Developing climate-smart agricultural systems in the North China Plain.

• A multi-objective assessment was conducted for alternative cropping systems in the NCP. • The dominant winter wheat-maize system had the largest ET, N leaching, and N 2 O emission. • Optimized winter wheat-maize system could perform best among the eight systems. • Conservation tillage could mitigate negative impacts of climate change and SOC decrease. • The study demonstrates a useful framework to develop climate smart agriculture systems. Developing climate-smart agricultural systems is essential for climate change adaptation and mitigation. In the past decades, the typical winter wheat- summer maize rotation system in the North China Plain (NCP) has produced high yield, but the overuse of nitrogen fertilizer and over-pumping of groundwater for irrigation have caused severe environmental problems. It is necessary to develop climate-smart agricultural systems through a comprehensive multiple-objective assessment and optimization of alternative cropping systems and agronomic managements. Here, with the agricultural system model of APSIM, eight alternative cropping systems at four typical sites across the NCP under two climate change scenarios and two tillage managements were comprehensively evaluated in terms of crop yield, water use efficiency (WUE), nitrogen use efficiency (NUE), evapotranspiration (ET), groundwater recharge (GWR), N 2 O emission, N leaching, surface soil organic carbon (SOC), and carbon footprint (CF). The results showed that under both baseline and future climate scenarios, the currently dominant winter wheat- summer maize rotation system had the largest ET, N leaching and N 2 O emission, a medium crop yield, WUE, and SOC, however a low NUE, and GWR. The rotation/intercropping systems could have higher grain yields, while the monoculture cropping systems could have advantage on water conservation. Maize had relatively higher yield, WUE, NUE, GWR, and SOC, and lower N loss and CF than wheat and soybean because it could have a high yield without irrigation. The optimized winter wheat-summer maize rotation system, with the optimal irrigation, fertilizer and cultivar, had the greatest advantage over other seven systems with the highest yields, WUE, NUE, high ET, GWR, and SOC, and the lowest N losses and CF. Compared with conventional tillage, each cropping system would have a little bit less negative response to future climate change with conservation tillage. The study demonstrated a useful framework to develop climate-smart agricultural systems and sustainable agricultural strategies to meet the challenges of global climate change, which can be widely applied to other cropping systems and regions. [ABSTRACT FROM AUTHOR]