College of Resources and Environment Hunan Agricultural University Changsha 410128 P.R.China;
Soil and Fertilizer Institute of Hunan Province Hunan Academy of Agricultural Sciences Changsha 410125 P.R.China;
Scientific Observing and Experimental Station of Arable Land Conservation (Hunan) Ministry of Agriculture Changsha 410125 P.R.China;
College of Bioscience and Biotechnology Hunan Agricultural University Changsha 410128 P.R.China;
Longping Branch Graduate School of Hunan University Changsha 410125 P.R.China;
Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China;
Chinese milk vetch; fertilizer application levels; rice yield; soil organic carbon; double-rice cropping system;