Contribution of Sentinel-1 radar backscatter/coherence and Sentinel-2 optical data to digital mapping of soil organic carbon in the Iberian Peninsula - Yajun Geng; Hongmin Zhang; Xueting Zheng; Junming Liu; Tao Zhou; Dongxu Dai; Xiaoyan Liu; Tingting Liu; Angela Lausch; Bingcheng Si; Shengxiang Xu; Feng Liu (Soil and Tillage Research, 2026)