<b>Topsoil Organic Matter of Chinese Croplands</b>

Three categories of factors were considered: environmental conditions, soil properties, and agriculture practices. The environmental conditions included mean annual precipitation (MAP), mean annual temperature (MAT), and elevation (DEM). The soil properties included the SOM basal value (SOMsec), total nitrogen (TN), available potassium (AK), soil bulk density (BD), clay content (Clay), sand content (Sand), and soil pH (pH). Agricultural management practices included large livestock (LL), pig farming volume (pig), fertilizer application (FA), machinery total power (MTP), and grain production (GP).