Fig. 4From: Rare earth element geochemistry in soils along arid and semiarid grasslands in northern ChinaDepth profiles (0–10, 10–20, 20–40, 40–60, and 60–100 cm) of relative geochemical fractions in soil at selected study sites. a S03, aridity index (AI) = 0.03, b S09, AI = 0.10, c S13, AI = 0.22, d S19, AI = 0.51)Back to article page