3.3. Nutrient uptake
In maize, 10 cm of topsoil depth decreased shoot N, P and K uptake by 13%, 15% and 54% at V7, respectively, compared to 30 cm of topsoil depth. There was no difference in the N and K uptake between 30 cm and 20 cm of topsoil depths. An increase in N, P and K uptake was found under 20 cm of soil depth compared to 30 cm of soil depth at R3 (P < 0.05, Fig. 3).
In soybean, nutrient uptake did not decrease with decreasing topsoil depth at R1 except for shoot K uptake. However, at R6, N, P and K uptake significantly decreased under 20 cm and 10 cm of topsoil depth, compared to 30 cm of topsoil depth (P < 0.05, Fig. 3d, e, f).
Root had a similar trend in N, P and K uptake in response to different soil depths (Fig. S1).