Dr Guocheng Wang1, Dr. Zhongkui Luo2, Dr. Enli Wang2, Dr. Wen Zhang1
1Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China, 2CSIRO Agriculture & Food, Canberra, Australia
The Huang-Huai-Hai (HHH) plain produces ~1/3 wheat and maize of China with high resource inputs, particularly synthetic nitrogen (N) fertilizers since the 1980s. Although fertilizer input has substantially increased crop yield and enhanced biomass carbon (C) input to the soil and thus stimulating soil C sequestration, GHG emissions (e.g., nitrous oxide (N2O)) relating to the fertilizers have been also dramatically increased. Yet, a systematic regional assessment on the trade-offs between crop yield, soil C sequestration and N2O emissions as impacted by management practices and environmental conditions is lacking. Here we calibrated a farming system model to conduct comprehensive assessment on crop yield and GHG emissions (soil CO2 and N2O emissions) during the period 1981-2010 across the HHH plain at the resolution of 10 km. We found that soil in HHH plain was a C sink with an annual C sequestration rate of 1.53 CO2-eq ha-1 yr–1 (0-30 cm soil) during the period under typical agricultural practices, but this sink could only offset about 68% of global warming potential from contemporary N2O emissions. By reducing the annual N input rate (from current more than 300 to ~250 kg N ha-1 yr-1) and enhancing residue retention rate (from current 30% to 100%), the HHH plain could act as a net sink of GHG without sacrificing yield. Apart from management, the effects of three key environmental factors, i.e., mean annual rainfall and temperature and initial soil organic carbon stock on dynamics of crop yield, soil CO2 and N2O emissions were also studied.
Dr. Guocheng Wang is a research scientist at Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP, CAS). His research interests are quantifying carbon cycling within terrestrial ecosystems and assessing their responses to environmental and anthropogenic changes. He graduated from the University of Chinese Academy of Sciences in July of 2013, and was awarded the doctorate at the same time. He is now the leader of two projects funded by National Science Foundation of China (NSFC) and the author of more than 20 published literatures. Details can be found at: https://www.researchgate.net/profile/Guocheng_Wang5