Supplement of Straw incorporation increases crop yield and soil organic carbon sequestration but varies under different natural conditions and farming practices in China: a system analysis 5 Xiao Han 1ǂ , Cong Xu 1ǂ , Jennifer A. J. Dungait 2 , Roland Bol 3 , Xiaojie Wang 1 , Wenliang Wu 1 , and Fanqiao Meng 1 1 Beijing Key Laboratory of Biodiversity and Organic Farming, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China 2 Sustainable Agriculture Sciences, Rothamsted Research, North Wyke, Okehampton, Devon EX20 10 2SB, UK 3 Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany ǂ These authors contributed equally to this work Correspondence to: Fanqiao Meng (mengfq@cau.edu.cn) 15