Spatial-temporal variability pattern of multi-depth soil moisture jointly driven by climatic and human factors in China

•Spatial SM variability in China was quite unbalanced during the 1950–2020 period.•The drought level of the drying region intensified steadily with increasing depth.•The drying region was mainly distributed in densely populated areas.•The wetting region was concentrated in mountainous areas with large glaciers.•The deeper the soil layer was, the more easily the SM was affected by human water withdrawals.