Journal Article Soil 7440-44-0 Carbon Research Support, Non-U.S. Gov't climate change CO2 mitigation Fertilizers N stock change N762921K75 Nitrogen Random Forest agricultural management agricultural policies bare soil carbon sequestration change detection earth observation fine fraction improved cultivation remote sensing soil fractionation soil organic carbon soil organic carbon stock change soil organic carbon stocks soil reflectance composite soil texture space–time model stabilization of soil organic matter steppe soils