefits and adverse effects of climate change. Furthermore, the challenges of enhancing mechanization and economic profits and perspectives of future research directions were discussed to promote the long-term sustainability and productivity of the rice-rapeseed cropping system.