Study on Simulating Soil Carbon Storage and Balance in High-yield Huabei Plain WANG Li—gang, QIU Jian—iun (Institute of Natural Resources and Regional Planning,CAAS,Beijing 100081.China) Abstract:DNDC model was employed with the support of GIS regional database simulating the soil carbon cycle regulation of agro—ecosystem in High—yield Huabei Plain,taking Handan district as study case . The