Data and methodology
3.1. Data and preparation
Three main datasets were used to analyse the relationships among soil erosion, cropping system changes, and agricultural production. The first, spatial data of cropping systems and other land-use categories on the Shandong Peninsula in 2000 and 2010, was derived from remote sensing images. Landsat Thematic Mapper (TM) images in early May, September, and late October for the years 1999–2001 were used to identify cropping systems and other land-use categories in 2000. Those images were acquired from the U.S. Geological Survey (USGS; www.usgs.gov). Huan Jing 1A (HJ1A) and Huan Jing 1B (HJ1B) images in early May, September, and late October for the years 2010–2012 were used to extract the cropping systems and other land-use categories in 2010. Those