Crop monitoring using remote sensing orientated for government decision making and agricultural management: a case study of China's soybean planting area estimation

China is one of the main soybean production countries in the world and soybean is of great importance in agricultural industry, domestic consumption and international trade. In recent years, however, China has become the largest soybean importer in the world. Therefore timely credible information about soybean planting area and production is essential for government decision making and agricultural management on domestic consumption and international trade. Moreover, information on soybean planting and continuous planting location is critical for distributing farmer subsidies and production management. In this paper, an operational system based on multi-resolution remotely sensed data was developed for the soybean area inventory and continuous cropping area monitoring. A stratified sampling method is employed to extract and locate major soybean-planting regions, which are later surveyed using remote sensing data. At the same time, sub regions are constructed based on cropping systems in which remotely sensed data of different resolutions are applied for the soybean area estimation and replanting area location assessment.