Supporting information Chinese cropping systems are a net source of greenhouse gases despite soil carbon sequestration Bing Gaoa,b, c, Tao Huangc,d, Xiaotang Juc*, Baojing Gue,f, Wei Huanga,b, Lilai Xua,b, Robert M. Reesg, David S. Powlsonh, Pete Smithi, Shenghui Cuia,b* a Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China b Xiamen Key Lab of Urban Metabolism, Xiamen 361021, China c College of Resources and Environmental Sciences, Key Laboratory of Plant-soil Interactions of MOE, China Agricultural University, Beijing 100193, China d College of Geography Science, Nanjing Normal University, Nanjing 210046, China e Department of Land Management, Zhejiang University, Hangzhou, 310058, PR China f School of Agriculture and Food, The University of Melbourne, Victoria, 3010 Australia g SRUC, West Mains Rd. Edinburgh, EH9 3JG, Scotland, UK h Department of Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, AL5 2JQ. UK i Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK Bing Gao & Tao Huang contributed equally to this work. Corresponding author: Xiaotang Ju and Shenghui Cui College of Resources and Environmental Sciences, Key Laboratory of Plant-soil Interactions of MOE, China Agricultural University, Beijing 100193, China. Phone: +86-10-62732006; Fax: +86-10-62731016. E-mail:
[email protected] Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, China. Phone: +86-592-6190777; Fax: +86-592-6190977. E-mail:
[email protected] S1. The proportions of the different cropping systems to national crop yields and sowing area Maize was mainly distributed in the “Corn Belt” from Northeastern to Southwestern China (Liu et al., 2016a).