Fig. S2. Effect of topsoil depth on total root length of maize
at the jointing (V7) and milk (R3) stages, and of soybean at the initial
flowering (R1) and seed-filling (R6) stages in the top 30 cm of soil
profile in 2017. Values with means ± standard error (n=3). Within a
growth stage of each panel, values with a same letter are not
significantly different (P > 0.05).